LONG-TERM EFFECTS OF FEEDING A HIGH COPPER DIET TO SOWS DURING GESTATION AND LACTATION

An experiment was conducted to assess the long-term effects of feeding a high Cu diet to sows during gestation and lactation. Fifty-five gilts averaging 152 kg BW and 10.3 mo of age were allotted on d 47 after mating to diets consisting primarily of corn and soybean meal and containing 0 to 250 ppm of added Cu (as CuSO4.5H2O). Both diets contained 8.8 ppm of Cu from the trace mineral mix, and both contained antibiotics (55 mg/kg of chlortetracycline in the gestation diet, 110 mg/kg each of neomycin and oxytetracycline in the lactation diet). Sows continued on their respective diets throughout gestation and lactation, until culled from the herd or until they farrowed their sixth litter. Feed intake averaged 1.90 kg/d during gestation and 4.82 kg/d during lactation. A total of 86 and 81 litters were farrowed by control and Cu-treated sows, respectively. Seven control and eight treated sows completed six parities. Farrowing rate (no. farrowed/no. bred) was less (P < .05) in gilts fed high Cu, but culling rate was reduced (P < .01) in sows receiving the high Cu diet. Sows fed high Cu diets were heavier in BW on d 108 of gestation before their second (P < .05) and third to fifth litters (P < .01) than controls. Sows fed high Cu diets farrowed larger litters of pigs (P < .10) and the pigs were 9% heavier at birth (P < .001) and 6% heavier at weaning (P < .01) than pigs from control sows. Total litter weight at weaning was 9% greater (P < .05) in sows fed Cu. Survival to weaning was the same (85% of pigs born alive) for both treatment groups. The interval from weaning to estrus was approximately 1 d less for sows fed Cu (P < .10). Concentrations of Cu were higher (P < .001) in the liver (1,899 vs 442 ppm of DM) and kidneys (59 vs 34 ppm) in sows fed high Cu diets. The results indicate that, except for a possible decrease in farrowing rate of gilts, the feeding of 250 ppm of Cu to sows for an extended period of time had no detrimental effect on reproductive performance; in fact, feeding high dietary Cu to sows increased birth and weaning weights of their pigs.