@conference {3672,
	title = {Modelling the effect of more lambs, faster growth and heavier carcasses on feed conversion efficiency and seasonality of demand},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {75},
	year = {2015},
	month = {07/2015},
	pages = {9-14},
	address = {Dunedin},
	abstract = { Feed conversion efficiency (FCE) and seasonality of feed demand were assessed within a demand-driven deterministic steadystate
model of a sheep livestock system. Weekly animal feed demands were simulated within ExcelTM. Overall flock structure and
seasonality of demand were then determined using linear programming. Key inputs were individual animal energy requirements
(MJME) for maintenance, pregnancy, lactation and growth. Whole-of-system FCE was measured as grams of meat carcass per
MJME. Overall system output was constrained by a fixed but arbitrary system limit of 10 million MJME. Increasing the lambing
percentage from 110\% to 170\% increased FCE by 20\%, with less total system feed required during the pregnancy period but with
more feed required post-weaning. Increasing pre-weaning liveweight gain from 250 g/day to 450 g/day increased FCE by only 1\%,
but with a transfer of feed demand from post-weaning to pre-weaning. Increasing post-weaning liveweight gain from 100 g/day
to 300 g/day increased FCE by 8\% with earlier slaughter reducing overall post-weaning requirements. Increasing carcass weight
from 12 kg to 24 kg increased FCE by 28\%, with a major shift in feed demand from pre-weaning to post-weaning. Implications
for improving pastoral sheep farm productivity and profitability are discussed.},
	issn = {1176-5283},
	author = {Klaassen PL and Woodford KB and Trafford GM}
}
@conference {3672,
	title = {New Zealand case studies of automatic-milking-systems adoption},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {75},
	year = {2015},
	month = {07/2015},
	pages = {127-131},
	address = {Dunedin},
	abstract = {Case studies were undertaken of six New Zealand farmers who have adopted automatic milking systems (AMS). Data were
collected during spring 2014. Farmer experience with AMS ranged from one to four years. Three farms were in the Waikato
and three were in Canterbury. Two farms use barns with fully-confined cows, two use pasture-based systems with year-round
pasture access, and two use hybrid systems where cows confinement for varying times depending on season. The key focus was
on documenting farmer experience. All six farmers met innovator criteria and were driven by the challenge of making the system
work. Farmers reported per cow production above their previous dairying experience and expectations. Cows-per-robot ranged
from 50 to 80 and were higher on pasture systems where daily milkings per cow were lower relative to confined systems. Annual
milksolids production ranged from 30,000 to 42,900 kg per robot. Total labour requirements did not always change but the type of
labour did change. Initial training of cows was stressful for farmers and time consuming. Farmers emphasised that it was a total
change of system requiring new ways of thinking. Farmers perceived capital cost as the major adoption constraint but remained
positive about the future of AMS.},
	issn = {1176-5283},
	author = {Woodford KB and Brakenrig MH and Pangborn MC}
}
@conference {89242,
	title = {Comparing herd selection strategies fo A2 beta-casein},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {73},
	year = {2013},
	month = {Jan},
	pages = {149-154},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Hamilton},
	abstract = {<p>Herd conversion strategies for A2 beta-casein were investigated within an inter-temporal simulation model with annual time-steps comprising three sub-herds based on allele status (A1A1, A1A2, and A2A2). Cows that are homozygous for the A2 allele of the beta-casein gene are known as A2 cows (A2A2), and produce milk known commercially as {\textquoteleft}A2 milk{\textquoteright}. The simplest herd conversion process is to use semen from A2A2 bulls. However, the conversionfunction is curvilinear and asymptotic and this strategy by itself cannot achieve herd purity. Conversion rates can be increased markedly through genotyping of calves and/or cows. This is necessary for completion of the conversion process. Mating of yearlings with A2 semen can have considerable impact, particularly in association with increased replacement rates. Combining these strategies can lead to pure A2A2 herds within 5 to 8 years, depending on initial herd structure. Use of sex-selected semen can further reduce the conversion period. There is potential for reduced cow herd gain in breeding worth as a result of non-use of elite bulls that are not A2A2. For example, a loss of 20 breeding worth units in the bull team would result in ten years being required to achieve breeding worth gains otherwise achievable in nine years.</p>
},
	issn = {1176-5283},
	author = {Mencarini IR and Woodford KB and Old KM}
}
@conference {89230,
	title = {A Longitudinal study of production and survivability of carry-over cows in a commercial dairy herd},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {73},
	year = {2013},
	month = {Jan},
	pages = {96-99},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Hamilton},
	abstract = {<p>In earlier work, we showed that two cohorts of carry-over cows produced 10\% more milksolids (MS) in the first lactation (2008/09) subsequent to the carry-over (non-lactating) season. Here we present further production data for this cohort through to the fourth post-carry-over lactation, together with production data for two further cohorts through to their second and third post-carry-over lactations respectively, and compare this to production from non-carry-over (annual calving) cows of similar breed and breeding worth (BW) in the same herd. Carry-over cow cohorts produced more MSthrough to and including the third post-carry-over lactation relative to non-carry-over cows. We term this additional production the {\textquoteleft}holiday effect{\textquoteright}. First year MS holiday effects were 57 kg (13\%) and 106 kg (23\%); second year holiday effects were 36 kg (8\%), 48 kg (10\%) and 31 kg (6\%); and third year effects were 48 kg (10\%) and 41 kg (8\%). Aggregate survivability through to the fourth post-carry-over lactations of 83\%, 82\% and 71\% respectively were broadly consistent with national survivability statistics. It is concluded that the bio-economics of carry-over cows are worthy of consideration, particularly for young cows of high BW and PW status which have previously given birth at least once.</p>
},
	issn = {1176-5283},
	author = {Pangborn MC and Woodford KB}
}
