|Loan, Raymond - TAMU, COLLEGE STATION, TX|
Submitted to: American Association of Bovine Practitioners Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: August 17, 2001
Publication Date: N/A
Technical Abstract: The prevention of bovine respiratory disease complex (BRDC) by simultaneous Mannheimia/Pasteurella vaccination and metaphylaxis (dual prophylaxis) at the first point of stocker-feeder calf assembly was evaluated. Experiment 1 was a comparison of no treatment, tilmicosin phosphate metaphylaxis alone, Mannheimia haemolytica biotype A, serotype 1 (MhA1) vaccination alone, and simultaneous metaphylaxis and vaccination (dual prophylaxis). Experiment 2 was a comparison of metaphylaxis alone versus dual prophylaxis. The study involved high risk, assembled calves of 410 lbs average weight (Experiment 1) and 414 lbs (Experiment 2). In Experiment 1, dual prophylaxis compared to no treatment resulted in an increase in healthy calves (28% vs 4.5%) during the receiving period (P<0.05). Compared to untreated control calves there was a reduction in calves experiencing two or more episodes of BRDC or death (39% vs 82%) during the same period (P<0.01). Tilmicosin alone also reduced the number of calves (50% vs 82%) experiencing this severe form of BRDC (P<0.05). In Experiment 2, dual prophylaxis compared to metaphylaxis alone resulted in more calves with no clinical illness (56% vs 33%) during the feedyard receiving period (P<0.05). Also with dual prophylaxis fewer calves (23% vs 47%) experienced two or more clinical episodes or died of BRDC (P<0.01). It is suggested that dual prophylaxis at first point of assembly of calves is a valuable management option for keeping high risk stocker-feeder calves healthy throughout their transition from ranch to feedyard.