Changes in the secretion rate and production of colostrum by ewes over the first 24 h post partum

Abstract

AbstractAn experiment was conducted to examine the changes in colostrum secretion rate and colostrum composition in ewes over the first 24 h post partum. Sixteen mature Suffolk × Cambridge ewes, which had produced one to four lambs, were used. Colostrum yield was estimated within 1 h of parturition and colostrum secretion rate measured between 3 and 6 h, 9 and 12 h, 15 and 18 h and 21 and 24 h post partum. Samples of colostrum were taken at each milking and the composition analysed. The mean yield (g) of colostrum at 1 h was 801 (s.d. 568·9) with a range from 35 to 2450 g. Mean secretion rates, in g/h, at 3 to 6 h, 9 to 12 h, 15 to 18 h and 21 to 24 h were 120 (s.d. 67·0), 104 (s.d. 55·2), 112 (s.d. 49·8) and 109 (s.d. 41·1) respectively. At 1 h, mean concentrations, in g/l, of total solids, fat, protein, ash and IgG were 367 (s.d. 76·9), 132 (s.d. 43·7), 203 (s.d. 43·2), 9.6 (s.d. 2·4) and 116 (s.d. 30·2) respectively. Corresponding values at 24 h were 242 (s.d. 38·8), 122 (s.d. 39·5), 71 (s.d. 11·2), 6.8 (s.d. 1·0) and 15 (s.d. 12·5).Sequential samples were taken throughout the milking process within 1 h of paturition from a further eight Dorset-cross ewes. There were no significant differences in the composition of colostrum due to stage of milking, although there was a suggestion that fat content was higher in the final sample than the first (140·1 v. 104·1 g/l, P = 0·084). It is clear that there is a large amount of variation in the secretion rate and composition of colostrum produced by ewes over the first 24 h post partum. However, a single sample taken between 3 and 12 h post partum would be a good indicator of 24 h yield (r = 0·88) and composition (total solids, r = 0·90 and IgG, r = 0·93).