1668 WS Effects of protein concentration and degradability on performance and carcass characteristics of finishing heifers receiving 0 or 400 mg ractopamine hydrochloride

2016 ◽  
Vol 94 (suppl_5) ◽  
pp. 812-813
Author(s):  
K. L. Samuelson ◽  
M. Hubbert ◽  
E. R. Oosthuysen ◽  
Z. Bester ◽  
C. A. Loest
Keyword(s):  
Protein Concentration ◽  
Carcass Characteristics ◽  
Ractopamine Hydrochloride

Effects of dietary protein concentration and ractopamine hydrochloride on performance and carcass characteristics of finishing beef steers1

2016 ◽  
Vol 94 (5) ◽  
pp. 2097-2102 ◽  
Author(s):  
K. E. Hales ◽  
S. D. Shackelford ◽  
J. E. Wells ◽  
D. A. King ◽  
N. A. Pyatt ◽  
...  
Keyword(s):  
Dietary Protein ◽  
Protein Concentration ◽  
Carcass Characteristics ◽  
Ractopamine Hydrochloride

scholarly journals 401 Effect of zinc source and ractopamine hydrochloride on the growth performance and carcass characteristics of steers fed in confinement to harvest

2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 160-160
Author(s):  
John Wagner ◽  
William T Nelson ◽  
Terry Engle ◽  
Jerry Spears ◽  
Jeff Heldt ◽  
...  
Keyword(s):  
Feed Efficiency ◽  
Average Daily Gain ◽  
Carcass Characteristics ◽  
Feedlot Cattle ◽  
Beef Steers ◽  
Live Animal ◽  
Zinc Source ◽  
Dressing Percentage ◽  
Ractopamine Hydrochloride ◽  
Daily Gain

Abstract Four hundred and thirty-two beef steers (346.3 ± 63.7 kg BW) were used to determine the effects of Zn source on feedlot cattle fed ractopamine hydrochloride. Cattle were blocked in groups of 54 by BW and housed in 48 pens containing 9 steers per pen. Pens within a weight block were randomly assigned to treatments in a 2 x 3 factorial arrangement, with factors being: 1) 0 or 30.1 mg of ractopamine HCl/kg DM fed during the final 29 days on feed; and 2) Zn source: 90 mg of supplemental Zn/kg DM from ZnSO4; Zn sulfate (67%) + Zn methionine (33%); and Zn from Zn hydroxychloride, fed through the entire feeding period. Cattle were fed a high concentrate finishing diet for 154 d and slaughtered at a commercial abattoir. Average daily gain, DMI, feed efficiency and carcass characteristics were determined after slaughter. Zinc source had no impact on live animal performance. Cattle fed ractopamine HCl had greater (P < 0.01) final BW, greater (P < 0.001) ADG, improved (P < 0.001) G:F, heavier (P < 0.01) HCW, and larger (P < 0.05) longissimus muscle compared to non-ractopamine supplemented steers. There was a Zn source by ractopamine interaction (P < 0.01) for dressing percentage. Cattle receiving ractopamine HCl with Zn hydroxychloride had a greater dressing percentage (P < 0.05) when compared to ractopamine HCl cattle fed other Zn sources. Cattle receiving ractopamine HCl with Zn sulfate had a lesser dressing percentage (P < 0.05) when compared to ractopamine HCl cattle fed other Zn sources. Additional Zn source by ractopamine HCl interactions were not significant. These data indicate that Zn source has minimal impacts on feedlot steer performance and carcass characteristics when supplemented to cattle receiving 0.0 or 30.1 mg of ractopamine HCl/kg DM.

scholarly journals Effects of voluntary removal of ractopamine hydrochloride (Optaflexx) on live performance and carcass characteristics of beef steers

2021 ◽  
Author(s):  
P J Rincker ◽  
J B Allen ◽  
M Edmonds ◽  
M S Brown ◽  
J C Kube
Keyword(s):  
Dry Matter ◽  
Carcass Characteristics ◽  
Carcass Weight ◽  
Dry Matter Intake ◽  
Beef Steers ◽  
Live Performance ◽  
Meet Residue ◽  
Ractopamine Hydrochloride ◽  
The Impact ◽  
Linear Manner

