Composition of colostrum and milk of South African indigenous Nguni goats grazing natural pasture and supplemented with concentrate

Abstract

Samples of colostrum, early and late lactation milk from thirteen South African indigenous Nguni goats (SAING) were analysed for contents of total solids (TS), solids-not-fat (SNF), fat, protein, lactose, ash and energy. Relationships between colostrum or milk and some parameters such as litter size (LS), milk yield (MY) and does kidding weight (DKW) were determined. Fat, protein and lactose contents of colostrum were poorly correlated (P > 0.05) with LS. Of relationships between early lactation parameters considered, only the coefficient between MY and DKW was significant (r = 0.72, P < 0.001). Correlations between protein and lactose contents of late lactation milk and LS were not significant (P > 0.05). However, the milk fat content of late lactation milk was significantly correlated with LS (r = 0.23, P = 0.041). Means of TS, SNF, fat and energy contents decreased with increased lactation period while ash content increased as lactation advanced. Protein and lactose contents were at maximum in colostrum and early lactation milk, respectively. Fat and TS contents of colostrum, early and late lactation milk samples were positively and significantly (P < 0.05) correlated. Fat content of colostrum and milk of SAING can be used to predict the dry matter (total solids) constituent of the goats' colostrum and milk.