@article {3672,
	title = {Impact of trait genetic gains on methane emissions from NZ beef and dairy farms},
	journal = {New Zealand Journal of Animal Science and Production},
	volume = {80},
	year = {2020},
	month = {09/2020},
	pages = {76-79},
	address = {Online},
	abstract = {The objective of this study was to provide estimates of the impact of trait genetic gains on methane emissions from NZ dairy and
beef farms. The effect of each trait on gross emissions (GE) and emissions intensity (EI) was modelled by estimating effects of trait
changes on per-animal feed consumption and the associated methane production, per-animal production and numbers of animals in
the system. In dairy, the annual gross emissions per breeding cow associated with genetic change were estimated to increase for all
traits except Residual Survival and Fertility. Conversely, emission intensity values were estimated to decrease for Milk Fat, Milk
Protein, Milk Solids, Residual Survival, Fertility and Body-condition Score (BCS) as genetic merit improves. In beef production,
increases in genetic merit for cow mature weight, cow BCS, cow calving ease and heifer pregnancy were estimated to increase the
annual gross emissions per breeding cow. Conversely, an increase in merit associated with stayability and gestation length reduced
annual gross emissions per breeding cow. The effect of increasing carcase weight on gross emissions depended on whether the
faster growth performance was used to slaughter the animal earlier, or to take the animal through to heavier finishing weights.

Keywords: methane; emissions intensity; gross emissions; dairy; beef},
	issn = {1176-5283},
	author = {Proctor LE and Archer JA and Sise JA and Zhang X and Crowley JJ and Amer PR}
}
@conference {79009,
	title = {A comparative analysis of genetic trends within the New Zealand sheep industry},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {72},
	year = {2012},
	month = {Jan},
	pages = {159-162},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {Rates of genetic progress made by Dual Purpose and Terminal Sire flocks in the New Zealand sheep industry between 1990 and 2007 have previously been examined (Amer 2009) and showed substantial gains in the rate of progress since the introduction of Sheep Improvement Ltd. (SIL) and SIL-ACE (Advanced Central Evaluation). Key findings from this earlier study showed that the rates of genetic progress doubled following the introduction of SIL, and increased by a further 50\% after the introduction of the Beef + Lamb New Zealand Central Progeny test (CPT), which effectively evaluates the performance of key industry sires, providing the ... continued},
	issn = {1176-5283},
	author = {Sise JA and Byrne TJ and Jopson NB and Young MJ and Amer PR}
}
@conference {75919,
	title = {Predicting the benefits of two stage genomic selection in young breeding rams},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {71},
	year = {2011},
	month = {Jan},
	pages = {266-269},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Invercargill},
	abstract = {A two stage selection index model was developed to assess the cost effectiveness of using genomic technologies to assist in selection decisions for retention of ram lambs for breeding within a ram breeder flock. The principle of two stage selection is that many of the benefits of an expensive, but more accurate, measure of genetic merit can be captured while drastically reducing measurement costs. This paper describes the two stage model used, and some of the potential benefits of testing the top 6{\textendash}50\% of selection candidates ranked according to estimated breeding values, prior to ranking on a combined score using genomic breeding values. The model assumes a hypothetical panel of markers and trait predictive accuracies to explore the benefits of selection using both types of breeding values. The value of genetic progress is assessed using selection index theory to predict trait changes according to a selection index recently revised for implementation as the recommended index for dual purpose sheep in New Zealand. Results suggest that maximum benefits were obtained when the top 10-20\% of selection candidates were tested, with the level of benefits dependent on both the prediction accuracy and price of the test.},
	issn = {1176-5283},
	author = {Sise JA and Linscott EM and Amer PR}
}
@conference {75896,
	title = {The role of breeding in reducing sheep GHG intensity},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {71},
	year = {2011},
	month = {Jan},
	pages = {162-167},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Invercargill},
	abstract = {Historic and potential future greenhouse gas (GHG) emission reductions resulting from genetic selection decisions in sheep have been quantified. Historic genetic trends in number of lambs born in maternal breeds and growth in terminal sire breeds were estimated to have reduced GHG emissions per kilogram of lamb carcass weight by 0.45\% and 0.09\% per year of genetic change, respectively. The implications of future selection using different indexes were also examined. Selection based solely on farm profits could lead to emission reductions per unit of product by 0.185 kg CO2-e/kg carcass weight, or a 0.59\% reduction in lamb carcass weight emissions per annum. Selection of sheep ignoring profit and solely targeting reduced GHG emissions per kilogram of lamb carcass weight could lead to emission reductions of 0.242 kg CO2-e/kg lamb carcass weight, equivalent to a 0.77\% reduction in total emissions per annum. However, doing this would come at a cost of 26.6 cents per breeding ewe reduction of 23.7\% per annum in annual genetic progress. An alternative index that provides a balance between reducing GHG emissions and improving farm profits was estimated to produce an annual 0.193 kg CO2-e/kg carcass weight or a reduction of 0.62\% reduction in emissions per annum in GHG emissions with minimal sacrifice in genetic improvement of farm profitability.
