Physiological changes in the peri-partum period and colostral IgG transfer in prolific D'man sheep: effects of parity and litter size.

The aim of this work was to assess maternal and neonatal changes in plasma proteins, glucose and cortisol and to quantify the colostral immunoglobulin G (IgG) transfer in the peri-partum period in D'man sheep, a prolific breed, taking into account the parity of the ewe. The concentrations of proteins and glucose were high in the ewes on day 7 and at lambing before decreasing. Likewise, cortisol plasma concentration was maximal during the 6 h following lambing and dropped at 12 h. Protein and glucose concentrations were low in lambs at 1 h of birth after which they increased. By contrast, cortisol level was the highest during the first 12 h of birth and then decreased. The colostral IgG level was high at lambing and dropped by over 87 % from 1 to 48 h post-partum. In the newborn, the plasma IgG concentration was lowest at birth and increased rapidly during the first 24 h of birth. Parity influenced maternal physiology with multiparous ewes having the lowest concentrations of proteins, glucose, IgG and cortisol, but the highest colostrum IgG level. Accordingly, lambs born from primiparous ewes had lower protein, glucose and plasma IgG concentrations than lambs born from multiparous ewes. The main outcome of this study was that lambs born from primiparous ewes are characterized by the lowest physiological indices and this may influence their survival chance.