RESUMO

Immunocastration (ImC) has been proposed as an animal welfare-friendly alternative to reduce sexual and aggressive behavior and to increase carcass fat deposition with positive effects on meat quality. The ß-adrenergic agonists (ß-AA) are known as repartitioning agents that acts increasing lean tissue deposition. The combined use of these technologies can positively affect meat quality and increase retail cuts yield. Thus, this research was conducted to evaluate the combined effects of ImC and ß-AA (zilpaterol hydrochloride (ZH) and ractopamine hydrochloride (RH)) on retail cuts, bones, and fat trim of feedlot finished Bos indicus (Nellore) cattle. No interaction was observed between sexual condition and diet for any trait. The ImC decreased cold carcass, hindquarter (HQ), forequarter (FQ) and combined brisket, short ribs and flank (BSF) weights. The ImC also showed smaller weights of retail cuts and bones on the HQ and on the FQ than non-castrated (NoC). Fat trim weights did not differ from ImC and NoC. The most of subprimal cuts were heavier in NoC than in ImC. Feeding ß-AA did not affect cold carcass weight; however, animals fed ZH had higher weights of HQ and retail cuts in HQ when compared with RH and control (CO) group, with no differences between RH and CO for both traits. The weights of FQ, BSF, retail cuts in FQ, as well as bones and fat trimmings were not affected by ß-AA. In summary, ImC decreases carcass and retail cut weights, whereas ZH supplementation leads to an improvement in carcass lean tissue and retail cuts.

Assuntos

RESUMO

ß-Adrenergic agonists (ß-AA) are non-hormonal growth promoters which promote muscle hypertrophy in supplemented animals. The effects of two ß-AA in combination with the immunocastration technique on the performance and carcass traits were evaluated using 96 feedlot Nellore males in a randomized complete block design with two sex conditions (immunocastrated (IC) v. non-castrated (NC)) and three treatments: CON (no ß-agonists added), RH (300 mg of ractopamine hydrochloride/day, for 33 days) or ZH (80 mg of zilpaterol·hydrochloride animal/day for 30 days, removed 3 days for required withdrawal period). The trial was carried for 100 days where in the first 70 days animals did not receive ß-AA (phase 1) and during the last 30 days they were treated with ß-AA (phase 2). The performance and ultrasound measurements of longissimus muscle area (LMA), backfat thickness (BFT) and rump fat thickness (RFT) were evaluated in both phases. No sex condition v. treatment interactions were observed for any trait. The NC animals had higher average daily gain (ADG) and final BW than the IC animals, but they did not differ in dry matter intake (DMI) and feed efficiency (gain to feed). The NC animals showed greater LMA (P=0.0001) and hot carcass weight (P=0.0006), and smaller BFT (P=0.0007), RFT (P=0.0039) and percentage of kidney, pelvic and heart fat (P<0.0001) when compared with IC animals. The animals fed ZH showed greater ADG (P=0.0002), G : F (P<0.0001) and dressing per cent (P=0.0136) than those fed RH and CON diets. No differences in BW and DMI were observed. A interaction between treatment and time on feed was observed for LMA and BFT, in which the animals fed ZH diet showed greater LMA (P<0.01) and lower BFT (P<0.01) at 100 days than the animals fed RH and CON diets, whereas RH and CON diets did not differ. Immunocastration decreases muscle development and increases carcass finishing. In contrast, ß-AA increases muscle and decreases fat deposition. The ZH has a higher action on the muscle metabolism than animals fed RH diet. However, RH diet achieves a better balance because it has an intermediary performance between non-supplemented and ZH animals and does not decrease the carcass fat.

Assuntos

RESUMO

Objetivou-se avaliar desempenho, características das carcaças e qualidade da carne de cordeiros mestiços Suffolk, alimentados com dietas contendo gordura protegida. Foram utilizados 18 cordeiros machos, não castrados, com 18,8 ± 2,1 kg e média de idade de 70 dias. Os animais permaneceram confinados por 63 dias recebendo dietas contendo 0%, 4,2% e 5,8% de gordura protegida e foram abatidos com 34,8 ± 5,2 kg. O delineamento experimental foi inteiramente casualisado e os resultados foram analisados por regressão. Observou-se efeito quadrático do teor de gordura protegida na dieta para ganho de peso médio diário e ingestão de proteína bruta, com o ponto de máximo para o teor de 4,2%. Houve efeito linear crescente para ingestão de extrato etéreo. Não houve efeito do teor de gordura protegida nas dietas sobre as características de carcaça. Houve efeito quadrático para força de cisalhamento, com maior valor (3,75 kg) para a carne dos animais que receberam teor de 5,8 % de gordura protegida na dieta. O teor de extrato etéreo da carne também aumentou conforme a adição de gordura na dieta. Com base nos resultados, não se recomenda a utilização de gordura protegida em dietas com elevada proporção de concentrado para terminação de cordeiros em confinamento...(AU)

