@article {3672,
	title = {Genetic parameters for urination traits and their relationships with production traits of dairy cattle grazing temperate ryegrass and white-clover pastures},
	journal = {New Zealand Journal of Animal Science and Production},
	volume = {81},
	year = {2021},
	month = {01/2022},
	pages = {153-158},
	address = {Online},
	abstract = {The objective of this study was to quantify genetic parameters of daily urination traits; urinary nitrogen (UN), urination volume (Uvol), urination number (Unum), average UN concentration (UNconc) and volume per urination event (VolEvent) including their genetic correlations with milk urea nitrogen concentration (MUN) and other production traits in New Zealand dairy cattle. Heritability estimates for urination traits measured on four consecutive days ranged from 0.17 to 0.35. Repeatability estimates ranged from 0.31 to 0.58, indicating that reliable prediction of urination measures would benefit from repeated measurement over a number of days. The heritability estimate for MUN was 0.29, similar to reports in the literature, whilst the estimate of repeatability (0.73) was greater than previously published values. Estimates of the genetic correlations between MUN and urination traits ranged from -0.39 to 0.41, however, due to the small number of animals in the current study, the confidence intervals were wide. The low genetic correlations may result from variation in voluntary feed intake from cow to cow that is a feature of pasture-based grazing systems. The results suggest that urination traits may be changed through selection. The low estimates of genetic correlations between MUN and urination traits suggest that MUN may not be a useful estimator of individual UN excretion in pasture-fed dairy cattle.


Keywords: urine traits; milk urea},
	issn = {1176-5283},
	author = {Handcock RC and Box LA and Glassey C and Garrick DJ}
}
@article {3672,
	title = {In sacco digestion kinetics of plantain and ryegrass-white clover harvested in the morning and afternoon},
	journal = {New Zealand Journal of Animal Science and Production},
	volume = {78},
	year = {2018},
	month = {07/2018},
	pages = {34-39},
	address = {Lincoln},
	issn = {1176-5283},
	author = {Box LA and Edwards GR and Bryant RH}
}
@conference {3672,
	title = {Milk production and urinary nitrogen excretion of dairy cows grazing perennial ryegrass-white clover and pure plantain pastures},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {76},
	year = {2016},
	month = {07/2016},
	pages = {18-21},
	address = {Adelaide},
	abstract = {Milk production and urinary nitrogen (N) concentration were measured in late lactation dairy cows grazing a perennial ryegrass-
white clover pasture, pure plantain and an area that is comprised of 50\% perennial ryegrass-white clover and 50\% pure
plantain by ground area (50-50 pasture-plantain), (n=12). Milksolids production was greater (P=0.01) for cows grazing plantain
(1.67 kg MS/cow/d) than those grazing pasture (1.50 kg MS/cow/d), with cows grazing 50-50 pasture-plantain intermediate (1.60
kg MS/cow/d). Urine-N concentration was 56\% lower (P<0.001) for plantain (2.4 g N/L) and 33\% lower for 50-50 pasture-plantain
(3.6 g N/L) than pasture (5.4 g N/L). Plantain may offer environmental benefits to dairy systems by reducing the urinary N
concentration deposited on the soil from grazing cows in late lactation.},
	issn = {1176-5283},
	author = {Box LA and Edwards GR and Bryant RH}
}
