Effect of high levels of copper or dichlorvos during late gestation and lactation on sow productivity

Abstract

One hundred and eighty-five crossbred (Yorkshire × Landrace) sows of mixed parity were randomly assigned to be fed either a basal diet or the same ration top dressed with either 500 ppm dichlorvos, 250 ppm copper or a combination of these additives. Top dressing was conducted from the time the sows entered the farrowing crate on day 106 of gestation until they were weaned 28 d postpartum. There was no effect of treatment on the number of pigs born alive, born dead or their birthweight. However, preweaning mortality, based as a percentage of pigs found alive, was 20.3% for control sows, 13.8% for sows fed the ration top dressed with copper, 12.3% for sows fed the ration top dressed with dichlorvos and 10.6% for sows fed the ration top dressed with the combination of feed additives (P = 0.02). There was no significant effect of treatment on the percentage of fat, protein, lactose or total solids in sows milk. There was also no effect of treatment on lactation feed intake, sow weight loss through lactation, the interval between weaning and successful service, conception rate, serum copper levels or total cholesterol. HDL cholesterol levels, serum copper, zinc and iron levels were generally higher in piglets from treated sows than controls. It was concluded that feeding high levels of copper or dichlorvos, alone or in combination, during late gestation and lactation may be useful as a means of reducing preweaning mortality in baby pigs. However, the increased survival rate of baby pigs is unlikely due to alterations in the composition of sow's milk or milk yield. Key words: Sow, reproduction, copper, dichlorvos, milk