Prepubertal plasma FSH concentrations and their relationship with reproductive performance in three Greek breeds of sheep

Abstract

Plasma FSH concentrations were studied in three Greek sheep breeds; the prolific Chios, the medium prolific Karagouniki and the less prolific Florina breeds. Correlation between plasma FSH concentrations and reproductive performance were estimated. FSH concentrations were greater in Chios than Florina ewe lambs at 10, 11 and 12 weeks of age ( p < 0.05). No differences were observed in FSH concentrations between Florina and Karagouniki ewe lambs during the period of 6–12 weeks of age. Chios ewe lambs had elevated FSH levels compared with Karagouniki ewe lambs, but the differences were non-significant during the above-mentioned period. No relationship was observed between prepubertal plasma FSH and age at puberty. Significant correlations were observed between FSH concentration at 11 weeks of age and ovulation rate at puberty in the Chios breed and also between FSH concentration at 12 weeks of age and litter size of the first lambing. No relationships were observed between prepubertal plasma FSH levels and ovulation rate at puberty for the Florina and Karagouniki breeds. Likewise, prepubertal plasma FSH levels appeared unrelated to litter size at first, second and third lambings for Florina and Karagouniki breeds. It was concluded that the plasma FSH concentrations during the period from 6–12 weeks of age of ewe lambs could be a suitable criterion for an early selection of litter size of adult Chios ewes, but not for Karagouniki and Florina ewes.