@article {3672,
	title = {Effect of farm system and milk urea phenotype on milk yield and milk composition of dairy cows in Canterbury},
	journal = {New Zealand Journal of Animal Science and Production},
	volume = {81},
	year = {2021},
	month = {01/2022},
	pages = {196-200},
	address = {Online},
	abstract = {To investigate the effect of farm system, and cow selection for milk urea nitrogen (MUN), on milk yield and milk composition,
a farmlet study was carried out between October 2018 and May 2019 in Lincoln, Canterbury. A farm system with a low stocking
rate and low N fertiliser input (LSR, 2.9 cows/ha) sown with a conventional ryegrass clover and plantain diverse pastures was
compared with a farm system with a moderate stocking rate and moderate N fertiliser (MSR, 3.9 cows/ha) using conventional
ryegrass and white clover pastures and supplementing 3 kg DM/cow/d as crushed barley grain. Each farmlet had total herd size of
40 mixed-age HF x J spring-calving dairy cows which included six cows selected solely for a high MUN or a low MUN. There was
no effect of farm system on milk fat, protein or lactose content but MUN was lower in LSR compared with MSR. Milk production
was also lower for LSR (466 vs 429{\textpm}12.4 kg MS/cow/ha, P<0.05), owing to poorer quality diet in mid lactation. Cows selected
for low MUN tended to produce less milk compared with high MUN cows (4478 vs 3987{\textpm}174 kg/cow, P<0.10) though this was
partially offset by increased protein content in milk of low MUN cows. Farm system and animal selection for MUN have a greater
impact on milk yield than on milk composition.

Keywords: Plantago lanceolata; somatic cell count; multi-species pastures;},
	issn = {1176-5283},
	author = {Bryant RH and O{\textquoteright}Conner PO and Robic Y and Curtis J and Handcock RC and Al-marashdeh O}
}
