title: Effect of long-term oral administration of a low dosage of clenbuterol on body fat percentage in working and nonworking adult horses.
abstract: OBJECTIVE
  To determine the anabolic and lipolytic effects of a low dosage of clenbuterol administered orally in working and nonworking equids.
  
  
  METHODS
  8 nonworking horses and 47 polo ponies in active training.
  
  
  METHODS
  Each polo pony continued training and received either clenbuterol (0.8 μg/kg) or an equal volume of corn syrup (placebo) orally twice daily for 21 days, and then was evaluated for another 21-day period. Nonworking horses received clenbuterol or placebo at the same dosage for 21 days in a crossover trial (2 treatments/horse). For working and nonworking horses, percentage body fat (PBF) was estimated before treatment and then 2 and 3 times/wk, respectively. Body weight was measured at intervals.
  
  
  RESULTS
  Full data sets were not available for 8 working horses. For working horses, a significant treatment effect of clenbuterol was detected by day 3 and continued through the last day of treatment; at day 21, the mean change in PBF from baseline following clenbuterol or placebo treatment was -0.80% (representing a 12% decrease in PBF) and -0.32%, respectively. By day 32 through 42 (without treatment), PBF change did not differ between groups. When treated with clenbuterol, the nonworking horses had a similar mean change in PBF from baseline from day 6 onward, which peaked at -0.75% on day 18 (an 8% decrease in PBF). Time and treatment had no significant effect on body weight in either experiment.
  
  
  CONCLUSIONS
  Among the study equids, long-term low-dose clenbuterol administration resulted in significant decreases in body fat with no loss in body weight.
authors.affiliation: Department of Clinical Studies, New Bolton Center, School of Veterinary Medicine, University of Pennsylvania, Kennett Square, PA 19348.
authors.forename: Rose D
authors.initials: RD
authors.lastname: Nolen-Walston
authors.forename: Caitlin M
authors.initials: CM
authors.lastname: Moore
authors.forename: Ciara A
authors.initials: CA
authors.lastname: Barr
authors.forename: Joy E
authors.initials: JE
authors.lastname: Tomlinson
authors.forename: Raymond C
authors.initials: RC
authors.lastname: Boston
authors.forename: Lawrence R
authors.initials: LR
authors.lastname: Soma
mesh_terms: D000273:Adipose Tissue / Q000187:drug effects* / Q000378:metabolism; D000284:Administration, Oral; D000818:Animals; D002976:Clenbuterol / Q000008:administration & dosage / Q000378:metabolism*; D018592:Cross-Over Studies; D004305:Dose-Response Relationship, Drug; D005260:Female; D006736:Horses / Q000378:metabolism*; D008297:Male; D013997:Time Factors
chemical_list: D002976:Clenbuterol