RESUMO: O estudo comparou os resultados econômicos entre cinco grupos de bezerros de raça holandesa com pesos vivos de chegada diferente, mas com idades semelhante em confinamento. Os pesos corporais médios de chegada foram 105, 112, 123 e 129 kg (30, 90, 87, 60 e 30 bezerros, respectivamente) com idade de 113 ± 1-d. Os bezerros foram distribuídos em um desenho não balanceado completamente aleatório. Os bezerros foram pesados da chegada ao confinamento e, posteriormente, nos dias 112, 22 e 361 do estudo. Os bezerros foram alimentados com dietas à base de milho floculado. A dieta de adaptação (2,21 Mcal de NEm / kg MS) foi fornecida durante os 112 dias iniciais de ração. Após 112 até o final do estudo todos os novilhos receberam a dieta de terminação (2,27 Mcal de NEm /kg MS). Diante do exposto, foram avaliados dois períodos parciais de alimentação e um período completo (1 a 112, 113 a 361 e 1 a 361 d, respectivamente). O lucro de cada grupo foi estimado subtraindo o custo de compra dos bezerros mais o custo total da alimentação da receita obtida com a venda dos novilhos. O ganho de peso geral e o consumo de ração aumentaram com o aumento do ABW, mas a eficiência alimentar foi melhor para os grupos intermediários ABW (112 e 117 kg), sendo os novilhos com ABW de 112 kg os mais lucrativos (USD 15, 8 a mais do que o grupo de 117 kg.)

ABSTRACT: The study compared the economic results between five groups of Holstein steers with different arrival body weights (ABW) but similar ages in the feedlot. The average ABW were 105, 112, 117, 123 and 129 kg (30, 90, 87, 60, and 30 calves, respectively) with an age of 113 ± 1d. The calves were randomly distributed using an unbalanced design. The calves were weighed upon arrival at the feedlot and subsequently on days 112, 224, and 361 of the study. The calves were fed a steam- flaked corn-based diets. A receiving diet (2.21 Mcal of NEm/kg DM) was provided during the initial 112 days of feeding. From day 112 until harvest all steers received a finishing diet (2.27 Mcal of NEm/kg DM). Because two different diets were used, two partial (day 1 to day 112 and day 113 to day 361), and one full period (day1 to day 361) feeding periods were evaluated. Statistical differences between the final weights of all the groups were observed, which allowed a profit estimation, obtained by subtracting the purchase cost of calves plus the total feed cost from the revenue obtained from the sale of the steers. Overall weight gain and feed intake were higher with increased ABW, feeding efficiency was better for intermediate ABW groups (112 and 117 kg), with the calves with ABW of 112 kg being the most profitable (USD 15.8 more profit than the 117 Kg. group)

ABSTRACT The effects of purging nut (Jatropha curcas, JCO) supplementation (0, 2, 4, and 6%, DM basis of diet) on carcass traits, tissue composition and conjugated linoleic acids (CLA) concentration in muscle was evaluated in twenty intact male lambs fed a finishing diet during 56 d. The linoleic acid proportion in JCO was 50%. Lambs were harvested at a final weight of 54.03±2.9 kg. There were no treatment effects on hot carcass weight (HCW), longissimus muscle (LM) area nor kidney-pelvic fat. However, as JCO supplementation increased, dressing percentage was decreased and fat thickness was increased. Increasing JCO in diet decreases the proportion of muscle and increases the proportion of fat in whole shoulder clod. Content of stearic acid (C18:0) in LM was not affected by JCO. However, JCO linearly increased total CLA, and hence, the CLA:C18:0 ratio. Empty body or visceral mass were not affected by JCO. Increasing JCO in diet increases visceral fat mainly through increased mesenteric fat. It is concluded that supplemental JCO does not negatively affect HCW and LM area, and represents a viable alternative for increasing CLA concentration in meat of finishing feedlot lambs.

