@conference {41724,
	title = {Effect of divergent selection for wool bulk on live weight and wool characteristics in Perendale sheep},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {67},
	year = {2007},
	month = {Jan},
	pages = {180-186},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Wanaka},
	abstract = {A sixteen year selection trial in a flock of Perendale sheep selected for either increased (H line) or decreased (L line) wool bulk at yearling (hogget) shearing, was undertaken at Whatawhata, and later Winchmore Research Stations. A total of 2,620 progeny sired by 172 rams joined in single sire matings were measured, with data from an additional 664 fleeces providing direct information on base flock characteristics. A restricted maximum likelihood (REML) animal model adjusting for fixed effects of year, sex, birth date and birth/weaning rank was fitted to the data. Heritability estimates {\textpm} standard errors for each of the measured characteristics were; core wool bulk (0.57 {\textpm} 0.03), pre-shear live weight (0.35 {\textpm} 0.04), greasy fleece weight (0.44 {\textpm} 0.04), washing yield (0.42 {\textpm} 0.03), clean fleece weight (0.45 {\textpm} 0.03), staple length (0.54 {\textpm} 0.03), total crimps (0.38 {\textpm} 0.03), crimp frequency (0.46 {\textpm} 0.03), mean fibre diameter (0.62 {\textpm} 0.04), fibre diameter variation (0.58 {\textpm} 0.04) and mean fibre curvature (0.67 {\textpm} 0.04). At the end of the trial, line divergence (H {\textendash} L) in core wool bulk and fibre curvature amounted to 2.5 phenotypic standard deviation units. It was associated with a positive divergence in crimp frequency and a negative divergence in staple length, washing yield and clean fleece weight of +2.1, -1.7, -1.4 and {\textendash}0.8 standard deviation units respectively, and lesser changes in other traits.},
	issn = {1176-5283},
	author = {Sumner RMW and Clarke JN and Cullen NG}
}
@conference {41894,
	title = {Effect on fleece weight of combining genes from four flocks independently selected for increased fleece weight},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {66},
	year = {2006},
	month = {Jan},
	pages = {195-199},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Napier},
	abstract = {This study investigated whether heterosis was present when crossing sheep from four closed Romney flocks selected for increased fleece weight. Three of the flocks had been developed by AgResearch (C, W and H) and one by Massey University (M). Each ewe was joined with a single ram according to a diallel design to generate single-line, two-line and four-line cross progeny. The trial ran from 1988 to 1996 with 599 records available for analysis. In rank order, the mean ({\textpm} standard error of mean) greasy yearling fleece weight (kg), adjusted for year, sex, pre-shearing live weight and days of wool growth was W (3.41 {\textpm} 0.08), H (3.39 {\textpm} 0.12), C (3.31 {\textpm} 0.10), M (3.10 {\textpm} 0.15) for the "single-line" groups, WC (3.40 {\textpm} 0.09), MW (3.36 {\textpm} 0.10), CH (3.24 {\textpm} 0.08), WH (3.16 {\textpm} 0.11), MH (3.14 {\textpm} 0.11), MC (3.14 {\textpm} 0.10) for the "two-line" crosses and 3.26 {\textpm} 0.06 for the four-line cross. Combining sheep from two or more flocks independently selected for increased fleece weight resulted, on average, in no heterosis in wool production among resultant progeny. },
	issn = {1176-5283},
	author = {Sumner RMW and Clarke JN and Blair HT and Cullen NG and Henderson HV}
}
@conference {41929,
	title = {Variation in the New Zealand ram breeding industry ? results from the Poukawa progeny test},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {66},
	year = {2006},
	month = {Jan},
	pages = {373-376},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Napier},
	abstract = {Between 1998 and 2004 a sire progeny test was run at the Poukawa Research Farm in Hawke{\textquoteright}s Bay. Four ewe genotypes were used (Romney, East Friesian x Romney, Finn x Romney and Poll Dorset x Romney) with up to 900 ewes mated each year. Data was collected on 4614 lambs born to 74 rams (an average of 62 progeny per ram). Rams used represented 13 different terminal sire and dual purpose breeds. Ewes were mated using AI or single-sire mated in the paddock for one cycle. Lambs were tagged and weighed within 24 hours of birth. At 12 weeks of age, lambs were weighed and scanned for eye muscle dimensions from which eye muscle area was estimated. Data were analysed using a REML animal model taking account of repeat matings among parents, genetic relationships among animals and incorporating adjustments for fixed effects associated with year, ewe genotype and litter size. At a mean lambing percentage of 165\%, the mean birth weight across all sires was 4.91 kg and ranged between 4.21 and 5.46 kg for individual sires. The mean 12 week liveweight was 29.8 kg and ranged from 26.5 to 33.1 kg for progeny from individual rams. There was a wide range in GR fat depth (mean 8.9 mm, sire range 6.9 to 12.3 mm) when corrected to a constant carcass weight of 18.3 kg. The top rams for liveweight were not necessarily top for other characteristics. Significant numbers of lambs are sold store at weaning on a liveweight basis and this makes it possible to place a value on pre-weaning growth. At $2/kg liveweight, the average lamb sired by the top ram for growth would be worth $66.20 and the progeny from the bottom ranked sire would be worth $53 - a difference of $13.20 per lamb. Assuming these rams had an active lifespan of 4 years and mated 80 ewes rearing 125\% per year, each ram would leave 400 progeny. At $13.20 per lamb the difference in value between the top and bottom ranked rams would be $5280. These results show the differences between rams and highlight the importance of using breeding values in the ram selection process. },
	issn = {1176-5283},
	author = {Muir PD and Thomson BC and Smith NB and Clarke JN}
}
@conference {41677,
	title = {Variation in the New Zealand ram breeding industry {\^u} results from the Poukawa progeny test},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {66},
	year = {2006},
	month = {Jan},
	pages = {373-376},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Napier},
	abstract = {Between 1998 and 2004 a sire progeny test was run at the Poukawa Research Farm in Hawke{\textquoteright}s Bay. Four ewe genotypes were used (Romney, East Friesian x Romney, Finn x Romney and Poll Dorset x Romney) with up to 900 ewes mated each year. Data was collected on 4614 lambs born to 74 rams (an average of 62 progeny per ram). Rams used represented 13 different terminal sire and dual purpose breeds. Ewes were mated using AI or single-sire mated in the paddock for one cycle. Lambs were tagged and weighed within 24 hours of birth. At 12 weeks of age, lambs were weighed and scanned for eye muscle dimensions from which eye muscle area was estimated. Data were analysed using a REML animal model taking account of repeat matings among parents, genetic relationships among animals and incorporating adjustments for fixed effects associated with year, ewe genotype and litter size. At a mean lambing percentage of 165\%, the mean birth weight across all sires was 4.91 kg and ranged between 4.21 and 5.46 kg for individual sires. The mean 12 week liveweight was 29.8 kg and ranged from 26.5 to 33.1 kg for progeny from individual rams. There was a wide range in GR fat depth (mean 8.9 mm, sire range 6.9 to 12.3 mm) when corrected to a constant carcass weight of 18.3 kg. The top rams for liveweight were not necessarily top for other characteristics. Significant numbers of lambs are sold store at weaning on a liveweight basis and this makes it possible to place a value on pre-weaning growth. At $2/kg liveweight, the average lamb sired by the top ram for growth would be worth $66.20 and the progeny from the bottom ranked sire would be worth $53 - a difference of $13.20 per lamb. Assuming these rams had an active lifespan of 4 years and mated 80 ewes rearing 125\% per year, each ram would leave 400 progeny. At $13.20 per lamb the difference in value between the top and bottom ranked rams would be $5280. These results show the differences between rams and highlight the importance of using breeding values in the ram selection process. },
	issn = {1176-5283},
	author = {Muir PD and Thomson BC and Smith NB and Clarke JN}
}
@conference {41441,
	title = {The benefits of across-flock analysis},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {63},
	year = {2003},
	month = {Jan},
	pages = {204-208},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Queenstown},
	abstract = {Recent and current developments by Sheep Improvement Ltd (SIL) to provide animal evaluations for a wide variety of flocks using Best Linear Unbiased Prediction (BLUP) methods have encouraged breeders to compare animals bred in different breeding flocks. The data requirements and analytical models needed for BLUP to handle this task are discussed with major emphasis on sire-referencing as a method for achieving adequate genetic linkages among flocks by which animals bred in different flocks may be compared. Despite the high ability of BLUP to accommodate this task and the benefits perceived by many breeders, few specific studies of potential benefits for particular breeding schemes have been reported. In general terms, the impact of across-flock evaluations on annual rates of genetic gain varies for different traits, mating strategies, flock and industry structures. They may not always be cost effective in comparison to within-flock performance selection, especially for larger flocks and when the costs of implementing the flock structures needed to make them accurate and effective in evaluating and disseminating genetic merit are taken into account. },
	issn = {1176-5283},
	author = {Clarke JN}
}
@conference {41197,
	title = {The benefits of sheep recording schemes for genetic research},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {60},
	year = {2000},
	month = {Jan},
	pages = {198-202},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Hamilton},
	abstract = {Recording schemes designed to provide genetic evaluations at the individual animal level contain basic pedigree and production records fundamental to genetic research. Accessibility, accuracy and consistency of their information and the flexibility of their database design to incorporate new indicator traits with prospects of providing a more accurate or more cost-effective identification of animals able to leave superior progeny influence their value to research. Much research is also likely to benefit from inclusion or access to industry data on animal products and their processing performance beyond the farm gate. Industry-wide evaluations of animals in different flocks can also identify useful contrasting animals for this research as well as for commercial exploitation. Examples of research using industry data from recording schemes are presented to demonstrate these features. They include estimates of non-genetic influences on animal performance, on methods of adjusting for their effects, estimates of phenotypic and genetic parameters, of genetic group and gene effects, of the effects of selection and culling and their impact on selection and crossbreeding strategies. Research embracing new molecular technologies is also discussed. Research of this sort can have high extension impact, especially that geared to early incorporation of results into the animal evaluation procedures of the scheme itself. },
