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The relationship between milk protein phenotypes and lactation traits in Brown Swiss and Canadienne |
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S. Kim, K. F. Ng-Kwai-Hang, J. F. Hayes |
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| Abstract |
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A total of 1033 Brown Swiss and 610 Canadienne cows were phenotyped for the genetic variants 慣s1-casein, 棺-casein, 觀-casein, 棺-lactoglobulin and 慣-lactalbumin. In Brown Swiss, frequency distributions were: 97.3% B and 2.7% C variant of 慣s1-casein; 31.6% A1, 51.8% A2, 0.5% A3 and 16.1% B variant of 棺-casein; 70.4% A, 29.3% B, and 0.3% C variant of 觀-casein; 41.7% A and 58.3% B variant of 棺-lactoglobulin; and 100% B variant of 慣-lactalbumin. Corresponding frequencies in Canadienne for those five milk proteins were: 98.6 and 1.4%; 58.5, 33.5, 0.08 and 7.9%; 78.8, 21.1 and 0.1%, 42.4 and 57.6%; and 100%. Analysis of variance by least squares showed possible association between milk protein phenotypes and some lactational production traits. There were no significant association of phenotypes of 慣s1-casein, 棺-casein and 棺-lactoglobulin with milk yield, fat yield, protein yield, fat percentage and protein percentage in both breeds during the three lactations. In the Brown Swiss, 觀-casein phenotype was associated with 305-day fat yield and protein yield during the first lactation. 觀-Casein AB was associated with higher milk, fat and protein yields during the second lactation. During the third lactation, 棺-lactoglobulin AA in Canadienne cows was associated with higher protein content in the milk (3.70%) when compared to phenotypes AB (3.54%) and BB(3.64%). |
| Keywords:
Brown Swiss; Canadienne; Genetic Variants; Milk; Fat; Protein |
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