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 gil ts 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 cont aining 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 antibioti cs (55 mg/kg of chlortetracycline in the gestation diet, 110 mg/kg eac h of neomycin and oxytetracycline in the lactation diet). Sows continu ed 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 lactat ion. A total of 86 and 81 litters were farrowed by control and Cu-trea ted sows, respectively. Seven control and eight treated sows completed six parities. Farrowing rate (no. farrowed/no. bred) was less (P < .0 5) in gilts fed high Cu, but culling rate was reduced (P < .01) in sow s receiving the high Cu diet. Sows fed high Cu diets were heavier in B W on d 108 of gestation before their second (P < .05) and third to fif th litters (P < .01) than controls. Sows fed high Cu diets farrowed la rger 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 s ows. Total litter weight at weaning was 9% greater (P < .05) in sows f ed Cu. Survival to weaning was the same (85% of pigs born alive) for b oth treatment groups. The interval from weaning to estrus was approxim ately 1 d less for sows fed Cu (P < .10). Concentrations of Cu were hi gher (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, excep t for a possible decrease in farrowing rate of gilts, the feeding of 2 50 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.