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THE RELATIONSHIP BETWEEN MILK PROTEIN PHENOTYPES AND LACTATION TRAITS IN AYRSHIRES AND JERSEYS

  • Kim, S. (Department of Animal Science, McGill University) ;
  • Ng-Kwai-Hang, K.F. (Department of Animal Science, McGill University) ;
  • Hayes, J.F. (Department of Animal Science, McGill University)
  • Received : 1996.03.29
  • Accepted : 1996.07.04
  • Published : 1996.12.01

Abstract

A total of 3,610 Ayrshire and 1,711 Jersey cows were phenotyped for the genetic variants of ${\alpha}_{s1}$-casein, ${\beta}$-casein, $\chi$-casein, ${\beta}$-lactoglobulin and ${\alpha}$-lactalbumin. Least squares analyses showed possible associations between milk protein phenotypes and lactational production traits. Depending on lactation number, ${\beta}$-casein phenotypes in Ayrshires were associated with milk production ($A^2A^2$ > $A^1A^2$ > $A^1A^1$), and with milk protein content. In the third lactation, Ayrshire cows with ${\beta}$-casein $A^1A^1$ produced milk with 3.43% fat compared to 3.37% fat for ${\beta}$-casein $A^2A^2$. In Ayrshire, $\chi$-casein phenotypes affected the protein content during the three lactations (BB > AB > AA) and ${\beta}$-lactoglobulin phenotypes significantly influenced the milk fat during the first lactation (4.06% for AA and 3.97% for BB). In Jerseys, protein content of milk was influenced by phenotypes of ${\alpha}_{s1}$-casein(3.98% for CC v/s 3.86% for BB in the first lactation). In the third lactation, $\chi$-casein AA of Jersey milk contained 5.35% fat compared to 4.82% for phenotype BB. The effects of ${\beta}$-lactoglobulin phenotypes on protein content were apparent in Jerseys during the second lactation with the A variant being superior to the B (4.00% for AA v/s 3.87% for BB).

Keywords

Ayrshire;Jersey;Genetic Variants;Milk;Fat;Protein

Acknowledgement

Supported by : National Sciences and Engineering Research Council of Canada

Cited by

  1. Polimorfismos genéticos da kappa-caseína e da beta-lactoglobulina e produção de leite em bovinos vol.65, pp.1, 2013, https://doi.org/10.1590/S0102-09352013000100039