Abstract There is a lack of consistency across the globe in how countries establish tissue ractopamine residue limits and which residue limits are applied to various tissues, particularly for edible noncarcass tissues. Therefore, some US beef slaughter organizations have recommended a 48-h voluntary removal of ractopamine before slaughter in order to meet residue requirements of specific export countries and maintain international trade. Our objective was to assess the impact of voluntary removal of ractopamine hydrochloride (Optaflexx®; Elanco, Greenfield, IN) up to 8 d before slaughter on growth performance and carcass characteristics. Crossbred beef steers (60 pens of 10 animals/pen) with an initial shrunk body weight (BW) of 611.8 ± 10 kg SEM were fed one of six treatments over 42 d. Treatments included a control that did not receive ractopamine, on-label use of ractopamine (0-d withdrawal), and 2, 4, 6, or 8 d of voluntary removal of ractopamine from feed before slaughter. The start of ractopamine feeding (30.1 mg/kg of diet dry matter for 32 d) was staggered so that blocks could be slaughtered on the same day. Dry matter intake was decreased by 0.5 kg/d when ractopamine was fed with a 0-d withdrawal (P = 0.04) compared to the control, but was not altered (P = 0.56) as the duration of ractopamine removal increased from 0 to 8 d. Final BW, total BW gain, and average daily BW gain were increased by feeding ractopamine with a 0-d withdrawal (P = 0.09) compared to the control, but these variables decreased in a linear manner (P = 0.10) as the duration of removal increased from 0 to 8 d. Gain efficiency was improved by 15% (P < 0.01) by feeding ractopamine with a 0-d withdrawal compared to the control, and gain efficiency decreased linearly (P = 0.06) as the duration of ractopamine removal increased. Approximately 2/3 of the increase in gain efficiency remained after 8 d of removal. Hot carcass weight was increased by 6 kg (P = 0.02) by feeding ractopamine with a 0-d withdrawal compared to the control. Measured carcass characteristics were not altered by ractopamine feeding or by removal before slaughter (P ≥ 0.24). The consequences of voluntary removal of ractopamine up to 8 d before slaughter were a linear decrease in live BW gain (0.64 kg/d), poorer gain efficiency, and numerically lighter carcass weight.

Effects of ractopamine hydrochloride on growth performance, carcass characteristics, and physiological response to different handling techniques1,2

2017 ◽  
Vol 95 (5) ◽  
pp. 1977-1992 ◽  
Author(s):  
J. A. Hagenmaier ◽  
C. D. Reinhardt ◽  
M. J. Ritter ◽  
M. S. Calvo-Lorenzo ◽  
G. J. Vogel ◽  
...  
Keyword(s):  
Growth Performance ◽  
Physiological Response ◽  
Carcass Characteristics ◽  
Ractopamine Hydrochloride

scholarly journals Effects of various ractopamine hydrochloride withdrawal periods on performance, health, and carcass characteristics in yearling steers

2019 ◽  
Vol 4 (1) ◽  
pp. 67-74
Author(s):  
Tony C Bryant ◽  
Josh I Szasz ◽  
Lois F G Pringle ◽  
Eddie Crispe ◽  
K Shawn Blood ◽  
...  
Keyword(s):  
Feed Efficiency ◽  
Dry Matter ◽  
Block Design ◽  
Average Daily Gain ◽  
Carcass Characteristics ◽  
Average Dose ◽  
Withdrawal Period ◽  
Feedlot Performance ◽  
Dressing Percentage ◽  
Ractopamine Hydrochloride

Abstract Ractopamine hydrochloride (RAC) is a β-adrenergic agonist approved for feeding during the last 28 to 42 d prior to cattle slaughter to improve feedlot performance and carcass characteristics. Three thousand crossbred yearling steers (527 ± 2.4 kg; AVG ± SD) were used in two periods to evaluate the effects of various RAC withdrawal times on feedlot performance, health, and carcass characteristics. In Period 1, 6 blocks of 30 pens totaling 1,500 steers were utilized, which was repeated for Period 2. In a randomized complete block design, cattle were assigned to 1 of 5 treatments consisting of 1) No RAC fed (CON), 2) 12-h RAC withdrawal (12-hRAC), 3) 2-d RAC withdrawal (2-dRAC), 4) 4-d RAC withdrawal (4-dRAC), and 5) 7-d RAC withdrawal (7-dRAC). Cattle were fed for a total of 62 d, and applicable treatments were supplemented with 30.0 ppm (dry matter basis) of RAC (average dose = 322 mg per steer per day) for 33 d at the end of the feeding period, corresponding to their respective withdrawal times. Initial body weight (BW) displayed a quadratic curve, with 2-dRAC and 4-dRAC withdrawal periods having the greatest BW. Accordingly, dry matter intake (DMI) responded quadratically (P = 0.034), with 2-dRAC and 4-dRAC treatments demonstrating the greatest DMI. No significant treatment differences (P ≥ 0.641) were observed in final live BW, average daily gain (ADG), or feed efficiency. Alternatively, when using a common dressing percentage to calculate live BW, cattle on RAC treatments exhibited 7.6 kg additional live BW (P < 0.001) compared to CON cattle. Furthermore, carcass-adjusted ADG and feed efficiency did not differ (P > 0.10) between RAC treatments but were improved compared to the CON treatment (P ≤ 0.002). Hot carcass weight (HCW) was on average 4.9 kg greater (P < 0.001) for RAC treatments vs. CON, and no differences were detected (P > 0.10) among RAC treatments. Within RAC treatments, carcass cutability responded quadratically (P ≤ 0.005) to withdrawal period, with the 2-dRAC and 4-dRAC treatments containing more Yield Grade 4 and 5 and fewer Yield Grade 1 and 2 carcasses than the other RAC treatments. On the basis of the results of this experiment, feeding RAC improves dressing percentage, HCW, and carcass-adjusted BW, ADG, and feed efficiency. Furthermore, extending the RAC withdrawal period to 7 d does not have a significant impact on cattle performance or health and has minimal effects on carcass characteristics.

