Duration of tolerance reflex in sows depending on birth quarter, sexshare and body weight at birth, and potential fertility
1999
Stasiak, A. | Walkiewicz, A. | Kamyk, P. | Wielbo, E. (Akademia Rolnicza, Lublin (Poland). Katedra Hodowli i Technologii Podukcji Trzody Chlewnej)
1152 of Polish Landrace and 576 Polish Large White gilts were divided into groups according to: (1) season of birth (4 three-month periods); (2) litter sex ratio (30, 50 and 70 gilts); (3) birth weight (1000 g, 1000-1200 g and 1200 g). Sexual activity of gilts was observed from 150 days of age for 3 spontaneous oestrus cycles. Gilts were then divided into groups depending on the length of the 3rd oestrus (24, 36, 48, 60 and 72 h). Half the gilts were slaughtered after the third oestrus between the 5th and the 10th day of the next oestrus cycle and the number of corpora lutea was recorded. The other gilts were mated and slaughtered between days 35 and 40 of pregnancy and the number of embryos was recorded. Fertility was not affected by season of birth, sex ratio, birth weight or breed. However, fertility was affected by the duration of the 3rd oestrus
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