193 The use of recombinant equine chorionic gonadotrophin in fixed-time artificial insemination programs in water buffaloes (Bubalus bubalis)

The use of fixed-time artificial insemination (FTAI) in the buffalo production system is recent. Although some established protocols exist, new pharmaceutical products have been recently developed that need an evaluation for this species. Protocols for synchronisation of follicular waves and ovulation to timed artificial insemination (TAI) based on the combination of gonadotrophin-releasing hormone, prostaglandin, and equine chorionic gonadotrophin (GnRH/PGF/ECG/GnRH) were used during the breeding season in buffalo female. Recently, a recombinant ECG preparation produced in Chinese hamster cells was brought to market, and has many advantages compared to its natural counterparts. This product has not been tested in buffaloes. This study aimed to compare the effect on pregnancy rates (PR) of the use of two sources of ECG: r-ECG (folli-rec) and natural (n-ECG) in buffaloes during a TAI protocol. This work was performed in March 2020, at the beginning of the breeding season on a farm located in General Donoban, Chaco, Argentina. 115 mature, grass-fed, anatomically normal buffalo (Bubalus bubalis) heifers with a weight of 495 ± 44 kg were assigned randomly to be TAI. Synchronised using GnRH/PGF/ECG/GnRH using either r-ECG or n-ECG 16 h after the last injection of GnRH, the animals were inseminated with frozen-thawed buffalo semen of one bull and inseminated with the same technician. The insemination was performed on the same day, and the time spent for the insemination procedure of all animals was 4 h. 25 days after insemination, pregnancy was evaluated by ultrasonography and recorded for analysis, a comparison of proportions test was applied, and statistically significant differences were considered when P < 0.05. PR was 55.05% and 53.19% for recombinant and natural ECG preparations, with no statistical differences (P = 0.9788). There was no effect of weight over the pregnancy. The PR reported results are quite good for the species, and there are no significant differences between the recombinant and natural PR. This allows us to have an alternative for the TAI of buffaloes. For now, the great advantage of the recombinant product is the price and the fact that it comes ready to be used. Future work in buffaloes will show whether there are effects on embryo mortality and its performance in other physiological states of the animals and synchronisation protocols.

The authors thank Universidad Nacional del Nordeste for financial support of the students.