@article {3672,
	title = {Supplementation of ewes on pasture to provide an epidemiological benefit for gastrointestinal parasitism},
	journal = {New Zealand Journal of Animal Science and Production},
	volume = {78},
	year = {2018},
	month = {07/2018},
	pages = {45-50},
	address = {Lincoln},
	abstract = {The potential epidemiological benefit of reducing the peri-parturient relaxation in immunity to gastro-intestinal nematode parasites
through supplementing twin-bearing ewes during the first four weeks of lactation was evaluated in a replicated farmlet study. In
two sequential years, ewes either grazed pasture alone or grazed pasture while supplemented with 0.5 kgDM/d of a high-protein
pellet. Supplementation did not affect ewe live weight or body condition score or weight of lamb weaned per ewe (P>0.05). Ewe
faecal egg counts (FEC) showed a time x supplementation interaction (P<0.05), being reduced by 50\% from week six of lactation
in both years, although this only resulted in transient and inconsistent reductions in pasture larval contamination. After weaning,
there was no consistent parasitological benefit to lambs grazing areas where ewes had been supplemented that were reflected in
either pasture larvae concentrations, lamb FEC, the requirement for anthelmintic treatment or lamb growth rate (P>0.05 for all).
Despite supplementation of ewes during the first four weeks of lactation successfully reducing ewe faecal egg count by 50\%, this
was not sufficient to provide a measureable and consistent epidemiological benefit to the lambs.},
	issn = {1176-5283},
	author = {Tambunan RD and Logan CM and Bywater AC and Greer AW}
}
@conference {3672,
	title = {BRIEF COMMUNICATION: Optimizing a fasting protocol to assess live weight of sheep},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {75},
	year = {2015},
	month = {07/2015},
	pages = {223-224},
	address = {Dunedin},
	abstract = { },
	issn = {1176-5283},
	author = {Wilson RF and Hardwick-Smith JA and Logan CM and Corner-Thomas RA and Bywater AC and Greer AW}
}
@conference {3678,
	title = {Predicting fleece weight from the difference in live weight pre- and post-shearing},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {74},
	year = {2014},
	month = {06/2014},
	pages = {68-72},
	address = {Napier},
	abstract = {Radio frequency identification (RFID) and automated weighing platforms facilitate the practicality and ease with which individual live weight (LW) can be recorded. This raises the possibility for the difference in recorded LW of sheep between pre- and post-shearing to provide an estimate of fleece weight (eFW) which, in turn, could allow selection pressure to be applied for improved wool production. The eFW of yearling ewes (n=98), yearling rams (n=274) and mixed-age ewes (n=305) were compared with their recorded fleece weight (FW). Positive linear correlations (P<0.001 for all stock classes) were observed between eFW and FW and also the eFW rank and FW rank. Although some variability between stock classes existed, for all data combined, FW rank was able to account for 42\% of the variation in eFW rank. Further, selecting individuals on eFW was able to retain an average of 64\% of the selection differential obtained using recorded FW. Overall, these results suggest eFW calculated from the difference in LW between pre- and post-shearing, in combination with RFID and automated weighing platforms, may provide a useful and practical tool to assist with selection for improved wool production in a commercial setting.},
	issn = {1176-5283},
	author = {Galway JM and Logan CM and Bywater AC and Greer AW}
}
@conference {75882,
	title = {Flexibility and climate risk management in high stocking rate dryland sheep farming systems},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {71},
	year = {2011},
	month = {Jan},
	pages = {96-102},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Invercargill},
	abstract = {A trial unit of 87.8 ha with conventional grass-based pastures and one of 85.1 ha with high legume-content pastures were used to investigate the impact of climate-risk management strategies on production and profitability of dryland sheep farming systems. The target stocking rate of both units was 14 stock units (SU)/ha, which is markedly higher than the regional monitor farm at 8.8 SU/ha. Information on the feed supply and animal feed requirement of the two units for 2008/09 and 2009/10 are presented, along with differences in weather patterns, soils moisture, climate-risk responses used, and stock sales between the two years. Results from the grass-based unit indicated that the flexible livestock policies used and climate-risk management responses imposed were able to increase farm profitability and reduce its variability between years in comparison to the local Ministry of Agriculture and Forestry monitor farm model. However, the same was not true for the high legume-content unit, which encountered a number of problems with high lamb deaths and poor lamb finishing in 2008/09. Soil moisture level in the top 25 cm proved to be a simple, inexpensive and effective indicator for making appropriate farm management decisions in response to changes in the climate.},
	issn = {1176-5283},
	author = {Bywater AC and Logan CM and Edwards GR}
}
@conference {75883,
	title = {Pasture growth and quality, and lamb growth rates in high stocking rate dryland sheep farming systems},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {71},
	year = {2011},
	month = {Jan},
	pages = {103-108},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Invercargill},
