The recommendations given in this paper are based upon 45 respiratory disease outbreaks involving 2480 beef cattle on commercial farms in Scotland attended by the author. All outbreaks of respiratory disease occurred within 30 days after housing. The average duration of respiratory disease was shorter in spring-born than autumn-born calves, and there were fewer antibiotic re-treatments. The overall mortality rate was 0.4 per cent; many of the 10 calves which died were amongst the first animals in the group to be affected and showed severe respiratory signs at the first veterinary examination. The outbreaks were controlled by daily or every second day monitoring of all at-risk calves during the outbreak with antibiotic treatment administered when the calves rectal temperatures exceeded 39.6 degrees C consistent with the British Veterinary Association's (BVA) guidance on responsible use of antibiomicrobials in veterinary practice. An initial antibiotic treatment response rate greater than 95 per cent was achieved with either tilmicosin, florfenicol or a fluoroquinolone antibiotic. Recurrence of pyrexia in calves after an interval of four or more days was common (27.8%) and successfully treated with the same antibiotic. These data are interpreted that recurrence of pyrexia results from re-infection due to compromised physical defence mechanisms of the respiratory tract; however, the formation of biofilms within the respiratory tract and recrudescence of infection is another explanation. Flunixin meglumine had no significant anti-pyretic effect in these studies when measured 24 hours after injection. Whilst it is acknowledged that regular monitoring of large numbers of calves, rather than whole group metaphylactic antibiotic injection, considerably increases practitioner and farmer workload for 7-14 days, this practice is cheaper and consistent with good veterinary practice and supports the BVA's 8-point plan for the responsible use of antimicrobials in veterinary practice launched on 18 November 2009.
The average daily liveweight gain of calves recorded for 40 to 300 days after treatment for respiratory disease was commonly in excess of 1.0kg/day, and did not differ significantly from untreated non-pyrexic calves in the same group (p>0.05) indicating prompt detection of disease.
|Number of pages||4|
|Publication status||Published - Oct 2010|