Pattern of FSH secretion from birth to 4 months of age in two Moroccan ewe breeds varying in prolificacy

Abstract

Plasma FSH concentration was monitored weekly for 17 weeks starting at birth in two Moroccan breeds differing in prolificacy: D'man (rate of ovulation=2.9, n=10) and Timahdite (rate of ovulation=1.1, n=10). Plasma FSH concentrations increased progressively from birth until 17 weeks of age in both breeds. In ewe lambs, there appear to be genotype differences for FSH at specific times during the neonatal period. Mean plasma FSH concentrations were significantly higher in D'man compared to Timahdite ewe lambs at 4–7 and 12 weeks of age ( p<0.0001, p<0.0009, p<0.006, p<0.002 and p<0.01, respectively). These results demonstrate that the D'man ewe lamb of high prolificacy is characterized early in life by elevated basal plasma FSH concentrations.