	abstract = {Pasture growth and quality, and lamb growth rates were measured on a conventional grass based trial unit of 87.8 ha and a high legume unit of 85.1 ha, established to investigate climate-risk management strategies within high stocking rate dryland sheep farming systems. There was no difference between the units in total pasture production with a pasture utilization of 71.7\% and 74.3\% on the grass and legume units, respectively. Metabolisable energy values remained close to, or above, the target values throughout the growing season. Preweaning lamb growth rates averaged 304 g/day on both units. There were significant differences between singles (342 g/day), twins (300 g/day) and triplets (254 g/day) and between lambs from first cycle (294 g/day) and main mob ewes (315 g/day). There were some differences in lamb growth rates between different pastures types but these were not consistent between years. Post-weaning growth rates averaged 137 g/day with significant differences attributable to litter size, mob and year. Growth from birth to sale averaged 295 g/day, slightly less than the target of 300 g/day. Thus high lamb growth rates are possible on a range of pasture types on dryland at low pasture covers of high quality.},
	issn = {1176-5283},
	author = {Bywater AC and Logan CM and Edwards GR and Sedcole JR}
}
@conference {41759,
	title = {Evaluation of a practical weaning weight index for extensively-grazed beef cows},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {67},
	year = {2007},
	month = {Jan},
	pages = {370-376},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Wanaka},
	abstract = {Little objective culling is practiced in many commercial beef herds in New Zealand possibly due to the absence of a performance recording system that is able to accurately predict the calf rearing ability of cows when calving date is unknown. Data of 1,306 calves from four different herds including birth, marking and weaning weights and dates was used to construct an Extensively Grazed Weaning Index (ECWIndex) to rank cows on their calf rearing ability without the use ofcalving date. Three indicator traits, marking weight, weaning weight and average daily gain (ADG) between marking and weaning (all adjusted for sex of calf and age of dam but not for age of calf) were used in the index as they were the most favourably correlated with 200 day weight of the readily measurable calf traits considered. A number ofeasily obtainable herd variables were used to calculate index weights for the indicator traits. When the model was applied to data from two additional herds the cow ranking based on the index was very similar to that based on 200 d weight (r = 0.95 and 0.92 and R2=91.2\% and 85.4\%). The use of the model will provide commercial herd managers an objective method for culling cows and selecting replacement heifers and may eventually allow the use of data from commercial herds in the calculation of breeding values of stud bulls.},
	issn = {1176-5283},
	author = {Thomas CW and Bywater AC and Miller SP}
}
@conference {40639,
	title = {Use of a grazing model to study management and risk},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {54},
	year = {1994},
	month = {Jan},
	pages = {377-382},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {A model which simulates the operation of a pastoral farm was used to  
perform a {\textquoteright}computer experiment{\textquoteright} on an irrigated Canterbury property.  The  
effects of seven stocking rates, ranging from 9 to 21 stock units per hectare  
(SU/ha), on the performance and profitability of a self-replacing sheep flock  
were tested.  The same experiment was performed under two scenarios  
(deterministic and stochastic).  The deterministic scenario was equivalent to a  
controlled experiment, where the same pasture growth pattern occurred every  
year, reflecting average production in the area.  The stochastic scenario  
introduced random variation between years, reflecting the area{\textquoteright}s natural  
variability in pasture production. 
 
In the deterministic experiment, maximum meat production (258 kg/ha) was  
obtained at 21 SU/ha, while maximum wool production (89 kg/ha) occurred at  
19 SU/ha.  Lambing percentage reached a maximum (135\%) at 13 SU/ha.   
Under the assumed set of costs and prices maximum gross margin was obtained  
by maintaining a stocking rate of 21 SU/ha.  Introducing stochastic behaviour  
caused maximum production levels to decrease and gross margin was  
maximised at a lower stocking rate (17 SU/ha), reflecting the costs associated  
with weather variability.  Results were used to examine the trade-off between  
profits and risk in stocking rate decisions. },
	issn = {1176-5283},
	author = {Cacho OJ and Bywater AC}
}
@conference {40644,
	title = {Use of simulation models in research},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {54},
	year = {1994},
	month = {Jan},
	pages = {403-412},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Simulation models are increasingly used in animal research both  
independently and in conjunction with experimental research.  This paper  
describes the potential uses of models within research programmes and  
categorises research into three main types, component research, systems  
research and management research.  The contribution of models to component  
research into lactation, growth, wool growth and feed intake is reviewed.   
It is suggested that the concepts and data concerning interactions within the  
pastoral livestock system are now sufficient for a comprehensive modelling  
analysis of this system to be undertaken.  The potential use of production  
systems models in management research is illustrated through the analysis of  
farm management factors affecting production and returns from fine wool using  
a pastoral sheep farm simulation model. 
 },
	issn = {1176-5283},
	author = {Bywater AC and Cacho OJ}
}
