The effect of parity on the efficacy ofan ovulation synchronization (O vsynch) protocol in buffalo (Bubalus bubalis)
Derar, RHussein, H AFahmy, SEl-Sherry, T MMegahed. G
The aim of the present study was to study the effect of parity on the efficacy of an Ovsynch protocol in buffalo. B uffalo heifers (HE ; n = 8 ) and cow s (BC ; n = 9 ) were used to monitor ovarian follicular dynamics and evaluate serum progesterone profile s during this protocol . A t otal of 385 control buffalo heifers (CHE ; n = 219 ) and cows (CBC ; n = 1 66 ) were used to compare conception rates follo wing the application of this protocol . The heifers and cows were cycling . All treated animals were injected with GnRH on day 0, PGF2 α on day 7 , GnRH on day 9 and artificially inseminated 1 6 h later. Ovarian changes were monitored daily using ultrasound and serum progesterone (P4) evaluated in the investigated animals . All heifers and 5 cows had follicles >8 mm at the first G n RH injection. The first GnRH injection resulted in ovulation in 7 /8 HE ( 8 7 . 5 %) and 5 /9 BC ( 55.5 %) . Following the second GnRH injection , ovulation occurred in 100 % of HE and 88.8 % of BC. Ovulation occurred earlier in BC (10.4 ± 7 .6 h) following the second GnRH injection than in HE ( 22.6 ± 5.4 h). A verage P4 concentrations of HE were higher than those of BC on day 7 (P < 0.04) . Conception r ates were 62.5% ( 429 / 686 ) in HE , 59.8 % ( 131/219 ) in CHE, 22.7 % ( 62/273 ) in BC and 59.6 % ( 99/166 ) in CBC. The present findings suggested that low conception rate s in buffalo cows , compared to heifers , may be attribut ed to earl ier ovulation and a less functi onal CL.(AU)
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