Stimulation of circulating insulin-like growth factor I (IGF-I) and insulin-like growth factor binding proteins (IGFBP) due to administration of a combined trenbolone acetate and estradiol implant in feedlot cattle.

Johnson, B. J.; Hathaway, Marcia; Anderson, Peter T.; Meiske, J. C.; Dayton, William R

doi:10.2527/1996.742372x

Cited by 73 publications

(56 citation statements)

References 21 publications

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“…Intramuscular moisture was also higher for TAE than PE, and others have shown that a growth promotant containing trenbolone acetate and estradiol increased carcass water (Johnson et al 1996b), as well as increased concentrations of insulin-like growth factor I and its binding protein (Johnson et al 1996a). Shear force indicated that rib eyes from TAE carcasses were less tender than rib eyes from PE, and Shackleford et al (1991) reported that a shear force greater than 3.9 kg would be perceived by consumers as "tough".…”

Section: Growth Promotantmentioning

confidence: 89%

Time of feeding and growth promotant effects on the winter growth performance and carcass traits of steers

Small¹,

Kennedy²,

Veira³

et al. 2004

Can. J. Anim. Sci.

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. 2004. Time of feeding and growth promotant effects on the winter growth performance and carcass traits of steers. Can. J. Anim. Sci. 84: 133-144. The effects of time of day of feeding and estrogenic growth promotant on growth performance and carcass traits were determined in three experiments conducted over 3 yr (winters 1998-1999, 1999-2000, 2000-2001). Crossbred steers (year 1, n = 144, year 2, n = 128, year 3, n = 144) were assigned at fall weaning on the basis of sire, age (190 ± 21 d, mean ± SD), and body weight (244 ± 34 kg) to one of eight pens in an outdoor lot at the Brandon Research Centre (49°54″N). In years 1 and 2, pens were assigned to either morning-fed (MF, 0900) or evening-fed (EF, 2000) treatments, and steers within pen were assigned to either Synovex Plus ® (TAE) or Synovex S ® (PE) growth promotants. In year 3, pens were assigned to either TAE or PE treatments and all were evening-fed. Beginning on Nov. 09 (0 d), steers were given a 20% hay, 80% concentrate (79.2% barley, 0.8% premix) mixed ration (88.6% dry matter, 13.7 MJ kg -1 digestible energy, 124 g kg -1 crude protein, 33.6 mg kg -1 lasalocid). Diets were fed, once daily, in amounts that were consumed before the next feeding, until steers were marketed. Growth promotants were administered at 0 and 84 d. The winter of year 2 was warmer (P < 0.05) than, and years 1 and 3 similar (P > 0.05) to, the 30-yr average ambient temperature (-8.8°C and -12.9°C, respectively). Evening feeding increased (P < 0.05) gain in body weight, especially in year 2 and backfat, especially in year 1, and this was reflected in heavier (P < 0.05) carcass weight in year 2, and whiter (P < 0.05) fat and greater (P < 0.05) rib eye moisture in year 1 and overall reduced (P < 0.05) feed cost of gain in winter. In all 3 yr TAE, relative to PE, produced greater (P < 0.05) body weight gain, and heavier, leaner carcasses with greater (P < 0.05) rib eye area, coarser (P < 0.05) meat texture and greater (P < 0.05) shear force, and reduced (P < 0.05) the feed cost of gain. Time of feeding and choice of growth promotant have significant potential to reduce the business risk of feeding steers in winter. Les auteurs ont étudié les effets du moment du repas et des oestrogènes employés comme accélérateur de croissance sur le rendement des bouvillons et les caractéristiques de la carcasse dans le cadre de trois expériences effectuées chacune une année distincte (hivers de 1998-1999, de 1999-2000 et de 2000-2001). Au moment du sevrage automnal, ils ont réparti des bouvillons hybrides (1 re année, n = 144; 2 e année, n = 128; 3 e année, n = 144) dans 8 enclos extérieurs en fonction du géniteur, de l'âge (190 ± 21 j, moyenne ± É.-T.) et du poids (244 ± 34 kg), au centre de recherche de Brandon (49°54″N). Les deux premières années, les animaux de chaque enclos ont été nourris le matin (9 h) ou le soir (20 h) et chaque animal de l'enclos a reçu l'accélérateur Synovex Plus ® (TAE) ou Synovex S ® (PE). La troisième année, les animaux ont tous été nourris en soirée et ont reçu un des...

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Section: Growth Promotantmentioning

confidence: 89%

Time of feeding and growth promotant effects on the winter growth performance and carcass traits of steers

Small¹,

Kennedy²,

Veira³

et al. 2004

Can. J. Anim. Sci.

