@article {3672,
	title = {Milk composition and productive and reproductive performance of cows from A1 and A2 β-casein variants, milked once or twice a day},
	journal = {New Zealand Journal of Animal Science and Production},
	volume = {80},
	year = {2020},
	month = {09/2020},
	pages = {137-142},
	address = {Online},
	abstract = {Protein is an important component of milk and it plays an essential role in all living organisms. β-casomorphins-7 (BCM-7) is
derived from A1 β-casein and has been implicated in some human health issues. This A1 β-casein is produced by cows with the
A1A1 or A1A2 genotype, whilst cows with the A2A2 genotype produce A2 β-casein, which has not been implicated in the same
human health issues. Given the potential importance of A2 milk for public health and its apparent commercial potential, selection
based on the A2 genotype and its impact on production and reproduction traits should be investigated. The objective of the current
study was to compare the productive and reproductive performance of dairy cows based on A2 genotype in two different dairy
farms. From July 2017 to May 2018, 206 cows (including 122 A2A2 genotype; {\textquotedblleft}A2 cows{\textquotedblright}) were milked once a day at Dairy 1
and 451 cows (including 217 A2 cows) were milked twice a day at Dairy 4. Records of lactation yields of milk, fat and protein,
fat percentage, protein percentage, days from start of mating to conception, pregnancy rate to first service, the submission rate
at 21 days and the pregnancy rate at 21 and 42 days (PR42) after the start of mating from 642 cows in two herds were analysed.
The effects of A2 genotype on production and reproduction traits were not significant. The interaction between farm and β-casein
genotype was significant for PR42 (P<0.05) but not for any other traits. The interactions between parity number and genotype
were not significant for any of the traits. The results indicated that cows of different β-casein genotypes have similar production
and reproductive performance.
Keywords: β-casein genotype; A2 milk; protein percentage; pregnancy rate at 42 days},
	issn = {1176-5283},
	author = {Lu Y and Hickson RE and Gedye K and Correa-Luna M and Donaghy DJ and Lopez-villalobos N}
}
@article {3672,
	title = {BRIEF COMMUNICATION: Differential expression of lactoferrin and insulin-like growth factor-1 genes in milk from cows milked once and twice a day},
	journal = {New Zealand Journal of Animal Science and Production},
	volume = {78},
	year = {2018},
	month = {07/2018},
	pages = {109-110},
	address = {Lincoln},
	abstract = {Dairy farming in New Zealand has traditionally utilized a twice a day (TAD) milking system, but milking once a day (OAD) for the
entire lactation is also practiced by a significant proportion of dairy farmers. This study reports on the differential gene expression
in milk from OAD and TAD cows. Three predominant dairy breed group of New Zealand, Holstein-Friesian (F), Jersey (J) and F{\texttimes}J
crossbred (F{\texttimes}J) were included in samples collected from both milking regimens. RNA was extracted from milk from 45 OAD and
42 TAD dairy cows during early lactation, and used to determine lactoferrin (LF) and insulin-like growth factor-1 (IGF-1) gene
expression using qPCR. Compared to TAD cows, cows milked OAD had higher expression of the LF gene (1.38 vs 1.30 folds,
P=0.08) and the IGF-1 gene (1.65 vs 1.48 folds, P=0.09). These results suggest that milking frequency affects the expression of
milk composition genes at early lactation.},
	issn = {1176-5283},
	author = {Gedye K and Notcovich S and CorreaLuna M and Ariyarathne P and Heiser A and Lopez-villalobos N}
}
