@conference {75905,
	title = {Effect of lactation stage and breed on the concentration of unsaturated fatty acids in milkfat of New Zealand dairy cattle},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {71},
	year = {2011},
	month = {Jan},
	pages = {203-207},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Invercargill},
	abstract = {Milkfat composition influences the nutritional value and manufacturing characteristics of milk. This research studied the influence of: 1) stage of lactation on the concentration of unsaturated fatty acids (UFA) in milkfat of Holstein-Friesian, Jersey and Crossbred cows, 2) segregation of cows according to their UFA concentration in milkfat. The concentration of UFA in milkfat was predicted with a calibration equation using Fourier transform infrared spectroscopy. The data (21,757 test-day records) were analysed using a mixed model with a third-order orthogonal polynomial. In the three breeds studied, after early lactation the concentration of UFA in milkfat decreased steadily as the lactation progressed, but in Holstein-Friesian cows it increased slightly at the end of lactation. Throughout lactation, Holstein-Friesian cows produced milkfat with a higher concentration of UFA than Jersey and Crossbred cows. In each herd, cows were split into a high and a low group according to the average UFA concentration of the herd. The high UFA group had higher (P <0.001) milk yield, but lower (P <0.001) yields and concentrations of fat and protein than the low UFA group. This study indicates that concentration of UFA in milkfat is affected by breed and stage of lactation in New Zealand dairy cattle.},
	issn = {1176-5283},
	author = {Silva-Villacorta D and Lopez-Villalobos N and Blair HT and Hickson RE and Spelman RJ and Melis J and Davis SR and Berry SDK and Lehnert K and Snell RG}
}
@conference {60943,
	title = {Breed effects for lactoferrin concentration determined by Fourier transform infrared spectroscopy},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {69},
	year = {2009},
	month = {Jun},
	pages = {60-64},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {A calibration equation based on partial least squares using Fourier transform infrared spectroscopy (FTIR) data was derived to predict concentration of lactoferrin (Lf) in bovine milk. The concordance correlation coefficient of the calibration equation was estimated at 0.81 using 246 milk samples collected in the 2003-04 season from second-parity crossbred cows during late lactation. The calibration equation was then used to predict the concentration of Lf (pLf) in 9,742 milk samples from 814 Holstein-Friesian (HF), 955 Jersey (J) and 842 crossbred HF x J cows sampled on average 3.7 times during the 2007-08 season. A repeatability animal model was used to obtain breed effects and estimates of variance components for pLf. Concentrations of pLF (mg/L milk) were significantly (P <0.001) different between breed groups (HF = 163 {\textpm} 3.8, HF x J = 175 {\textpm} 5.0 and J = 193 {\textpm} 6.3). Heritability and repeatability of pLf concentration were 0.16 {\textpm} 0.036 and 0.35 {\textpm} 0.012, respectively. These results confirm previous studies showing that Lf concentration in milk can be predicted using FTIR spectroscopy and that there are significant breed differences and animal variation that can be exploited in a breeding program. },
	issn = {1176-5283},
	author = {Lopez-Villalobos N and Davis SR and Beattie EM and Melis J and Berry S and Holroyd SE and Spelman RJ and Snell RG}
}
@conference {41491,
	title = {Effect of timing of insemination of dairy cows with liquid semen relative to the observation of oestrus},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {64},
	year = {2004},
	month = {Jan},
	pages = {140-142},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Hamilton},
	abstract = {Many studies have confirmed that the best conception rates are obtained when cows are inseminated from mid to late oestrus. The conclusions of Trimberger, (1948) has led to the universally accepted AM - PM schedule for inseminating cows. The guideline suggests that cows found in oestrus during the AM period be inseminated at the following PM and the cows in oestrus at the PM be inseminated the following AM. Variations of this rule have been tested with single and multiple AI during oestrus periods and once daily AI after the AM milking with no adverse effect on conception rates. The objective of this study was to determine the effect of time of insemination on Non Return Rates (NRR{\textquoteright}s) in a sample of seasonal breeding New Zealand dairy cows submitted for insemination once a day after following the AM - PM guideline. Two hundred farms participated in this trial with over 12,000 animals representing Friesian, Jersey and Cross breeds were included in this dataset. The farmers were asked to keep accurate records on when cows were first detected in oestrus during the first two weeks of mating. There was no significant difference in 18 to 24 day non return rates for all cows observed in heat at the two time periods and inseminated the following AM (71.8\%, PM and 71.6\% AM respectively, p = 0.18). There was no effect of bulls or age of cows. A nominal effect of breed of cow was observed. In conclusion, there was no effect on NRR when cows were inseminated at the one time period after AM milking whether they were first observed in heat the previous PM or the AM just prior to insemination. },
	issn = {1176-5283},
	author = {Vishwanath R and Melis J and Johnson DL and Xu ZZ}
}
