[Cu, Co and Se nutritive value of compound trace elements controlled-release boluses for grazing ruminants]

Twenty cattle with the similar old and weight were randomly divided into two groups for 135 d, while twenty white goats were randomly divided into two groups for 60 d. Each group consisted of ten animals, and the ratio of male and female was same. Each of animals in one group was administered an initial bolus, used as treatment group. In the other group, animals were not administered the bolus, used as control group. In the cattle feeding experiment, five cattle of each group was supplemented feed, and the other five cattles were not supplemented feed. In the goat feeding experiment, all of goats were grazing, and not supplemented feed. At the end of goat feeding experiment, three goats of each group were randomly selected to slaughter. Liver, kidney, spleen, muscle, heart, blood and matter in the rumen were collected to assay for Cu, Co and Se. The results showed that the average daily gain of cattle supplemented and no supplemented feeds in the administered and no administered group was 483.00 g, 302.83 g, 445.84 g and 282.23 g, respectively. There had significantly difference between the administered group and no administered group(p < 0.05). The average daily gain of goats in the administered and no administered groups was 68.83 g and 50.67 g, and significant difference between the two groups (p < 0.01). Administering the boluses improved the contents of Cu, Co and Se in the tissues of goats, significantly.