	issn = {1176-5283},
	author = {Clarke JN and Garrick DJ}
}
@conference {41198,
	title = {Genetic parameters for improvement of dual-purpose flock productivity with constraints on mature ewe body weight},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {60},
	year = {2000},
	month = {Jan},
	pages = {203-206},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Hamilton},
	abstract = {SIL provides opportunity for inclusion of information on mature ewe body weight in animal evaluations. This paper reports estimates of the parameters needed for these evaluations. Traits analysed were: weaning weight (WWT) and hogget liveweight in May (ALW); hogget yearling liveweight (HLW) and greasy fleece weight (HFW); and pre-mating body weights (ELW), number of lambs born (NLB) and greasy fleece weights of ewes at 2 to 5 years of age. EFW and especially ELW, were highly repeatable (>0.9), the pattern of genetic correlations suggesting that breeding ewes had reached maturity in these traits by 40 months of age. Direct and maternal genetic effects on WWT showed similar heritabilities (0.14{\textpm}0.02 \& 0.18{\textpm}0.02) and were positively correlated (0.20{\textpm}0.08). Maternal influences on traits measured at old ages were much reduced, direct heritabilities being similar to published estimates. WWT showed a high direct genetic correlation with LW8 and HLW (0.82{\textpm}0.02), but lower with ELW (0.70{\textpm}0.06 for 3-year old ewes). LW8 and HLW showed even higher direct genetic correlations with ELW (of the order of 0.90{\textpm}0.02). EFW was highly correlated genetically with HFW (0.80{\textpm}0.03), HLW (0.25{\textpm}0.04), ELW (0.23{\textpm}0.05) and LW8 (0.21{\textpm}0.04). Dual-purpose genetic response predictions were derived using SIL{\textquoteright}s recently revised relative economic values for a dual-purpose index. Its correlation with aggregate breeding value was 0.67. It predicted positive selection responses (per generation and standard deviation of selection pressure) in all traits: LW8 (2.1 kg), EFW (0.14 kg), NLB (0.038 lambs/ewe) and ELW (2.4 kg or 87\% of the predicted single trait response despite the negative economic weight for this trait). Restraining the response in ELW to zero required a ten-fold increase in the negative relative economic value for this trait, and reduced the correlation of the index with aggregate breeding merit to 58\% of its previous value. Such restriction greatly increased the relative contribution of fleece weight to economic response, made little difference to the contribution of NLB (although the absolute rate of progress was nearly halved), and reduced the contribution of growth; maternal effects on weaning weight became relatively more important. },
	issn = {1176-5283},
	author = {Clarke JN and Dobbie JL and Jones KR and Wrigglesworth AL and Hickey SM}
}
@conference {41196,
	title = {The Sheep Improvement Limited (SIL) genetic engine},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {60},
	year = {2000},
	month = {Jan},
	pages = {195-197},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Hamilton},
	abstract = {The Sheep Improvement Limited (SIL) genetic engine (GE) interfaces with the SIL national database. It calculates breeding values from data provided by the database and reports these back to the database along with adjusted deviations and genetic trends graphs. The SIL system is a distributed and modular design, with the database and the GE located on separate computers connected via the Internet. The individual GE components are also modular and version 2 consists of 6 separate goal trait modules: growth, meat, wool, reproduction, survival and host resistance to internal parasites. This modular design allows each goal trait module to be easily upgraded and additional modules can be added as required. The GE uses across flock and year multivariate animal model BLUP. Evaluations can be requested as required by the user via Internet access to the database. The size of the job submitted scales transparently up to requests involving more than 200,000 animals, sufficient for the largest across flock sire referencing schemes. The intention is that the system will be continuously extended and improved. Near term developments are likely to extend to across breed analyses, the inclusion of a facial eczema module, and improved diagnostics. In the longer term it is anticipated that information from genetic markers will be included. },
	issn = {1176-5283},
	author = {Newman SA and Dodds KG and Clarke JN and Garrick DJ and McEwan JC}
}
@conference {41191,
	title = {Sheep industry structure and genetic improvement},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {60},
	year = {2000},
	month = {Jan},
	pages = {175-179},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Hamilton},
	abstract = {The sheep industry consists of a nucleus or ram-breeding sector that accounts for 1-2\% breeding ewes and a commercial sector that relies on the ram-breeding sector for the supply of flock rams. The rate of genetic change in the whole industry is dictated by the rate of genetic gain in the nucleus sector. Increasing the size of the nucleus sector has little affect on genetic gain but increases the costs of genetic improvement. Industry structure is determined by the behaviour of breeders and farmers but there is often little individual incentive for these players to alter their practices despite overall benefit to the industry. The advent of performance recording, open-nucleus breeding schemes and the introduction of new sheep breeds have all resulted in modifications to the NZ breeding industry structure. The introduction of new biotechnology, notably DNA and cloning technologies could markedly alter future industry structure. },
	issn = {1176-5283},
	author = {Garrick DJ and Blair HT and Clarke JN}
}
@conference {41138,
	title = {Discriminating among animals for improved rewards from traditional meat cuts},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {59},
	year = {1999},
	month = {Jan},
	pages = {269-271},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {The influence of biological variation on animal numbers meeting specifications based on alternative indicators of carcass merit to GR and carcass weight (CW), and the value of live animal indicators in meeting particular goals were investigated. Percentages of carcasses achieving a two-trait (GR: 5.5 to 9.5mm; and CW: 15.5 to 17.5kg) and a three-trait (GR, CW and various leg lengths: T) specification were analytically derived over multivariate normal distributions. Two {\textquoteleft}populations{\textquoteleft} of sheep were considered; one with a mean CW, GR and T of 14.6kg, 6.8mm and 184mm, respectively, and the second with mean values of 15.5kg, 6.8mm and 186mm. Adding conformational traits reduced the proportion achieving the specification, with the reduction being greater if the correlations between traits were antagonistic. Analysis of potential carcass merit indicators from experimental dissection data indicated that 8\% of the variation in leg weight was associated with sire breed, sire, sex and birth rank effects, while 32\% was associated with animal variations in six linear indicators (high GR, low subcutaneous leg fat depth, high carcass length, T, high proximal leg circumference, and low total length of the leg joint). Together these two classes of indicators accounted for 36\% of the total variation among lambs. },
	issn = {1176-5283},
	author = {Jopson NB and Clarke JN}
}
@conference {41060,
	title = {Genetic effects in GrowBulk sheep},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {59},
	year = {1999},
	month = {Jan},
	pages = {14-16},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {GrowBulk sheep are a strain of long-wool type sheep growing high bulk wool developed by introgressing high-bulk genes from Texel and Dorset rams into Romney ewes. Progeny selection was planned to minimise decreases in clean fleece weight. Rams have been released to four multiplier flocks. Genetic effects were evaluated in the nucleus and multiplier flocks using a restricted maximum likelihood animal model. Heritability estimates were 0.46{\textpm}0.05 for bulk and 0.30{\textpm}0.05 for clean fleece weight with a genetic correlation of -0.48{\textpm}0.09. The crossbred genotypes represented in the nucleus flock showed a range in average breeding merit for bulk of 27 to 31 cm{\textthreesuperior}/g, their weighted mean genetic superiority over contemporaneous Romneys being 5.3 cm{\textthreesuperior} /g. The first crop of commercial progeny by rams from this flock showed an average genetic superiority in bulk over their dams of approximately 4 cm{\textthreesuperior}/g. Genetic trends indicate that selection has been able to maintain the bulk advantage of the crossbreds while at the same time improving their fleece weight. },
	issn = {1176-5283},
	author = {Clarke JN and Sumner RMW and Cullen NG}
}
@conference {41063,
	title = {Sex and age effects on genetic parameters for wool production and qualities},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {59},
	year = {1999},
	month = {Jan},
	pages = {23-26},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Heritabilities and genetic correlations were estimated for New Zealand Romney sheep from within the selected and control lines of a 25-year selection experiment for greasy hogget fleece weight and yearling body weight. Average repeatability of clean fleece weight in 1 to 5 year-old ewes was 0.56, 25\% higher than the average heritability of 0.44. The average genetic correlation among measurements at different ages was 0.89. Sexual dichotomy in the relative predictive power of hogget records was most apparent for greasy and clean fleece weights but was evident to some degree for bulk and brightness as well, due mainly to lower heritabilities in male compared to female hoggets. Average co-heritability of greasy hogget with adult clean fleece weights was 25\% lower for male (0.26) compared to female (0.35) hoggets, in this case due to a lower genetic correlation (0.69 vs 0.81) as well as a lower heritability (0.33 vs 0.43, respectively). A repeatability model seemed an adequate approximation for estimation of breeding merit for most wool quality traits studied but not for lifetime wool production. },
