ABSTRACT The objective of this study was to evaluate residual feed intake (RFI), residual intake and body weight gain (RIG) and their relationship with other traits of efficiency, performance, and economic analysis of sheep. Lambs (n = 102) were evaluated during 56 days and a herd consisting of 500 ewes was simulated with the mean of dry matter intake (DMI) and final body weight of the lambs, the same as that of the experimental lambs. The lambs were fed hay-based diet of Tifton 85 (Cynodon spp.), corn, and soybean in the voluminous:concentrate ratio of 35:65. Residual feed intake and RIG were correlated with DMI, feed conversion ratio, and feed efficiency. Residual intake and body weight gain were positively correlated with average daily gain, relative growth rate, and Kleiber's rate. The most efficient production systems (lower RFI and higher RIG) had lower costs and higher profit margins. The net present value (NPV) and internal rate of return (IRR) were higher in systems with more efficient lambs. In systems with less efficient lambs, NPV and IRR were negative and lower, respectively. Efficient animals for RFI and RIG showed satisfactory performance and better economic results.

O objetivo deste estudo foi avaliar a digestibilidade e o balanço de nitrogênio (BN) do volumoso cana-de-açúcar hidrolisada sob diferentes condições, na alimentação de cordeiros. Foram utilizados 15 cordeiros Ile de France, em média, com 23,5kg de peso corporal. Os tratamentos foram: cana-de-açúcar in natura, cana-de-açúcar hidrolisada com 0,6% de óxido de cálcio (CaO), sob condição aeróbica e cana-de-açúcar hidrolisada, com 0,6% de CaO, sob condição anaeróbica, constituindo um delineamento inteiramente casualizado com cinco repetições por tratamento. Os tratamentos foram fornecidos aos animais, juntamente com o concentrado. Ambas as condições das hidrólises tiveram o intuito de alterar o padrão de fermentação da cana-de-açúcar e, com isso, melhorar a digestibilidade de suas fibras. Os cordeiros foram confinados em baias individuais e a dieta foi fornecida permitindo 10% de sobras. Estas sobras foram amostradas diariamente por cinco dias, bem como as fezes e urina foram coletadas para determinar a digestibilidade e o BN. Foi observado, para cordeiros alimentados com ANA, maior digestibilidade da fibra em detergente neutro, corrigido para proteína e cinzas (57,05%), matéria orgânica (85,39%), hemicelulose (72,09%), maior BN (29,46g dia-1 e 2,78g kg-0,75 dia-1) e taxa de nitrogênio absorvido (3,00g kg-0,75 dia-1), em comparação ao IN (41,17%, 73,76% e 53,80%, 21,39g dia-1, 2,00g kg-0.75 dia-1 e 2,22g kg-0.75 dia-1, respectivamente). Como volumoso, ANA otimiza o balanço de nitrogênio e é mais eficiente em melhorar a digestibilidade de alguns nutrientes, comparado à IN. AER tão eficiente quanto ANA e IN

This study aimed to evaluate the digestibility and nitrogen balance (NB) of lambs fed sugarcane hydrolyzed under different conditions. Fifteen Ile de France lambs at, on average, 23.5kg of body weight were evaluated. Treatments were: in natura sugarcane (IN), sugarcane hydrolyzed using 0.6% calcium oxide (CaO) under aerobic condition (AER), and sugarcane hydrolyzed using 0.6% CaO under anaerobic condition (ANA). Therefore, a completely randomized design was constituted with five replicates per treatment. Treatments were supplied to animals along with concentrate. Both hydrolysis conditions aimed to alter the sugarcane fermentation pattern, therefore improving fiber digestibility. Lambs were housed in individual pens and fed with diet allowing 10% of refusals. Refusals, feces and urine were sampled daily during five days. They were collected to determine the digestibility and NB. A higher digestibility of neutral detergent fiber corrected for ash and protein (57.05%), organic matter (85.39%), hemicellulose (72.09%), NB (29.46g day-1 and 2.78g kg-0.75 day-1) and rate of nitrogen absorbed (3.00g kg-0.75 day-1) were observed for lambs fed with ANA than for those fed IN (41.17%, 73.76%, 53.80%, 21.39g day-1, 2.00g kg-0.75 day-1 and 2.22g kg-0.75 day-1, respectively). As roughage, ANA in the lamb diet, optimizes the nitrogen balance and is more efficient to improve the digestibility of some nutrients compared to IN. Whereas AER was as efficient as ANA and IN

The objective of this investigation was to evaluate the weight and percentage of the non-carcass components and the mineral content (macro minerals and trace minerals), crude protein, ether extract, moisture and vitamin E of the heart, liver, tongue, lungs, reticulum, kidneys and meat from the longissimus dorsi of lambs in feedlot finishing. Thirty-two non-castrated Ile de France male lambs, fed diets containing sunflower seeds and vitamin E from 15 to 32 kg of body weight were allotted in a completely randomized design in a 2 × 2 factorial arrangement. The weight of the gastrointestinal tract was higher in the lambs fed diets containing vitamin E (10%). No difference was observed in the liver as to the mineral matter, crude protein, ether extract, moisture (2.01; 20.03; 2.39 and 74.78 g/100 g, respectively), the macro minerals and trace minerals, except iron. In the tongue, lungs, reticulum, kidneys and meat there was no in fluence of diets in the studied variables. The liver and the meat presented different values of crude protein (20.01 and 18.34 g/100 g, respectively), and the heart (1.03 mg/100 g) showed a higher content of vitamin E. High contents of manganese, zinc and copper were observed in the liver. The evaluated non-carcass components were nutritionally equal to the sheep meat, once, in addition to their high yield in relation to the body weight at slaughter, the non-carcass components are sources of nutrients.

