Abstract The objective of the meta-analysis was to evaluate the effects of beef cows weight variation during the 2nd and / or 3rd trimester pregnancy on some parameters of the progeny carcass. The cow weight gain during this gestational period was calculated to standardize the treatments: moderate loss (ML= cows that lost 0 to 5 % of weight) and moderate gain (MG= cows that gained 0 to 5 % of weight). The effect size for all parameters was calculated as medium difference (MD) with a 95% confidence interval and heterogeneity determined using the Q test and the I2 statistic. A random effects meta-analysis was performed for each indicator separately as the medium control and experimental groups. The cow’s weight variation during the studied time variation did not influence the progeny carcass characteristics (P>0.05). Although, a trend towards greater hot carcass weight (P=0.15) and thickness of subcutaneous fat (P=0.10) was observed in calves from MG cows in relation to calves from ML cows. However, the meta-analysis demonstrated that small variations in cow weight during the final half of pregnancy do not affect progeny carcass characteristics.

Resumen El objetivo del meta análisis fue evaluar los efectos de la variación del peso de vacas de carne durante el 2º y/o 3º trimestre de gestación en algunos parámetros de la canal de la progenie. La ganancia de peso de la vaca durante este período gestacional se calculó para estandarizar los tratamientos: pérdida moderada (PM= vacas que perdieron de 0 a 5 % de peso) y ganancia moderada (GM= vacas que ganaron de 0 a 5 % de peso). El tamaño del efecto para todos los parámetros se calculó como la diferencia de medias (DM) con un intervalo de confianza del 95 % y la heterogeneidad se determinó utilizando la prueba Q y el estadístico I2. Se realizó un meta análisis de efectos aleatorios para cada indicador por separado como grupo de control medio y experimental. La variación del peso de la vaca durante la variación de tiempo estudiada no influyó en las características de la canal de la progenie (P>0.05). Aunque se observó una tendencia hacia un mayor peso de la canal caliente (P=0.15) y del grosor de la grasa subcutánea (P=0.10) en terneros de vacas GM en relación con terneros de vacas PM. Sin embargo, el meta análisis demostró que las pequeñas variaciones en el peso de la vaca durante la mitad final de la gestación no afectan las características de la canal de la progenie.

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.

Objetivou-se com este estudo avaliar os parâmetros comportamentais e as estratégias de deslocamento e alimentação de vacas de descarte em pastagens de milheto ou capim sudão. Os tratamentos consistiram em: pastagem de milheto (Pennisetum americanum (L.) Leeke) ou pastagem de capim sudão (Sorghum bicolor cv. sudanense), ambos tratamentos submetidos ao pastejo contínuo de vacas de descarte, ao longo de 63 dias experimentais, subdividido em três períodos. Foram utilizadas 20 vacas de descarte cruza Charolês x Nelore, de idade média de 8 anos e peso vivo médio inicial de 445 kg. Os animais foram distribuídos em 10 piquetes, sendo utilizados cinco piquetes para cada tratamento comportando duas vacas. As avaliações comportamentais foram realizadas durante 24 horas ininterruptas. O delineamento experimental foi inteiramente casualizado com 2 tratamentos e 3 períodos de avaliação. O tempo de pastejo das vacas apresentou interação (P=0,0035) entre tratamento e período, sendo o menor tempo destinado à atividade no primeiro período na pastagem de milheto (504 minutos) comparado com o segundo período desse mesmo tratamento (587 minutos) e terceiro período nas pastagens de capim sudão (535 minutos). Os tempos de ruminação e ócio foram semelhantes entre os tratamentos; no entanto, o de ócio diminuiu e o de ruminação aumentou com o avanço dos períodos. As espécies de forrageiras não influenciaram as variáveis relacionadas às estratégias de deslocamento e alimentação. Com o avanço do ciclo das pastagens, o número de passos por minuto, estações por minuto e por dia diminuíram enquanto a taxa de bocado e número de bocados por dia aumentaram. Os parâmetros comportamentais de vacas de descarte em pastagens de milheto ou capim sudão são similares; no entanto, o avanço do ciclo vegetativo dessas espécies proporciona modificações no padrão comportamental dos animais.