	issn = {1176-5283},
	author = {Clarke JN and Dobbie JL and Jones KR and Wrigglesworth AL and Hickey SM}
}
@conference {41011,
	title = {Genetic parameters for liveweight and live animal ultra-sound fat and eye muscle dimension in a synthetic terminal sire breed},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {58},
	year = {1998},
	month = {Jan},
	pages = {140-142},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {During 1993-97, approximately 7000 lambs were weighed at weaning (WW), re-weighted (LW) and ultrasonically scanned for subcutaneous fat depth (FD) and eye muscle dimensions (depth (MD) and width (MW)) at 6 months of age. Animals belonged to Landcorp{\textquoteleft}s {\textquoteleft}Lamb Supreme{\textquoteleft} terminal sire breeding programme, derived in 1989-91 from mainly Romney ewes mated to Romney, Wiltshire, Coopworth, Texel and Poll Dorset sires selected for fast growth and leanness. Records representing the selection criteria were analysed by univariate and multivariate animal-model REML methods able to take account of the effects of selection on variance components. Heritabilities were higher for LW (0.33 {\textpm} 0.03) than WW (0.28 {\textpm} 0.03) and litter contributions (as a proportion of phenotypic variance) lower (0.29 {\textpm} 0.02 and 0.44 {\textpm} 0.02, respectively). Heritability estimates for all traits were similar in both sexes except for MW, which was higher in females (0.34 {\textpm} 0.05) than males (0.23 {\textpm} 0.05). Averaged across sexes, estimates were: FD (0.30 {\textpm} 0.03), MW (0.29 {\textpm} 0.04) and MD (0.33 {\textpm} 0.03), litter contributions being lower for FD (0.13 {\textpm} 0.02) than MW (0.22 {\textpm} 0.01) or MD (0.19 {\textpm} 0.02). MD was closely related genetically with MW (0.97 {\textpm} 0.01), but less closely associated with LW (0.44 {\textpm} 0.06) than was MW (0.57 {\textpm} 0.05). Both muscle traits showed similar genetic correlations with FD (0.48 {\textpm} 0.07 for MW; 0.43 {\textpm} 0.07 for MD). Parameter estimates indicated positive genetic trends for LW (regression of estimated breeding values on year of birth) more than two-fold higher than those previously published, and with little concomitant increase in FD. },
	issn = {1176-5283},
	author = {Clarke JN and Nicoll GB and Mowat CM}
}
@conference {40975,
	title = {Techniques for extraction of proteins for enzymatic measurements from ram spermatozoa and sheep muscle},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {58},
	year = {1998},
	month = {Jan},
	pages = {19},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {A method for the preparation of enzyme active representative homogenates of muscle is described. This method was also  valuated for spermatozoa and it was observed that the protocol needs to be adapted for various tissue types.},
	issn = {1176-5283},
	author = {Upreti GC and Oliver JE and Clarke AG and Clarke JN and Smith JF}
}
@conference {40955,
	title = {Comparison of weight-selected Romney hoggets for growth and ultrasonic fat and eye muscle dimensions.},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {57},
	year = {1997},
	month = {Jan},
	pages = {263-266},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Lines of Romney sheep selected for either weaning (WWW) or yearling body weight (TYW and HYW) for 25 years were compared relative to their respective controls in a common environment using two unselected crops of male and female progeny. The weaning weight (WWW) line and one of the yearling weight (TYW) lines were derived from a common base flock, of diverse origin. The WWW line maintained a similar body weight advantage of approximately 20\% over its control at 5, 8, 10 and 14 months of age. All control lines showed very similar average body weight trends with age (28.0{\textpm}0.5, 33.9{\textpm}0.05, 35.3{\textpm}0.06 and 42.6{\textpm}0.7). In contrast the yearling weight lines showed increasing divergence with age from 22\% in February to 28\% (TYW) and 31\% (HYW) at 13 months. All lines, and especially the yearling weight lines showed some weight increase over the winter (May to July). Eye muscle depth and width changed little over the winter compared with the previous autumn or the following spring, in contrast to fat depth trends which increased in all lines but for which however, there was little line divergence among the yearling weight lines during the winter. All selected lines had significantly lower eye muscle dimensions at the same liveweight than their controls (by 4\% for width and 5\% for depth). Lines also showed contrasting divergence in average weight-adjusted fat depth relative to their controls, especially those derived from the same base population. As judged by reductions in subcutaneous fat depth, the WWW line lost its initial leanness superiority (4\% lower fat depth) during the winter, the TYW line increasing its superiority (16-17\% lower fat depth) during the winter and spring. The other yearling liveweight line (HYW) showed only half the leanness superiority over its control at these times. Thus, lines selected for improved growth alone had different patterns of muscle and especially subcutaneous fat development in a desirable direction for commercial lean lamb production, but responses were variable. },
	issn = {1176-5283},
	author = {Clarke JN and Dobbie JL and Jones KR and Uljee AE and Wrigglesworth AL}
}
@conference {40954,
	title = {Cost-benefit analysis of ultrasound scanning in meat breed ram breeding flocks.},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {57},
	year = {1997},
	month = {Jan},
	pages = {260-262},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {New software, able to account for the impact of early selection on genetic variances and covariances, was used to evaluate two-stage sequential selection schemes for genetic gains in terminal sire flocks. The objective was to increase carcass lean and decrease carcass fat. Ultrasound scanning of both ram and ewe replacements was financially rewarding. There was little difference between autumn and spring scanning for rams. Ultrasound scanning was significantly more rewarding in the South Island Intensive situation than the North Island Hard Hill Country. The scale of rewards varied significantly with generation interval in the ram breeding flocks.},
	issn = {1176-5283},
	author = {Binnie DB and Clarke JN and Rae AL}
}
@conference {40956,
	title = {Muscle distribution in lamb progeny from several breeds.},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {57},
	year = {1997},
	month = {Jan},
	pages = {267-270},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Leg and shoulder composition (fat, muscle and bone) and some linear fat and muscle distribution measurements were taken on 458 lambs produced by 39 strains and breeds of ram born in 1992, 1993 and 1994. Lambs were either Romney or Romney-cross. Texel-cross lambs had the highest proportion of muscle in the leg and shoulder cuts with the Poll Dorset-cross lambs having a similar amount. Southdowns, American Suffolks and Romney strains had least muscle, and apart from the American Suffolk, also had most fat. The fat selected Southdown-cross had the highest \% carcass fat. There was no significant difference between any of the sire groups in the proportion of the major defatted leg primal cuts. All genotypes had a similar leg muscle cut distribution, breed differences being only in the relative proportions of muscle to fat and bone. The Texel-cross had the highest weight (at the same carcass weight) of psoas muscle and the ultrasonically selected Poll Dorset progeny had the highest proportion of measured lean as longissimus muscle. },
	issn = {1176-5283},
	author = {Kirton AH and Duganzich DM and Mercer GJK and Clarke JN and Dobbie JL and Wilson JA}
}
@conference {40805,
	title = {Genetic improvement of meat quality in sheep and cattle},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {56},
	year = {1996},
	month = {Jan},
	pages = {157-162},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Genetic variations in body composition are apparent as differences  among breeds, crosses, selected strains and sire groups. Crossbreeding, use  of terminal sires and selection within breeds has tended to concentrate on  total meat output rather than quality, despite consistent consumer signals  against fat. Evidence suggests that, in males selected using live animal  ultrasound measurements of fat and muscle depths, about half of the  selection pressure available to improve growth rate should be sacrificed in  order to maximise economic response through decrease in carcass fat  content. Genetic variations in lean/fat partitioning to different regions and muscles of  the carcass, and in traits affecting the wider sensory appeal of cooked meat,  are also important to the range and consistency of meat products. Indirect  live animal indicators are vital to minimising the high cost of progeny  testing. Meat product tenderness is one example. Much of the variation is  under the control of the calpain system for which genetic differences have  been found among breeds and crosses, related families, selection lines, and  in strains segregating for major genes and genetic markers (e.g. calpastatin  and the CSSM18 and TGLA122 markers of the callipyge gene in sheep).  Decreased post mortem tenderness is associated with decreased proteolytic  enzyme activity which in some cases is related to increased lean growth  rates in the live animals as well. Between and within muscle variations in actin/myosin interactions, lipid,  myoglobin contents and solubilities can also give rise to genetic variations  in tenderness, meat flavour, colour and the heat gellation properties of  myosin. The biochemical basis of these effects suggests useful indicator  traits (e.g. LDH and ICDH enzyme activity associations with fibre type,  intra-muscular fat and haem iron contents) which are likely to offer  innovative genetic solutions to long-term industry competitiveness.},
	issn = {1176-5283},
	author = {Clarke JN and Morris CA and Speck PA and Upreti GC and Nicoll GB}
}
@conference {40801,
	title = {Quality Meats From The NZ Beef And Sheep Industries - Consistent quality meat products},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {56},
	year = {1996},
	month = {Jan},
	pages = {146},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Meat quality has different definitions for different people and in different countries, depending on their posi-tion in the value chain. However, the consumer who repre-sents the endpoint of the chain has clearly signaled inconsistent quality of meat as a major consideration in the declining purchases of red meat.},
