Variability of colostrum yield and colostrum intake in pigs.

Colostrum yield and composition of 40 Landrace×Large White sows were determined from the onset of parturition until 24 h post partum. Colostrum yield was calculated by adding individual piglets' colostrum intakes for each litter. Colostrum was assayed for prolactin, progesterone, oestradiol-17β, immunoglobulin G and its nutritional composition was determined. Piglets' individual colostrum intake averaged 300 ± 7 g and sows' colostrum yield averaged 3.67 ± 0.14 kg (minimum 1.91 kg, maximum 5.31 kg). Live weight and characteristics at birth (umbilical cord already ruptured, splayleg, difficulty to breathe) were the major factors influencing individual colostrum intake. Colostrum yield was not affected by litter size, tended to be influenced by parity (P = 0.059) and was lower when farrowing was induced (P = 0.017). On the other hand, no relationships were found between hormone concentrations in colostrum and colostrum yield. Mean piglet birth weight and litter weight variation at birth were related to colostrum yield (r = 0.38; P = 0.015 and r = -0.34; P = 0.030, respectively). These results suggest that determinism of colostrum yield depends, in part, on global vitality of the litter but seems to be, most probably, affected by the capacity of sows to produce enough colostrum for the whole litter. Further studies are needed to understand the endocrine regulation of colostrum secretion in sows.