RESUMEN Los efectos de la suplementación (0, 2, 4, y 6%, en base seca de la dieta) de aceite de nuez purgante (Jatropha curcas, JCO) sobre las características de la canal, la composición tisular y la concentración de ácidos linoleicos conjugados (CLA) en músculo se evaluó en veinte corderos machos intactos, alimentados con una dieta de finalización durante un periodo de 56 días. La proporción de ácido linoleico en JCO fue de 50%. Los corderos fueron faenados con un peso final de 54,03 ± 2,9 kg. No hubo efecto de los tratamientos en el peso de la canal caliente (PCC), el área del músculo longissimus (ML) o la grasa pélvica-renal. Sin embargo, a medida que aumentó la suplementación de JCO, se disminuyó el rendimiento de la canal y aumentó el espesor de grasa dorsal. El aumentar JCO en la dieta disminuyó la proporción del músculo y aumentó la proporción de grasa en la paleta. El contenido de ácido esteárico (C18:0) en ML no se vio afectado por JCO. Sin embargo, JCO aumentó linealmente el total de CLA en ML, y por tanto, la proporción CLA:C18:0. El peso corporal vacío o la masa visceral no fueron afectados por JCO. El incrementar JCO en la dieta aumentó la grasa visceral por el aumento de la grasa mesentérica. Se concluye que la suplementación con JCO no afecta negativamente el PCC o el área de ML y representa una alternativa viable para aumentar la concentración total de CLA en la carne de corderos en finalización.

Abstract Fifty Holstein steers calves (121 ± 4 kg) were used in order to determine the effects of route of administration of vitamin E at the time of arrival of feedlot cattle on levels of plasma alphatocopherol concentrations during the initial 16 days following their arrival into the feedlot. Ten steers served as controls, the remaining 40 steers (20 steers/treatment) were injected either intramuscular (IM) or subcutaneous (SQ) with 1500 IU of vitamin E (d-alpha tocopherol). Vitamin E treatments were administered on days 1 and 8 of the arrival, while blood samples were obtained on days 1, 4, 8, 12 and 16. Injection sites were examined visually on day 16 to determine if route of administration affected incidence of injection-site inflammation. Steers were fed a steam-flaked corn based receiving diet with a 72:28 concentrate-to-forage ratio. Plasma alpha-tocopherol concentrations of control steers remained low (range from 0.06 to 0.10 mg/dL) throughout the 16-d period. Vitamin E injection increased (P<0.01) 4-fold the plasma alphatocopherol concentration. Route of vitamin E administration did not influence (P > 0.10) the incidence of injection site inflammation, averaging 17.5% (χ2, P>0.05). Plasma alpha-tocopherol concentrations were not affected (P > 0.30) by the presence of injection site inflammation. Since the risk of lesions in meat are considerably higher with intramuscular application and plasma alpha-tocopherol concentrations were not different between routes of application, it is concluded that subcutaneous administration is a practical alternative to the traditional intramuscular of administration of injectable vitamin E for feedlot cattle.

Resumen Cincuenta becerros Holstein (121 ± 4 kg) se utilizaron con el objetivo de determinar la eficacia de la vía de administración de la vitamina E al tiempo de llegada de los becerros al corral de engorda sobre los niveles de concentración plasmática de alfa-tocoferol durante los primeros 16 días de su llegada al corral. Diez becerros se utilizaron como testigos y los 40 restantes (20 becerros por tratamiento) fueron inyectados con 1500 IU de vitamina E (d-alfa tocoferol) ya sea por vía intramuscular (IM) o por vía subcutánea (SC). Los tratamientos de vitamina E se administraron al primer día y al día 8 de la llegada, mientras que las muestras de sangre se obtuvieron en los días 1, 4, 8, 12 y 16. Los sitios de inyección se examinaron visualmente en el día 16 para determinar si la vía de administración afectaba la incidencia de la inflamación. Los becerros fueron alimentados con una dieta de recepción conteniendo una proporción concentrado: forraje de 72:28. La concentración plasmática de alfa-tocoferol permaneció baja (rango de 0.06 a 0.10 mg/dL) en el grupo testigo durante los 16 días. La inyección de vitamina E incrementó (P<0.01) 4 veces la concentración de alfa-tocoferol en plasma. La vía de administración de vitamina E no influyó (P> 0.10) la incidencia de la inflamación en el lugar de la inyección promediando 17,5% (χ2, P> 0,05). Las concentraciones de alfa-tocoferol en plasma no se vieron afectados (P> 0.30) por la presencia de inflamación en el lugar de inyección. La administración subcutánea de vitamina E inyectable es una alternativa práctica a la tradicional ruta de administración intramuscular.

