Limited efficacy of antimicrobial metaphylaxis in finishing pigs: A randomized clinical trial.

Pigs that die from pathogens associated with porcine respiratory disease complex (PRDC) in the late finishing period represent a significant economic wastage. While it is common to apply antimicrobial metaphylaxis (AM) to control PRDC, there are few studies exploring the potential cost-saving benefits of AM. In this study we examined the value of using AM in commercially reared, late finishing pigs, from farms with endemic PRDC. A total of 732 pigs from four AIAO wean to market sources, were blocked into 2 matching cohorts, based on enrollment body weight, sex, and rectal temperature. The cohorts received either control (C) or AM (Tulathromycin 2.5mg/kg IM, Zoetis, Florham Park, NJ, USA). Post treatment weight gain over the 21 day period was used as a measure of health and productivity. The AM treated pigs in the lowest weight quartile at enrollment, showed a significantly improved weight gain over controls (18.5 kg vs. 16.4 kg, mean difference=2.1 kg, CI 1.10-3.10, p=0.005) that was not evident in any other starting weight quartiles. These results indicate that the biological advantage and associated improvement in growth efficiency associated with the use of AM against PRDC, is only conferred to a specific sub-set of animals. The economic advantage of this strategy is therefore, only likely if the indicators of potential benefit (e.g., lighter weight cohort) can be reliably established. Further studies are needed to determine whether targeted AM could be effectively applied across the industry.

Bioeconomic evaluation of sow longevity and profitability.

Sow production indicators, including litter size, litter weight, and the length of time that sows remained in the herd (sow longevity), were used to characterize sow performance and profitability. Sow longevity and production records from 148,568 sows in 32 commercial herds from Central Illinois from January 1995 to May 2001 were analyzed using survival and repeatability models, respectively. The factors studied included sow genetics (32 genetic lines), with eight major lines present in multiple herds, and the combination of herd and year of entry in the herd. The largest difference in longevity between the major genetic lines was approximately one parity. There were differences (P < 0.05) in the instantaneous sow removal rate or hazard from the major lines. These differences constitute evidence that sow longevity could be improved by using replacements from specific genetic lines. The net present value per sow (present value of future cash flows and the present value of the sow) was used to evaluate the effect of sow longevity and production traits on economic returns. Assuming a zero discount rate per parity, genetic lines with longer herd life resulted in greater profit than genetic lines with shorter herd life. This difference was reduced with increasing discount rates and was reversed with high discount rates and low net income per litter. These results suggest that the magnitude of the economic improvement attained through the use of sow genetic lines with longer longevity depends on the economic context under which the evaluation is made.

Postgraduate education in therapeutics: experience in Merseyside.

A teaching programme in therapeutics for general practitioners in Merseyside, which was led by a group of clinical pharmacologists, had as its principal aim to emphasise the importance of rational drug prescribing. The course comprised 15 sessions restricted to 25 GPs, and the topics were suggested by both the organisers and the GPs. Though each session was introduced by a clinical pharmacologist, the emphasis was an open discussion and exchange of views. This programme may serve as a pattern for other centres.