Oestrous behaviour in relation to fertility and fecundity of gilts [pigs]
1982
Cronin, G.M. | Hemsworth, P.H. | Winfield, C.G. (Animal Research Inst., Werribee, Vic. (Australia))
The reproductive performance of 2484 gilts was recorded over a 12-month period at a large intensive piggery in southern Australia. Between 29 and 35 weeks of age, gilts were examined daily for response to the back-pressure test (BPT). Those subjectively assessed as showing a moderate or high response were taken to a boar for mating. Gilts that had showed a moderate response to the BPT on their first day of mating had lower average litter size than gilts showing a high BPT response (9.05 and 9.35 piglets, respectively; P0.05). A quantitative assessment of sexual receptivity was made while the gilt was with the boar. Gilts that were mated while showing low sexual receptivity on the first day of mating had poorer farrowing rate (78.1 vs. 83.1%, respectively; P0.05), as well as lower litter size (9.03 vs. 9.35 piglets, respectively; P0.05) than gilts that were mated when showing high sexual receptivity. A moderate BPT response was followed by either low sexual receptivity or failure to mate on 81.4% of occasions, compared with 12.8% for a high BPT response. Since 75% of gilts that showed a moderate BPT response on the first day of mating showed a high response on the following day, it was concluded that mating should only be attempted when gilts exhibit a high response to the BPT. The mean farrowing rate and litter size for gilts at their first farrowing was 82.4% and 9.31 piglets (8.62 alive and 0.69 dead), respectively.
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