The experiment was carried out in two stages with the objective of determining the effect of parenteral supplementation of 50 mg Cu on the reproductive behaviour of both hypo-and normocupremic cyclic female cattle. In the first stage, 62 hypocupremic, cyclic animals were selected, 32 heifers (16 in the control group and 16 in the treatment group) and 30 cows (12 in the control group and 18 in the treatment group). In the second stage, 98 normocupremic, cyclic heifers were selected (49 in the control group and 49 in the treatment group). 50 mg of Cu were administered to the animals in the treatment groups parenterally (subcutaneously) every two months until three successive applications were completed, while the control animals were not given copper supplementation. The effects of the copper therapy on cupremia and the percentage of heat and gestations presented were determined. The relative risk of treated animals of presentating anoestrus and service repetition was evaluated by the formation of a 2 × 2 contingency table and the application of a χ² test. The levels of serum copper were compared using a t-test, while heat and gestations were compared using a proportion comparism test. The parenteral administration of 50 mg Cu in hypocupremic, cyclic heifers and cows led to significant increases of cupremia (P<0.001) and the percentages of heat presentations and gestations (P<0.01); in the normocupremic animals, there were significant increases in the values of serum copper (P<0.0001), heat presentations (P<0.01) and gestations (P<0.001), especially in animals with cupremia values below 14 mmol/L. The treatment reduced the relative risk of reproductive disorders. It is concluded that the parenteral administration of 50 mg Cu in female cattle with Cu blood serum level <14 mmol/L increased cupremia and the percentages of heat presentations and gestations, and reduced the relative risk of reproductive disorders.

The objective of the present study was to determine the parenteral dosage of the trace mineral copper (Cu) which re-establishes serum and hepatic levels in hypocupperhemic animals without causing intoxication in the liver or residuals in milk. The experiment was carried out in two phases; in the first phase, 20 hypocupperhemic animals were used. Those were divided into 4 groups of 5 cows each: 3 groups which received 25, 50 and 100 mg of Cu respectively and 1 control group without supplementation, but with induced copraemia 5 days before and after the treatment. The milk of the cows treated with 100 mg Cu was examined for residuals of this element for one month. In the second phase, 25 animals were selected and divided into 5 groups of 5 cows each: 1 control group and 4 groups which received 25, 50, 100 and 200 mg of Cu respectively. The impact of this Cu dosages on liver reserves of this element, on hepatic enzymes (alanine-amine-transaminase, aspartate-amine-transferase, alkaline phosphatase and glutamate dehydrogenase) and on bilirubin was analyzed. The groups treated with 50 and 100 mg Cu showed increased levels in blood serum and hepatic tissues (P<0.05) in comparison to the control group and the one treated with 25 mg, obtaining the physiological level considered normal in cows during 60 days without an effect to the level of Cu in milk or to the liver's enzymatic activity. We conclude that treatment with this dosage results in a restoration of the Cu concentration in blood serum and hepatic tissues without toxic effects or residuals.