Variation in milk whey composition throughout lactation in cows
of different Beta-lactoglobulin phenotypes.
S-A.Turner, M.J. Auldist, P.C. Molan and C.G. Prosser
AgResearch, Ruakura Research Centre, Private Bag 3123, Hamilton.
Proceedings of the New Zealand Society of Animal Production. 1998,
58: 52-54
The association between Beta-lactoglobulin (Beta-LG) variants and milk
composition throughout lactation was determined by sampling from 44
Friesian cows (22 homozygous for Beta-LG AA and 22 homozygous for Beta-LG BB)
in early (day 6 postpartum), established (1- 3 months postpartum) and
late lactation (on the day of drying off). Results indicated that
differences between Beta-LG AA and BB phenotype milk (expressed as a
percentage of the level in phenotype AA) in concentrations of bovine
serum albumin (BSA; -15.9%, -32.0%, -42.5%) and Beta-LG (5.9%, 16.0%,
32.2%), in early, established and late lactation respectively, increased
steadily as lactation progressed. The differences in alpha-lactalbumin
concentrations were less variable (1.2%, -9.0%, -9.1%). These results
provide new evidence that compositional differences are not seen between
Beta-LG AA and BB phenotype milk until established lactation.
Keywords: NZSAPAB;
milk composition; Beta-lactoglobulin phentoypes; whey proteins.
Last Updated 12-09-1998
