Effects of growth-promoting agents and season on yearling feedlot heifer performance.
نویسندگان
چکیده
Angus x crossbred heifers (270 per trial) were used in an experiment conducted over one 105-d summer and one 104-d winter feeding period. Treatments were identical for each trial and included: 1) control, 2) estrogenic implant (E), 3) trenbolone acetate implant (TBA), 4) E + TBA (ET), 5) melengestrol acetate (MGA) in the feed, and 6) ET + MGA (ETM). Each treatment was replicated in five pens, with nine heifers per pen in each season. Initial weights (mean = 384 kg, SE = 57) were the same for each season. There were no treatment x season interactions for final BW, ADG, G:F, water intake, or carcass characteristics. Heifers receiving a growth-promoting agent were 11.6 kg (SE = 4.08) heavier and gained 0.108 kg/d (SE = 0.04) more (P < 0.05) than control heifers. Heifers receiving ET gained 0.09 kg/d (SE = 0.032) more (P = 0.05) than heifers not receiving ET. Heifers receiving ET (with and without MGA) had greater G:F (P < 0.05) than control, E, and TBA heifers. Carcass weights of ET-treated heifers were greater (P < 0.05) than carcass weights for unimplanted heifers, those fed MGA only, and heifers receiving either E or TBA implants. Marbling scores were increased (P < 0.05) by feeding MGA to ET-treated heifers. Water intake was greater (P < 0.01) in the summer (31 L/d) than in the winter (18 L/ d), with no difference among implant treatments. Heifers fed in the winter had heavier carcasses, less 12th-rib fat, greater marbling scores, larger LM area, and a greater incidence of liver abscesses than heifers finished in the summer (P < 0.01). A treatment x season interaction (P = 0.07) was evident for DMI during the 35-d coldest and hottest portions of the year. Heifers fed MGA and implanted with ET tended (P = 0.07) to have greater DMI in the summer but lesser DMI in the winter. In general, differences among growth-promotant programs were relatively similar over the entire summer and in winter.
منابع مشابه
Evaluation of Growth Performance of Local and Dorper × Local Crossbred Sheep in Eastern Amhara Region, Ethiopia
The present study was performed to evaluate the on-station growth performance of local and Dorper × local crossbred sheep in eastern Amhara region, Ethiopia. Data on 302 lambs collected over a 4-year period (2009 to 2012) on local and Dorper × local crossbred sheep at Sirinka breeding, evaluation and distribution site were used in this study. Fixed effects considered were breed, lamb sex, birth...
متن کاملEffects of Supplement Type on Growth and Pregnancy Rate of Yearling, Brahman-Crossbred Heifers
The effects of winter supplement type on growth and pregnancy rate of fall-born, yearling heifers was investigated over 2 consecutive years. During both years, heifers were stratified by breed (Braford and Brangus-crossbred) and BW and randomly assigned to one of two treatments consisting of (1) wheat middling-based range cube, or (2) molasses-cottonseed meal slurry (n=34 and 24 heifers/treatme...
متن کاملEffect of Intensive Winter Management, Partial Season Grazing, and Sorting on Performance and Economics of a Long Yearling Steer Production System
A 2-yr study (200 steers/yr) was conducted to evaluate effects of grazing management and sorting by BW at feedlot entry on performance and economics of yearling steers. At receiving, steers (247 ± 21 kg) were randomly allotted to 1 of 2 treatments: low (0.75 kg/d, NORM) or high (0.90 kg/d, INT) gains during backgrounding. After wintering, NORM and INT grazed native range for 128 and 78 d, respe...
متن کاملPasture Deworming and(or) Subsequent Feedlot Deworming with Fenbendazole (Safe-Guard®) I. Effects on Grazing Performance, Feedlot Performance, and Carcass Traits of Yearling Steers
متن کامل
Effects of feeding a multivalent polyclonal antibody preparation on feedlot performance, carcass characteristics, rumenitis, and blood gas profile in Bos indicus biotype yearling bulls.
The objective of this study was to evaluate effects of feeding monensin (MON) or a multivalent polyclonal antibody preparation (PAP) against several rumen microorganisms on feedlot performance, carcass characteristics, blood gas profile, and rumenitis of Bos indicus biotype (BT) yearling bulls. The study was designed as a completely randomized design with a 3 × 2 factorial arrangement, replicat...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- Journal of animal science
دوره 82 8 شماره
صفحات -
تاریخ انتشار 2004