	issn = {1176-5283},
	author = {Speck PA and Kirton AH and Clarke JN}
}
@conference {40809,
	title = {Repeatabilities of blood plasma metabolites and their associations with leanness in genotypes showing a wide divergence in carcass composition},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {56},
	year = {1996},
	month = {Jan},
	pages = {180-183},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Strain differences in lean : fat partitioning were typified by a marked  contrast in a lean growth index giving equal but opposite emphasis to the  weights of protein and fat, in line with previous publications. Strains  showed characteristic differences in blood metabolites which did not  necessarily reflect genetic variations within a strain and correlated responses  to within-breed selection for changes in body composition. High repeatabilities of blood metabolites within a strain were found for  pasture-fed lambs aged between 5 and 14 months for samples collected on  the same day following overnight fasts of 20 vs 24 hours, but were lower for  samples taken from fasted animals at different ages. Between-age within- strain repeatabilities (averaged across two trials) were moderate for plasma  urea (0.24) creatinine (0.38) and non-esterified fatty acids (0.18), but low for  beta-hydroxybutyrate (0.09). Similar moderate heritability estimates were  found for urea and creatinine. Although standard errors were very high for  this small dataset based on only 12 sires, estimates for carcass composition  were in broad agreement with other more reliable published values. Also in  line with other results, sire-progeny variations in urea and beta- hydroxybutyrate were more positively related to carcass protein than carcass  fat, while the reverse was true for creatinine. Metabolically contrasting pairs  of metabolites showed potentially useful predictive associations with sire- progeny variations in protein:fat partitioning.},
	issn = {1176-5283},
	author = {Clarke JN and Binnie DB and Dobbie JL and Jones KR and Mowat CM and Purchas RW and Uljee AE}
}
@conference {40682,
	title = {Effects of genotype and nutrition on sheep carcass fat and eye muscle development between weaning and 14 months of age},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {55},
	year = {1995},
	month = {Jan},
	pages = {104-107},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Although several studies have implicated cortisol in the control of  body composition in sheep, the precise mechanisms are unclear. Cortisol  basal concentration and response to an ACTH challenge was studied in  Coopworth wethers selected for (Fat) or against (Lean) fatness in both the  fed and 48 hour fasted states at two stages (15 and 33 weeks). The aim was  to investigate whether fasting, age or genotype would influence cortisol  secretory parameters.   Mean basal cortisol concentration was higher for fasted than fed lambs (13.6  versus 8.9 ng/ml, p<0.001), but did not differ significantly with genotype or  overall stage of development. Maximal cortisol response to ACTH was  greater for the fat than the lean genotype, at both 15 weeks (86.3 versus 65.3  ng/ml, p<0.01) and 33 weeks (108.2 versus 91.1 ng/ml, p<0.01) of age.   Maximal cortisol response was also significantly greater with fasting and  increasing age, but the effect of fasting on cortisol increase was greater at 15  than 33 weeks of age. Clearance of cortisol was significantly slower after  fasting, but unaffected (p>0.05) by genotype and development.   Basal cortisol concentrations was not associated with differences in body  composition between the fat and lean genotypes. However the larger  maximal response in the fat genotype may indicate that the adrenal gland  plays a role in determining body composition.  },
	issn = {1176-5283},
	author = {Binnie DB and Clarke JN and Clayton JB and Mowat CM and Purchas RW}
}
@conference {40683,
	title = {Evaluation of muscling using Texel and Oxford cross Romney and Hight Romney lambs},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {55},
	year = {1995},
	month = {Jan},
	pages = {108-110},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Selection for out-of-season breeding ability could be enhanced if an  early indication of the trait was available. The onset of hogget oestrus has  been proposed as such a trait and has been examined for 362 ewe progeny  coming from early and late-lambing selection lines over 3 years.   In each year the early lambing (BV-) hoggets had an earlier (P<0.05) mean  date of onset of oestrus than the hoggets from the late-lambing (BV+) line.   In 1992 and 1993 this effect was confounded by the season of birth such that  nearly all the BV- animals were autumn born (AB) and the BV+ animals  born in the spring (SB). In 1993 animals from both lines were produced in  both seasons. Their mean day of first oestrus in 1994 (expressed as day of  year },
	issn = {1176-5283},
	author = {Kirton AH and Mercer GJK and Clarke JN and Dobbie JL and Duganzich DM and Wilson JA}
}
@conference {40732,
	title = {Genetic parameters of lifetime wool production},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {55},
	year = {1995},
	month = {Jan},
	pages = {268-271},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Heritabilities and genetic correlations were estimated from the selected  and control lines of a 25-year selection experiment for hogget greasy fleece  weight (GFW). The heritability of GFW was higher in the selected than the  control line and in female hoggets (0.48) compared with males (0.32). Inter-  age genetic correlations were less than unity, and higher in fleece weight  selected animals. Average genetic correlations between hogget and adult  records were higher in ewe than ram hoggets. Together these parameters  gave co-heritability estimates (pooled across lines) for greasy hogget with  clean adult ewe fleece weights of nearly half the average magnitude in males  (0.21) compared with female (0.36). These results have important  repercussions to the design of effective selection strategies for improvement  of lifetime wool production.  },
	issn = {1176-5283},
	author = {Clarke JN and Dobbie JL and Hickey SM and Jones KR and Wrigglesworth AL}
}
@conference {40751,
	title = {New sheep - a catalyst for change},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {55},
	year = {1995},
	month = {Jan},
	pages = {318-320},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {New sheep may be alternative breeds brought in from other  environments, new synthetic breeds developed by crossbreeding or as  specific crossbred combinations, or new strains of existing breeding  populations developed by selection for production traits, identifiable  genes or gene complexes. Changing gene frequency is the main underlying  feature of all these approaches to genetic improvement. Selection of  parents is the common operational ingredient.    New products have been a major factor in changing the breed structure of  our sheep industry. New more productive breeds have also been produced  utilising the complementary features of existing breeds, but with little  widespread development of crossbreeding systems based on first cross  ewes.    Improved reproductive rate from selection or use of new fecund genotypes  offers much scope for specialised production of quality market lambs,  especially when stratified production a major stimulus to the  improvement of terminal sire breeds. They are re-focusing the balance  of emphasis on lamb growth and carcass and encourage a search for unique  genetic effects on meat quality traits.   },
	issn = {1176-5283},
	author = {Clarke JN}
}
@conference {40753,
	title = {Sires for more valuable lambs},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {55},
	year = {1995},
	month = {Jan},
	pages = {324-326},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Specialist terminal sire breeds offer several advantages to the  commercial farmer, particularly their ability for rapid change in  relevant traits in response to market signals. The production, survival  and disease resistance benefits resulting from the hybrid vigour in the  crossbred progeny have also widely documented. Terminal sires breeds  also provide for efficient utilisation of between breed differences in  carcass quality and mature weight. However, terminal sires are  presently under utilised by the NZ sheep industry.    In future this situation is expected to change. Long term trends  suggest that carcasses will be paid for on the basis of weight of lean  meat. In addition, terminal sire breeders are increasingly using  performance recording systems allied with methods of estimating carcass  composition, both of which have markedly improved in recent years.  Terminal sire breeds are the logical method to distribute major genes  affecting growth and carcass quality. The identification,  characterisation and "packaging" of these genes will become increasingly  routine.   },
	issn = {1176-5283},
	author = {McEwan JC and Davis GH and Fennessy PF and Clarke JN}
}
@conference {40684,
	title = {Ultrasonic scanning of lamb carcasses for non-destructive carcass quality measurements},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {55},
	year = {1995},
	month = {Jan},
	pages = {111-113},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Compensatory growth in cattle has been regularly reviewed (Allden,  1970; O},
	issn = {1176-5283},
	author = {Binnie DB and Farmer RJ and Clarke JN}
}
@conference {40590,
	title = {Repeatability of seasonal wool growth in Merino Sheep},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {54},
	year = {1994},
	month = {Jan},
	pages = {163-166},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Wool samples were clipped from the midside of 27 Merino rams and 33  
unmated Merino ewes born in 1990 at 4 or 8 weekly intervals, depending on  
the season, between July 1991 and January 1994.  Wool growth rat and mean  
fibre diameter were measured. 
 
Both wool growth rate and mean fibre diameter exhibited seasonal growth  
cycles which were synchronous.  The rhythm of the seasonal cycle for each  
characteristic was calculated as:- 
 
Rhythm (\%) = (Max-Min) / ((Max+Min) / 2) x 100 
 
The rhythm for wool growth rate exceeded that for mean fibre diameter while  
the rhythms for both characteristics increased significantly between the first  
and second year but not between the second and third years.  Although wool  
growth rate and mean fibre diameter were strongly correlated between adjacent  
clipping periods, the derived rhythm estimates for both characteristics were  
only weakly correlated between years.  Adjustment of the rhythm estimates for  
liveweight change during the same period significantly improved between  
sheep repeatability of the seasonality estimates. 