},
	issn = {1176-5283},
	author = {Ludemann CI and Byrne TJ and Sise JA and Amer PR}
}
@conference {60956,
	title = {Background effects on ewe lambing and weaning performance in well recorded breeding flocks},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {69},
	year = {2009},
	month = {Jun},
	pages = {115-117},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {Results of analyses of Sheep Improvement Ltd. (SIL) data (27 flocks and 128,203 lambings) showed a substantial impact of ewes being scanned pregnant but failing to rear a lamb (wet-dry), on weight of lamb weaned at the next lambing. Compared to ewes that reared a lamb at the previous lambing, {\textquoteright}wet-dry{\textquoteright} ewes had 0.3 to 0.5 less lambs born per ewe lambing, lamb survival rates were lower by 60 to 70 percentage points and weaning weights up to 0.5 kg lighter per lamb weaned. These effects compounded into 30 to 40 kg less weight of lamb weaned per ewe. The failure to rear part of a litter, such as one lamb of a set of twins, had less effect on performance at next lambing and weaning, than loss of the whole litter. Those ewes that previously gave birth to three lambs weaned 4 kg less lamb weight than ewes that previously gave birth to singles, after allowing for their higher genetic drive for prolificacy. A modest but significant effect of previous litter size was observed on weight of lamb weaned within each litter size category. Lamb survival was observed to be 2\% lower (P <0.01) for twin ewes that had failed to rear one of their two lambs, compared with those that had reared both in their previous lambing. },
	issn = {1176-5283},
	author = {Amer PR and Sise JA and Jopson NB and Bray AR}
}
@conference {60981,
	title = {A simulation model to partition ewe efficiency into component traits for genetic analysis},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {69},
	year = {2009},
	month = {Jun},
	pages = {223-227},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {Ewe efficiency is extremely topical in the New Zealand sheep industry. This paper describes a stochastic simulation model which facilitates partitioning of a defined ewe efficiency equation into its component genetic traits. It accounts for, and simplifies, the complex and sometimes unfavorable interactions among components of ewe efficiency. The model tracks simulated genetic effects, inherited from the ewe{\textquoteright}s sires, in breeding ewes and their lambs for key performance recorded traits. The traits simulated are weaning weight, mature weight, number of lambs born, lamb survival, and longevity. Ewe efficiency is defined as the difference between value of lambs weaned and ewe and lamb costs, rather than as a ratio. Output value in NZ$ for the efficiency equation is computed on a ewe by ewe basis, as a function of number of lambs born, lamb survival and weight of lamb weaned, with each of these components partly influenced by one or more genetic effects inherited from simulated sires of the breeding ewes. Preliminary results from the model have identified litter size, ewe longevity, maternal lamb survival, and maternal weaning weight as being important drivers of ewe efficiency. The relative balance of their importance is influenced by farm production levels and environment. },
	issn = {1176-5283},
	author = {Sise JA and Shackell GH and Byrne TJ and Glennie SF and Amer PR}
}
@conference {41782,
	title = {SNiP and cut: Quantifying the potential benefits of genomic selection tools for genetic fault elimination in sheep},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {68},
	year = {2008},
	month = {Jan},
	pages = {33-36},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Brisbane, Australia},
	abstract = {Whole genome single nucleotide polymorphism marker (SNP) technologies are rapidly being developed and could well play a role in the future selection of farmed animals. In sheep, work is being carried out to identify SNP{\textquoteleft}s associated with economically important production traits and disease resistance. Stud sheep breeders routinely cull up to 30\% of lambs born due to a variety of faults. Despite this culling pressure, the faults keep occurring, suggesting low heritability, recessive inheritance or incomplete penetration of fault causing genes. The objective of this paper was to identify the potential of SNP fault detection and elimination in sheep. Simulation was used to predict changes in gene frequencies and in an index of genetic merit of production traits over time when between two and 30 SNPs were used to aid selection. The SNPs are assumed to predict the presence of deleterious recessive genes. As selection pressure applied to individual or combination SNPs increased, the rate of increase in production trait genetic merit slowed down. Thus, a balance would be required between the emphasis on SNPs actively used to select against genetic faults, relative to emphasis on genetic merit. This work identified scope for substantial economic benefits from application of SNP technology for removal of faults to both stud breeders and commercial sheep farmers. },
	issn = {1176-5283},
	author = {Sise JA and Auvray B and Dodds KG and Amer PR}
}
@conference {40281,
	title = {DNA variation among seven New Zealand sheep breeds},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {51},
	year = {1991},
	month = {Jan},
	pages = {47-54},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Karyotype analysis, used for screening chromosomal anomalies in  humans and livestock, is being evaluated as a means of identifying sheep  carrying the Booroola fecundity gene. This has involved comparing the  chromosomes of metaphase spreads from animals heterozygous for the  Booroola gene (FecB+) to screen for numerical or physical abnormalities  between the chromosome pairs using Giemsa (GTG) banding. A number of  anomalies have been observed from 18 of 3 FecB+ rams and 4  FecB+ ewes. The anomalies were spread throughout most chromosomes, but  none were present in all karyotypes. No alteration in chromosome number  was observed. These preliminary results suggest that the Booroola  mutation is not the result of a major chromosomal alteration.  },
	issn = {1176-5283},
	author = {Sise JA and Montgomery GW and Hill DF}
}
@conference {40250,
	title = {The Booroola F gene is excluded from close genetic linkage with either the haemoglobin Beta or follicle stimulating hormone Beta loci},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {50},
	year = {1990},
	month = {Jan},
	pages = {411-416},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {No abstract supplied   },
	issn = {1176-5283},
	author = {Montgomery GW and Tate ML and Sise JA and Hill DF}
}
