@conference {89253,
	title = {Can milk urea nitrogen differentiate nitrogen use efficiency of lactating cow groups raised on New Zealand pasture},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {73},
	year = {2013},
	month = {Jan},
	pages = {199-201},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Hamilton},
	abstract = {<p class="rtejustify">Improving nitrogen use efficiency (NUE) (g of milk nitrogen output/g of nitrogen intake) of dairy cows helps to maximise profitability and minimise nitrogen losses on farm. However, the traditional nitrogen balance technique used indoors to measure dry matter intake (DMI) and NUE is labour intensive, costly and unsuited to pasture-based grazing systems. In The Netherlands, milk urea nitrogen (MUN) has been used as a non-invasive and easy-to-conduct test to differentiate NUE of dairy cow groups (Kuipers et al. 1999). Generally, higher values of MUN are associated with a lower NUE. However, the usefulness of MUN in New Zealand pasture-based grazing systems is uncertain for numerous reasons. Firstly, MUN excretion reaches a maximum when dietary crude protein (CP) exceeds 20\% of feed dry matter (DM), reducing the sensitivity of MUN to differentiate NUE in high dietary CP systems (Reynolds \&amp; Kristensen 2008). Secondly, water intake has been identified as one of the factors influencing the concentration of MUN, but it is not normally quantified in grazing systems (De Campeneere et al. 2006). Lastly, when individual cow samples are used, MUN may be subject to diurnal variation (Cheng et al. 2010).</p>
},
	issn = {1176-5283},
	author = {Aizimu W and Hodge S and Edwards GR and Dewhurst RJ and Cheng L}
}
@conference {89231,
	title = {Estimation of protein utilization efficiency and metabolisable protein efficiency in lactating cows grouped by breeding worth},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {73},
	year = {2013},
	month = {Jan},
	pages = {100-102},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Hamilton},
	abstract = {<p>The efficiency of conversion of feed protein to milk protein (protein use efficiency (PUE)) is important in ruminants as protein is the most valuable component of milk (Ryan et al. 2011). It is also essential to reduce nutrient and resource costs when the efficiency of nutrient use is low (Roberts, 2008). In ruminants, dietary protein has three main routes of metabolism, namely microbial fermentation in the rumen, absorption in the small intestine, and catabolism and excretion of excess digestible protein into faeces and urine nitrogen (Agricultural Research Council 1980). This makes PUE difficult to explain and predict because of the interaction of these pathways. Rumen degradable protein (RDP) and metabolisable protein (MP) are the two main protein pools for milk protein production.</p>
},
	issn = {1176-5283},
	author = {Wheadon NW and Cheng L and Dewhurst RJ and Edwards GR}
}
@conference {69472,
	title = {Investigation of N isotopic fractionation in dairy cows using milk samples collected at the morning and afternoon milkings},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {70},
	year = {2010},
	month = {Jun},
	pages = {65-66},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Palmerston North},
	abstract = {Conversion of feed protein into milk protein is a basis of sustainable dairy production systems from both economic and environmental perspectives. This project addresses the need for rapid screening tools to support nutritional and breeding strategies to improve the efficiency of converting feed into milk protein. The approach is based on the phenomenon of N isotopic fractionation, whereby N sinks become relatively enriched or depleted in 15N, as a result of differential incorporation during various biochemical reactions. Macko et al. (1986) showed that N isotopic fractionation was related to the deamination and transamination of amino acids. Sick et al. (1997) conducted a feeding experiment with rats and found that plasma protein was enriched and plasma urea was depleted in 15N relative to the diet. Furthermore, Robbins et al},
	issn = {1176-5283},
	author = {Cheng L and Dewhurst RJ and Larkin J and Buckley F and Thackaberry C and Nicol AM and Edwards GR}
}
@conference {60929,
	title = {Presidential Address 2008: Where are we going and who{\textquoteright}s driving?},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {69},
	year = {2009},
	month = {Jun},
	pages = {1-3},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {I come to the 2008 Presidential Address in the unusual, but not unique, situation of preparing to leave New Zealand and move to a new research leadership position overseas. I hope that this will give me an even better platform from which to make some constructive and objective comments about the direction of our research and livestock industries. I will take the approach recommended by a previous research director of... continued },
	issn = {1176-5283},
	author = {Dewhurst RJ}
}