 
These data indicate that a significant proportion of the variation in both 
wool growth rate and mean fibre diameter was, after adjustment for liveweight  
change, associated with permanent phenotypic differences among the sheep in  
the rhythm of their seasonal wool growth cycle. },
	issn = {1176-5283},
	author = {Sumner RMW and Clarke JN and Pearson AJ and Speedy PM}
}
@conference {40524,
	title = {Heritability of ultrasonic fat and muscle depths in Romney sheep},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {53},
	year = {1993},
	month = {Jan},
	pages = {347-350},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Twelve buffalo (5 bulls \& 7 steers) at c.33 mo of age were compared with 16 Friesian cross cattle (6 bulls \& 10 steers) at c. 29 mo of age. The 2 species had not been run together, but were slaughtered and processed concurrently. Carcass weights were unaffected by species or castration (mean=258.6 kg). Relative to cattle, buffalo had shorter carcasses, higher dressing-out percentages, greater fat depths, more kidney and pelvic fat, and lower eye-muscle areas (all P<0.01). Buffalo had heavier hearts and spleens (P<0.001), and lighter livers and weights of rumen digesta (P<0.001). Buffalo rumen digesta contained fewer particles over 4.0 mm, but the size of particles in the abomasum was similar for both species. Yields of commercial cuts did not differ between buffalo and steers, but cattle steers had more fat trim, less meat, heavier striploins, and a higher ratio of hind-to forequarter meat than bulls (all P<0.05). Relative to the cattle, buffalo carcasses had lighter inside and cube roll cuts, but heavier outside flats, more fat trim, and a higher proportion of forequarter meat (all P<0.05). Buffalo fat was less yellow. Ultimate pH of cube-roll (M. longissimus) samples were higher for bulls than steers within cattle, and higher for cattle than buffalo (each P<0.05), possibly because the buffalo had been handled more. Other quality differences that could have been pH-related were the lower shear values (indicating more tender meat) and lower water-holding capacity (each P<0.01) of buffalo meat.  However, colour (L*, a*, b* values), and sarcomere lengths were similar.  Intramuscular fat levels were similar for meat from buffalo and cattle steers, but were much lower for bull beef. This is the first set of cattle/buffalo comparative data for carcass and meat quality collected under New Zealand conditions and will be of value when evaluating the role of Buffalo in this country.},
	issn = {1176-5283},
	author = {McEwan JC and Clarke JN and Hickey SM and Knowler KJ}
}
@conference {40529,
	title = {Plasma prolactin in Romney sheep selected for hogget fleece weight},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {53},
	year = {1993},
	month = {Jan},
	pages = {371-376},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Seventy nine mature, alpacas were scanned every 10-14 days using real time ultrasonography to visualise the foetus. There was a 24\% foetal loss between days 21-30 of gestation and parturition, with the maximum loss occurring between days 21-30 and days 31-40 of gestation. There was a 5\% loss of foetuses after day 100 of gestation.},
	issn = {1176-5283},
	author = {Clarke JN and Pearson AJ and Sumner RMW and Johnson DL and Dobbie JL and Wildermoth JE and Wrigglesworth AL}
}
@conference {40415,
	title = {Comparison of growth, hogget fleece weight and reproductive traits of three sheep breeds from a flock selected for prolificacy and a Romney control flock},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {52},
	year = {1992},
	month = {Jan},
	pages = {211-216},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {The total glucose concentration of a medium changes with the  extent of serum supplementation, and this may have an effect on  embryonic development in vitro. In this study, 1- and 2-cell sheep  embryos (N+109) were cultured for approximately 120 hours at 39 C under  humidified 5\% CO2, 5\%)2 and 90\% N2 in Synthetic Oviduct Fluid medium  (SOF) supplemented with 20\% human serum and a total glucose concentration  of either 1.5 mM (modified-SOF) or 2.3 mM (unmodified-SOF). A slight  effect was observed on the proportion of embryos developing to at least  the expanded blastocyst stage (63\% and 48\% for modified-SOF and  unmodified-SOF, respectively, P<0.1). Twenty-eight blastocysts from  each treatment were selected and transferred to 28 synchronised, mature  ewes (2 blastocysts per ewe). Pregnancy and number of foetuses were  determined by ultrasonography 54 days after transfer. All ewes were  pregnant and survival of embryos was 82\% and 71\% for modified-SOF and  SOF, respectively. However, a high post-natal mortality rate was  observed (37\%), which was mostly attributed to a relatively high  birthweight of dead lambs (6.4 },
	issn = {1176-5283},
	author = {McEwan JC and Davis GH and Dodds KG and Fennessy PF and Clarke JN and Bruce GD and Hishon MG}
}
@conference {40375,
	title = {Effect of selection for productive traits on internal parasite resistance in sheep},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {52},
	year = {1992},
	month = {Jan},
	pages = {53-56},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {The distribution of condensed tannins (CT) in plants, their mode  of action and benefits to ruminant nutrition are briefly reviewed. Data  are presented showing the CT in lotus species reduced rumen degradation  of protein and increased its flow to the intestine, but an increased  amino acid absorption only occurred with Lotus corniculatus,  suggesting the CT in Lotus pedunculatus prevented enzymic  hydrolysis of the protected protein. The extent to which CT in Lotus  pendunculatus depressed nitrogen (N) digestion was similar when fed  as a sole diet and when fed as a third of the diet with pasture. The  implications of these results are that both concentration and type of CT  are important in affecting nutritive value, and that these factors need  to be resolved before an effective plant selection program can be  undertaken.  },
	issn = {1176-5283},
	author = {McEwan JC and Mason P and Baker RL and Clarke JN and Hickey SM and Turner K}
}
@conference {40369,
	title = {Expected responses in carcass composition to selection for muscularity in sheep},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {52},
	year = {1992},
	month = {Jan},
	pages = {29-32},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Fifty nine mixed age ewes from high (H) and low (L) faecal egg  count (FEC) selection lines were used in a MOET programme. Three years  of reproductive data were also recorded in 714 ewes from the 2 selection  lines and their control line (C). The mean (},
	issn = {1176-5283},
	author = {Waldron DF and Clarke JN and Rae AL and Woods EG}
}
@conference {40393,
	title = {The National Database for sheep genetic evaluation and research},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {52},
	year = {1992},
	month = {Jan},
	pages = {121-124},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Lactating and non-lactating does were allocated on August 1989  down lengths to seven groups. Four of the groups received a single slow  release melatonin implant (Regulin) on either 16 October, 30 October, 13  November or 25 November 1989. Two groups received single implants on 16  October and 25 November or 13 November and 25 December. The seventh  group was an untreated control. Total down length in all treated groups  was greater than the control (p<0.005). The goats treated on 16 October  had the greatest response to melatonin and produced a 45\% longer down  fleece than the controls.   The first fleece (16.8 },
	issn = {1176-5283},
	author = {Garrick DJ and Clarke JN and Callow CF}
}
@conference {40350,
	title = {Analysis of lamb schedules and relative economic values of lean and fat},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {51},
	year = {1991},
	month = {Jan},
	pages = {405-410},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {A model is constructed to give the probability of conception  conditional on the previous calving date in a herd of Angus beef cows.  The parameters of the model are the anoestrous period following calving,  the length of the oestrous cycle (both independent random variables  having normal probability distributions), and the conception rate at  each oestrus occurring within the mating period. The anoestrous period  is assumed to depend linearly on the calving date.   The observed calving distributions of 10 consecutive years in a beef cow  herd were used in the model to estimate the optimum herd conception rate  for the parameters "anoestrous period" and "regression between  anoestrous and calving date".   A conception rate at each oestrous during mating of 0.7 was assumed.  Anoestrous period was constrained by experiment to between 50 and 90  days. The regression between anoestrous and calving date was  constrained to between 0 and -0.5 days per day. These constraints  constituted a non-linear programming problem.   The optimum values for the anoestrous period under these conditions lay  between 60 and 70 days for the 10 years of data analysed. It is shown  that the anoestrous period has very little effect on herd in calf rate  below 70 days in the calving distributions considered. It is suggested  that resources should not be used to reduce the anoestrous period below  70 days.   The anoestrous period tended to have a greater effect on herd conception  rate if less than 90\% of the herd had calved before day 40 of the  calving period, and the anoestrous period was longer than 70 days.   Beginning mating 7 days earlier generally increased the herd conception  rate by about 1\% over the 10 years considered.  },
	issn = {1176-5283},
	author = {Waldron DF and Clarke JN and Rae AL}
}
@conference {40331,
	title = {Comparative wool production of Texel, Oxford Down, Finnish Landrace and Romney sheep},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {51},
	year = {1991},
	month = {Jan},
	pages = {303-308},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Two lines of Perendale sheep selected for an against loose wool  bulk as yearlings at hogget shearing were established at Whatawhata  Research Centre in 1987. Each line consists of approximately 100 mixed  age breeding ewes.   At ewe hogget shearing in 1989 loose wool bulk of the selection lines  differed by 5.2},
	issn = {1176-5283},
	author = {Dobbie JL and Sumner RMW and Clarke JN and Speedy PM}
}
@conference {40330,
	title = {Computer software to increase the efficiency of the New Zealand sheep industry},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {51},
	year = {1991},
	month = {Jan},
	pages = {299-302},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Loose wool bulk has been identified as a desirable objective  characteristic associated with superior end-product performance in many  of the present uses of wool. These are specifically, improve appearance  retention of carpets and improved insulation of knitting yarns and loose  wool batts. Breeds have been shown to differ in their ability to  produce high bulk wools. Loose wool bulk is strongly inherited in the  adult fleece, it is not however expressed in the lamb fleece and  subsequently cannot be used as a selection criteria until hogget  shearing. Fibre crimp appears to be the major factor associated with  bulk. Crimp formation in Merinos is related to follicle structure, cell  mitotic activity and cellular differentiation within the follicle bulk  resulting in the production of different cortical cell types. At this  time it is not known if a similar situation applies to crossbred wool  type sheep. The identification of a suitable measurable structural  characteristic would facilitate the selection of high loose wool bulk  crossbred wool type sheep at a young age.  },
