Akademik Veri Yönetim Sistemi
Acta Veterinaria Brno, cilt.71, sa.3, ss.297-302, 2002 (SCI-Expanded)
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. For that purpose, anoestrous ewes (n = 21) were divided into three equal groups and placed into three separated rooms. The experiment commenced two months before the expected breeding season. Body weights and body condition scores of ewes were recorded prior to the experiment Into the Female group (n = 7), long-acting progestins plus oestradiol injected ewes (n = 4) were included; into the Male group (n = 7) long-acting testosterone injected rams (n = 4) were included; and into the Control group (n = 7), sexually inactive ewes (n = 4) were introduced. In order to remove the between animal variance, blood samples for LH were taken twice, before and after the introduction, for 8 h at 15 min intervals. The results showed that 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, when the LH data obtained before and after introduction were compared, it was seen that LH pulse frequency tended to decrease following the introduction in Female group (P = 0.078). Body weights and condition scores were not different between the groups but LH pulse frequency was higher in ewes that had condition scores higher than 2.00 units. Additionally, there was a significant positive correlation between condition score and LH pulse frequency (P = 0.004; R 2 = 0.368). In conclusion, it appears that although female sheep tend to reduce LH pulse frequency of anoestrous ewes, body energy reserves appear to be the major effector of LH pulse frequency during the anoestrous period studied.