Effect of lupin (Lupinus angustifolius) supplementation on ovarian and pituitary activity in ewes

In each of three experiments, thirty seasonally anoestrous Border Leicester ewes were fed on a maintenance ration of oaten chaff. Fifteen of them were given a supplement of 500 g lupin grain per head per day. The ewes were treated with 10 mg follicle stimulating hormone (Expt 1), 600 I.U. pregnant mare serum gonadotrophin (Expt 2) and either 150 or 300 micrograms gonadotrophin releasing hormone (Expt 3) to determine whether the ovaries and/or the anterior pituitary were capable of responding to the nutrient status of the animals and influencing ovulation rate. In each experiment, the number and size of corpora lutea and follicles in the lupin-supplemented and -unsupplemented groups were similar. It was concluded that the mechanism by which lupins increase the ovulation rate is probably neural and not a result of direct effect on either the pituitary or the ovaries.