Productive performance, composition and carcass yield of lambs treated with zeranol

Abstract

-Twenty weaned male hair lambs with average body live weight of 19.20 kg±2.18 kg (SD) were used to evaluate the effect of zeranol on growth, composition and carcass yield. The animals were distributed into a completely randomized design with two treatments: no anabolics (control); and treatment with zeranol, using a subcutaneous dose of 10 mg/50 kg body live weight. Lambs received a diet with 15 g/100 g of crude protein and 2.8 Mcal of metabolizable energy/kg dry matter for 84 days. At the end of experiment all animals were harvested and entire carcass and its parts (neck, shoulder, loinrib, loin-skirt and leg) were weighed to determine the composition of muscle and bone. Control animals had higher dry matter intake (1.01 vs 0.88 kg/d), average daily gain (198 vs 172 g/animal) and total weight gain (12.9 vs 10.9 kg) compared with those treated with zeranol. Zeranol group had higher muscle weight (1.76 vs 1.98 kg) and less bone (0.86 vs 0.61 kg) in leg section. The leg area represented about 16 kg/100 kg of the carcass weight for both treatments. No differences for other carcass traits were observed. Lambs treated with zeranol have better leg conformation because they develop more muscle mass, though their average feed intake and daily gain decrease.

Effect of Implant Different Levels of Zeranol on Growth Performance, Carcass Trait and Body Composition of Awassi Lambs

“…Although lambs implanted with 12 mg zeranol are more efficient in converting feed ( 4.62 kg/kg gain ) as compared with the control (5.77 kg/kg gain ) and lambs implanted with 24 mg zeranol ( 5.66 kg/kg gain ) however, it was impossible to analyze the date of feed efficiency statistically due to that lambs are fed as a group bases. Also, it have been reported by Landau et al, (1987), Castillo et al, (2014) and Alkass and Kak (2015), that implantation of lambs with zeranol had no effect on feed efficiency. The fattening period required by lambs to attain their prescribed slaughter weight (40kg) are not significantly different and averaged 61.62, 58.00 and 66.22 days for intact lambs, treated with 12mg ,24 mg zeranol, respectively.…”

“…Similarly, Sharp and Dyer (1970) observed increased (P<0.05) percent body water and protein and decreased (p<0.05) percent body fat. However, other workers including Field et al (1993), Nasahlas et al 2002, Castillo et al (2014) and Alkass and Kak (2015) who observed minimal effects on carcass composition between lambs implanted with zeranol and control lambs. Table (2): Effect of Zeranol implantation on some carcass characteristics of Awassi lambs (mean ± s.e).…”

“…Hence, slaughter weight and carcass weight of experimental groups are almost similar, so this result is expected. Previously, several authors indicated that treated lambs with zeranol had no significant effect on dressing percentage in lambs (Hutcheson et al, 1992;Eckerman, 2011;Eckerman, 2013;Castillo et al, 2014; Alkass and kak, 2015) in goat (Alkass and Blind 2016), as well as in cattle (Nwokolo., (1972).…”

Desempeño productivo y análisis económico de una engorda intensiva de corderos tratados con zeranol y andrógenos inyectable bajo condiciones tropicales

“…En el mercado existen anabólicos estrogénicos en soluciones oleosas (Zeranol) y androgénica de varios compuestos (Nandrolona + Trembolona + Boldenona) para ser administrados vía parenteral, lo cual facilita su uso. Sin embargo, la información científica sobre sus efectos en el desempeño productivo y económico es escasa e inconsistente (Solis et al, 2009;Castillo et al, 2014). Por lo anterior, el objetivo del estudio fue comparar el desempeño productivo y la rentabilidad de una engorda de corderos machos y hembras en confinamiento tratados con zeranol (ZL), andrógenos (AND) y ZL+AND.…”