This study evaluated the effects of narasin on intake and rumen fermentation characteristics of Bos indicus steers offered a high-forage diet for 140 d. On day 0 of the study, 30 rumen-fistulated Nellore steers [initial body weight (BW) = 281 ± 21 kg] were assigned to 30 individual pens in a randomized complete block design according to their initial BW. Animals were randomly assigned to 1 of the 3 treatments: 1) forage-based diet without narasin (CONT; n = 10), 2) CONT diet plus 13 ppm of narasin (13NAR; n = 10), and 3) CONT diet plus 20 ppm of narasin (20NAR; n = 10). The forage used was Tifton-85 (Cynodon dactylon spp.), whereas the carrier for narasin was a 50:50 mixture of soybean hull:corn. The experimental period was divided into 5 periods of 28 d each. Throughout the experimental period, total dry matter intake (DMI) was recorded daily, whereas mineral salt intake was recorded weekly. Blood and ruminal fluid samples were collected on day 0 (prior to treatment feeding), 28, 56, 84, 112, and 140 of the study. Moreover, total tract apparent nutrient digestibility was performed for a 5-d period every 28 d. No treatment effects were observed on forage, mineral, concentrate, or total DMI (P ≥ 0.22). Nonetheless, 13NAR tended to have a greater mineral intake vs. 20NAR cohorts (P = 0.08) Narasin-supplemented animals had reduced rumen acetate, Ac:Pr ratio, as well as greater (P ≤ 0.02) rumen propionate concentrations vs. CONT cohorts. Moreover, 13NAR increased rumen propionate and decreased butyrate, Ac:Pr vs. 20NAR cohorts (P ≤ 0.01). Throughout the experimental period, narasin-supplemented animals had reduced ammonia concentrations vs. CONT cohorts (P < 0.01), whereas no differences were observed between 13NAR and 20NAR (P = 0.80). No treatment or dose effects were observed (P ≥ 0.23) on DM, organic matter (OM), protein, neutral detergent fiber (NDF), acid detergent fiber (ADF), and mineral digestibility. Animals fed 13NAR had a reduced mean plasma urea concentration vs. CONT cohorts (P = 0.03), whereas no further differences were observed (P ≥ 0.12). In summary, narasin supplementation to beef steers offered a high-forage diet did not impact forage, mineral, and total DMI, as well as nutrient digestibility, whereas rumen fermentation characteristics, rumen ammonia, and plasma urea concentrations were positively impacted and lasted throughout the experimental period. Additionally, 13 ppm of narasin resulted in a reduced Ac:Pr ratio and rumen ammonia when compared to animals supplemented with 20 ppm.

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Resumo -O objetivo deste trabalho foi avaliar a influência de grãos de soja (GS) no desempenho, características e rendimento de cortes de carcaça de cordeiros confinados. Sessenta e quatro cordeiros Santa Inês, com peso vivo inicial de 19,5±0,19 kg e 75±2 dias de idade, foram distribuídos em blocos ao acaso de acordo com o peso vivo e a idade no início do experimento. Os GS participaram com 0, 7, 14 e 21% na matéria seca (MS) das rações isonitrogenadas experimentais. O consumo de MS (1,1, 1,0, 0,9 e 0,9 kg por dia), proteína bruta (199,2, 181,5, 179,0 e 175,2 g por dia) e o ganho de peso vivo (298, 275, 280 e 255 g por dia) diminuíram linearmente, e o consumo de extrato etéreo (43,8, 49,7, 57,2 e 66,0 g por dia) aumentou linearmente com o aumento da participação de GS nas rações. Não houve efeito na conversão alimentar, características e rendimento de cortes da carcaça. A inclusão de GS na ração com alto teor de concentrado proporciona desempenho satisfatório aos cordeiros em confinamento.Termos para indexação: confinamento, gordura, Santa Inês, ovino. Performance and carcass characteristics of feedlot lambs fed raw soybeanAbstract -The objective of this work was to evaluate the effects of raw soybean on lamb performance, carcass yield and lamb cuts. Raw soybean was added at 0, 7, 14 and 21% of the diet dry matter (isonitrogenous). Sixtyfour Santa Inês lambs (initial body weight 19.5±0.19 kg and 75±2 days old) were assigned to a complete randomized block design according to body weight and age at beginning of the trial. Dry matter intake (1.1, 1.0, 0.9 and 0.9 kg per day), crude protein intake (199.2, 181.5, 179.0 and 175.2 g per day) and average daily gain (298, 275, 280, 255 g per day) decreased linearly, and ether extract intake (43.8, 49.7, 57.2 and 66.0 g per day) increased linearly, as levels of raw soybean increased. Feed conversion, carcass yield and lamb cuts were not affected by raw soybean inclusion in the diet. The inclusion of raw soybean in high concentrate diets provides satisfactory feedlot lamb performance.Index terms: feedlot, fat, Santa Inês, sheep. IntroduçãoO rebanho nacional de ovinos é de aproximadamente 15 milhões de cabeças, representando 1,4% do efetivo mundial, e concentra-se nas regiões Sul (30%) e Nordeste (58%) (Brasil, 2006). A produção de carne é uma atividade alternativa, capaz de aumentar a renda nos negócios, não só de ovinocultores, mas de toda a atividade rural.Apesar de a população brasileira não ter o hábito de consumir carne ovina, observa-se aumento do consumo nos últimos anos. O consumo per capita de carnes no Brasil é da ordem de 65 kg por ano; o consumo de carne de ovinos é de 0,7 kg por ano (Couto, 2001), valor considerado subestimado, já que a maior parte do comércio de carne ovina é informal.Ao se considerar o elevado custo da terra, principalmente na Região Sudeste, o confinamento é uma estratégia capaz de satisfazer tanto o produtor quanto o consumidor, uma vez que permite reduzir o ciclo de produção e disponibilizar ao mercado carcaças de animais jovens e, conse...

