The Study of Fixed-time Artificial Insemination Using PMSG+HCG in Multiparous Sows
To explore the effects of PMSG + HCG on the conception rate,litter size,and post-weaning estrus of multiparous sows in timed AI,120 multiparous crossbred sows with 2 or more parities,in good physical condition,and without vaginal inflammation were randomly divided into 2 groups,each with 60 heads.Control group did not receive hormone treatment and was mated after natural estrus identification;Experimental group was treated with a timed AI program using PMSG + HCG.The conception rate,litter size,and post-weaning estrus of the sows in the two groups were statistically analyzed.The results showed that the conception rate of the sows in control group was 78.33%,and the conception rate of the sows in experimental group was 91.67%,with a significant difference between the two groups.The total number of piglets born in control group was 581,with a litter size of 12.36±3.40,and the total number of piglets born in experimental group was 691,with a litter size of 12.79±3.38.Although there was no significant difference between the two groups in terms of litter size,the t value of the experimental group was greater than that of the control group,indicating that the experimental group had an advantage over the control group in terms of litter size.The natural estrus rate after weaning in control group was 88.89%,and the natural estrus rate after weaning in experimental group was 90.38%.There were no significant differences between control group and experimental group in terms of post-weaning estrus rate.