Hr. Bingham et al., Evaluation of the ability of orally administered aspirin to mitigate effects of 3-methylindole in feedlot cattle, AM J VET RE, 61(10), 2000, pp. 1209-1213
Objective-To evaluate the ability of orally administered aspirin to mitigat
e 3-methylindole (3MI)-induced respiratory tract disease and reduced rate o
f gain in feedlot cattle.
Animals-244 beef cattle.
Procedure-In a masked, randomized, controlled field trial, calves were untr
eated (controls) or received a single orally administered dose of aspirin (
31.2 g) on entry into a feedlot. Serum 3 MI concentrations were measured on
days 0, 3, and 6. Rumen 3MI concentration was measured on day 3. Cattle we
re observed daily for clinical signs of respiratory tract disease. Lungs we
re evaluated at slaughter for gross pulmonary lesions.
Results-Mean daily gain (MDG) in cattle treated with aspirin, compared with
control cattle, was 0.06 kg greater in the backgrounding unit and 0.03 kg
greater for the overall feeding period. Neither serum nor rumen 3MI concent
rations appeared to modify this effect. Cattle treated with aspirin were mo
re likely to be treated for respiratory tract disease. Mortality rate, gros
s pulmonary lesions, and serum and rumen 3MI concentrations were similar be
tween groups. Increased rumen 3MI concentration was associated with a small
difference in risk of lung fibrosis.
Conclusions and Clinical Relevance-Cattle given a single orally administere
d dose of aspirin on feedlot entry had higher MDG in the backgrounding unit
and for the overall feeding period, but this finding could not be attribut
ed to mitigation of effects of 3MI. This may have been influenced by low pe
ak 3MI production and slow rates of gain.