@article {3672,
	title = {A model to assess the impact of potential genetic selection of dairy cows for volume per urination and total urine volume per day on nitrogen leaching},
	journal = {New Zealand Journal of Animal Science and Production},
	volume = {80},
	year = {2020},
	month = {09/2020},
	pages = {60-64},
	address = {Online},
	abstract = {The purpose of this paper is to assess the impacts of changes in herd average urine genetic traits on nitrogen (N) leaching per
hectare per year. Two potential urine traits being considered for genetic selection are total volume of urine per cow per day (at
constant urinary N output), and average volume per urination (at a constant daily urinary volume and N output). To understand
the potential reduction in N leaching that would arise if these traits could be changed using genetic selection, a model of urine
patches was developed to derive the necessary relationships between urine genetic traits, patch characteristics, and N leaching. To
simulate the effect on N leaching of genetic selection the mean for each urine trait was then changed from base model values by
{\textpm}10\%. Increasing total urine volume per cow per day by 10\% was more effective (4.5\% less N leaching) than decreasing volume
per urination by 10\% (2.9\% less N leaching). Also, selection for urine traits at higher stocking rates (four cows/ha) and higher N
intake (650 g/N/day) had a lower impact on N leaching compared with lower stocking rates (two cows/ha) and lower N intakes
(450 g N/day). This study showed that genetic selection for urine traits could have a positive, but limited, impact on N leaching
and would be a useful tool for New Zealand dairy farmers.

Keywords: Urine traits; urine patches; nitrate leaching},
	issn = {1176-5283},
	author = {Kennett JM and Romera A and Beukes P and Amer P}
}
@conference {41099,
	title = {The importance of date of birth records in genetic evaluation of deer},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {59},
	year = {1999},
	month = {Jan},
	pages = {129-130},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {This paper addresses one particular difficulty associated with performance recording and genetic evaluation of deer, that is, the
problem of recording pedigrees. A deterministic simulation was carried out using parameters based on deer populations where birthday has been recorded. For weaning weight, failure to record birth date resulted in reductions by 29\% and 19\% in selection accuracy, with selection on the records from the individual or from 20 progeny respectively. Corresponding reductions for yearling weight were 11\% and 5\% respectively. It was concluded that while genetic progress in deer will be compromised by lack of date of birth records, selection for growth traits can still be effective.},
	issn = {1176-5283},
	author = {Amer P and Garrick D and Nicoll G}
}
@conference {40875,
	title = {An Index to assist multiple trait selection of terminal beef sires in the UK},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {57},
	year = {1997},
	month = {Jan},
	pages = {15-18},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {A selection index with the objective of achieving economic improvements in saleable meat yield, calving ease and feed intake has been used in the UK beef industry since the mid 1980{\textquoteleft}s. In this paper, an improved index, which incorporates estimated breeding values for traits currently recorded in UK pedigree beef cattle, is described. The recorded traits are taken as birth weight, calving ease, gestation length, 400 day weight, ultrasonic fat and muscle depths, and muscling care. The breeding objective is made up of commercial carcass traits, calving ease and gestation length and is directed exclusively towards terminal sire buyers. When all available traits have been recorded in pedigree beef cattle herds, calving traits (birth weight, gestation length and calving ease) explain approximately 30\% of the variability in index scores, with the remainder explained by the growth and carcass traits. The expected economic superiority of progeny from the top 40\% of bulls ranked on the index, over the average bull, is {\textsterling}2.48 for carcass weight, {\textsterling}.79 for carcass conformation score, {\textsterling}-.05 for carcass fat score, {\textsterling}.37 for gestation length and {\textsterling}.24 for calving case. The overall economic superiority of progeny from the top 40\% of bulls ({\textsterling}3.82 is reduced by 17\% if both ease and gestation length are not recorded and by 10\% if ultrasonic scanning traits are not recorded. Two component indices (for calving and production trait groups respectively) are also proposed to allow commercial bull and semen buyers to adjust emphasis on the two groups of traits depending on their individual production circumstances. In conclusion, the new index incorporates new selection criteria, and a more rigorously defined and transparent breeding objective which should maximise future benefits from performance recording and Best Linear Unbiased Prediction (BLUP) genetic evaluations in UK beef cattle. },
	issn = {1176-5283},
	author = {Amer P and Simm G}
}
