Abstract

The properties of the milk serum protein alpha-lactalbumin are reviewed with special emphasis being placed on its central role in determining the lactose and water content of milk. Much circumstantial evidence suggests that artificial depression of alpha-lactalbumin synthesis should decrease lactose synthesis and that this will, in turn, decrease the water content of milk. Experimental evidence indicates, however, that patterns of alpha-lactalbumin gene expression in lactating ovine and bovine mammary tissue are complex and we should be cautious in making such predictions. Studies with transgenic mice expressing either elevated or depressed levels of alpha-lactabumin will be required to settle this question. In the meantime, a promising line of research is the investigation of dairy cattle carrying variant alpha-lactabumin genes. It is possible that correlations will be found between some of these variants and both the water content and protein yield of milk. Conceivably, selective breeding of cattle carrying variant proteins may prove a more practical means of altering alpha-lactalbumin synthesis than current transgenic techniques.

VK, Rugambwa, CW Holmes, and ACP Chu

Proceedings of the New Zealand Society of Animal Production, Volume 51, , 167-172, 1991