The objective of this study was to evaluate the performance and carcass and meat quality traits of crossbred Suffolk lambs fed diets containing protected fat. Eighteen uncastrated male lambs with a mean age of 70 days and weighing 18.8 ± 2.1 kg were used. The animals were kept in feedlots for 63 diets where they received diets containing 0%, 4.2% and 5.8% protected fat, and were slaughtered at 34.8 ± 5.2 kg. A completely randomized experimental design was used and the results were analyzed by regression. There was a quadratic effect of dietary protected fat content on average daily weight gain and crude protein intake, with a peak at a fat content of 4.2%. A linear increase was observed for ether extract intake. Dietary protected fat content had no effect on carcass traits. There was a quadratic effect on shear strength, with the highest value (3.75 kg) being observed for meat of animals fed the diet with 5.8% protected fat. The ether extract content of meat also increased with the addition of fat to the diet. On the basis of the results, we do not recommend the use of protected fat in diets containing a high proportion of concentrate for feedlot finishing of lambs...(AU)

Assuntos

RESUMO

O objetivo foi avaliar a utilização do grão de soja tratado termicamente (processado) em dietas para a terminação de cordeiros, com dois níveis de concentrado, sobre a composição tecidual e características qualitativas da carne de cordeiro. Vinte cordeiros sem raça definida (SRD) não castrados, com 22,6 ± 2,06 kg de peso corporal inicial foram alojados, durante a fase de terminação, em baias individuais e distribuídos em um delineamento inteiramente casualizado num arranjo fatorial 2x2 (grão de soja in natura ou processado x 50% ou 80% de concentrado). Os animais foram abatidos ao atingirem a condição corporal 3,0, sendo o peso médio de abate 32,51 ± 3,08 kg. Após o abate e refrigeração das carcaças, amostras do lombo foram coletadas para realização das dissecações e separação dos tecidos componentes do corte comercial. Posteriormente, a porção muscular foi submetida às análises qualitativas. Não houve efeito de interação (P>0,05) entre processamento do grão de soja e nível de concentrado na dieta. O lombo dos animais alimentados com maior nível de concentrado foi mais pesado (0,80 kg). Os animais alimentados com maior proporção de concentrado e com dietas contendo grão de soja processado também apresentaram maior quantidade de músculo (0,56 e 0,54 kg). Os tratamentos com grão de soja processado proporcionaram maior relação músculo:osso (5,62) e maior percentual de músculo (68,13%). Os tratamentos não influenciaram (P>0,05) as características qualitativas da carne. O processamento térmico do grão de soja proporciona melhora na porção comestível, sem alterar as características qualitativas da carne de cordeiros...(AU)

The objective of this study was to evaluate the effect of thermally treated (processed) soybeans in finishing diets for lambs containing two levels of concentrate on the tissue composition and qualitative traits of lamb meat. Twenty uncastrated mongrel lambs with an initial body weight of 22.6 ± 2.06 kg were housed in individual pens during the finishing phase and allocated to a completely randomized design in a 2x2 factorial scheme (fresh or processed soybeans x 50% or 80% concentrate). The animals were slaughtered once they had reached a body condition score of 3.0 and the mean slaughter weight was 32.51 ± 3.08 kg. After slaughter and carcass cooling, loin samples were collected for dissection and separation of the tissue components of the commercial cut. Next, the muscle portion was submitted to qualitative analysis. There was no effect of the interaction between soybean processing and concentrate level in the diet (P>0.05). The loin of animals fed the higher concentrate diet was heavier (0.80 kg). A higher quantity of the muscle was also observed in animals fed the higher proportion of concentrate and diets containing processed soybeans (0.56 and 0.54 kg). The treatments including processed soybeans provided a higher muscle:bone ratio (5.62) and higher muscle percentage (68.13%). The treatments did not influence qualitative meat traits (P>0.05). Heat treatment of soybeans improves the edible portion without altering the qualitative traits of lamb meat...(AU)

