EFFECTS OF AN LH-RH AGONIST ON REPRODUCTIVE RESPONSES AND ENDOCRINOLOGIC PARAMETERS IN LANDAIS GANDERS

Semen quantitative (sperm production) and qualitative parameters (perc entage of live and normal spermatozoa, sperm motility, egg fertility a nd hatchability), as well as hormonal parameters (LH and testosterone plasma concentrations) were compared for landais ganders, which were t reated or not, with an LK-RH agonist prior to being sexually active. T reatment with the LH-RH agonist at this physiological stage delayed th e onset of sperm production in some of the treated males. Although, co mparable data were obtained during the first half of the reproductive period, treatment with the LH-RH agonist maintained sperm output at hi gher levels during its second half. Although the percentage of normal and live spermatozoa, sperm motility and true hatchability did not dif fer, the LH-RH agonist treatment had a positive effect on gosling prod uction because of the higher fertility of the treated birds during the second part of the reproductive period. Treatment induced a large sho rt-term decrease in testosterone levels followed by a rebound, leading to higher levels during the second half of the reproductive period. W e conclude that treatment of ganders with an LH-RH agonist partially p revented the naturally occurring decline in sperm production and induc ed an increase in the rate of fertility rates during the second half o f the productive period.