The effect of feed level during the oestrous cycle on ovulation, embryo survival and anterior pituitary LH potency in the gilt.

A series of experiments was conducted to investigate the effect of basal feed level and increased feed intake during oestrus on ovulation rate, early embryo survival, and residual pituitary LH potency in the pig. All the gilts used were fed 1\m=.\8kg food/day from puberty to second heat. Gilts whose food intake was reduced from 1\m=.\8kg to 1\m=.\4 kg/day following second heat had more atretic follicles at third heat and had fewer CL and fewer embryos at Day 20 of gestation, than control gilts fed 1\m=.\8kg throughout, but these differences were not significant. Increasing the feed intake of gilts fed only 1\m=.\4kg between second and third heat to 3\m=.\6kg on Day 1 of oestrus only resulted in CL counts intermediate between those of the other two groups. The number of mature and atretic follicles during oestrus was not affected. Anoestrus