Effect of undernutrition on gonadotrophin profiles in non-pregnant, cycling goats

Gonadotrophin profiles were studied in does during an oestrous cycle in which they were fed rations which provided maintenance or 25% of maintenance requirements. Undernutrition had no significant effect on basal LH and FSH profiles, but was associated with a decrease in the number of goats exhibiting a preovulatory surge of gonadotrophins, reduced magnitude of the surge, and reduced incidence of ovulation. In a further experiment, intravaginal progestagen sponges were used to synchronise oestrus in goats fed maintenance and restricted diets. A single intravenous injection of GnRH (13 μg) was administered 12 days after sponge removal. The magnitude of the surge of gonadotrophins following GnRH administration tended (P < 0.1) to be less in does on restricted feeding than in does on adequate nutrition. Short-term undernutrition appeared to decrease reproductive performance by interfering with gonadotrophin release.