Fixed timed artificial insemination during different seasons in Argentina (2016; 2019)

BANDEO, A. S.; BERDUGO, J. A.; CRUDELI, G. A.; MALDONADO-VARGAS, P.; KONRAD, J. L.

REPRODUCTION FERTILITY AND DEVELOPMENT

CSIRO PUBLISHING

Año: 2021 vol. 33

1031-3613

The objective of this work was to evaluate pregnancy rates in buffaloes subjected to fixed-time AI (FTAI) during the year in Argentina. The data analysed was collected between 2016 to 2019 in a farm located in Paso Florentin City (27°20′33″ latitude and 58°08′27″ longitude) in Corrientes, Argentina. The animals were grazing native pastures (Andropogon lateralis, Paspalum almum). Ten fixed-time AI (FTAI) sessions were performed, 6 within the favourable season (BS, March?June) and 4 in the outbreeding season (OBS; September?December). Murrah and Mediterranean breed (n = 141) buffaloes were used. All animals were healthy, without anatomical alterations and with normal reproductive tracts. Heifers (H), adult females with calf (AFC), and dry buffaloes (DB) were used. The average (± s.d.) weight of the animals were 459.0 ± 37.5 kg, 581.3 ± 53.6 kg, and 583.3 ± 53.1 kg, respectively. The presence of corpus luteum (CL) or a dominant follicle (≥8 mm) at the beginning of the protocol was recorded. BS ovulation induction: Ovsynch (n = 182); Day 0 gonadotrophin-releasing hormone (GnRH; 100 μg, busereline acetate), Day 7 prostaglandin F2α (150 μg, cloprostenol), Day 9 GnRH and FTAI 16 h after the last GnRH injection. For the OBS (n = 85): Day 0 intravaginal device (700 mg of P4) + oestradiol benzoate (0.2 g), Day 8 removal of the device + prostaglandin F2α + oestradiol cypionate (0.1 g) + eCG (400 IU) and Day 10 FTAI (52?56 h) after device removal. Semen from 5 bulls of proven fertility was used, and the same technician performed all the inseminations. A specifically designed format to record the data were used and the average ± s.d. of the physiological and the meteorological parameters were calculated. Pregnancy was detected 40 days after FTAI using ultrasonography. Comparison within variables were performed using ANOVA and Tukey test, with InfoStat-Statistical Software. A total of 267 inseminations were performed, and the overall pregnancy rate (PR) was 37.45% (100/267). Comparing BS with OBS, PR were 40.7% (74/182) and 30.6% (26/85) (P