Review: Development, adoption, and impact of assisted reproduction in domestic buffaloes.

The domestic buffalo (Bubalus bubalis), also known as water buffalo, comprises two sub-species the River buffalo (B. bubalis ssp. bubalis; 50 chromosomes) and the Swamp buffalo (ssp. carabanensis; 48 chromosomes). Domestic buffaloes are a globally significant livestock species. In South Asia, the River buffalo is a primary source of milk and meat and has a very important role in food security. The River buffalo also supports high-value, differentiated food production in Europe and the Americas. The Swamp buffalo is an important draft animal and a source of food in Southeast Asia and East Asia. The growing importance of buffaloes requires that they undergo an accelerated rate of genetic gain for efficiency of production, product quality, and sustainability. This will involve the increased use of assisted reproduction. The initial application of reproductive technology in buffaloes had variable success as it relied on the adoption of procedures developed for cattle. This included artificial insemination (AI), sperm cryopreservation, and embryo technologies such as cloning and in vitro embryo production (IVEP). Reproductive technology has been progressively refined in buffaloes, and today, the success of AI and IVEP is comparable to cattle. Ovarian follicular superstimulation (superovulation) combined with in vivo embryo production results in low embryo recovery in buffaloes and has limited practical application. The contribution of elite female buffaloes to future genetic improvement will therefore rely mainly on oocyte pickup and IVEP. This will include IVEP from females before puberty to reduce generation intervals. This review provides for the first time a clear chronology on the development, adoption, and impact, of assisted reproduction in domestic buffaloes.

Can blood progesterone concentration identify non-pregnant buffaloes to support oestrous resynchronization?

This study compared the plasma progesterone concentrations from pregnant and non-pregnant buffaloes to identify non-pregnant females and submit cows earlier to oestrous resynchronization. Forty-four multiparous mix-breed Murrah buffaloes were selected for the study. The cows were subjected to hormonal oestrous synchronization and separated into 4 groups, P12 (pregnant, n = 8) and P18 (n = 8) at 12 and 18 days post-insemination; NP12 (non-pregnant, n = 7) and NP18 (n = 7) at 23 and 29 days after the onset of synchronization, respectively. The embryos and blood were collected, and the plasma was separated for centrifugation and used to determine progesterone concentration. Progesterone concentration was higher in P18 than P12 (p = .02) and NP18 groups (p < .001). The steroid was also increased in the P12 group compared with NP12 (p = .031). There was no difference between NP12 and NP18 (p = .906). We conclude that the plasma progesterone concentration can be an alternative to identify earlier non-pregnant buffaloes, advancing the oestrous resynchronization or natural service to improve productivity.

Assisted reproductive technologies (ART) in water buffaloes.

Our expanding knowledge of ovarian function during the buffalo estrous cycle has given new approaches for the precise synchronization of follicular development and ovulation to apply consistently assisted reproductive technologies (ART). Recent synchronization protocols are designed to control both luteal and follicular function and permit fixed-time AI with high pregnancy rates during the breeding (autumn-winter) and nonbreeding (spring- summer) seasons. Additionally, allow the initiation of superstimulatory treatments at a self-appointed time and provide opportunities to do fixed-time AI in donors and fixed-time embryo transfer in recipients. However, due the scarce results of in vivo embryo recovery in superovulated buffaloes, the association of ovum pick-up (OPU) with in vitro embryo production (IVEP) represents an alternative method of exploiting the genetics of high yeld buffaloes. Nevertheless, several factors appear to be critical to OPU/IVEP efficiency, including antral follicle population, follicular diameter, environment, farm and category of donor. This review discusses a number of key points related to the manipulation of ovarian follicular growth to improve assisted reproductive technologies in buffalo.

Evidence of congenital transmission of Neospora caninum in naturally infected water buffalo (Bubalus bubalis) fetus from Brazil.

The aim of this study was to determine the congenital infection by Neospora caninum in the water buffalo (Bubalus bubalis), a natural intermediate host. Nine pregnant water buffalos, raised under free-grazing condition, were slaughtered, and their fetuses were collected. Samples of brain and thoracic fluid were obtained from those fetuses, with gestational ages ranging from 2 to 5 months. The DNA of N. caninum was detected and identified in the brain of one of those fetuses, using two PCR assays, one directed to the Nc5 gene and the other, to the common toxoplasmatiid ITS1 sequence. The DNA fragments produced on PCR were sequenced, and N. caninum was confirmed in the samples. No antibodies to N. caninum were detected on any sample of thoracic fluid by immunofluorescent antibody test (IFAT < 25). This is the first confirmation of congenital transmission of N. caninum in water buffalos.

Control of ovulation with a GnRH agonist after superstimulation of follicular growth in buffalo: fertilization and embryo recovery.

The potential to use a GnRH agonist bioimplant and injection of exogenous LH to control the time of ovulation in a multiple ovulation and embryo transfer (MOET) protocol was examined in buffalo. Mixed-parity buffalo (Bubalus bubalis; 4-15-year-old; 529 +/- 13 kg LW) were randomly assigned to one of five groups (n = 6): Group 1, conventional MOET protocol; Group 2, conventional MOET with 12 h delay in injection of PGF2alpha; Group 3, implanted with GnRH agonist to block the preovulatory surge release of LH; Group 4, implanted with GnRH agonist and injected with exogenous LH (Lutropin, 25 mg) 24 h after 4 days of superstimulation with FSH; Group 5, implanted with GnRH agonist and injected with LH 36 h after superstimulation with FSH. Ovarian follicular growth in all buffaloes was stimulated by treatment with FSH (Folltropin-V, 200 mg) administered over 4 days, and was monitored by ovarian ultrasonography. At the time of estrus, the number of follicles >8 mm was greater (P < 0.05) for buffaloes in Group 2 (12.8) than for buffaloes in Groups 1(8.5), 3 (7.3), 4 (6.1) and 5 (6.8), which did not differ. All buffaloes were mated by Al after spontaneous (Groups 1-3) or induced (Groups 4 and 5) ovulation. The respective number of buffalo that ovulated, number of corpora lutea, ovulation rate (%), and embryos + oocytes recovered were: Group 1 (2, 1.8 +/- 1.6, 18.0 +/- 13.6, 0.2 +/- 0.2); Group 2 (4,6.1 +/- 2.9, 40.5 +/- 17.5, 3.7 +/- 2.1); Group 3 (0, 0, 0, 0); Group4 (6, 4.3 +/- 1.2, 69.3 +/- 14.2, 2.0 +/- 0.9); and Group 5 (1, 2.5 +/- 2.5, 15.5 +/- 15.5, 2.1 +/- 2.1). All buffaloes in Group 4 ovulated after injection of LH and had a relatively high ovulation rate (69%) and embryo recovery (46%). It has been shown that the GnRH agonist-LH protocol can be used to improve the efficiency of MOET in buffalo.