SUMMARYThe purpose of the current study was to evaluate the effect of different levels of crude glycerine (CG, 810·9 g glycerol/kg) replacing dry ground maize on intake, digestibility, microbial nitrogen (N) synthesis and N utilization in grazing beef cattle. Five Nellore bulls (332 ± 29·6 kg initial body weight (BW)) were used in a 5 × 5 Latin square design. The animals grazed five Marandu grass (Urochloa brizantha cv. Marandu) paddocks of approximately 0·32 ha. Five supplements were evaluated: mineral supplementation (control, only ad libitum access to a mineral mixture) and 4 g of protein-energy supplementation/kg of BW with four levels of CG (0, 330, 660 and 1000 g/kg) replacing dry ground maize. Bulls that received protein-energy supplementation had greater organic matter (OM) pasture and digested OM (DOM) intakes than the control. No differences were observed among CG levels with regard to OM pasture, neutral detergent fibre and DOM intakes. However, ether extract intake increased linearly as CG levels increased. Protein-energy supplementation enhanced efficiency of microbial N synthesis, N balance and ammonia concentration, but they were not influenced by the CG levels. In conclusion, partial or total replacement of dry ground maize by CG in protein-energy supplements for grazing beef cattle exerted no changes on pasture intake, digestibility and N utilization. Therefore, the use of CG as an energy source in supplements for grazing cattle can be recommended.

Objetivou-se avaliar o efeito dos níveis de suplementação sobre o desempenho de bovinos em sistema de terminação no período das águas em pastagem de capim Panicum maximum cv. Mombaça e sua viabilidade econômica. No experimento foram utilizados 68 bovinos não castrados da raça Nelore, sendo conduzido segundo delineamento inteiramente casualizado, com dois níveis de suplementação de concentrado na proporção de 1,2% e 1,8% peso vivo (PV) com base na matéria seca (MS). Os níveis de suplementação não diferiram nos pesos corporais dos animais nas pesagens feitas durante o experimento e final. Os animais suplementados com 1,8% do PV obtiveram maior ganho de peso total, área de olho de lombo final e espessura de gordura subcutâneo final. Os níveis de suplemento não influenciaram significativamente no peso de carcaça quente, conformação da carcaça e rendimento da carcaça. Os animais que receberam o maior nível de suplementação tiveram maior acabamento da carcaça. O maior nível de suplementação gerou maior custo inicial, médio, final e maior custo por ganho de peso dos animais. Assim, a suplementação com 1,2% do PV resulta em menor custo por quilo de carne produzida, sendo o mais indicado para bovinos terminados a pasto.Palavras-chave: análise econômica, confinamento a pasto, Panicum maximum cv. Mombaça, pastejo, terminação. EFFECT OF SUPPLEMENTATION LEVELS ON BEEF CATTLE PERFORMANCE IN SEMI-CONFINED SYSTEMS ABSTRACT: The objective of this study was to evaluate the effect of the supplementation levels on the performance of cattle in the finishing system in the period of waters in pasture of Panicum maximum cv. Mombasa and its economic viability. In the experiment, 68 Nellore bulls were used, and were conducted in a completely randomized design with two levels of concentrate supplementation at the ratio of 1.2% and 1.8% live weight (LW) based on the dry matter (DM). Supplementation levels did not differ in body weights of animals during weighing done during the experiment and final. The animals supplemented with 1.8% of the LW obtained greater total weight gain, final loin eye area and final subcutaneous fat thickness. Supplement levels did not significantly influence hot carcass weight, carcass conformation, and carcass yield. The animals that received the highest level of supplementation had a better finishing of the carcass. The higher level of supplementation generated higher initial, average, final cost and higher cost for weight gain of the animals. Thus, the supplementation with 1.2% of the LW results in a lower cost per kilogram of meat produced, being the most suitable for beef cattle.Keywords: economic analysis, feedlot in pasture, Panicum maximum cv. Mombaça, grazing, termination.

ResumoNas últimas décadas o mercado brasileiro de carne ovina aumentou substancialmente, e o estado de Mato Grosso apresentou a maior taxa de crescimento do Brasil, apesar da falta de informações sobre os sistemas de produção nesta região. Este estudo teve como objetivo caracterizar os sistemas de produção de ovinos da região meio-norte do Mato Grosso, utilizando um questionário com perguntas qualitativas e quantitativas. Dentre as 40 propriedades avaliadas foram predominantes (82,5%; 33/40) rebanhos com menos de 100 animais, com exploração semi-intensiva, voltada para a produção de carne. A ovinocultura foi citada como atividade econômica secundária em 92,5% (37/40) dos rebanhos e, em 60,0% (24/40) das propriedades, os animais eram mantidos apenas para consumo familiar. O manejo sanitário deficiente resultou na ocorrência de diversas doenças, sendo os casos de miíases os mais citados (65,0%; 26/40). A ovinocultura possui grande potencial para o desenvolvimento em Mato Grosso. No entanto, a atividade ainda é negligenciada em muitos aspectos, incluindo a saúde animal.Palavras-chave: ovinocultura, perfil dos rebanhos, saúde animal. AbstractIn recent decades, the Brazilian market for sheep meat has increased substantially, and the State of Mato Grosso had the highest growth rate in Brazil. However, information about ovine production systems in this region is lacking. This study aimed to characterize productive systems of sheep in the medium northern region of Mato Grosso, by application of qualitative and quantitative questionnaires. Among 40 properties evaluated, herds there were predominately with fewer than 100 animals (82.5%, 33/40), with semi-intensive exploration focused on meat production. Livestock sheep was a secondary economic activity in 92.5% (37/40) of farms, and sheep were kept only for family consumption in 60.0% (24/40). Poor health management resulted in the occurrence of various diseases, and myiasis was the most frequently cited disease (65.0%, 26/40). Sheep farming has a great potential for development in Mato Grosso. However, the activity is neglected in many ways, including animal health.