|Abstract or Summary
- Two concurrent studies were conducted to evaluate the effect
of selenium (Se) supplementation on beef cows. Trial 1 was designed
to evaluate the safety and efficacy of two intrareticular Se supplementation
delivery systems. Trial 2 was designed to evaluate the
transfer of Se across the placenta and through the colostrum in beef
One hundred fifty, selenium (Se) deficient, pregnant crossbred
beef cows were assigned to 1 of 4 treatment groups: group A, negative
control; group B, 1 Dura-Se bolus at 0 and 119 d; group C, 1 Dura-se
at 0 d; and group D, 2 Permasel pellets at 0 d. Cattle were maintained
on selenium deficient pastures or forages prepared from these
pastures. Blood samples were collected from cows before treatment
administration (0 time) and thereafter at 28, 52, 119, and 220 d.
Calves from cows selected for data collection above were sampled at
birth. Blood samples were collected from calves, prior to suckling,
and were analyzed for whole blood selenium (WBSe) concentration.
Colostrum samples were collected from dams and analyzed for total Se
concentration. Additional samples were collected from calves 24-48
hours post suckling and analyzed for WBSe concentration and serum
creatine kinase (CK) level. Weight and health data were recorded on
all cows at each blood collection date. Birth weight, sex, and
health were recorded on all calves at parturition.
Whole blood selenium concentration of cows from all supplemented
groups were significantly higher (P<.001) than controls at all sample
dates after treatments began. By the end of the 220 d study, treatment
group B attained significantly higher (P<.001) WBSe concentrations
than any other group. Calves from all Se treated groups had
significantly (P<.001) higher WBSe concentrations, both pre- and
post-suckling, than controls. Post-suckle WBSe concentration of
calves were not significantly (P>.05) different than pre-suckle
concentrations in any of the groups. Colostrum selenium concentration
from Se supplemented cows were significantly (P.001) higher
than from control cows. No difference (P>.05) was determined in
plasma CK activities or birth weights between groups of calves.
Seven animals died, two of which showed signs of Se deficiency.
Necropsy of 5 calves provided no evidence linking these deaths to
selenium treatments. No differences (P>.05) in mortality between
groups were determined.