Authors : F. Lamrani , A. Benyounes , J. Sulon , G. Khaldi , B. Rekik , R. Bouraoui , J.F. Beckers and A. Tahar
Abstract: The objective of this research was to study the effects of repeated use of oestrous induction/ synchronisation hormones (FGA+PMSG) on oestrous cycles and reproductive performances of Ouled Djellal ewes. A total of 56 adult ewes were divided into 4 groups where: the first group included 15 ewes that have not previously received hormonal Treatments (T1: used as control ewes), the second group included 20 ewes that received two successive Treatments (T2), the third group included 16 ewes that received three times successive Treatments (T3) and the last group included 5 ewes and that received four successive Treatments (T4). Groups were homogenous with respect to mean age, live weight and body condition score. Consecutive PMSG administrations were 8 months apart. Measures of anti-PMSG antibody concentrations were obtained using radio-immuno-assay on plasma samples taken before treatments begun (FGA deposit corresponds to j = 1) and at 7, 14, 18, 25, 30, 35 and 40 days after PMSG administration. Gestation diagnosis was realised by dosing PAGo. Fractions of individual binding following PMSG injections (day 7 to day 40) were small and reached rarely 12%. There were no significant differences among treatments (p>0.05) with respect to anti-PMSG antibody concentrations. Furthermore, regardless of the treatment number, accumulated results for classes (< 3-7%) of anti-PMSG antibody treatments showed no depressing effects of residual antibodies on oestrus activities of ewes compared to the control treatment. However, negative effects of residual anti-PMSG antibodies on ewes` reproductive behaviour were observed for the 3-7% class. Repeated use of PMSG at 8 month intervals seemed not to affect reproductive performances of ewes in natural breeding mode. It should be possible to induce synchronised oestrus cycles of Ouled Djellal ewes by repeated use of PMSG without compromising ewes` reproductive performances.
F. Lamrani , A. Benyounes , J. Sulon , G. Khaldi , B. Rekik , R. Bouraoui , J.F. Beckers and A. Tahar , 2008. Effects of Repeated Use of PMSG on Reproductive Performances of the Ouled Djellal Ewes. Research Journal of Animal Sciences, 2: 22-30.