Influence of Crude Protein Intake on the Duration of Delivery and Litter Size in Sows

The aim of the study was to evaluate the influence of different intakes of crude protein during the period from 94 to 100 days of pregnancy to the parturition, lengths of pregnancy and delivery, number and birth weights of piglets and concentrations of progesterone, 17-β estradiol and cortisol on days 100, 110 and 114 of pregnancy in sows. Daily feed intake of the sow represented 2.5 kg of complete mixtures containing 13% (group A, n = 23), 15% (group B, n = 52), 18% (group C, n = 10) and 21% (group D, n = 10) of crude protein. Lengths of pregnancy in experimental groups were not significantly different. The mean durations of delivery synchronously increased with the intake of crude protein; significant difference was found between groups A (4.5 h) and D (8.6 h) (p p < 0.05). The average birth weights of piglets did not differ between experimental groups. No statistical differences in hormone concentrations were found between experimental groups. High intake of crude protein in sows before parturition prolonged delivery and increased the number of stillborn piglets