Biochemical changes in sows after eleven or more farrowings.

The animals examined were 30 sows after eleven or more farrowings (pluriparous sows) and 26 primiparous sows. The pluriparous animals were 75.1 months old on the average and had farrowed an average of 13.23 litters. The mean age of the primiparous sows was 12.8 months. The blood sera of pluriparous sows had higher concentrations of total protein and urea and lower levels of 11-hydroxycorticosteroids (11-OHCS) and lower aspartate aminotransferase, alanine aminotransferase and alkaline phosphatase activities than those of primiparous sows. The pluriparous sows showed mild hypoglycaemia and hypocholesterolaemia. When insulin was injected i.m. in the dose of 1 I.U. per kg body mass, a decrease in blood serum glucose, total protein and potassium levels was recorded 60 min later in both pluriparous and primiparous sows; a significant rise in 11-OHCS concentration occurred only in the primiparous sows. It was concluded that the response of the hypothalamo-pituitary-adrenal axis in pluriparous sows to an insulin load is reduced. Studies of pluriparous sows contribute to a better understanding of the ontogenetic development of pigs throughout their postnatal development.