Factors affecting postweaning oestrus in the sow
Karlberg, K.
Nordisk Veterinaermedicin 32(5): 185-193
1980
ISSN/ISBN: 0029-1579 PMID: 7189881 Document Number: 168345
Data on 3019 weaned sows were analysed. Of primiparous sows, 31.2, 52.3, 65.4, 78.7 and 94.3% exhibited oestrus within 5, 7, 14, 28 and >35 days resp. of weaning v 52.3, 77.7, 85.0, 92.9 and 98.1% of multiparous sows. Of 26 primiparous and 23 multiparous sows slaughtered an average of 48 days after weaning, due to anoestrus, 12 and 18 resp. had functional corpora lutea. The inverval between weaning and oestrus was significantly correlated with herd size (-0.33) for all sows, and differed significantly between seasons for primiparous sows (17.1 days in July-Sep. and 20.2 days in Oct.-Dec. v 11.9 and 11.7 days resp. in Jan.-Mar. and Apr.-June). Length of the interval between weaning and 1st oestrus was not affected by the presence of a boar in the herd, lighting conditions, length of lactation or housing of the sows after weaning. For sows fed at a high level during the 1st wk after weaning, the interval from weaning to oestrus averaged 8.5 days v 11.5 for sows fed at a low level (P<0.01).