Resumo O objetivo desta pesquisa foi mensurar o comportamento ingestivo de novilhos terminados exclusivamente com concentrado contendo casca do grão de soja (moída) e/ou grão de aveia branca. Foram utilizados 32 novilhos, com predominâncias raciais Charolês ou Nelore. Os animais foram distribuídos ao acaso nos tratamentos, bloqueados conforme predominância genética e alocados em baias individuais. As dietas foram isonitrogenadas, sendo os tratamentos: Casca do grão de soja; Grão de aveia branca e a Mistura (partes iguais), acrescidos de calcário calcítico e núcleo proteico. Os animais que receberam dieta à base de casca de soja permaneceram mais tempo em ócio, comparados aos que receberam a mistura; estes, por sua vez, permaneceram mais tempo em ócio em relação aos que tiveram acesso à dieta à base de aveia branca. Os novilhos que consumiram dieta à base de casca de soja ruminaram menos tempo que os da mistura e estes, por sua vez, menos tempo que os novilhos alimentados à base de aveia branca. Dietas exclusivamente com concentrado à base de casca de soja, embora apresentem elevado teor de fibra solúvel em detergente neutro, não são suficientes para promover adequado comportamento ingestivo de novilhos de predominância racial Charolês ou Nelore.

Abstract The objective of this research was to measure the ingestive behavior of steers finished exclusively with concentrate containing soybean hulls (ground) and/or white oat grain.We used 32 steers with Charolais or Nellore predominance.The animals were randomly distributed in the treatments, blocked according to genetic predominance, and allocated in individual pens. Diets were isonitrogenous, being the treatments: Soybean hulls; White oat grain or the Mixture (equal parts), plus limestone and protein nucleus. Steers that received the diet based on soybean hulls remained more time in idle compared to the ones that received the mixture, and these remained more time in idle than the steers that received the diet based on white oat grain. Steers that received the diet based on soybean hulls ruminated less time than the steers fed the mixture, and these less time than those fed white oat grain. Exclusively concentrate diets based on soybean hulls although presenting high soluble fiber content in neutral detergent, are not sufficient to promote an appropriate ingestive behavior of steers of Charolais or Nelore racial predominance.

Resumo Este trabalho objetivou avaliar os efeitos da inclusão da borra de soja no comportamento ingestivo de 30 novilhos mestiços Charolês/Nelore, confinados, com 20 meses de idade e peso médio inicial de 328,3 kg. Cada grupo experimental foi composto por seis animais, distribuídos nos tratamentos: 00; 30; 60; 90 e 120 g de borra de soja por 1000 g de matéria seca na dieta, os quais continham 29,0; 47,3; 66,7; 86,8 e 106,8 g de extrato etéreo, respectivamente. O aumento no nível de inclusão de borra de soja na dieta não interferiu no tempo de alimentação, ruminação e ócio (3,11; 13,33 e 7,55 h, respectivamente). As variáveis número de mastigações por bolo, tempo de mastigação por bolo, número de bolos, número de mastigações diárias e tempo de mastigação total (h/dia) (62; 58; 470; 28978 e 10,65, respectivamente) também não sofreram efeito dos tratamentos. O consumo de matéria seca foi similar, em contrapartida, o consumo de fibra detergente neutro (kg/dia) e a eficiência (g FDN/h) da referida fração apresentaram comportamento linear decrescente com aumento da inclusão de borra. A borra de soja pode ser incluída na dieta de novilhos mestiços confinados até o nível de 120 g por 1000 g de matéria seca sem que haja efeitos negativos sobre as principais variáveis relativas ao comportamento ingestivo.

Abstract This study aimed to evaluate the effects of soybean sopastock inclusion on the ingestive behavior of 30 crossbred Charolais / Nellore steers on feedlot, at 20 moths of age and with initial average weight of 328.3 kg. Each experimental group was composed by six animals, distributed into treatments: 00; 30; 60; 90 and 120 g of soybean soapstock per 1,000 g of dry mater in the diet. Each treatment contained 29.0; 47.35; 66.6; 86.8 and 106.8 g of ether extract, respectively. The increase of soybean soapstock in diet did not interfere with feeding, rumination, and idle times (3.11; 13.33 and 7.55 hours, respectively). The variables number of chews per bolus, time of chew per bolus, number of daily chews and total chew time (h/day) (62; 58; 470; 28,978 and 10.65, respectively) also were not affected by the treatments. Dry matter intake was similar among treatments; however, neutral detergent fiber intake (kg/day) and the efficiency of this fraction (g FDN/h) decreased linearly with the inclusion of soybean soapstock to diet. Therefore, the inclusion of soybean soapstock did not change the ingestive behavior of steers, and it can be used in diets of crossbred steers in feedlot up to the level of 120 g per 1000 g of dry matter.

