Lactational oestrus in the sow 1. The effect of the interval between farrowing and grouping on the incidence and timing of lactational oestrus in sows

Abstract

ABSTRACTIn an experiment on the occurrence of lactational oestrus, 92 multiparous Camborough sows and their litters were grouped in multi-accommodation pens at either 10, 15, 20 or 25 days post partum. The sows were fed ad libitum on a proprietary diet containing 160g crude protein per kg. A boar was introduced to the group the day following grouping. Weaning took place at 42 days post partum.All sows except one showed oestrus in the period from grouping to weaning. Lactational oestrus occurred on average 10·9, 9·2, 12·2 and 7·3 (s.e. of difference 1·3) days after grouping (P < 0·05), and 21·0, 24·6, 32·2 and 32·8 (s.e. of difference 1·4) days following farrowing (P < 0·001) for the grouping treatments at 10, 15, 20 and 25 days. Subsequent farrowing rates were 48, 61, 78 and 45% and the number of pigs born 9·2, 9·5, 12·2 and 10·6 (s.e. of difference 1·3), respectively.Piglet mortality in the suckling litters was higher on the day 10 treatment than either the day 20 or day 25 treatment. This led to a significantly lower litter weight for the day 10 treatment compared with any of the other treatments.