Pregnancy and calving rates following transfer of in-vitro-produced river and F1 (river x swamp) buffalo (Bubalus bubalis) embryos in recipients on natural oestrus or synchronised for ovulation.

The main objective of this study was to compare pregnancy and calving rates following transfer of in-vitro-produced fresh river and F1 (river x swamp) buffalo embryos in recipients synchronised by Ovsynch protocol or following natural oestrus. River embryos were produced from cumulus-oocyte complexes (COCs) derived by ovum pick up (OPU) on 40 Murrah and Nili-Ravi donor buffaloes over a twice-weekly collection schedule for 120 single OPUs. F1 embryos were produced by fertilisation of swamp COCs recovered from abattoir ovaries coincubated with river sperm cells. Both groups of embryos were produced following the same protocol for in vitro production. With regard to the OPU source of COCs, 923 antral follicles were punctured and 647 COCs were recovered (70%). From 462 selected COCs for IVM, 257 (55.6%) cleaved zygotes were recorded leading to 93 blastocysts (20.1%). In total, 590 swamp COCs were aspirated from abattoir ovaries and 476 were selected for IVM leading to 270 (56.7%) cleaved zygotes and resulting in 137 blastocysts (28.8%). River and F1 embryos were transferred between Day 6 to 7 of in vitro development, corresponding to blastocyst-expanding blastocyst, into F1 recipients synchronised by Ovsynch and swamp buffaloes following natural oestrus, respectively, each of them receiving two embryos. According to palpation per rectum of the ovaries at the time of embryo transfer, 26 of the 47 (55.3%) F1 recipients synchronised by Ovsynch were considered suitable for transfer, resulting in seven pregnancies (26.9%) and four calvings (15.3%) owing to three abortions occurring between 2 and 3 months of pregnancy. In total, 29 swamp recipients following natural oestrus were judged suitable as recipients, resulting in 12 pregnancies (41.4%) and 10 calvings (34.5%) owing to two abortions at 2 and 3 months of gestation respectively. Pregnancy and calving rates following transfer of river and F1 embryos were similar. Likewise, weight at birth of calves derived from transfer of river and F1 embryos was not different: 30.5 +/- 1.4 and 32.9 +/- 2.4 respectively. Pregnancy and calving rates following AI in a group of river and swamp buffaloes considered for reference in this study were similar to recipients carrying in-vitro-produced embryos. Collectively, no apparent postnatal complications were recorded in resulting live calves.

Effect of season, late embryonic mortality and progesterone production on pregnancy rates in pluriparous buffaloes (Bubalus bubalis) after artificial insemination with sexed semen.

The use of sexed semen technology in buffaloes is nowadays becoming more and more accepted by farmers, to overcome the burden of unwanted male calves with related costs and to more efficiently improve production and genetic gain. The aim of this study was to verify the coupling of some variables on the efficiency of pregnancy outcome after deposition of sexed semen through AI. Pluriparous buffaloes from two different farms (N = 152) were screened, selected, and subjected to Ovsynch protocol for AI using nonsexed and sexed semen from four tested bulls. AI was performed in two distinct periods of the year: September to October and January to February. Neither farms nor bulls had a significant effect on pregnancy rates pooled from the two periods. The process for sexing sperm cells did not affect pregnancy rates at 28 days after AI, for nonsexed and sexed semen, respectively 44/73 (60.2%) and 50/79 (63.2%), P = 0.70, and at 45 days after AI, for nonsexed and sexed semen, respectively 33/73 (45.2%) and 33/79 (49.3%), P = 0.60. Pregnancy rate at 28 days after AI during the transitional period of January to February was higher when compared with September to October, respectively 47/67 (70.1%) versus 47/85 (55.2%), P = 0.06. When the same pregnant animals were checked at Day 45 after AI, the difference disappeared between the two periods, because of a higher embryonic mortality, respectively 32/67 (47.7%) versus 40/85 (47.0%), P = 0.93. Hematic progesterone concentration at Day 10 after AI did not distinguish animals pregnant at Day 28 that would or would not maintain pregnancy until Day 45 (P = 0.21). On the contrary, when blood samples were taken at Day 20 after AI, the difference in progesterone concentration between pregnant animals that would maintain their pregnancy until Day 45 was significant for both pooled (P = 0.00) and nonsexed (P = 0.00) and sexed semen (P = 0.09). A similar trend was reported when blood samples were taken at Day 25, being highly significant for pooled, nonsexed, and sexed semen (P = 0.00). Hematic progesterone concentration between the two periods of the year was highly significant for pregnant animals at 28 days from AI when blood samples were taken at Day 20 after AI for pooled, nonsexed, and sexed semen, respectively P = 0.00, 0.00, and 0.06, and for pregnant animals at Day 45 for pooled, nonsexed, and sexed semen, respectively P = 0.00, 0.00, and 0.01. From these results, it can be stated that hematic progesterone concentration measurement since Day 20 after AI can be predictive of possible pregnancy maintenance until Day 45. Furthermore, the transitional period of January to February, although characterized by a higher pregnancy outcome when compared with September to October, suffers from a higher late embryonic mortality as evidenced by a significant different hematic progesterone concentration between the two periods at Day 20 after AI.

Oocyte source and hormonal stimulation for in vitro fertilization using sexed spermatozoa in cattle.

The aim of this study was to investigate the efficiency of in vitro embryo production in cattle utilizing sexed sperm from two bulls and oocytes recovered by OPU. Twenty donor animals were employed in eight OPU replicates: the first four OPU trials were conducted on animals without hormone treatment, and the last four were run on the same animals, following FSH subcutaneous and intramuscular administration. A higher rate of blastocyst development was recorded in stimulated, as compared to nonstimulated animals, (25.2% versus 12.8%, P = .001). Ocytes derived from slaughterhouse (SH) ovaries were also fertilized with sperm from the same bulls. Overall, non-sexed sperm used with oocytes derived from SH ovaries was significantly more efficient for blastocyst development than was sexed sperm with these same SH derived oocytes and sexed sperm with stimulated donor oocytes (39.8% versus 25.0% and 25.2%, P = .001). In conclusion, the use of sexed sperm with OPU-derived oocytes resulted in a significantly higher blastocyst development when donors were hormonally stimulated; furthermore, the level of efficiency achieved was comparable to that attained when the same sexed sperm was tested on oocytes derived from SH ovaries.