Objetivou-se avaliar os parâmetros produtivos das pastagens de milheto (Pennisetum glaucum (L.) R. BR) e capim sudão (Sorghum bicolor cv. sudanense) submetidas ao pastejo contínuo de vacas destinadas ao abate. O delineamento experimental foi o inteiramente casualizado com dois tratamentos e três períodos, sendo cinco repetições (área). Os parâmetros produtivos das pastagens foram similares na comparação entre os tratamentos (P<0,05). O ciclo vegetativo das pastagens não alteraram a massa de forragem (1.606,93 kg e 1.617,47 de matéria seca (MS)/ha) e a oferta de forragem (9,42 e 8,29 kg de MS/100 kg de PV) das pastagens de milheto ou capim sudão. No entanto, as médias para taxa de acúmulo de matéria seca e proteína bruta demonstraram maiores valores nos primeiros 21 dias de utilização das pastagens (130,77 kg de MS/ha e 17,04 g/kg de MS), seguidas de reduções nos dois últimos períodos, sendo as médias do segundo período (65,53 kg/ha de MS e 12,96 g/kg de MS) superior à do terceiro período experimental (36,13 kg/ha de MS e 10,01 g/kg de MS). Os valores para fibra em detergente neutro foram similares nos dois períodos iniciais (48,81; 49,01 g/kg de MS), seguida de aumento nos últimos 21 dias de utilização das pastagens (56,54 g/kg de MS). A taxa de lotação em kg/ha de PV demonstrou interação entre tratamento e período; no entanto, os valores médios entre os tratamentos foram similares (1741,1 kg/ha de PV para milheto e 1881,7 kg/ha de PV para sudão). Pastagens de milheto ou capim sudão se equivalem em relação às características produtivas, sob sistemas de pastejo contínuo com vacas de descarte.

This study aimed to evaluate the productive parameters of pearl millet (Pennisetum glaucum (L.) R. BR) and Sudan grass (Sorghum bicolor cv. Sudanense) pastures, under continuous grazing by cows destined to slaughter. We used 22 crossbred Charolais and Nellore cows, kept under continuous grazing on Sudan grass or pearl millet pastures, over 63 experimental days, divided into three periods (21 days each). The experimental design was completely randomized with two treatments and three periods, with five replicates (area). The productive parameters of the pastures were similar when treatments were compared (P < 0.05). The growing cycle of pastures did not affect forage mass (1617.47 and 1606.93 kg of dry matter (DM)/ha) and forage offer (9.42 and 8.29 kg of DM/100 kg BW) on pearl millet or Sudan grass pastures. However, the average rate of accumulation of dry matter and crude protein showed higher values on the first 21 days of pasture use (130.77 kg DM/ha and 17.04 g/kg DM), followed by reductions in the last two periods, and the averages of the second period (65.53 kg DM/ha and 12.96 g/kg DM) were higher than those of the third experimental period (36.13 kg DM/ha and 10.01 g/kg DM). The values for neutral detergent fiber were similar in the two earlier periods (48.81, 49.01g/kg DM), followed by an increase in the last 21 days of pasture use (56.54 g/kg DM). The stocking rate in kg/ha of BW showed an interaction between treatment and period, however, the mean values were similar between treatments (1741.1 kg/ha of the BW for pearl millet and 1881.7 kg/ha of BW for Sudan grass). The average daily live weight gain did not differ between treatments (1.04 for pearl millet and 0.96 for Sudan). The average daily gain per area (4.18, 4.55 kg/ha of BW) was similar on the first 42 days of pasture use and higher than on the last 21 experimental days (2.39 kg / ha of BW). Pearl millet or Sudan grass pastures are equivalent with respect to the production characteristics under continuous grazing by culling cows.

Production parameters of intercropped pastures of oat and rye grass managed with beef heifers supplemented with brown rice meal and/or protected fat were evaluated. Twenty-eight Charolais × Nellore crossbred heifers at initial average age of 18 months and initial average live weight of 274.9 kg were utilized in the experiment. Animals were kept on oat + rye grass pastures and distributed in the following treatments: no-supplementation (NS): heifers kept only in pastures; Megalac (MEG): supplementation with protected fat; brown rice meal (BRM): supplementation with BRM; BRM + MEG: supplementation with BRM plus protected fat. The greater participation of oat leaf was from July 5th to August 10th, 2009 and of rye grass, from August 30th to September 26th, 2009. The crude protein content increased until the 55th day (225.1 g/kg). Pasture total digestible nutrients presented a cubic behavior, with an average of 722.0 g/kg. The highest supply of leaf blades, 5.17 kg of dry matter/100 kg of live weight, was found in the second period. Pasture intake increased throughout the periods. Forage mass and support capacity of the animal did not differ between treatments, presenting means of 1245.02 kg of dry matter/ha and 882 kg of live weight/ha, respectively. Stoking rate, forage loss and pasture intake were not affected by the treatments. Supplementation of beef heifers with rice meal and/or protected fat did not change production parameters of oat + rye grass pastures or pasture intake. Increase in daily accumulation rate of dry matter and supporting capacity of the animals increases forage losses.

