THE EFFECTS OF LOW DIETARY COPPER INTAKE DURING PREGNANCY ON PHYSIOLOGICAL FLUIDS AND REPRODUCTIVE-PERFORMANCE OF FIRST-LITTER GILTS

Seven pairs of first littermate gilts were used to study the influence of low copper supply and Pregnancy on physiological fluids and reprod uctive performance of first-litter gilts. They were fed semi-purified diets containing either 2.13 or 12.25 mu g/kg of Cu from 30 days of ge station through two weeks of lactation. Low-Cu gilts had lower plasma Cu in early- and mid- gestation and farrowed piglets with lower plasma Cu and higher plasma Zn concentrations (p<0.05). Plasma Pe and Mn con centrations were not affected by Cu supply (p>0.05). Plasma Cu and Fe levels of newborn piglets were lower than those of their darns (p<0.05 ) but this was not true for plasma Zn and Mn (p>0.05). Low-Cu gilts ha d lower Cu and higher Zn content in colostrum and also lower Cu in mil k than control gilts (p<0.05). No significant differences were found i n Fe and Mn levels in colostrum and milk between the two treatments (p >0.05). Colostrum was richer in Cu and Zn than milk (p<0.05) but not i n Fe and Mn (p>0.05). The low-Cu diet did not affect (p>0.05) weight c hanges during pregnancy. The duration of parturition was shorter for l ow-Cu than for control gilts (3.19h vs. 5.71h, p<0.05). Control gilts farrowed larger litters than low-Cu gilts (9.71 vs. 7.57 piglets, p>0. 05). There were no significant differences in live litter weights at b irth, one wk. or two wks. of age (p>0.05). The results indicated that a low-Cu diet and pregnancy had some effect on plasma, colostrum and m ilk mineral concentrations, as well as on litter size of gilts. An int eraction between Cu and Zn was found.