	issn = {1176-5283},
	author = {Binnie DB and Clarke JN and Cooke AC and Johnson DL and Rae AL}
}
@conference {40339,
	title = {Effect of selecting Perendale hoggets for loose wool bulk on fleece characteristics and wool end-product performance},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {51},
	year = {1991},
	month = {Jan},
	pages = {347-352},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Hoggets from the Massey University fleeceweight-selected (FW)  line were previously shown to have lower sulphur (S) concentrations in  midside wool than control (C) hoggets at 14 months of age. This study  involved two experiments. The first examined wool S concentrations at  different body positions in 14-month hoggets and the second examined  midside wool S concentration and blood parameters in young lambs. In  Experiment 1, 16 FW hoggets and 16 C hoggets were wool sampled at 11  positions over the body. The wool S concentration of FW hoggets was  found to be significantly (P<0.01) lower than that of C hoggets (2.77\%  vs 2.94\%). Discriminant analysis was used to classify hoggets to their  respective lines based on wool S measurements. The combination of sites  which most correctly classified the hoggets was the midside plus base of  the tail. In the Experiment 2, 40 FW and 40 C lambs were wool sampled  on the midside at 28 day intervals from 21 November (1 week before  weaning) to 13 February. FW lambs had significantly (P<0.05) lower  midside wool S concentrations of urea, but not of creatinine, than C  lambs. Results suggest that wool S concentration and plasma urea  concentrations may be useful genetic markers for high fleece production  but that the ability to discriminate between animals of high versus low  genetic merit for fleece weight on the basis of wool S will depend on  the sampling position and age of animals.  },
	issn = {1176-5283},
	author = {Sumner RMW and Maddever DC and Clarke JN}
}
@conference {40349,
	title = {Selection for lean and against fat in sheep},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {51},
	year = {1991},
	month = {Jan},
	pages = {401-404},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {A model quantifying outputs of carcass from pasture inputs was  used to study factors affecting biological efficiency (BE) of finishing  beef from 6 months to slaughter.   Two factors which determined biological efficiency (BE, kg carcass  gain/ha/yr) on pasture were pasture utilisation and animal conversion  efficiency. Effects of stocking rate, length of finishing period (1 v 2  years), mature size and maintenance efficiency of beasts on BE and its  components were studied.   Stocking rate was the major factor affecting utilisation rate however  more lighter (eg. 12\% more 750 kg than 900 kg mature sized) cattle need  to be run to achieve equivalent pasture utilisation. Nine percent less  cattle can be run in a 2 year system.   Average conversion efficiency was 40\% lower from finishing at 2 years  than 1 year. An increase in mature size from 750 to 900 kg increased  animal conversion by 14\%. A 20\% decrease in maintenance requirements  increased animal conversion by 10\%.   Constraints to produce specified carcass weights further favoured BE  with high mature weight beasts, particularly at intermediate carcass  weights (250 kg).   Breeding cattle for high mature size appears the best way of improving  the cattle available for finishing.  },
	issn = {1176-5283},
	author = {Clarke JN and Rae AL}
}
@conference {40247,
	title = {Comparison of growth and carcass traits of ram lambs of three breeds from a flock screened for prolificacy and a Romney control flock},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {50},
	year = {1990},
	month = {Jan},
	pages = {397-402},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {This paper reviews the application of intraruminal chromium   controlled release capsules (CRC, Captec (NZ) Ltd, Auckland) to the   measurement of herbage intake in ruminants. The capsules are designed   to provide for the linear release of Cr2O3 over c. 25 days in sheep and   c. 20 days in cattle. Uniform release of Cr2O3 is achieved 2 to 3 days   after oral administration of the CRC but steady state levels of Cr2O3 in   the faeces are usually not achieved until day 7 or 8 in sheep and day 5   or 6 in cattle. Where cross-over or multiple feeding level experimental   designs are applied, time should be allowed for Cr2O3 to adjust to a new   steady state in the faeces before sampling for each new treatment. The   period of time required varies from 3 to more than 5 days depending on   the size of feed intake change. The continuous mode of marker release   in the rumen reduces diurnal variation of Cr2O3 in the faeces and this   allows rectal sampling regimens to be applied at different times of each   sampling day. Sward sampling of faeces reduced disturbance of animal   grazing to a minimal level since Cr2O3 is delivered by a single CRC   application. The effects of level of feed intake and feed type on the   rate of Cr2O3 release are usually small, but release rates may be up to   13\% lower in rumen-fistulated than in non-fistulated animals and may   differ for capsules of the same time applied to different ruminant   species. Reduced animal handling, flexible faecal sampling times and   lower labour requirements with CRC technology, compared to daily   drenching of Cr2O3, enable the number of experimental animals to be   increased. This improves the likelihood of detecting differences in   mean intake between groups. Intakes of individual animals will not be   reliably estimated with chromic oxide CRC until the digestibility of   herbage consumed by individual animals can be measured more accurately.    },
	issn = {1176-5283},
	author = {McEwan JC and Davis GH and Dodds KG and Fennessy PF and Clarke JN and Hishon M}
}
@conference {40186,
	title = {Inheritance of loose wool bulk},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {49},
	year = {1989},
	month = {Jan},
	pages = {297-302},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {The digestive efficiency of deer, goats and sheep fed on chaffed   lucerne hay was compared during summer (S) and winter (W). VFI, rumen   pool size and rumen ammonia concentration showed seasonal cycles in red   deer, with maximum values in S and minimum values in W, whereas rumen   FOR showed lower values in S than in W, especially for particulate   matter. Despite an increase in VFI, deer were thus able to maintain DM   and fibre digestibility in S, due to simultaneously increasing rumen   size and reducing outflow rate. Goats showed higher fibre digestibility   relative to sheep, associated with a larger proportion of small   particles in rumen digesta. Goats also had the highest rate of rumen   ammonia production. Relative to goats and sheep, deer showed very low   levels of VFI and rumen pool size in W, emphasising the importance of   understanding the factors controlling winter inappetence in red deer,   whilst the superior fibre digesting capability of goats suggests they   could be most efficiently used to utilise low quality fibrous feeds.    },
	issn = {1176-5283},
	author = {Sumner RMW and Clarke JN and Johnson DL}
}
@conference {40167,
	title = {Technical aspects of the Animalplan system},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {49},
	year = {1989},
	month = {Jan},
	pages = {197-202},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {The relationships between sward height, bite dimensions and bite weight for one-year-old Friesian steers and bulls were examined. Eighteen turfs of uniform area of each of 3 pasture heights (5, 10, 15 cm) were cut from a ryegrass dominant sward in early spring and placed in polystyrene boxes. Sward height was measured prior to grazing and swards trimmed where necessary so that height in the surface horizon was uniform. The turfs were offered over 3 days to 3 bulls and 3 steers in a latin square design so that each animal had 20 bites of a turf of each height daily. Turfs were weighed to the nearest 0.1g before and after grazing. The height of grazed tillers was measured and all pasture was then removed above this height. The turf was then reweighed. Bite weight, depth, volume and area were then calculated for the steers and bulls. There was no significant difference between bulls and steers in bite dimensions. Sward height, which determines bite depth, appears to be the major determinant of bite weight and consequently of daily intake. The technique described has proved to be extremely useful in the study of specific sward structures and their effect on intake.},
	issn = {1176-5283},
	author = {Johnson DL and Rae AL and Clarke JN}
}
@conference {40151,
	title = {Ultrasonic fat depths in Romney lambs and hoggets from lines selected for different production traits},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {49},
	year = {1989},
	month = {Jan},
	pages = {113-120},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Forty four feral males, 30 Saanen males and 20 Saanen females, all yearling or younger, were slaughtered and their chemical and dissectible composition determined. The ferals, reared on hill country, were leaner than the Saanens reared on better grazing. Females tended to be fatter than males in most measures of fatness. All three groups were low in fat, both total chemical fat, and dissected fat in the leg. The fat content of lean tissue was extremely low.},
	issn = {1176-5283},
	author = {McEwan JC and Clarke JN and Knowler MA and Wheeler M}
}
@conference {40088,
	title = {Carcass composition of exotic sheep breeds},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {48},
	year = {1988},
	month = {Jan},
	pages = {53-56},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	issn = {1176-5283},
	author = {Clarke JN and Parratt AC and Malthus IC and Amyes NC and Uljee AE and Woods EG}
}
@conference {40087,
	title = {Early growth and reproduction of exotic sheep breeds - a preliminary report},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {48},
	year = {1988},
	month = {Jan},
	pages = {49-52},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	issn = {1176-5283},
	author = {McMillan WH and Malthus IC and Clarke JN and Amyes NC}
}
@conference {40064,
	title = {Genetic variation among six strains of Romneys and Border Leicester and Coopworth crosses},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {47},
	year = {1987},
	month = {Jan},
	pages = {101-105},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {In an 11 month copper supplementation trial in Northland, weaner steer (initial live weight 210 kg) showed decreased liveweight gain when supplemented with copper, from November to March. Pasture copper concentrations were adequate throughout the trial. Serum copper concentrations tended to be low, especially in spring.},
	issn = {1176-5283},
	author = {Baker RL and Clarke JN and Meyer HH and Harvey TG and Bigham ML}
}
@conference {40005,
