
TY  - JOUR
A1  - Sillence, M. N. 
A1  - Matthews, M. L. 
A1  - Badran, T. W. 
A1  - Pegg, G. G. 
T1  - Effects of clenbuterol on growth in underfed cattle
JF  - Australian Journal of Agricultural Research
JO  - Aust. J.  Agric. Res.
Y1  - 2000
VL  - 51
IS  - 3
SP  - 401
EP  - 406
KW  - &#946;-adrenergic agonists, &#946;-adrenergic receptors.
UR  - https://doi.org/10.1071/AR99109 
N2  - This study examined the effects of clenbuterol on the growth of young cattle (160 kg) that were fed a restricted quantity of a low-quality hay to simulate dry-season pasture conditions in the tropics. Twenty Brahman steers were used. Ten control animals lost an average of 0.24 kg/day in the first 17 days, then maintained their liveweight for the remaining 21 days of the experiment. By contrast, 10 clenbuterol-treated animals lost 0.3 kg/day for the first 17 days of the experiment, then continued to lose weight at a steady rate of 0.15 kg/day. In control steers, plasma concentrations of urea-nitrogen decreased over the course of the experiment, and this effect was accelerated by clenbuterol treatment (P &#60; 0.05). There were no marked changes in plasma concentrations of glucose, potassium, or Nt-methylhistidine in response to clenbuterol treatment. Clenbuterol had no effect on &#946;2 -adrenoceptor density in the longissimus muscle, but there was a marked increase in &#946;2-adrenoceptors in both groups of cattle over time. Despite their loss of liveweight, the carcasses of clenbuterol-treated cattle were not lighter than controls (74.3 v. 72 kg, respectively) and contained 10% more protein (P &#60; 0.05). This was reflected by a trend towards increased weight of the biceps femoris muscle (9%; P &#60; 0.1). These findings are consistent with clenbuterol causing a drive to deposit muscle protein at the expense of other tissues, even when dietary protein and energy are limited. 
ER  -