Assuntos

RESUMO

O objetivo foi avaliar a utilização do grão de soja tratado termicamente (processado) em dietas para a terminação de cordeiros, com dois níveis de concentrado, sobre a composição tecidual e características qualitativas da carne de cordeiro. Vinte cordeiros sem raça definida (SRD) não castrados, com 22,6 ± 2,06 kg de peso corporal inicial foram alojados, durante a fase de terminação, em baias individuais e distribuídos em um delineamento inteiramente casualizado num arranjo fatorial 2x2 (grão de soja in natura ou processado x 50% ou 80% de concentrado). Os animais foram abatidos ao atingirem a condição corporal 3,0, sendo o peso médio de abate 32,51 ± 3,08 kg. Após o abate e refrigeração das carcaças, amostras do lombo foram coletadas para realização das dissecações e separação dos tecidos componentes do corte comercial. Posteriormente, a porção muscular foi submetida às análises qualitativas. Não houve efeito de interação (P>0,05) entre processamento do grão de soja e nível de concentrado na dieta. O lombo dos animais alimentados com maior nível de concentrado foi mais pesado (0,80 kg). Os animais alimentados com maior proporção de concentrado e com dietas contendo grão de soja processado também apresentaram maior quantidade de músculo (0,56 e 0,54 kg). Os tratamentos com grão de soja processado proporcionaram maior relação músculo:osso (5,62) e maior percentual de músculo (68,13%). Os tratamentos não influenciaram (P>0,05) as características qualitativas da carne. O processamento térmico do grão de soja proporciona melhora na porção comestível, sem alterar as características qualitativas da carne de cordeiros...

The objective of this study was to evaluate the effect of thermally treated (processed) soybeans in finishing diets for lambs containing two levels of concentrate on the tissue composition and qualitative traits of lamb meat. Twenty uncastrated mongrel lambs with an initial body weight of 22.6 ± 2.06 kg were housed in individual pens during the finishing phase and allocated to a completely randomized design in a 2x2 factorial scheme (fresh or processed soybeans x 50% or 80% concentrate). The animals were slaughtered once they had reached a body condition score of 3.0 and the mean slaughter weight was 32.51 ± 3.08 kg. After slaughter and carcass cooling, loin samples were collected for dissection and separation of the tissue components of the commercial cut. Next, the muscle portion was submitted to qualitative analysis. There was no effect of the interaction between soybean processing and concentrate level in the diet (P>0.05). The loin of animals fed the higher concentrate diet was heavier (0.80 kg). A higher quantity of the muscle was also observed in animals fed the higher proportion of concentrate and diets containing processed soybeans (0.56 and 0.54 kg). The treatments including processed soybeans provided a higher muscle:bone ratio (5.62) and higher muscle percentage (68.13%). The treatments did not influence qualitative meat traits (P>0.05). Heat treatment of soybeans improves the edible portion without altering the qualitative traits of lamb meat...

Assuntos

RESUMO

Objetivou-se avaliar desempenho, características das carcaças e qualidade da carne de cordeiros mestiços Suffolk, alimentados com dietas contendo gordura protegida. Foram utilizados 18 cordeiros machos, não castrados, com 18,8 ± 2,1 kg e média de idade de 70 dias. Os animais permaneceram confinados por 63 dias recebendo dietas contendo 0%, 4,2% e 5,8% de gordura protegida e foram abatidos com 34,8 ± 5,2 kg. O delineamento experimental foi inteiramente casualisado e os resultados foram analisados por regressão. Observou-se efeito quadrático do teor de gordura protegida na dieta para ganho de peso médio diário e ingestão de proteína bruta, com o ponto de máximo para o teor de 4,2%. Houve efeito linear crescente para ingestão de extrato etéreo. Não houve efeito do teor de gordura protegida nas dietas sobre as características de carcaça. Houve efeito quadrático para força de cisalhamento, com maior valor (3,75 kg) para a carne dos animais que receberam teor de 5,8 % de gordura protegida na dieta. O teor de extrato etéreo da carne também aumentou conforme a adição de gordura na dieta. Com base nos resultados, não se recomenda a utilização de gordura protegida em dietas com elevada proporção de concentrado para terminação de cordeiros em confinamento...

The objective of this study was to evaluate the performance and carcass and meat quality traits of crossbred Suffolk lambs fed diets containing protected fat. Eighteen uncastrated male lambs with a mean age of 70 days and weighing 18.8 ± 2.1 kg were used. The animals were kept in feedlots for 63 diets where they received diets containing 0%, 4.2% and 5.8% protected fat, and were slaughtered at 34.8 ± 5.2 kg. A completely randomized experimental design was used and the results were analyzed by regression. There was a quadratic effect of dietary protected fat content on average daily weight gain and crude protein intake, with a peak at a fat content of 4.2%. A linear increase was observed for ether extract intake. Dietary protected fat content had no effect on carcass traits. There was a quadratic effect on shear strength, with the highest value (3.75 kg) being observed for meat of animals fed the diet with 5.8% protected fat. The ether extract content of meat also increased with the addition of fat to the diet. On the basis of the results, we do not recommend the use of protected fat in diets containing a high proportion of concentrate for feedlot finishing of lambs...

Assuntos