Total protein and γ-globulin contents of mammary secretion during early post-partum period of Nubian goats in the Taiwan area

Abstract

Variation in total protein and γ-globulin contents of the mammary secretion during early post-partum period was studied in two herds of Nubian goats raised in two different areas of Taiwan. A commercial agarose gel electrophoresis system migrating at pH 8.4–8.8 was used to separate and quantify the γ-globulin fraction in fat-free colostrum. Colostrum samples were obtained at birth and 6 h, 12 h, 18 h, 24 h, 36 h, 48 h, 3 d, 4 d, and 5 d post-partum, respectively. The electrophoresis results showed that colostral γ-globulin expressed similar mobility to that of serum γ-globulin. α-lactalbumin/ β-lactoglobulin constituted a stable part of the total protein, while casein was not a significant component throughout the studies. Colostral total protein and γ-globulin were decreased from 16.46, 16.15 and 7.22, 7.92 g dl −1 at parturition to 9.10, 7.86 and 3.94, 2.40 g dl −1 12 h later for the two herds, respectively. Values decreased more slowly at 18 h post-partum. Colostral total protein content was not affected by herds from different areas; colostral γ-globulin content was not significantly different at birth but was lower in one herd within 24 h post-partum. These results suggest that colostral γ-globulin might be more susceptible to influencing factors than total protein especially during the critical absorption period.