Effects of sexually activated rams or ewes on pulsatile LH secretion in anoestrous sheep
2002
Yildiz, S. | Uzun, M. | Cenesiz, M. | Ucar, O. | Kaya, M. | Onder, F. (University of Kafkas, Kars (Turkey). Faculty of Veterinary Medicine)
The aim of this study was to test whether anoestrous ewes respond differentially, in terms of pulsatile LH release, to sexually activated males or females. Anoestrous ewes (n=21) were divided into 3 equal groups and placed into 3 separated rooms. Long-acting progestins plus oestradiol injected ewes (n=4) were included into the female group (F). Long-acting testosterone injected rams (n=4) were included into the male group (M). Sexually inactive ewes (n=4) were introduced into the control group. Blood samples were taken before and after the introduction of the animals into the groups, each time during 8 h at 15 min intervals. The mean and smoothed mean LH concentrations, LH pulse frequency, LH pulse amplitude and duration were not different between the experimental groups neither before nor after the introduction. However, LH pulse frequency tended to decrease following the introduction in F group (P=0.078). LH pulse frequency was higher in ewes that had condition scores higher than 2 units. There was a significant positive correlation between condition score and LH pulse frequency (P=0.004; R**2 = 0.368).
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