The objective of this study was to evaluate behavior patterns of heifers grazing on black oat (Avena strigosa Schreb.) and ryegrass (Lolium multiflorum Lam.), fed supplementation with brown rice meal and/or protected fat. A total of 28 Charolais × Nellore crossbred heifers at average initial age of 18 months and with initial live weight of 274.9±4.97 kg were used in the experiment. Animals were kept in oat + ryegrass pastures and distributed in the following treatments: no supplementation; Megalac (MEG): protected fat supplementation; supplementation with brown rice meal (BRM); and supplementation with BRM + MEG. The neutral detergent fiber (NDF) intake of pasture either in kg or in percentage of live weight was not changed by supply of supplement, but increased linearly (0.045 kg per day) over grazing periods. Supplementation with BRM and BRM + MEG reduced grazing time, 49.63%, in relation to non-supplemented animals and animals supplemented with MEG, 63.13%. Feeding seasons per minute increased over the experimental period with reduction in time spent in each feeding station. The number of bites per feeding station decreased linearly, with a variation of 34.48% in the late grazing period. Heifers supplemented with BRM and BRM + MEG require less time for grazing and increase their idle time, with no modification in displacement patterns within the paddocks and pasture ingestion. Grazing and idle time does not change in the distinct periods of pasture use, but rumination time increases with days of pasture use and with increase in NDF intake.

O estudo foi realizado com o objetivo de avaliar as características de carcaça de novilhos e vacas de descarte de dois grupos genéticos sob diferentes frequencias de alimentação. Foram utilizados 12 novilhos e 12 vacas de descarte, de modo que cada categoria foi formada de seis animais 5/8 Charolês (C) - Nelore (N) e seis animais 5/8NC, submetidos a três frequencias alimentação; duas vezes ao dia (às 7 e 19 h); três vezes ao dia (às 7, 13 e 19 h); e quatro vezes ao dia (às 7, 11, 15 e 19 h). Os animais foram terminados em confinamento recebendo como volumoso silagem de milho e concentrado à base de farelo de trigo, grão de milho moído, farelo de soja, calcário calcítico e sal, com relação volumoso:concentrado 40:60. O aumento na frequência de alimentação não influenciou a qualidade da carcaça dos animais. As vacas apresentaram maiores pesos de abate e de carcaça quente e fria (509,7; 280,0; e 277,1 kg) em comparação aos novilhos (414,5; 230,5 e 228,1 kg), no entanto, os rendimentos de carcaça quente e fria e as perdas por resfriamento foram semelhantes entre novilhos e vacas de descarte. As características que expressam a musculosidade da carcaça foram melhores nas vacas, que apresentaram maior espessura de coxão (25,88 vs 23,33 cm). As características métricas foram mais expressivas nas vacas, que tiveram carcaças mais longas (132,8 vs 122,3 cm) e maior espessura de gordura (6,21 vs 3,83 mm). As vacas também foram superiores quanto aos pesos de dianteiro e traseiro (103,5 e 133,0 kg) em comparação aos novilhos (84,7 e 111,8 kg), que apresentaram maior percentual de traseiro na carcaça (49,06 vs 48,04%). Entre os grupos genéticos, os animais 5/8C 3/8N apresentaram maior espessura de coxão, área do músculo Longissimus dorsi e comprimento de carcaça (25,7 cm; 64,0 cm² e 137,0 cm) em comparação aos 5/8N 3/8C (23,5 cm; 57,0 cm² e 124,8 cm).

The objective of this study was to evaluate carcass characteristics of steers and cull cows from two genetic groups, under different feeding frequencies. Twelve steers and twelve cull cows were used and each category consisted of six animals 5/8 Charolais (C) - Nellore (N) and six animals 5/8NC, under three feeding frequencies: twice a day (7 a.m. and 7 p.m.); three times a day (7 a.m., 1 p.m. and 7 p.m.) and four times a day (7 a.m., 11 a.m., 3 p.m. and 7 p.m.). The animals were feedlot finished receiving corn silage as forage and concentrate based on wheat bran, corn ground, soybean meal, limestone and salt, with a forage:concentrate ratio of 40:60. The increase in feeding frequency did not influence the animal carcass quality. The cows showed higher slaughter, hot and cold carcass weights (509.7; 280.0; and 277.1 kg) compared to the steers (414.5; 230.5 and 228.1 kg), but the hot and cold carcass dressing percentages and carcass chilling loss were similar in the steers and cull cows. The characteristics that express carcass muscularity were better in the cows that had greater thigh thickness (25.88 vs 23.33 cm). The metrical characteristics were more expressive in the cows which had longer carcasses (132.8 vc 122.3 cm) and greater fat thickness (6.21 vs 3.83 mm). The cows also were superior for forequarter and sawcut weights (103.5 and 133 kg) compared to the steers (84.7 and 111.8 kg), which presented higher sawcut percentage in the carcass (49.06 vs 48.04%). Between the genetic groups, 5/8C3/8N animals presented higher thigh thickness, Longissimus dorsi area and carcass length (25.7 cm; 64 cm² and 137 cm) compared to 5/8N3/8C (23.5 cm; 57 cm² and 124.8 cm).