Twelve buffalo heifers of similar age (21-25 month) and body weight (325-385 kg) were superovulated during mid luteal phase using pFSH (total 65 NIH unit Super-Ov divided into 6 equal dose, 1.4 ml each, for 3 consecutive days) and lutalyse (25mg injected with the 5th injection). To improve the ovarian response to the variable doses of LH (0,2,4,5,7 and 10 thousands USP Unit, Steris, Lab. Inc Phoenix, Arizona) were injected at the morning of the 4th day of the treatment in 6 trials (n=2 ). Fertile bulls were allowed to mount heifers frequently after 24 hour (h) from onset of estrus. Heifers were classified into 3 equal groups (2 trials/each) which slaughtered at various time intervals from the onset of estrus: 72-89, 100-106 and 118-120 (h). After slaughter, the intact genitalia were dissected free and transported to the lab in a thermos container at 4C°. The number of newly formed corpora lutea (CL) and unovulated large follicles (UF) in both ovaries were done. Flushings of the oviduct and uterine horn were performed separately using phosphate buffer saline to identify the numbers and locations of embryos.
The duration of estrus(h),numbers of CL and UF were 41.5± 11.2, 3.1±1.3 and 1.1±0.76 respectively. The overall ovulation and embryo recovery rates were 72.5 and 54% respectively.Group without LH gave low response (50 and 0% respectively). The higher ovulation rate(66-100%) were recorded for heifers supplemented with 4000 and more USP unit LH while the higher embryo recovery rates (50-100%) were associated with the doses of 4000-7000 unit .
At 72-89h postestrus (48-65h post-insemination) 6 embryos were collected from the oviducts and one embryo from the uterus. Some non-motile spermatozoa were observed in the oviduct. At 100-106 and 118-120 h postestrus (76-82 and 94-96 h post-insemination)7 and 6 embryos were recovered respectively from the uterus. The rate of embryo transport in the oviduct of superovulated buffalo heifers appeared to be 30 h and more faster than in buffalo or bovine cows.