The influence of lactation stage on the milk constituents of Sahelian goats

Abstract

Twelve lactating Sahelian goats aged between 2 and 3 years and averaging 25kg body weight were selected from the herd at the University of Maiduguri Teaching and Research Farm, for a 19- week lactation study. The does were classified into early, mid, and late lactation stages and maintained daily on 1kg concentrate mixture per animal in addition to grazing on Gamba grass. Milk collected were analysed for total solids (TS), butterfat, protein, solids -not-fat (SNF), Ash and energy. The mean percentage values (M+SE) of colostrum were TS 14. 96+0.41; butterfat 8.58+1.00; protein 5.64+0.31; ash 0.93+0.07; SNF 6.37+0.51; and energy 3.21+0.39 MJ/ kg. The overall mean values for mature milk were 13.18+0.27, 7.52+0.18, 4.81+0.14, 0.76+0.03, 5.66+0.16% and 2.79+0.12 MJ/ KG respectively for TS, fat, protein, ash SNF and energy. There was a gradual decline in the values of all the components of colostrum from day 1- 6 after kidding. Generally, colostrum constituents were higher in concentration than those of mature milk on the 7th day after parturition. The mature milk constituents were significantly affected (P<0.05) by stage of lactation. These constituents tended to increase with advancing lactation. Milk constituents (especially Fat, protein and SNF), as evident from thus study could be manipulated through feeding.
Key Words:Sahelian goats, lactation stage, milk composition.