Mechanical maceration enhances site and extent of digestion of low-moisture, low-quality forages. Four Holstein steers (172 ± 8 kg) with cannulas in rumen and proximal duodenum were used in 4x4 Latin square design to evaluate the process of mechanical maceration of sudangrass hay on the characteristics of ruminal and total tract digestion. Treatments consisted of a steam-flaked corn-based growing diet supplemented with 21 % forage (DM basis) as: i) wheat straw (Triticum aestivum, STRW), ii) sudangrass hay (Sorghum sudanense, SG), iii) macerated SG at intensity of 4,134 kPa (MAC600) and 4) macerated SG at intensity of 6,200 kPa (MAC900). All forages were ground to pass through a 3.8 cm screen before incorporation into complete mixed diets (21:79 forage to concentrate ratio). Maceration did not affect (p ≥ 0.17) on site and extent of OM, N and ADF, and DE of sudangrass supplemented diets. Characteristics of ruminal digestion of OM, ADF, starch, as well as, microbial efficiency (microbial N, g kg-1 of OM fermentad) and protein efficiency (nonammonia N, g g-1 of N intake) were not different (p ≥ 0.11) for wheat straw versus sudangrass supplemented diets. However, total tract digestion of OM, ADF, N, and DE diet were greater (p ≤ 0.05) for sudangrass than for wheat straw supplemented diets. Using the replacement technique, DE value of SG averaged 9.59 MJ kg-1, very close to the expected value given its chemical composition. Mechanical maceration did not enhance the feeding value of sudangrass hay. Increase the intensity of maceration from 4,134 to 6,200 kPa did not altered ruminal or total tract digestion of OM, NDF or energy value of processed hay

Cuatro novillos Holstein (167kg) con cánulas en rumen y duodeno proximal fueron distribuidos en un diseño Cuadro Latino 4×4 para estimar el valor alimenticio comparativo del pasto kikuyo (Pennisetum clandestinum var. Whittet) cosechado en verano e invierno con el de henos de gramínea de verano (pasto sudán; Sorgum sudanense) e invierno (ryegrass anual; Lolium multiflorum var. Oregon). Las dietas experimentales (88,4% MO, 35,5% FDN y 11,8% PC) fueron formuladas con 70% forraje y 30% suplemento. No hubo efecto de tratamientos (P>0,05) en digestión ruminal de la FDN, N, eficiencia microbial ruminal (g de NM/kg de MO fermentada), ni en eficiencia ruminal del N (N no amoniacal que entra a tracto bajo/N consumido). No hubo efecto (P>0,10) de la estación (cosecha en verano vs invierno) en la digestión ruminal y total de la MO, FDN y N en dietas con kikuyo. La digestión ruminal y total de MO, FDN y N fueron similares (P>0,10) para dietas compuestas por kikuyo y sudán. Sin embargo, la digestión ruminal y total de MO y N fue menor (19, 12 y 9%, respectivamente) para dietas con kikuyo a la observada con ryegrass (P<0,05). Las dietas con kikuyo presentaron mayor (P<0,05) proporción molar de acetato y relación acetato/propionato que con ryegrass y sudán. No hubo efecto (P>0,05) en la relación acetato-propionato. Se concluye que kikuyo tiene un valor alimenticio similar a sudán y representa una alternativa en la alimentación animal como cultivo perenne con aceptable valor nutricional durante el verano

Four Holstein steers (167kg) with cannulae in the rumen and proximal duodenum were used in a 4×4 Latin Square design to evaluate the comparative feeding value of seasonal Kikuyugrass hay (Pennisetum clandestinum var. Whittet) harvested in winter and summer vs. summer (Sudangrass; Sorghum sudanense) and winter (Annual Ryegrass; Lolium multiflorum var. Oregon) grass hays. Experimental diets (88.4% OM, 35.5% NDF, and 11.8% CP) were formulated with 70% forage and 30% supplement. There were no effects (P>0.05) on ruminal NDF and N digestion, ruminal microbial efficiency (grams MN/ kg OM fermented) and ruminal N efficiency (non-ammonia N entering the small intestine/ N intake). There were no seasonal effects (summer vs winter harvest; P>0.10) on ruminal and total tract digestion of OM, N or NDF of kikuyugrass-based diets. Ruminal and total tract digestion of OM, NDF and N were similar (P>0.10) for sudangrass- and kikuyugrass-based diets. However, ruminal digestion of OM and total tract digestion of OM and N was lower (19, 12, and 9%, respectively; P<0.05) for the kikuyugrass-based diets than for the annual ryegrass-based diet. Kikuyugrass-based diets had higher (P<0.05) ruminal molar proportions of acetate and acetate/propionate ratio than ryegrass- and sudangrass-based diets. There were no treatment effects (P>0.05) on acetate/propionate ratio. Kikuyugrass has a feeding value similar to that of sudangrass hay and an acceptable nutritive quality in the summer

