Copper metabolism in goat-kid relationship at supplementation of inorganic and organic forms of copper

Abstract

The aim of the experiment was to compare the effect of inorganic and organic forms of copper (Cu) supplementation on Cu status of goats and their kids, colostrum and milk composition and quality, and on the Cu concentrations in amniotic fluids and fetal membranes. The experiment involved 22 clinically healthy pregnant goats with similar mean Cu concentration in blood serum. Goats were divided into 3 groups: E1, E2, and C. Basal feed ration differed only in Cu form and concentration in a grain mixture. The goats of experimental groups E1 and E2 received the supplement of Cu sulfate and Cu chelate, respectively. Control group C was without Cu supplementation. Blood samples from goats and kids were collected on the day of parturition (day 0; in kids before colostrum intake) and on days 2, 7, and 21 postpartum. On the same days the kids were weighed. Colostrum or milk samples were collected on days 0, 5, and 30. During delivery, also samples of amniotic fluids and fetal membranes were collected. Both forms of Cu supplementation resulted in higher average concentration of Cu (compared to control group) in blood serum of goats (19.5 ± 1.7 and 18.5 ± 2.5 vs. 15.2 ± 4.4 µmol/l, respectively) and blood serum of kids (6.7 ± 0.8 and 6.0 ± 0.5 vs. 6.0 ± 1.0 µmol/l, respectively). Significant differences in Cu serum concentration on the day of parturition in goats were observed in group E1 compared to control (P < 0.05) and also in kids of group E1 compared to group E2 and control (P < 0.05). The Cu concentration in the blood of kids on the day of parturition was significantly (P < 0.01) lower compared to that in maternal blood. Percentages of Cu concentration in the blood of kids in groups E1, E2, and C were 34, 33, and 39% of that in maternal blood. The results of Cu concentration in blood serum of goats on days 2, 7, and 21 were without significant differences between groups. Significantly higher Cu serum concentrations (P < 0.05) were observed in kids on day 2 in group E1 compared to control group and also on day 21 in group E1 compared to group E2. Colostrum Cu concentration was significantly (P < 0.05) higher in group E1 (10.6 ± 3.3 µmol/l) compared to group E2 (7.1 ± 1.5 µmol/l). There were no significant differences observed in Cu concentration in amniotic fluids and fetal membranes. The kids on both forms of Cu supplementation (on day 0 in group E1 and on days 2, 7, and 21 in group E2) had significantly (P < 0.05) higher average weight than the kids from control group. Our results are suggesting that the inorganic form of Cu (copper sulfate) is more efficient than organic (copper chelate) in influencing the Cu metabolism in goat-kid relationship and that Cu supplementing has a positive effect on the weight of kids.

Keywords

• trace elements
• organic copper
• inorganic copper
• ruminants
• colostrum
• milk
• fetal membranes
• amniotic fluid
• weight gains