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A Comparison Of Performance, Carcass Characteristics And Meat Quality From Intact Male Beef Cattle Relative To Castrated Male Beef Cattle Administered Growth Promotion Technology
Castration is a surgical procedure in male beef cattle that has raised animal welfare concerns. Steroid implants and beta adrenergic agonist are fed to steers after castration to improve feed efficiency and growth rates but can have negative impact on carcass quality. Yearling bulls that are raised for breeding purposes that fail the breeding soundness exam are castrated and administered growth promotion technology then fed for beef. The purpose of this study was to compare the effects on performance, carcass characteristics and meat quality of intact male cattle not administered any growth promotion technology verses castrated male yearling cattle that are administered growth promotion technology. Angus bulls (n = 24; 605 + 37 kg) averaging 16 m of age were stratified by weight and randomly assigned to one of two treatments: uncastrated control (BULL) and castrated with growth promotion technology (STR) treatment. Cattle assigned to STR treatment were implanted with 120 mg trenbolone acetate and 24 mg estradiol on D 0, and fed ractopamine hydrochloride (300mg/d) the last 28 d of feeding. Cattle were fed a rolled corn based finishing ration with a NEg of 0.64 Mcal/lb, for 62 d (final wt = 680 +/-37 kg). Carcass samples and data were collected at a commercial abattoir. BULL treatment had an higher ADG (1.40 vs. 1.05 kg; P < 0.05) and tended to have increased G:F (0.09 vs 0.07 kg; P < 0.10). Feed intake for BULLS and STR (14.87 vs 15.05 kg P > 0.20) was not different. There was no difference between treatments for quality grade, yield grade, HCW, back fat thickness, and dressing percent. Longissimus muscle area was greater in BULL compared to STR (100.1 cm2 vs. 89.3 cm2; P< 0.05). There was no difference in tenderness for BULLS and STR based on Warner Bratzler shear force (WBSF) measures (4.82 and 4.32 kg of force; P <0.05). There was no difference between BULL and STR cattle for; myofibrillar tenderness (5.24 vs 5.43), juiciness (5.18 vs 4.98), beef flavor intensity (5.29 vs 5.27), connective tissue amount (5.97 vs 6.26), overall tenderness (5.34 vs 5.58), and off flavor intensity (7.73 vs 7.70). The castration of yearling bulls administered metabolic modifier technology did not improve performance, carcass characteristics, WBSF, or sensory panel items. Eliminating an animal welfare concern along with removing the cost and management of metabolic modifiers while maintaining meat quality and improving performance; castration is unnecessary for this age of bulls.
Keywords: castration