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“…However, we elected to measure circulating IGF-I as an indirect positive marker of responses of cattle to growth-promoting steroid implants (Johnson et al, 1996b;Johnson et al, 1998). Additionally, it has been previously shown that implants containing E2 or T+E have a greater ability to stimulate circulating IGF-I than implants containing only TBA (Pampusch et al, 2008).…”

Section: Discussionmentioning

confidence: 99%

Steroid implants and markers of bone turnover in steers

et al. 2012

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Steroidal implants are used extensively in beef cattle management to take advantage of welldocumented improvements in growth performance and efficiency. In addition to muscle growth, steroids bring about changes in bone and cartilage formation, hastening bone ageing. The current study was designed to test the hypothesis that recently identified indicators of bone and cartilage turnover could be detected in the peripheral circulation, and that these markers might reflect accelerated ageing effects of the widely used steroidal implants, trenbolone acetate (TBA) and estradiol-17β (E2). Thirty-two crossbred yearling steers were given one of four treatments to determine whether these markers of bone turnover could be detected and reflect steroid-induced bone maturity in the periphery: non-implanted controls; 25.7 mg estradiol-17β (E2); 120 mg trenbolone acetate (TBA); or 120 mg TBA and 24 mg E2 (T+E). Blood was collected on days 0, 7, 14 and 28 and serum analysed by ELISA for concentrations of IGF-I, osteocalcin, C-terminal telopeptides of Type I collagen (CTX-I) and C-terminal telopeptides of Type II collagen (CTX-II), as markers of the somatotropic-endocrine axis, bone formation, bone resorption and cartilage resorption, respectively. Circulating IGF-I was greater in E2 or T+E treated steers than controls on days 7 and 14. Osteocalcin was unaffected by treatment, but increased from day 0 on days 7, 14 and 28. Treatment did not affect CTX-I. However, CTX-II was elevated in the treated animals as opposed to the controls. Although these markers of bone and cartilage turnover are detectable, results suggest that implant-induced changes are not evident in the circulatory system.

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“…Hormonal growth implants have been shown to improve final live weights and hot carcass weights of steers (Calkins et al 1986;Perry et al 1991;Platter et al 2003;Roeber et al 2000) and their mode of action is through growth hormone and insulin-like growth factor-I (Johnson et al 1996). Hormonal growth implants induce hypertrophy of muscle fibres (Ono et al 1996) or a shift in muscle fibre type to fast glycolytic (FG) from fast oxidative glycolytic (FOG) fibres (Fritsche et al 2000).…”

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confidence: 99%

Modification of muscle inherent properties through age at slaughter, growth promotants and breed crosses

et al. 2011

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. 2011. Modification of muscle inherent properties through age at slaughter, growth promotants and breed crosses. Can. J. Anim. Sci. 91: 635Á648. A 2 4 factorial experiment tested the interactions of slaughter age (12Á13 or 18Á20 mo), growth hormone use, b-adrenergic agonist (b-AA) use and breed cross [HerefordÁAberdeen Angus (HAA) or CharolaisÁRed Angus (CRA)] on the composition, fibre types, and connective tissue characteristics of m. semitendinosus (ST) and m. gluteus medius (GM) from 112 crossbred steers. Muscle weights increased with slaughter age, implantation and CRA genetics (PB0.05), but were not affected by ractopamine hydrochloride (RAC) (P 0.10). Animal age increased fast glycolytic (FG) and decreased fast oxidative glycolytic (FOG) fibre percentages by 7.2 and 6.6%, respectively, in the ST and increased slow oxidative (SO) and FOG fibre areas in both muscles (PB0.05). Cross-sectional areas of all fibre types were increased in the ST with implantation. In the GM, implantation increased SO (3.1%) and reduced FOG (3.2%) fibre percentages, while RAC reduced the SO (3.8%) and increased the FG (6.1%) fibre percentages (P B0.05). Only GM total collagen content increased with slaughter age (PB0.05), but collagen solubility decreased with slaughter age for both muscles (PB0.05). CRA genetics increased FG percentage in the GM of yearling-fed steers and increased moisture and protein and reduced fat contents of both muscles (PB0.05). In the muscles studied, IMP, slaughter age and animal genetics induced greater changes in muscle inherent properties than RAC.

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Stimulation of circulating insulin-like growth factor I (IGF-I) and insulin-like growth factor binding proteins (IGFBP) due to administration of a combined trenbolone acetate and estradiol implant in feedlot cattle.

Cited by 73 publications

References 21 publications

Time of feeding and growth promotant effects on the winter growth performance and carcass traits of steers

Time of feeding and growth promotant effects on the winter growth performance and carcass traits of steers

Steroid implants and markers of bone turnover in steers

Modification of muscle inherent properties through age at slaughter, growth promotants and breed crosses

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