The biological significance of differences in cows and sows colostrum and milk composition.

The objective of this work was to compare the composition of colostrum and milk of cows and sows (content of dry matter, protein, milk fat and lactose, concentration of IGF-I and insulin) in samples taken on the first, second, third and seventh day after parturition, and then based on the differences in composition to determine a biological significance of nutrition of newborn during the earliest stages of their life. The investigation inluded 14 cows of Holstein breed and 14 sows of Landrace breed. The content of dry matter and the concentration of proteins in both colostrum and milk samples were statistically significantly higher in regard to sows mammary glands secretion, taken on the first day after the parturition (p<0,01 and p<0,001, individually), but their decrease in mammary glands secretion was more pronounced in the cows than the sows, during the first seven days. The concentration IGF-I was statistically significantly higher in the cows colostrum and milk in regard to the sows during the whole investigation period, while the concentration of insulin was significantly higher in the sows in regard to the cows during the same period. The concentrations of milk fat and lactose in cows milk samples were significantly lower in regard to the sows in all period of the study. On the basis of the obtained results, it can be concluded that there are significant differences in the composition of milk and colostrum of both the investigated animal species. The differences are probably the result of evolutionary adaptation of mammal gland function to nutrition, energy and protection requirements of these young animals in their early postnatal life. [Projekat Ministarstva nauke Republike Srbije, br. III 46002]