Non Nutritional Factors Affecting Milk Composition

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a) Breeding
Breeding is of considerable importance, since fat and protein levels in the milk are heritable characteristics.
Gains in milk composition made from breeding are permanent and accumulate from year to year. Benefits of sire and cow selection, and of mating decisions made today, will continue to be realized in all future descendants of the herd. In this respect, selection is a very productive means of improving milk composition.

The use of breeding to improve milk composition must be clearly understood, since selection to improve one production trait may lead to a decline in another. Selection based on milk yield will result in an increase in milk, fat and protein yields, but will reduce fat and protein percentages.

b) Stage of lactation
The composition of milk varies with the stage of lactation. Cows that calve in good condition produce milk with a high fat and protein content during early lactation. The percentages of both fat and protein decline during the first six to eight weeks of lactation, then progressively rise after the cow becomes pregnant to reach their highest levels in late lactation.

c) Age
Although fat and protein contents decrease with increasing age, these changes are small. Since the age structure of a herd is not readily changed, the age composition of the herd is unlikely to contribute significantly to herd variation in milk composition.
d) Seasonal conditions
Environmental factors that affect feed intake can be associated with pronounced variations in milk yield and composition. Temperatures consistently above 30C will reduce milk yield as well as the percentage of milk protein, because of a reduction in energy intake. Cows in early to mid-lactation and receiving little or no supplementation (that is, relying on high pasture intakes) will be affected the most by heat stress.
e) Mastitis
Clinical and subclinical mastitis decrease milk yield and so reduce fat and protein yields.

Titany answered the question on April 25, 2022 at 06:53

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Non Nutritional Factors Affecting Milk Composition

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