Relationship of single and double ovulations with serum progesterone concentrations and fetal numbers in Mamasani goats

Determining the effect of single versus double ovulations on progesterone concentration and luteal tissue volume is so important for better reproductive management in goats. The aim of the present study was to establish the relationship between ovulation number, luteal tissue volume and progesterone concentrations in Mamasani goats. For this purpose, the uteri and ovaries of 192 goats were collected in a slaughterhouse during the breeding and nonbreeding seasons. Before slaughtering, blood samples were taken and analyzed for assaying progesterone concentrations. Study groups in the nonbreeding season were: 1single ovulation, 2unilateral double ovulations and 3bilateral double ovulations of nonpregnant goats. The groups in the breeding season were: 1nonpregnant single ovulation, 2nonpregnant unilateral double ovulations, 3nonpregnant bilateral double ovulations, 4pregnant single ovulation with one fetus, 5pregnant single ovulation with two fetuses, 6pregnant unilateral double ovulations with one fetus, 7pregnant unilateral double ovulations with two fetuses, 8pregnant bilateral double ovulations with one fetus, and 9pregnant bilateral double ovulations with two fetuses. Results showed that the right ovary had a pivotal role in ovulation during the nonbreeding and breeding season. In both pregnant and nonpregnant gravid goats, the total volume of corpora lutea (CLs) as well as the serum progesterone concentration was higher after double ovulations. The total volume of CLs and the concentrations of serum progesterone in goats carrying two fetuses with single ovulation was significantly higher than that of animals with single ovulation and one fetus. It was concluded that although a higher concentration of progesterone in goats is associated with the total volume of luteal tissue, this level is not a reliable predictor for the number of fetuses per goat.