O objetivo deste estudo foi avaliar a qualidade da carne de cordeiros Ile de France alimentados com dietas contendo grãos de girassol e vitamina E. Trinta e dois cordeiros pesando inicialmente 15kg foram alojados em baias individuais e abatidos ao atingir 32kg de peso corporal. Os tratamentos consistiram de quatro dietas experimentais: D1) cana-de-açúcar + concentrado sem grãos de girassol; D2) cana-de-açúcar + concentrado com grãos de girassol; D3) cana-de-açúcar + concentrado grãos de girassol, mais 1000mg de vitamina E kg-1 de matéria seca (MS) da dieta; e D4) cana-de-açúcar + concentrado com grãos de girassol e 1000mg de vitamina E dieta kg-1 de MS. Os parâmetros temperatura, pH, cor, perda de peso ao cozimento, força de cisalhamento e capacidade de retenção de água foram determinados nos tempos de maturação de 0, 7 e 14 dias no músculo Longissimus dorsi. As características qualitativas da carne não foram afetadas pelas dietas contendo grãos de girassol combinado com vitamina E, no entanto, pH 24 horas foi afetado (P<0,05) pela dieta contendo grãos de girassol com vitamina E. A perda de peso por cozimento não foi influenciada (P>0,05) pelos tempos de dieta ou de maturação, por outro lado, a força de cisalhamento e capacidade de retenção de água foi significativamente afetada (P<0,05). O uso da vitamina E resultou em carne com maior capacidade de retenção de água. O tempo de maturação influenciou nos parâmetros pH, cor e força de cisalhamento. Carne de cordeiro com 7 dias de maturação apresentou menor força de cisalhamento.

The objective of the study is to evaluate meat quality from Ile de France lamb fed diets supplemented with sunflower seeds and vitamin E. Thirty-two lamb weighing initially 15kg were housed in individual stalls and slaughtered when body weight reached 32kg. The treatments consisted of four experimental diets: D1) sugarcane + concentrate without sunflower seeds; D2) sugarcane + concentrate with sunflower seeds; D3) sugarcane + concentrate without sunflower seeds plus 1000mg vitamin E kg-1 diet dry matter (DM); and D4) sugarcane + concentrate with sunflower seeds and 1000mg vitamin E kg-1 diet DM. The parameters temperature, pH, color, cooking loss, shear force and water holding capacity were determined at maturation times of 0, 7 and 14 days on the Longissimus dorsi muscle. Qualitative characteristics of the meat were not affected by the sunflower seed combined with vitamin E diet; however, pH 24 hours was affected (P<0.05) by the sunflower seed combined with vitamin E diet. Cooking loss was not significantly influenced (P>0.05) by diet or maturation times. On the other hand, shear force and water holding capacity were significantly affected (P<0.05) by the treatments. The use of vitamin E resulted in lamb meat with higher water holding capacity. Maturation time influenced the parameters pH, color and shear force. Lamb meat that matured for 7 days displayed the lowest shear force.

Avaliaram-se o desempenho e as características de carcaça de 36 cordeiros machos não-castrados, Santa Inês puros e mestiços Dorper × Santa Inês e Texel × Santa Inês, manejados em três sistemas (intensivo semi-intensivo e extensivo) e abatidos com peso médio de 38,41 ± 1,24 kg. Os melhores ganhos de peso foram observados nos cordeiros criados em sistema intensivo, que apresentaram também os maiores pesos e rendimentos de carcaça. Poucas influências foram constatadas sobre as medidas de carcaça e dos cortes comerciais, sobretudo para maiores pesos nos cortes provenientes do manejo intensivo, proporcionado pelo maior peso da carcaça. O percentual relativo dos cortes em relação à carcaça fria praticamente não variou entre os sistemas. O sistema intensivo proporcionou melhor desempenho, independentemente do grupo genético. A utilização das raças Texel e Dorper em cruzamento com Santa Inês eleva o rendimento das carcaças.

It was evaluated the performance and the carcass characteristics of 36 non-castrated male lambs, Santa Inês purebreed and crossbreeds from Dorper × Santa Inês and Texel × Santa Inês, managed in three different systems (intensive, semi-intensive and extensive), slaughtered at 38.41 ± 1.24 kg. It was observed the highest weight gain for lambs reared in intensive system, which also showed the greatest carcass yield. The management systems did not influence carcass measures of animals in intensive system much because of the greater weight of the carcass. The intensive system provided the best performance, regardless the genetic group. The use of Texel and Dorper breeds in crossings with Santa Inês increases carcass yield.