	title = {Further development of sheep recording in New Zealand},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {46},
	year = {1986},
	month = {Jan},
	pages = {117-120},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Comparisons were made of ewe and lamb weaning weights under 2 lambing dates (6 August and 6 September) with ewes at 2 pre-lambing ewe live weights (52 and 64kg) on 2 levels of pre-lambing pasture mass (approximately 1000 and 400 kg DM/ha) in a 2},
	issn = {1176-5283},
	author = {Callow CF and Clarke JN and Rae AL}
}
@conference {40001,
	title = {Inheritance of foot and jaw abnormalities in sheep},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {46},
	year = {1986},
	month = {Jan},
	pages = {93-100},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {There are a total of some 710 000 winterfed sheep in Iceland, all of which are of the native Iceland breed. The organisation of the breeding work is in the hands of the Agricultural Society of Iceland. Sheep recording schemes have a long-standing tradition in Iceland. There are 140 local associations recording about 200 000 ewes. The most important traits in Icelandic sheep breeding are fecundity of ewes and weaning weight of lambs, but conformation and wool quantity are also considered. Level of productivity is high. The use of AI is of great importance in the sheep breeding work. Nearly all the selection of lambs for replacement is within flocks and selection work must be undertaken during a few weeks in the autumn when the sheep are taken from mountain grazing.},
	issn = {1176-5283},
	author = {Baker RL and Clarke JN and Harvey TG and Meyer HH}
}
@conference {40002,
	title = {Repeatability of reproductive performance following active immunisation of ewes},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {46},
	year = {1986},
	month = {Jan},
	pages = {101-104},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {The New Zealand sheep industry has been supported by a national sheep recording scheme, Sheeplan, for nearly 20 years. Sheeplan is directed towards genetic improvement of the national sheep flock. Its personnel have recently prepared a plan for future development which aims to extend the scope of the scheme, the accuracy of selection decisions made and the flexibility and efficiency of the recording service. It is proposed that the improved scheme be developed under Sheeplan{\textquoteright}s existing organisation as a centralised recording scheme and that restructuring of the data storage and data processing system be undertaken to enable Sheeplan to develop the following specific areas: improved adjustments for non-genetic factors; greater breeding value accuracy; development of across-flock relationships among animals; extension of the Sheeplan database; establishment of an industry-wide database; improved operational efficiency; accommodation of electronic developments for data collection and transmission; provision of opportunities for data analysis; and improve documentation of the scheme. The estimated financial benefit of implementing the plan is a doubling of the annual return to the sheep industry, from $9.6 million from the current Sheeplan to $19.7 million. This is achieved through a 40\% increase in accuracy of selection decisions; a 10\% increase in Sheeplan membership; and a 30\% increase in effective use of Sheeplan records.},
	issn = {1176-5283},
	author = {Clarke JN and Smith JF and Johnson DL}
}
@conference {39974,
	title = {Implications of steroid immunisation for programmes of genetic improvement of sheep},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {45},
	year = {1985},
	month = {Jan},
	pages = {189-192},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {No abstract supplied},
	issn = {1176-5283},
	author = {Clarke JN}
}
@conference {39979,
	title = {Inheritance of loose wool bulk in Romney and Perendale sheep},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {45},
	year = {1985},
	month = {Jan},
	pages = {213-216},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Lifetime performance data were collected from flocks of 200 mixed-age Romney, Coopworth and Perendale ewes at Whatawhata Hill Country Research Station which were shorn either once yearly in November or twice yearly in May and November beginning in 1978, together with the lifetime performance data of 2-year-old replacement ewes entering these flocks in 1979 and 1980. Twice-shorn ewes were consistently heavier after shearing in November with an apparent carryover effect the following May. More of the twice- shorn ewes required dagging before shearing in November. There was a significant frequency-of-shearing x breed interaction for both total greasy and total clean wool production. Twice-shorn Romney and Perendale ewes grew more wool than once-shorn ewes. Wool growth of the Romney was greater following shearing in May compared with the other 2 breeds. Frequency of shearing did not affect ewe survival, number of lambs born, lamb survival, or weight of lamb weaned per ewe. Incidence of casting was insignificant. Average net wool returns were greater for once-shorn ewes.},
	issn = {1176-5283},
	author = {Bigham ML and Sumner RMW and Clarke JN and Johnson DL}
}
@conference {39924,
	title = {Dressing percentages of lambs},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {44},
	year = {1984},
	month = {Jan},
	pages = {231-234},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Overseas comparisons have indicated sheep breeds and strains with improved growth rates and lean meat production to those currently available in New Zealand.  Most studies in U.K. and Eire have generally shown fastest growth and lean tissue gain amongst offspring by the large down breeds, the Suffolk and Oxford. These results are generally comparable with New Zealand studies. In addition, there has been considerable European interest shown in the Texel for its high yield of lean relative to fat and bone, including lean yield in high value areas of the carcass. The white fleece and moderate fecundity of this breed also favour its maternal use to improve flexibility of lean lamb production. In most studies in the U.S. crossbred lambs sired by Suffolk rams fastest to reach slaughter weights before other meat breeds. This breed is of widespread popularity for lamb production in the U.S.  Indirect comparisons suggest a greater growth superiority (5\%) of crossbred lambs sired by U.S. Suffolks overseas compared with those sired by New Zealand Suffolks in this country.},
	issn = {1176-5283},
	author = {Kirton AH and Carter AH and Clarke JN and Duganzich DM}
}
@conference {39923,
	title = {The effects of lamb breed, slaughter age and sex on carcass fat depth and export grade},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {44},
	year = {1984},
	month = {Jan},
	pages = {227-230},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {A least squares analysis of the weight of 15 individual export cuts from 808 carcasses of 20-month old steers identified significant effects of carcass weight, carcass fat measurements, carcass grade and sire breed on the weight of export cuts. Increasing carcass weight had a positive effect on cut weight but increasing carcass fatness had a variable effect on weight of cut. The weight of cut marketed with negligible subcutaneous fat (cube roll) decreased in weight by 7\% as carcass fat depth increase from 4 to 12 mm. In contrast a cut which included subcutaneous fat increased in weight by 15\% over the same fatness range. The data show that the most equitable pricing system (schedule) would take account of weight of individual cuts.},
	issn = {1176-5283},
	author = {Geenty KG and Young SR and Clarke JN and Wilson JA}
}
@conference {39927,
	title = {Expected selection responses in lamb carcass composition and weight},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {44},
	year = {1984},
	month = {Jan},
	pages = {243-248},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Twenty eight Border Leicester 2-tooth rams (mean live weight 70 kg) were scored for fatness on a 10-point scale by 6 drafters and back fat thickness was measured by ultrasonic probe (UFD). Chemical fat percentage (mean 33.9\%) was determined on a half-carcass of each ram. Mean carcass weight, measurement C and GR were 38.0 kg, 12 mm and 28 mm respectively. Mean drafters{\textquoteright} fat score was more highly correlated with \% carcass fat (+0.83) than UFD (+0.67). The prediction of fat-free carcass weight (FFCW) from live weight plus UFD (R2=0.72, RDS 1.24 kg) or drafters{\textquoteright} fat score (R2=0.76, RSD 1.14 kg) was superior to prediction from live weight alone (R@=0.59, RSD 1.49 kg). The inclusion of UFD o9r drafters{\textquoteright} fat score increased the efficiency with which rams were ranked for fat-free carcass weight. Selection of the top 10\% of rams ranked on the prediction of FFCW from live weight achieved 75\% of the potential selection differential. Inclusion of either UFD or drafters{\textquoteright} score improved the potential to 95\%.},
	issn = {1176-5283},
	author = {Bennett GL and Clarke JN}
}
@conference {39920,
	title = {Relationship of subcutaneous fat depth and weight changes induced by stocking rate of 4 lines of lambs},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {44},
	year = {1984},
	month = {Jan},
	pages = {215-218},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Live weights, carcass weights and GR measurements from 566 Coopworth lambs were used to retrospectively establish criteria that would have directed carcass production away from discounted grades into those receiving premium payments. Greatest financial returns would have been achieved by slaughtering lambs when they approached fatness limits, before penalties applied. When live weights were the only means of selection, returns were greater at weights that resulted in production of some carcasses penalised for fatness and/or heavy weights than at weights that avoided discounted grades.},
	issn = {1176-5283},
	author = {Bennett GL and Clarke JN and Rattray PV and MacLean KS}
}
@conference {39926,
	title = {Relative performance of meat breeds of sheep in New Zealand and overseas},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {44},
	year = {1984},
	month = {Jan},
	pages = {239-242},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {A sheep breeding experiment at Woodlands Research Station consists of 5 self-contained Romney selection lines (closed in 1973). Four lines are selected respectively for dam{\textquoteright}s number of lambs born (dam NLB), 100-day weight, hogget fleece weight, and a production index in which all 3 traits are combined, while the fifth line is a randomly selected control. Back fat thickness was measured in the 1982 born ewe lamb progeny at approximately 8 and 14 months of age. Relative to the controls (back fat 6.3 mm) the dam NLB (5.0 mm) and the production index (4.8) lines had 20\% lower back fat depths (P<0.01) in May after variance adjustment for live-weight. The differences were slightly lower when measured in November. The fat thickness of the 100-day weight and hogget fleece weight line progeny were similar to the controls. The heritability of back fat depth adjusted for live weight by half-sib analysis was 0.28},
	issn = {1176-5283},
	author = {Clarke JN and Bennett GL and Kirton AH}
}
@conference {39928,
	title = {Selection for productive traits on back fat depth in ewe lambs},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {44},
