Anoestrus prevention in sows after first and second parturition

The procedure of prevention of anoestrus after the weaning of piglets was verified in 389 experimental and 332 control sows of the Prestice breed. The set of animals under study included 77 experimental and 122 control primiparae, 68 experimental and 71 control secundiparae, and 244 experimental and 139 control multiparae (i.e. sows with three or more parturitions). The experimental sows were treated with 1000 IU of serum gonadotropin ad usum vet. -Bioveta- (PMSG) the first day after the weaning of piglets and with 300 IU of chorion gonadotropin (HCG) in the Praedyn inj. Spofa preparation together with 1 ml of Dirigestran inj. Spofa (0.000040 g LHRH) 72 hours later. Control sows were not treated with hormones. The treated primiparae and secundiparae respectively, had a significantly higher percentage of oestrus onset within 10 days after weaning and lower occurrence of anoestrus over 10 days after weaning by 31.25 per cent, and 21.36 per cent respectively as compared with untreated controls. In the set of secundiparae, the studied hormonal treatment speeded oestrus onset by a significant shortening of the interval from weaning to the first insemination by 0.79 day and by a more frequent onset of oestrus within only 5 days after weaning of piglets. The values of the other criteria of reproduction studies, i.e. percentage of pregnancies after the first insemination, total number of born piglets and number of liveborn piglets converted per one litter in treated primiparae and secundiparae did not differ significantly from the control. In the set of sows with more parturitions, the preventive hormonal treatment had no statistically significant influence on the reproduction parameters under study. On the basis of the results obtained, the evaluated procedure appears suitable for prevention postweaning anoestrus in primiparae and secundiparae in those stocks and those seasons when this dysfunction affects the reproductive process more significantly, above a level economically bearable for the breeder.