Effet De L'Imposition De Deux RGimes Lumineux Deux Stades Physiologiques Sur Le Taux De RForme Pour Anoestrus Et Non Gestation Chez La Cochette Et La Truie

Pagé, S.; Charuest, J.-P.; Dufour, J.J.

Canadian Journal of Animal Science 68(4): 1001-1014


ISSN/ISBN: 0008-3984
DOI: 10.4141/cjas88-115
Accession: 068493511

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During a 3-yr period, Landrace-Yorkshire gilts of an average age of 225 d were randomly assigned to 4 h light — 20 h dark (4) or 16 h light — 8 h dark (16), as they entered the herd. In the gestation room (G), the two light treatments were maintained until culling or 1 wk prior to farrowing. For the lactation period (L), the gilts were either maintained on the same light treatment as the gestation or switched to the opposite one before going back again at weaning to the light treatment received in gestation. Four light treatments were then formed, namely: G4-L4, G4-L16, G16-L4 and G16-L16 and the practical consequences of such light regimens evaluated in a commercial herd. In gilts, the culling rate for anestrus (at 304 d of age) was 6.6% for the 956 gilts available for the study and was unaffected by photoperiod imposed during gestation. The culling rate for failure to maintain pregnancy was 4.7% for the 1150 gilts available and was higher (P < 0.01) in gilts exposed to the 4 h light (G4). In primiparous sows, the culling rates for anestrus (40 d after weaning) and failure to maintain pregnancy were 10.7% and 6.2%, respectively, for the 475 and 678 sows available for the study. The culling rates for anestrus and failure to maintain pregnancy were higher for sows exposed to the 16 h light in lactation (L16, P < 0.06 and P < 0.02, respectively). After two and three farrowings, the culling rates were negligible for all treatments. Among females culled for anestrus, 62% of gilts and 58% of primiparous sows showed luteal structures (corpora lutea and/or corpora albicantia) at slaughter and were unaffected by treatments. Among females culled for anestrus and failure to maintain pregnancy, 24% of gilts and 19% of primiparous sows had genital abnormalities. These data indicate that the effect of photoperiod on the culling rate for reproductive failure in swine was dependent upon parity and physiological stage at which it is imposed. Key words: Gilt, sow, photoperiod, culling, anestrus, failure to maintain pregnancy