Two experiments were conducted to determine the effects of sustained
-release copper (Cu) boluses on growth and reproductive traits of beef bulls.
Two groups of bulls were used in consecutive years (n=26 in experiment 1;
n=20in experiment 2). Bulls in each experiment were allotted by weight and
breed into two equally numbered treatment groups (control (C); treated (T)).
Bulls were housed together and offered a balanced diet containing 9 ppm Cu
for an ADG of 1.4 kg. Treated bulls in each experiment were given 1 Cu bolus
(Cupra,® Pitman-Moore, Mundelein, IL in experiment 1; Copasture ™ Copasture-
25 bolus Schering-Plough, Kenilworth, NJ in experiment 2). All bulls were
bled, had blood samples taken and had scrotal circumferences (SC) measured
on d 0,28,56,84,112, and 140. Blood was collected via jugular venipuncture to
determine serum Cu and plasma ceruloplasmin (Cp) concentrations. Breeding
soundness examinations (B S E) were conducted on all bulls on d 140 and 185 in
experiment 1 and d 168 in experiment 2. Body weight and SC were not affected
by treatment in either experiment (P > .05). Serum Cu and plasma Cp
concentrations were not affected by treatment in experiment 2 (P > .05).
Serum Cu was higher for the T bulls on d 56, 84, and 112 in experiment 1 (P <
.05). All serum Cu concentrations for both experiments were within the
normal range for cattle. Plasma Cp concentrations were recorded only for d 1,
112, and 140 in experiment 1 and were significantly higher for the C group on
d 112 (P < .05). There were no significant effects of treatment on the results of
the BSE (SC, percentage of normal sperm, progressive motility, and primary or
secondary abnormalities) in either experiment. These data suggest that the Cu
bolus in experiment 2 had no effect on body weight gains, SC, serum Cu and
plasma Cp concentrations, sperm normality, progressive motility, and primary
and secondary abnormalities. These data also suggest that the Cu bolus in
experiment 1 had no effect on body weight gains, SC, and sperm normality,
progressive motility, and primary and secondary abnormalities; however,
treatment in experiment 1 did increase serum Cu concentrations on some but
not all days and did not increase concentrations above the normal range for
beef cattle. The conclusion made from these experiments is that the sustained
Cu boluses used in these studies do not significantly affect growth and
reproductive traits in beef bulls with adequate Cu status.