The efficacy of low doses of tylvalosin was investigated by J. Homedes of Universidad CEU Cardenal Herrera in Valencia and co-authors there and with Esteve Veterinaria in Barcelona. Their paper, published in Poultry Science, examined the effects on the control of clostridiosis in broilers and on productive parameters.

The study was carried out under field conditions in a commercial farm, and 1,440 as-hatched Ross-308 broilers were included. Broilers were randomly distributed into 24 experimental four-metres-square pens (60 broilers/pen).

Pens were randomised to the three treatment groups:

1. tylvalosin 10mg per kg live bodyweight for two days
2. positive control (tylosin for two days), and
3. negative control (no treatment).

The drugs were provided in the water supply.

Mortality, individual bodyweight and feed intake were assessed. Clostridium presence was assessed in faecal and caecal samples, coccidial oocyst counts were assessed in faecal samples and bacterial diversity was assessed in ileal content.

Live bodyweight at 42 days was significantly better in the tylvalosin group than in tylosin and no-treatment groups, with tylvalosin-treated broilers reaching 80 to 100g higher final live weight. Average daily gain results mirrored bodyweight findings. The improvement of feed conversion rate with tylvalosin amounted to 0.13 and to 0.10 versus tylosin and no-treatment, respectively, with mortality being similar in all groups.

There were significant reductions in sulphite-reducing Clostridium and Clostridium perfringens counts in tylvalosin and tylosin groups versus the no-treatment group were observed in caecal content samples.

Garcés-Narro and co-authors concluded from their results that tylvalosin, at doses substantially lower than registered for poultry in Europe, has proven effective in controlling the colonisation of the caecum by Clostridium ssp. in broilers, improving some measures of productive performance.

Reference

^{Garcés-Narro C., J. I. Barragán, M.D. Soler, M. Mateos, M.C. López-Mendoza and J. Homedes. 2013. Efficacy of low-dose tylvalosin for the control of clostridiosis in broilers and its effect on productive parameters. Poult. Sci. 92(4):975-978. doi: 10.3382/ps.2012-02750}