	year = {1984},
	month = {Jan},
	pages = {249-252},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {No abstract supplied.},
	issn = {1176-5283},
	author = {McEwan JC and Fennessy PF and Clarke JN and Hickey SM and Knowler MA}
}
@conference {39859,
	title = {Genetic variation in uterine efficiency and differential responses to increased ovulation rate in sheep},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {43},
	year = {1983},
	month = {Jan},
	pages = {201-204},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Four antioxidants - butylated hydroxytoluene (BHT), butylated hyroxyanisole (BHA), alpha-tocopherol and propyl gallate - have been tested for their ability to ameliorate the harmful effects of the facial eczema toxin, sporidesmin, in sheep. A moderate decrease in sporidesmin-induced liver damage (39\% and 35\% respectively, based on gross pathological assessment of liver injury) was observed in sheep pre-treated with BHT and BHA; smaller effects were recorded in animals receiving the other compounds. The possibility of an additive effect between antioxidants and zinc has also been investigated. It was shown that marked protection against sporidesmin toxicity, significantly greater than that given by either prophylactic alone, was afforded by simultaneous administration of BHT and zinc.},
	issn = {1176-5283},
	author = {Meyer HH and Clarke JN and Harvey TG and Malthus IC}
}
@conference {39784,
	title = {A comparison of the composition and carcass quality of Kelly and Russian castrate, ram, wether and ewe lambs},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {42},
	year = {1982},
	month = {Jan},
	pages = {117-118},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Data on M. longissimus dorsi (LD) area, width and depth were examined on 1957 lamb carcasses graded for export as either P (moderate to heavy fat cover) or Y (light fat cover) over 3 slaughter seasons. Lambs were sired by 1 of 11 different breeds mated to Romney ewes. Carcasses in the 2 grades differed in mean weight and LD measurements in the different seasons. After adjustment for differences in carcass weight and the effect of sire breed, LD area did not differ between the P and the Y grades. After adjusting the A (width) and B (depth) measurements of differences in carcass weight and sire breed, P grade LD{\textquoteright}s were significantly narrower and deeper than those from the Y grade, but the differences were small (maximum of 5\% for depth in 1970/1 season) and of little practical significance. Thus if the leaner Y grade carcasses are desired, and this is done on a within breed basis, the LD area or shape should not be adversely affected provided carcass weights are not reduced.},
	issn = {1176-5283},
	author = {Kirton AH and Clarke JN and Hickey SM}
}
@conference {39761,
	title = {Effect of ewe ovulation rate and uterine efficiency on breed and strain variation in litter size},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {42},
	year = {1982},
	month = {Jan},
	pages = {33-36},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Two experiments investigated the relationship between growth rate, hogget oestrus and subsequent reproduction. In Experiment 1 there were increases in the proportion of two-tooth ewes ovulating multiples due to high plane rearing from late December to mid July or the presence of hogget oestrus, after the correction of two-tooth pre-mating live weight. None of the four-tooth lambing differences due to rearing or hogget oestrus was significant after correction for two-tooth pre-mating live weight. There were no significant differences due to any factor at the six-tooth lambing. In Experiment 2 there was an increase in the proportion of two-tooth ewes twinning due to the presence of hogget oestrus after correction for two-tooth pre-mating weight. There were significant effects of hogget oestrus on four-tooth twinning rates, before but not after, correction for two-tooth pre-mating live weight. There were no significant effects on twinning at the six-tooth lambing.},
	issn = {1176-5283},
	author = {Meyer HH and Clarke JN}
}
@conference {39790,
	title = {Evaluation of dam breeds and crosses for export lamb production},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {42},
	year = {1982},
	month = {Jan},
	pages = {133-136},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {The effects of castrating and surgically dehorning male Drysdale and Tukidale lambs at birth or docking on subsequent horn growth were investigated in 3 lamb crops at Whatawhata Hill Country Research Station. Castration was more effective than dehorning in reducing subsequent horn growth. A combination of castration at birth and dehorning at docking was the most effective way to treat lambs to reduce horn growth. Excision of germative tissue around the base of the horn following dehorning increased the effectiveness of dehorning. Attainment of meat inspection standards for horned breeds is more dependent on the "trimmers" on the slaughter chain than the time of dehorning.},
	issn = {1176-5283},
	author = {Clarke JN and Atkins KD and Geenty KG and Johnson DL and Hickey SM and Wilson JA}
}
@conference {39755,
	title = {Level of nutrition of the ewe and lamb survival},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {42},
	year = {1982},
	month = {Jan},
	pages = {13-14},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {No abstract supplied},
	issn = {1176-5283},
	author = {Johnson DL and Clarke JN and MacLean KS and Cox EH and Amyes NC and Rattray PV}
}
@conference {39735,
	title = {Effect of mating Romney ewe hoggets on lifetime production - Preliminary results},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {41},
	year = {1981},
	month = {Jan},
	pages = {198-203},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	issn = {1176-5283},
	author = {Baker RL and Clarke JN and Diprose GD}
}
@conference {39696,
	title = {Liveweight variation in Sheeplan flocks},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {40},
	year = {1980},
	month = {Jan},
	pages = {254-257},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	issn = {1176-5283},
	author = {Johnson DL and Clarke JN and Robinson CA}
}
@conference {39607,
	title = {Genetic and environmental effects on incidence and causes of lamb mortality},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {38},
	year = {1978},
	month = {Jan},
	pages = {181-184},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	issn = {1176-5283},
	author = {Meyer HH and Clarke JN}
}
@conference {39562,
	title = {Breeding Objectives for New Zealand Sheep Production},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {37},
	year = {1977},
	month = {Jan},
	pages = {182},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	issn = {1176-5283},
	author = {Morris CA and Clarke JN}
}
@conference {39570,
	title = {A comparison of sire and dam breeds for the production of export lambs slaughtered at 3, 4?, and 6 months of age},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {37},
	year = {1977},
	month = {Jan},
	pages = {235-242},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	issn = {1176-5283},
	author = {Geenty KG and Clarke JN}
}
@conference {39568,
	title = {Reproductive performance, growth and wool production of exotic sheep and their crosses with the Romney},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {37},
	year = {1977},
	month = {Jan},
	pages = {220-229},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	issn = {1176-5283},
	author = {Meyer HH and Clarke JN and Bigham ML and Carter AH}
}
@conference {39563,
	title = {Technical Aspects of the National Sheep Recording Scheme (Sheeplan)},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {37},
	year = {1977},
	month = {Jan},
	pages = {183-197},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	issn = {1176-5283},
	author = {Clarke JN and Rae AL}
}
@conference {39519,
	title = {The effect of level of nutrition on the productivity of sheep of different genetic origin},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {36},
	year = {1976},
	month = {Jan},
	pages = {170-178},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	issn = {1176-5283},
	author = {Joyce JP and Clarke JN and MacLean KS and Lynch RJ and Cox EH}
}
@conference {39480,
	title = {Estimates of genetic variation and covariation from New Zealand National Board Performance Testing Data},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {35},
	year = {1975},
	month = {Jan},
	pages = {151},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	issn = {1176-5283},
	author = {Clarke JN and Adam JL and Hargreaves K}
}
@conference {39475,
	title = {Relationships between milk yield, milk consumption and lamb growth in Romney, Dorset and Crossbred sheep},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {35},
	year = {1975},
	month = {Jan},
	pages = {137},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	issn = {1176-5283},
	author = {Geenty KG and Clarke JN and Wright DE and Wright GJ and Jones BA}
}
@conference {39413,
	title = {Comparison of pen and paddock systems for the pedigree mating of sheep},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {34},
	year = {1974},
	month = {Jan},
	pages = {23-27},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	issn = {1176-5283},
	author = {Clarke JN and Geenty KG and Bennett RG and Christensen GN and Wilson JA}
}
@conference {39412,
	title = {Sources of variation for wool, body weight and oestrous characters in Romney hoggets},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {34},
	year = {1974},
	month = {Jan},
	pages = {19-22},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	issn = {1176-5283},
	author = {Baker RL and Clarke JN and Carter AH}
}
@conference {39364,
	title = {Current Levels of Performance in the Ruakura Fertility Flock of Romney Sheep},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {32},
	year = {1972},
	month = {Jan},
	pages = {99-111},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	issn = {1176-5283},
	author = {Clarke JN}
}
@conference {39342,
	title = {Breeds of Sire for Export Lamb Production},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {31},
	year = {1971},
	month = {Jan},
	pages = {175},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	issn = {1176-5283},
	author = {Kirton AH and Carter AH and Clarke JN and Sinclair DP and Jury KE}
}
@conference {39341,
	title = {Crossing Experiments for the Utilization of Sheep Breeds in New Zealand},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {31},
	year = {1971},
	month = {Jan},
	pages = {164-174},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	issn = {1176-5283},
	author = {Clarke JN}
}
@conference {39204,
	title = {Hormonal synchronization of oestrus in Romney ewes during the breeding season},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {26},
	year = {1966},
	month = {Jan},
	pages = {107-122},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	issn = {1176-5283},
	author = {Clarke JN and Roberts EM and Carter AH and Kirton AH}
}
@conference {39194,
	title = {Extent and nature of weight losses due to pre-slaughter fasting of lambs},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {25},
	year = {1965},
	month = {Jan},
	pages = {184-194},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	issn = {1176-5283},
	author = {Kirton AH and Clarke JN and Carter AH and Sinclair DP}
}
