The objective of this study was to evaluate the effects of dietary addition of ground oilseed sources on the quality, fatty acid profile, and CLA content of meat from zebu steers. Thirty-one zebu steers with an initial average age of 23 mo and an initial BW of 365 kg were used in this study. The experimental period was 84 d, which was preceded by an adaption period of 28 d. The diet was provided ad libitum with a forage:concentrate ratio of 40:60. Corn silage was used as the forage source. Four different concentrates were formulated for each treatment: without additional lipids (control) or with ground soybeans (SB), ground cottonseed (CS), or ground linseed (LS). The SB, CS, and LS diets were formulated to have 6.5% ether extract on a total dietary DM basis. The experiment was set up as a completely randomized design. After slaughter, samples were taken from the longissimus thoracis muscle for the measurement of fatty acid concentration and the evaluation of meat quality. The luminosity index was greater in the control and LS diets (P < 0.01). The greatest percentages of myristic acid (C14:0), palmitic acid (C16:0), trans octadecenoic acid (C18:1 trans-10, trans-11, or trans-12), and SFA in the subcutaneous fat were observed in the CS treatment (P < 0.01). Moreover, the least percentages of oleic acid (C18:1 cis-9) and total unsaturated fatty acids in the subcutaneous fat were observed in the CS diet (P < 0.01). The meat linoleic acid and α-linolenic acid percentages were greatest in the SB and LS treatments, respectively (P < 0.001). The unsaturated fatty acid:SFA ratio was smallest for the CS diet (P < 0.01). A gradual increase in oxidation was observed as a function of storage time; however, the diets did not affect the rancidity of the meat (P > 0.05). The fatty acid profile of subcutaneous fat was impaired by the addition of CS. Supplying ground oilseeds did not increase the content of CLA in the meat.

The objective of the present study was to evaluate the meat quality and fatty acid (FA) profile of the muscle and subcutaneous fat of young bulls fed ground soybean grain (SB) or rumen protected fat (RPF) with (230 mg head(-1) day(-1)) or without monensin. Forty animals with an initial weight of 359 kg were allotted in a 2×2 factorial arrangement of treatments. The use of monensin increased the arachidonic and α-linolenic acids in the longissimus dorsi (LD) muscle and subcutaneous fat, respectively (P<0.05). The meat from the animals receiving RPF had greater C18:1 content (P<0.01). The CLA and C18:2 contents were greater in the LD muscle of the animals fed SB (P<0.01). However, α-C18:3 was greater in the LD muscle of animals fed RPF (P<0.01). In the subcutaneous fat, SB reduced C12:0 and C14:0 contents (P<0.01) and increased C18:0 (P<0.05). The inclusion of RPF increased the C18:1 and CLA contents (P<0.01) in the subcutaneous fat. Soybean elevated PUFA contents and increased susceptibility of muscle and subcutaneous fat to lipid oxidation.

Our objective was to evaluate carcass and meat characteristics of Guzerat-crossbred bulls finished in feedlot. Carcasses from 18 bulls, randomly selected from a larger group of 36 bulls, consisting of F1 Guzerat×Holstein ("Guzholstein"); F1 Guzerat×Nellore ("Guzonell"); and 1/2 Simmental+1/4 Guzerat+1/4 Nellore (Three-Cross; n=6 each group) were used. Cold carcass weight was greater (P=0.01) for Three-Cross compared with "Guzonell" and "Guzholstein". Three-Cross carcasses had greater (P<0.01) rib-eye-area and 100-kg-adjusted rib-eye-area among groups. Longissimus lumborum length did not differ (P>0.05) among groups, but depth was greater (P<0.01) for Three-Cross compared with other groups. "Guzholtein" had lesser (P=0.05) shear force compared with "Guzonell", with Three-Cross being intermediate. We conclude that "Guzholstein" is an adequate option for producers willing to finish this kind of genetic group, as it is comparable or better than Bos indicus crosses and B. indicus×Bos taurus bulls.

