Differences in copper status and copper metabolism among Angus, Simmental, and Charolais cattle.

Thirty-eight pregnant Angus, Charolais, and Simmental heifers and their offspring were used to determine whether differences in Cu metabolism existed among breeds. The heifers were fed either 0 or 10 mg of supplemental Cu per kilogram of DM. Calves were born between d 70 and 125 of the 280 d experiment. There were few differences among breeds in plasma Cu concentration and ceruloplasmin activity when heifers were fed supplemental Cu. When heifers were not fed supplemental Cu, Angus heifers had greater (P < .10) plasma Cu concentrations than Simmental heifers from d 0 until 140 and Charolais heifers from d 28 until 140. Angus heifers had greater (P < .10) ceruloplasmin activity than Charolais and Simmental heifers between d 28 and 196. When dams were fed supplemental Cu, Angus calves had greater (P < .10) plasma Cu concentrations than Simmental calves on all days tested and Charolais calves on d 252 and 280. Ceruloplasmin activity of Angus calves in the Cu-supplemented group was greater (P < .10) than that of Charolais calves on d 224 and 280 and Simmental calves from d 224 until 280. Angus calves born to dams not receiving supplemental Cu had greater (P < .10) plasma Cu concentrations and ceruloplasmin activities than Simmental calves on all days tested. Angus calves also had greater (P < .10) plasma Cu concentrations than Charolais calves on d 196 and greater ceruloplasmin activities than Charolais calves from d 168 until 224. Eight Angus and eight Simmental steers were used to evaluate apparent Cu absorption and retention.(ABSTRACT TRUNCATED AT 250 WORDS)