Quatro novilhos Holstein (167 kg) com cânulas em rúmen e duodeno proximal foram distribuídos em um desenho Quadro Latino 4×4 para estimar o valor alimentício comparativo do capim quicuio (Pennisetum clandestinum var. Whittet) colhido no verão e inverno com o de fenos de gramínea de verão (capim sudão; Sorgum sudanense) e inverno (azevém anual; Lolium multiflorum var. Oregon). As dietas experimentais (88,4% MO, 35,5% FDN e 11,8% PC) foram formuladas com 70% forragem e 30% suplemento. Não houve efeito de tratamentos (P>0,05) em digestão ruminal da FDN, N, eficiência microbial ruminal (g de NM/kg de MO fermentada), nem em eficiência ruminal do N (N não amoniacal que entra a trato baixo/N consumido). Não houve efeito (P>0,10) da estação (colheita no verão vs inverno) na digestão ruminal e total da MO, FDN e N em dietas com quicuio. A digestão ruminal e total de MO, FDN e N foram similares (P>0,10) para dietas compostas por quicuio e sudão. No entanto, a digestão ruminal e total de MO e N foi menor (19, 12 e 9%, respectivamente) para dietas com quicuio à observada com azevém (P<0,05). As dietas com quicuio apresentaram maior (P<0,05) proporção molar de acetato e relação acetato/propionato que com azevém e sudão. Não houve efeito (P>0,05) na relação acetato/propionato. Conclui-se que quicuio tem um valor alimentício similar a sudão e representa uma alternativa na alimentação animal como cultivo perene com aceitável valor nutricional durante o verão

Excluyendo las interacciones asociativas, el valor de EN de las grasas alimenticias es una función altamente relacionada con su digestibilidad intestina. Por lo anterior, una gran atención se ha dirigido para comprender los factores intrínsecos (naturaleza y calidad de la grasa) y extrínsecos (método de adición y nivel de consumo) que afectan su valor como alimento animal. De esos factores, el nivel de consumo de grasa ha demostrado ser el de mayor impacto. Cuando el consumo total de grasa supera la proporción de 0.96 g de grasa/kg de peso vivo, el valor energético de la grasa disminuye en forma lineal como resultado directo de la disminución de la digestibilidad intestinal de los ácidos grasos, principalmente C18:0; lo anterior, posiblemente resultado de una limitada capacidad de producción biliar en el bovino cuando consume altas cantidades de lípidos.

Except for associative interactions, the NE value of dietary fat is largely a function of its intestinal digestibility. Thus, attention has been directed to understanding intrinsic (nature and fat quality) and extrinsic (fat method addition and inclusion level) factors that influence its value as feed. Among these factors, fat intake level has the greatest impact on its energy value. When total fat intake exceeds 0.96g/kg BW, the NE of fat decreases linearly, as a result of the decline in postruminal fatty acid digestibility, mainly of C18:0; the latter probably explained by a limited capacity of bile production in the ruminant at high levels of fat intake.

Excluindo as interações associativas, o valor de EN das gorduras alimentícias é uma função altamente relacionada com sua digestibilidade intestinal. Pelo anterior, uma grande atenção se tem dirigido para compreender os fatores intrínsecos (natureza e qualidade da gordura) e extrínsecos (método de adição e nível de consumo) que afetam seu valor como alimento animal. Desses fatores, o nível de consumo de gordura tem demonstrado ser o de maior impacto. Quando o consumo total de gordura supera a proporção de 0.96 g de gordura/kg de peso vivo, o valor energético da gordura diminui em forma linear como resultado direto da diminuição da digestibilidade intestinal dos ácidos graxos, principalmente C18:0; o anterior, possivelmente resultado de uma limitada capacidade de produção biliar no bovino quando consome altas quantidades de lipídeos.