Effect of molybdenum/sulfur-induced copper deficiency upon enzyme levels and reproduction in heifers

To evaluate the effects of molybdenum (Mo)- and sulfur (S)- induced copper (Cu) deficiency, 99 prepubertal heifers were allotted into two groups. Treated heifers (n = 72) were fed a grass hay naturally high in Mo (Mo = 8 ppm and Cu = 3.2 ppm). Sulfur was supplemented to achieve a dietary level of .3%. Control heifers (n = 27) received a grass hay with normal levels of Mo (Mo = .47 ppm and Cu = 1.5 ppm). Copper was supplemented to achieve a dietary level of 8 ppm. Diets were fed for a period of 163 d. Liver samples were collected and analyzed for total Cu. Copper-containing enzyme activity (ceruloplasmin and Cu,Zn-superoxide dismutase [Cu,Zn-SOD]), and progesterone were measured in blood serum. Heifers in the treated group had lower concentrations of liver Cu and decreased ceruloplasmin activity, with no differences noted in Cu,Zn-SOD activity or onset of puberty. No difference was detected in first-service conception rate following artificial insemination (AI). Overall AI pregnancy rate tended to be higher for control heifers

The effects of slow-release copper boluses on cow reproductive performance and calf growth

Two Kansas cow/calf herds known to be copper deficient were utilized to examine the effect of slow-release copper boluses. In herd I, 34 spring-calving cows and calves were divided into a treated and control group at 3-4 months following calving. In herd II, 1106 fall-calving cows and 172 calves were divided into a treated and control group at 3-4 months following calving. In both herds, cow liver and serum samples were collected and assayed for copper and iron. Cows in herd II were also examined for various reproductive parameters. Calf ADG was monitored over a 42-day treatment period in herd I, and a comparison of calf weaning weights was made in herd II. We concluded that copper boluses elevated liver copper levels. However, no effect on reproductive performance was noted, and calf performance was adversely affected

Interrelationship between copper and bovine health

Trace mineral nutrition is important to production efficiency and animal health. Trace mineral imbalances may be the roots of many diagnosed or undiagnosed problems in a herd. The low cost of a complete mineral analysis when compared to production losses encourages its use in the evaluation of any bovine herd in which trace mineral imbalances are suspected. A systematic gathering of information on mineral intake, antagonist intake, and serum and tissue values is necessary in order to make a diagnosis and a rational treatment decision. It is important to understand the complex interactions between minerals so that supplementation with one element does not make a complicated situation worse. Because of the many interactions between nutrients and the cost of mineral supplements, recommending use of higher levels of trace minerals in a ration or supplement without a complete diagnosis is economically and nutritionally unjustified

The effect of dietary zinc level and source on yearling bull growth and fertility

To study the effect of dietary zinc level and source on bull growth and fertility, 325 yearling Angus bulls were allotted by weight into six pens (three pens of heavy and three pens of lightweight bulls). The three supplemental zinc (Zn) treatments were 1) 40 ppm inorganic Zn all supplied by Zn sulfate (ZnI); 2) 40 ppm Zn with 1/3 supplied by Zn proteinate and 2/3 supplied by Zn sulfate (ZnPI); and 3) 60 ppm ZnI all supplied by Zn sulfate (ZnHi). Initial and final liver biopsies (10 per pen) were collected and analyzed for zinc concentration. Individual weights and scrotal circumferences also were recorded at the start and conclusion of the trial. Bull s intended for public sale (n=167) had their semen collected and evaluated for motility and morphological abnormalities. Bulls with percent normal sperm cell counts of less than 70% or with motility scores less than fair (motility scores = poor, fair, good, very good) were considered classification deferred (CD). Following 126 days of treatment, ZnHi bulls had a greater (P=.058) percent change in liver Zn concentration than ZnI, but similar increases to ZnPI. No difference s in bull ADG or percent change in scrotal circumference were detected. ZnPI and ZnHi bulls had a higher (P<.05) percent of normal sperm cells than ZnI bulls. ZnPI and ZnHi treatments had fewer (P<.05) CD bulls than ZnI. In all fertility measures observed , bulls receiving the Zn proteinate/Zn sulfate combination at 40 ppm had improved semen quality when compared to bulls supplemented with 40 ppm Zn sulfate