Effect of gonadotropins during hot summer season given at different times after weaning on selected reproductive indicators of the sow
2008
Franek, S.P.,Bilkei Consulting, Duebendorf (Switzerland) | Bilkei, G.,Bilkei Consulting, Duebendorf (Switzerland)
The experiment was performed on a large indoor herd during a hot season period. The post-weaning sows (F1 and F2 of Large White x Landrace mated to Duroc boars were divided into four groups of similar body condition, lactation length and parity and were treated as follows: Group 1: sows (n=420) were injected subcutaneously with 400 I.U. of Gonadotropinum sericum (PMSG) and 200 I.U. of Gonadotropinum chorionicum (HCG) one day after weaning. Group 2: sows (n=405) received subcutaneously 4 mL of saline injection one day after weaning. Group 3: sows (n=425), purposely chosen from among animals that did not show heat within 7 days after weaning, were treated on day 7 post-weaning with PMSG and HCG as the animals in group 1. Group 4: sows (n=415), purposely chosen from among animals that did not show heat within 7 days after weaning, were treated on day 7 post-weaning as group 2. Sows expressing oestrus, sows ovulating after treatment, treatment to oestrus intervals and follicular sizes were evaluated. The number of sows expressing oestrus, sows ovulating, and treatment to oestrus intervals differed between the groups (group 1 vs. 2: P less than 0.05, group 3 vs. 4: P less than 0.01). Group 3 sows had smaller (P less than 0.05) follicular diameters compared to the sows that were treated one day after weaning. Group 4 sows had a smaller follicular diameter than group 1 animals (P less than 0.001) and 3 (P less than 0.01). The present results show that the gonadotropin treatment one day after weaning or in the case of anoestrus 7 days after weaning overrides the negative effects of the hot summer season and effectively prevents seasonal infertility of the breeding sow.
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