The concentration of creatine and creatine phosphate in sow colostrum and milk throughout lactation and weaning

The concentrations of creatine and creatine phosphate were determined by enzymatic analysis of mammary secretions from a total of 63 saws from pre-farrowing (PF), during farrowing, and on Days 1, 2, 3, 4, 5, 7, 11, 18, and 28 (at weaning) of lactation. Three sows were sampled on all days and on Days 1, 2, 3, 4, and 5 post weaning. Samples were collected from an additional 5 sows on the sampling days PF to Day 28 of lactation. The concentration of creatine remained constant at 1.4+/-0.02 mM (mean+/-s.e.m.) prior to farrowing and throughout lactation. The concentration of creatine phosphate was 0.41+/-0.05 mM prior to farrowing until Day 2 of lactation. The concentration of creatine phosphate then increased gradually from Day 3 to reach a peak at 1.1+/-0.05 mM by Day 7 and then remained unchanged throughout lactation. The concentrations of creatine and creatine phosphate decreased 30-42 h post weaning, and by 118 h post weaning both creatine and creatine phosphate were undetectable in milk samples. The within-sow variation in the concentration of creatine and creatine phosphate in colostrum before farrowing was small (CVs 2-9% and 6-9%, respectively). However, during farrowing, throughout lactation, and post weaning, the variations in the concentration of creatine and creatine phosphate were much larger (CVs 19-27% and 25-80%, respectively). In contrast, the between-sow variations in the concentration of creatine and creatine phosphate in mammary secretion collected at all of these stages of the lactation cycle were large (CVs 15-41% and 19-57%). It was concluded that concentrations of creatine and creatine phosphate may reflect mammary gland metabolic activity and could be involved in the development of the piglet during the suckling period.