Quatro vacas lactantes, em arranjo fatorial 2x2, no delineamento Quadrado Latino 4x4, receberam os seguintes tratamentos: milho moído grosso; milho floculado; moído grosso + polpa cítrica; floculado + polpa cítrica. A floculação (efeito processamento) aumentou as digestibilidades aparentes (%) no trato total da MS, MO, amido e proteína, reduziu a concentração de N-NH 3 ruminal, a proporção de acetato, mas aumentou propionato. A floculação tendeu a aumentar eficência alimentar percentual e produção de proteína do leite. Inclusão de polpa não afetou a ingestão de MS e aumentou digestibilidade de fibra. Inclusão de polpa aumentou a digestibilidade do amido (%) no tratamento moído grosso. Amonia ruminal e proporção de propionato não foram afetadas pela inclusão de polpa, mas houve significativo aumento de acetato. Houve interação processamento x polpa sobre concentração de glicose plasmática. Produção de leite corrigida, eficiência alimentar, percentual e produção de gordura do leite aumentaram com a inclusão de polpa.

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The aim of the present study was to evaluate the inclusion of narasin, salinomycin, or flavomycin for 140 d on ruminal fermentation parameters, apparent nutrient digestibility, and performance of Nellore cattle offered a forage-based diet. In experiment 1, 32 rumen-cannulated Bos indicus Nellore steers [initial body weight (BW) = 220 ± 12.6 kg] were assigned to individual pens in a randomized complete block design according to their initial shrunk BW. Within block, animals were randomly assigned to 1 of 4 treatments: (1) forage-based diet without feed additives (CON; n = 8), (2) CON diet plus 13 ppm of narasin (NAR; n = 8), (3) CON diet plus 20 ppm of salinomycin (SAL; n = 8), or (4) CON diet plus 3 ppm of flavomycin (FLA; n = 8). The experimental period lasted 140 d and was divided into 5 periods of 28 d each. The inclusion of feed additives did not impact (P ≥ 0.17) dry matter intake (DMI), nutrient intake, and apparent total tract digestibility of nutrients. Nonetheless, steers fed NAR had lower (P < 0.01) molar proportion of acetate compared with CON, SAL, and FLA steers, whereas ruminal acetate tended to be greater (P < 0.09) for SAL vs. CON and FLA, but did not differ (P = 0.68) between CON vs. FLA steers. Ruminal propionate was the highest (P < 0.01) for steers fed NAR and did not differ (P > 0.20) between CON, SAL, and FLA. Consequently, NAR steers had the lowest (P < 0.01) Ac:Pr ratio, whereas Ac:Pr did not differ (P > 0.18) among CON, SAL, and FLA. Total volatile fatty acids were greater (P < 0.04) for NAR and CON vs. SAL and FLA, but did not differ (P > 0.67) among NAR vs. CON and SAL vs. FLA. In experiment 2, 164 Nellore bulls (initial shrunk BW = 299 ± 2.5 kg) were assigned to feedlot pens for 140 d in a randomized complete block design. Within block (n = 10), animals were randomly assigned to the same treatments used in experiment 1. Average daily gain was greater (P < 0.01) in NAR vs. CON, SAL, and FLA bulls, and did not differ (P > 0.12) between CON, SAL, and FLA bulls. Bulls fed NAR had greater (P < 0.02) DMI (as kg/d or % BW) and final shrunk BW compared with CON, SAL, and FLA bulls, whereas DMI and final shrunk BW did not differ (P > 0.26) between CON, SAL, and FLA bulls. Feed efficiency, however, was not impacted (P = 0.51) by any feed additives used herein. Collectively, narasin was the only feed additive that benefited performance and ruminal fermentation of Nellore animals fed a forage-based diet.

Four primiparous Holstein cows were used in an experiment with a 5 x 4 Youden square design. The effects of heat processing and particle size of cottonseed used in the diets of dairy cows were investigated. Dietary treatments were control (3.6% tallow, 4.5% casein), whole cottonseed, ground cottonseed, roasted whole cottonseed, and roasted ground cottonseed. Diets consisted of 55% corn silage, 1.54% urea, and cottonseed at 18.1% or dry matter. Cottonseeds were roasted at 149 degrees C and steeped for 30 min. Roasting increased the amount of ruminally undegradable protein measured in vivo, the ratio of ruminal acetate to propionate, pH, and milk protein percentage. Ruminal digestibilities of organic matter (OM) and neutral detergent fiber and biohydrogenation of fatty acids were reduced by roasting. The grinding of cottonseed increased the total tract digestibility of OM and N and tended to increase ruminally undegradable protein of cottonseed in vivo. Interactions between heat treatment and particle size of cottonseed revealed that roasted ground cottonseed resulted in the highest total tract digestibility of OM, N, and neutral detergent fiber. Utilization of cottonseed may be improved by heat or mechanical processing as was indicated by this study.

RESUMO -Objetivou-se avaliar os efeitos do fornecimento de polpa cítrica na dieta sobre as características de carcaça e a qualidade da carne de cordeiros em confinamento. Utilizaram-se 32 cordeiros Santa Inês distribuídos em delineamento de blocos completos casualizados com quatro tratamentos e oito repetições, os quais foram definidos pelo peso e pela idade dos animais no início do experimento de desempenho. Os animais foram alimentados com rações contendo 90% de concentrado (milho moído e/ou polpa cítrica, farelo de soja e minerais) e 10% de feno de coastcross