Four experiments were conducted to investigate the effects of ractopamine hydrochloride (RAC) on ruminal fermentation and proteolysis. In Exp. 1, in vitro gas and VFA production was measured in flasks incubated with 0, 0.226, 2.26, 22.6, and 226.0 mg of RAC/L of buffered ruminal fluid. Ractopamine hydrochloride had a quadratic effect on in vitro gas production (P < 0.05; 177, 181, 185, 190, and...

A study was conducted to determine the clinical effects of 2% ractopamine hydrochloride (RAC) Type A Medicated Article on growth performance in tom finishing turkeys (576, Nicholas, Large White) during 3 different age periods: 15–17, 17–19, and 19–21 wks of age. After a one week acclimation period, turkey finisher toms were fed one of 2 treatments with and without RAC (4.6 g/ton) for the last 1...

The objective of this study was to determine if a higher-fiber diet alters the response of finishing pigs to an antimicrobial (tylosin phosphate [TP]) and a nutrient partitioning agent (ractopamine HCl [RAC]) in terms of N and water utilization and energy digestibility. Seventy-two gilts (initial BW = 107.4 ± 4.2 kg) were blocked by weight and allotted to 1 of 8 dietary treatments. Treatments w...

Thiago Santos ARAÚJO*, Laura Cristina JARDIM PORTO, Érica GUILHEN MARIO, Luciano José PEREIRA, Matheus Soares DA SILVA FERREIRA, Márcio Gilberto ZANGERÔNIMO, Marcelo Henrique NAPIMOGA, Leida Maria BOTION, Raimundo Vicente DE SOUSA Department of Veterinary Medicine, Physiology and Pharmacology Sector, Federal University of Lavras, Lavras, Minas Gerais, Brazil Department of Food Science, Nutritio...

Methods: A total of 1050 pigs were assigned to pens (n = 48) on the basis of weight and gender. Average body weight at trial initiation was 78.5 kg. Four dietary treatments were randomly assigned to pens and stratified across weight and gender. Dietary treatments included control (0 g/ tonne RAC for 35 days); constant (5.0 g/ tonne RAC for 35 days); Step 2 (5.0 g/ tonne RAC for 14 days then 10....

The objectives of this study were to examine the effects of ractopamine (RAC) on the behavior and physiology of pigs during handling and transport. Twenty-four groups of three gilts were randomly assigned to one of two treatments 4 wk before slaughter: finishing feed plus RAC (10 ppm) or finishing feed alone. Pigs were housed in the same building in adjacent pens with fully slatted floors and a...

Carcass characteristics, meat quality traits, and sensory attributes were evaluated in late-finishing barrows and gilts, weighing between 100 to 130 kg of BW, fed 0, 5, or 7.4 mg/kg of ractopamine hydrochloride (RAC) for the final 21 to 28 d before slaughter. Carcass data were collected from carcasses from barrows and gilts (n = 168), and all primal cuts from the right sides of these carcasses ...

The current study represents a comprehensive investigation of the occurrence and fates trenbolone acetate (TBA) metabolites 17?-trenbolone (17?-TBOH), 17?-TBOH, trendione (TBO); melengesterol (MGA); less commonly studied ?-andrenergic agonist ractopamine (RAC) in two 8 month cattle feeding trials simulated rainfall runoff experiments. Cattle were administered TBA, MGA, or RAC, their residues me...