scholarly journals Effects of ractopamine hydrochloride supplementation on feeding behavior, growth performance, and carcass characteristics of finishing steers1,2

2019 ◽  
Vol 3 (4) ◽  
pp. 1143-1152
Author(s):  
Ronald J Trotta ◽  
Kasey R Maddock Carlin ◽  
Kendall C Swanson
Keyword(s):  
Feeding Behavior ◽  
Growth Performance ◽  
Treatment Period ◽  
Radio Frequency Identification ◽  
Animal Health ◽  
Average Daily Gain ◽  
Carcass Characteristics ◽  
Eating Time ◽  
Total Period ◽  
Ractopamine Hydrochloride

Abstract Ractopamine hydrochloride (RAC) is a β-adrenergic agonist that functions as a repartitioning agent to improve muscling in feedlot cattle. Many studies have investigated the effects of RAC on growth performance and carcass characteristics; however, there is minimal information about the influence of RAC on feeding behavior. Sixty-nine steers (body weight [BW] = 364 ± 3.9 kg) predominately of Angus and Simmental breeding were subjected to a 126-d (n = 46) or 154-d (n = 23) feeding period and randomly assigned to one of two treatment groups: supplementation to provide 0 (CON; n = 34) or 267 ± 4.9 mg/d of RAC (n = 35). Ractopamine was provided as Optaflexx 45 at 0.024% of the diet (dry matter [DM] basis; Elanco Animal Health, Greenfield, IN). Dietary treatments were fed the final 42 d in the feed yard (treatment period). Feeding behavior and growth performance were measured using radio frequency identification tags and the Insentec feeding system. Following the final day of treatment, steers were slaughtered and carcass measurements were recorded. Data were analyzed using MIXED models in SAS. There were no differences in BW, average daily gain (ADG), DM intake (DMI), gain:feed ratio (G:F), or feeding behavior during the pretreatment period (P > 0.44). Ractopamine supplementation increased G:F during the treatment period (P = 0.02) and during the total period (P = 0.03) and tended to increase ADG during the treatment and total period (P ≤ 0.08). DMI was not affected during the treatment or total period (P > 0.67). Eating time per visit, per meal, and per day were decreased (P < 0.02) in steers supplemented with RAC during the treatment period. DMI per minute was increased (P = 0.02) in steers supplemented with RAC. Hot carcass weight, dressing percentage, and 12th rib fat were not influenced by RAC supplementation. Ractopamine supplementation decreased marbling (P = 0.008) and kidney, pelvic, and heart percentage (P = 0.04) and increased longissimus muscle area (P = 0.01). These data demonstrate that RAC supplementation for 42 d improves feed efficiency, increases the rate of DMI without altering DMI, and increases muscling in finishing cattle.

Effects of ractopamine hydrochloride on growth performance, carcass characteristics, and physiological response to different handling techniques

2017 ◽  
Vol 95 (5) ◽  
pp. 1977 ◽  
Author(s):  
J. A. Hagenmaier ◽  
C. D. Reinhardt ◽  
M. J. Ritter ◽  
M. S. Calvo-Lorenzo ◽  
G. J. Vogel ◽  
...  
Keyword(s):  
Growth Performance ◽  
Physiological Response ◽  
Carcass Characteristics ◽  
Ractopamine Hydrochloride
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