Influence of type of diet on the fat constituents of goat and sheep milk

• Published in: Small ruminant research 2007-03, Vol.68 (1), p.42-63
• Main Authors: Sanz Sampelayo, M.R., Chilliard, Y., Schmidely, Ph, Boza, J.
• Format: Article
• Language: English
• Subjects: Agricultural sciences; animal feeding; CLA; dairy products; dietary fat; dietary supplements; ewe milk; Fat composition; Fat content; fat intake; Fat supplementation; fatty acid composition; feed intake; feed supplements; Goat milk; Life Sciences; lipid composition; lipid content; literature reviews; milk fat; product quality; Rumenic acid; ruminant nutrition; Sheep milk; species differences; Vaccenic acid
• ISSN: 0921-4488; 1879-0941
• DOI: 10.1016/j.smallrumres.2006.09.017

The specific composition of milk fat of the small ruminant makes it especially valuable nutritionally and for consumer health. The aspects of the nature and composition of the animal's diet that have an influence on the fat content of its milk and its composition has been reviewed. The various studies have been, fundamentally, aimed at optimising the production of milk. Particular account is taken of the industrial use made today of sheep and goat milk, as it comprises the raw material for the manufacture of different dairy products, especially of cheese. The physical form in which the forage proportion of the diet is presented and/or the forage/concentrate ratio in the diet are aspects for special consideration in determining the fat content of the milk. In the case of the goat, this seems to depend particularly on the energy intake achieved in each case. Dietary supplementation with different types of fat, unprotected or protected against the ruminal metabolism, is considered a crucial strategy. Not only does this alleviate certain limitations in the diet provided from the production system that is practiced. The semi-extensive production system of the small ruminant is most common in arid and semi-arid zones. It enables the producer to control the content and composition of milk fat. The scope of effect depends on the nature and amount of the dietary fat and on the existence of interactions between the basal diet (forage type, starchy concentrate, etc.) and dietary lipids. Besides the production system, the involvement of other factors, such as stage of lactation and the productive capability of the animal, should, also be taken into account. From the available information, it can be concluded that the nature of fat content of sheep and goat milk, in comparison with cow milk, presents advantages for consumer health. This composition makes them directly or in the form of dairy products, foods of choice for segments of the human population with specific requirements. Different nutritional strategies are designed with the aim of optimising the composition of these milks with respect to their fat content and composition. Experimental results in goat nutrition, show that lipid supplementation does not change net energy intake and milk yield, but increases in most cases, milk fat content and allows much less saturated fatty acids, much more oleic and/or vaccenic and rumenic acids, more linolenic acid, and other trans fatty acids. The responses of goats are di