The objective of this study was to evaluate the fatty acid profile and qualitative characteristics of meat from feedlot young bulls fed ground soybean or ground cottonseed, with or without supplementation of vitamin E. A total of 40 Red Norte young bulls, with an initial average age of 20 months, and an initial average BW of 339 ± 15 kg, were allotted in a completely randomized design using a 2 × 2 factorial arrangement, with two oilseeds, and daily supplementation or not of 2500 IU of vitamin E. The experimental period was for 84 days, which was preceded by an adaptation period of 28 days. The treatments were ground soybean (SB), ground soybean plus vitamin E (SBE), ground cottonseed (CS) and ground cottonseed plus vitamin E (CSE). The percentage of cottonseed and soybean in the diets (dry matter basis) was 24% and 20%, respectively. Diets were isonitrogenous (13% CP) and presented similar amount of ether extract (6.5%). The animals were slaughtered at average live weight of 464 ± 15 kg, and samples were taken from the longissimus dorsi muscle for the measurement of fatty acid concentration and the evaluation of lipid oxidation and color of the beef. Before fatty acid extraction, muscle tissue and subcutaneous fat of the longissimus dorsi were separated to analyze fatty acid profile in both tissues. Supplementation of vitamin E did not affect fatty acid concentration, lipid oxidation and color (P > 0.05). Subcutaneous fat from animals fed CS diet had greater C12:0, C16:0 and C18:0 contents (P < 0.03). In addition, CS diets reduced the C18:1 and C18:2 cis-9, trans-11 contents in subcutaneous fat (P < 0.05). The muscle from animals fed CS tended to higher C16:0 and C18:0 contents (P < 0.11), and decreased C18:1, C18:2 cis-9, trans-11 and C18:3 contents (P < 0.05) compared with SB. The Δ 9 -desaturase index was greater in muscle from animals fed SB (P < 0.01). At 42 days of age, meat from cattle fed SB had a greater lipid oxidation rate (P < 0.05). Meat from animals fed SB diets had less lightness and redness indices than meat from animals fed CS diets after 14 days of age. In conclusion, the addition of ground cottonseed in the finishing diets did increase the saturated fatty acid content of the longissimus dorsi. However, animals fed cottonseed exhibited greater lightness and redness of beef. In this study, the addition of vitamin E did not affect qualitative characteristics of meat.

RESUMO: Objetivou-se avaliar a viabilidade econômica do confinamento de ovinos alimentados com dietas contendo diferentes fontes volumosas. Foram utilizados 21 ovinos machos Santa Inês, não castrados, distribuídos em três tratamentos: silagem de milho (SM); palma forrageira associada ao bagaço de cana-de-açúcar (BC); palma forrageira associada ao feno de Tifton 85 (FT) em delineamento inteiramente casualizado. Foi avaliada a viabilidade econômica e os parâmetros produtivos dos ovinos em cada dieta ofertada. Os ovinos do tratamento FT tiveram maior (P<0,05) ganho em peso, melhor conversão alimentar e menor custo de produção. Os ovinos alimentados com SM apresentaram o pior (P<0,05) desempenho e os maiores custos de produção. Os ovinos alimentados com BC não diferiram (P>0,05) quanto ao desempenho produtivo dos demais tratamentos. Os custos superaram a receita resultando em rentabilidade negativa para as dietas testadas. A terminação em confinamento, com dietas a base de silagem de milho, feno de Tifton 85 associada à palma ou bagaço de cana associada à palma, apresenta alto custo de produção e inviabiliza a atividade.Palavras-chave: custos de produção, feno de Tifton 85, palma forrageira, silagem de milho, confinamento. ECONOMIC VIABILITY OF THE USE OF DIFFERENT ROUGHAGE SOURCES IN SHEEP FEEDLOT DIETSABSTRACT: The objective of this study was to evaluate the economic viability of feedlotting sheep fed diets containing different roughage sources. Twenty-one uncastrated male Santa Ines sheep were assigned to three treatments in a completely randomized design: corn silage (CS); forage palm combined with sugarcane bagasse (SB), and forage palm combined with Tifton 85 hay (TH). Economic viability and productive parameters of the animals were evaluated in each treatment. Animals of treatment TH had higher weight gain, better feed conversion, and lower productions costs (P<0.05). The worst performance and highest productions costs were observed for sheep fed CS (P<0.05). Sheep fed SB did not differ (P>0.05) in productive performance from the other treatments. The costs exceeded the revenue, resulting in negative profit for the diets tested. The high production costs of feedlot finishing using diets based on corn silage or palm combined with Tifton 85 hay or sugarcane bagasse make this activity unfeasible.