Abstract—This study aimed to evaluate the muscularity and tissue composition of 24 legs of Ile de France lambs. They were fed with diets containing “in nature” or hydrolyzed sugarcane with 0.6% of calcium oxide in aerobic and anaerobic environments. Animals entered the trial at 15 and were slaughtered at 32 kg of body weight. The leg tissue composition, as well as muscularity (0.47), muscle:bone (6.66) and muscle:fat (4.25) were not affected (P>0.05) by treatments. The proportions found were: 67.62% for muscle, 17.52% for bone and 10.15% for fat. In relation to lambs fed with “in nature” sugarcane, hydrolyzed sugarcane with calcium oxide in aerobic and anaerobic environments did not affect muscularity and leg tissue composition of lambs. Keywords—calcium oxide, feedlot, Saccharum officinarum I. INTRODUCTION HE use of specialized breeds for meat production has great potential for weight gain in less time and with better yield and grade of the carcasses [1]. The use of methods that assess the carcasses and allow to predict their quality, composition, muscle, bone and fat, as well as cut yields is essential [2]. A very accurate method to determine the tissue composition of the carcass is the dissection of some commercial cuts, such as leg, shoulder and loin. The method consists in the separation of the muscle, bone and fat, but the dissection of the whole carcass is only justified in some cases once it is a laborious and time consuming procedure. According to [3], the dissection of the leg or shoulder is more common due to their high correlation with carcass tissue composition and together constitute over 50% of the lamb carcass. The proportion of muscle in the carcass can also be estimated by the muscularity of the leg, which considers the average depth of a group of muscles surrounding the femur in relation to the length of this bone [4]. The amount of muscle in the carcass is the most important component to the consumer market. Fat amount is the second most important and it varies according to the preference of each region. Therefore, the consumer market seeks a carcass that provides maximum deposition of muscle and enough fat to provide satisfactory organoleptic characteristics to whom tastes it [5]. Currently, is not enough to produce greater quantities of meat cheaply, the consumer market increasingly requires uniformity and quality of carcass cuts, and it is needed studies about factors that influence tissue composition of carcass cuts to provide good quality [6]. Viviane Endo.. Faculdade de Ciências Agrárias e Veterinárias, Unesp – Campus de Jaboticabal, São Paulo, CEP 14834-900 Brazil (phone: 55 16 8121-9570. e-mail: endo_vica@hotmail.com). Américo Garcia da Silva Sobrinho, Natália Ludmila Lins Lima, Gabriela Milani Manzi, Luís Gabriel Alves Cirne, Valéria Teixeira Santana, Fabiana Alves de Almeida. Faculdade de Ciências Agrárias e Veterinárias, Unesp – Campus de Jaboticabal, São Paulo, CEP 14834-900, Brazil. Ruminants diet is composed of concentrate and roughage. Concentrates are responsible for higher costs, meanwhile roughage have more affordable prices [7]. Thus, the use of sugarcane as roughage is feasible because it is a tropical grass. It presents a high potential for production of dry matter and energy per unit of area. Provides in one cut 15 to 20 tons of natural matter per hectare, besides maintains its productivity during dry periods of the year, when there is shortage of forage. However, it has limitations such as low crude protein (2 to 4%), high levels of non-degradable fibers, slowly ruminal degradation fibers and low content of minerals, especially phosphorus, sulfur, zinc and manganese. Diets containing sugarcane need to be corrected with protein and mineral supplements of good quality [2]. Alkaline hydrolysis has been used in order to reduce fiber levels and increase the consumption by ruminants. It also enables its storage for few days while minimizing costs with work hours. Calcium oxide is a mineral product with better economic value, easy and efficient acquisition and storage because it fixes the calcium content of sugarcane with low risk of contamination [8]. The application of calcium oxide in the sugarcane raises the pH and after aerobic exposure decreases it. This occurs linearly, but it is not interesting, because the drop in pH occurs by action of microorganisms. They consume the soluble carbohydrates and cause acidification of sugarcane, thus the aerobic stability of sugarcane decreases [9]. In the sugarcane hydrolysis in anaerobic environment, i.e., without the exposure of oxygen, theoretically, in the course of time pH gradually decreases less than aerobic hydrolysis exposure, this may result in a less favorable environment for development of aerobic microorganisms, such as yeasts. This study aimed to evaluate the muscularity index, tissue composition, muscle:bone ratio and muscle:fat ratio from legs of Ile de France lambs fed with “in nature” or hydrolyzed sugarcane with 0.6% of calcium oxide. II. MATERIAL AND METHODS The study was conducted at the Faculdade de Ciências Agrárias e Veterinárias - FCAV / Unesp, Jaboticabal, São Paulo. It was used 24 uncastrated lambs Ile de France, animals entered the trial at 15 and were slaughtered at 32 kg of body weight. The treatments were IN: “in nature” sugarcane + concentrate; AER: hydrolyzed sugarcane with 0.6% calcium oxide (CaO) in aerobic environment + concentrate and ANA: hydrolyzed sugarcane with 0.6% with 0.6% CaO + concentrate, providing a completely randomized design with 8 replicates per treatment. Feedlot lambs were raised individually in approximately 1.0m 2 with slatted and suspended floor, equipped with individual feeders and water drinkers installed in covered sheds, with diets contend 21% crude protein (CP), allowing 10% of leavings. V. Endo, A.G. Silva Sobrinho, N.L.L. Lima, G.M. Manzi, L.G.A. Cirne, V.T. Santana, F.A. Almeida Muscularity and Leg Tissue Composition of Lambs Fed with Hydrolyzed Sugarcane T World Academy of Science, Engineering and Technology International Journal of Animal and Veterinary Sciences Vol:6, No:7, 2012 495 International Scholarly and Scientific Research & Innovation 6(7) 2012 ISNI:0000000091950263 Open Science Index, Animal and Veterinary Sciences Vol:6, No:7, 2012 publications.waset.org/10264/pdf