The objective of this study was to evaluate the behavioral parameters and strategies of displacement and feeding of cull cows grazing millet or sudan grass. The treatments consisted of: pearl millet (Pennisetum americanum (L.) Leeke) or sudan grass (Sorghum bicolor cv. Sudanense). Both treatments were submitted to continuous grazing of cull cows over 63 experimental days subdivided into three periods. Using 20 Charolais x Nellore cull cows, at the average age of 8 years and average weight of 445 kg. The animals were divided into 10 paddocks, five paddocks used for each treatment comprising two cows. The behavioral assessments were carried out for 24 hours straight. The experimental design was completely randomized with two treatments and three periods. The grazing time of cows showed interaction (P = 0.0035) between treatment and period, and the shortest time for the activity in the first period on pearl millet (504 minutes) compared to the second period of that same treatment (587 minutes) and the third period on sudan grass pastures (535 minutes). The times of rumination and idling were similar between treatments; however, the idling time decreased and rumination increased with time periods. The forage species did not affect the variables related to the strategies of displacement and feeding. With the advancement of cycle pastures the number of steps per minute, stations per minute and per day decreased while the bite rate and the number of bites per day increased. The behavioral parameters of cull cows grazing sudan grass or millet are similar; however, the advancement of the vegetative cycle of these species provides changes in the behavioral pattern of the animals.

The objective of this study was to evaluate the effect of carbohydrate sources (corn, soybean hulls or wheat bran) in the diet on performance of feedlot steers in the finishing phase. Twenty-four Charolais × Nellore crossbred steers, aged 22 months and initial weight of 335.0±10.9 kg were used in the experiment. Diets contained 40% sorghum silage and 60% concentrate. The intakes of dry matter (DM; 10.68, 10.16 and 10.34 kg/day) and crude protein (1.66, 1.70 and 1.72 kg/day) were not affected by diets with corn, soybean hulls or wheat bran, respectively. The intakes of neutral and acid detergent fiber were higher for soybean hulls, but the diet containing corn provided higher intake of non-fibrous carbohydrates, total digestible nutrients and digestible energy. Weight gain was higher and better feed conversion for animals fed corn (1.57 kg/day, 6.85 kg DM/kg gain) or soybean hulls (1.58 kg/day and 6.61 kg DM/kg gain) compared with steers receiving wheat bran (1.29 kg/day and 8.14 kg DM/kg gain) in the diet. There was no significant effect of carbohydrate sources on the final body score (3.78 points), energy conversion (28.25 Mcal digestible energy/kg gain), hot carcass yield (57.63 kg/100 kg BW) and fat thickness (3.1 mm). From an economic point of view, soybean hulls can be an alternative source of carbohydrate to corn in diets of finishing steers with 60% concentrate.

The response of energy supplementation was evaluated on the development and reproductive performance of beef heifers on temperate grasslands. Twenty-eight Charolais × Nellore heifers, with initial average age of 18 months and initial live weight of 274.9 kg were utilized. The animals were maintained on oat + ryegrass pasture and distributed in the following treatments: no supplementation (NS): heifers kept exclusively on pasture; MEG: supplementation with protected fat Megalac®; BRM: supplementation with brown rice meal; BRM+MEG: supplementation with BRM + protected fat. The average final weight of the heifers was of 403.4 kg and corresponded to 89.5% of the adult weight. The body condition of heifers increased linearly with daily increase of 0.012 points, correlating positively with the final weight. There was interaction between treatment and period for average daily weight gain. The highest daily weight gain, 1.395 kg, occurred in the first period when the animals were supplemented with BRM+MEG. In the last period, the NS animals presented the lowest daily weight gain, 0.888 kg. Supplementation with brown rice meal and/or protected fat does not interfere in the intake of pasture by heifers or increase the total intake of dry matter, not changing, therefore, the average daily weight gain at the end of the period of grazing. The daily weight gain does not change during supplementation. The use of temperate pasture with and without supplementation promotes the proper development of the structure and reproductive tract of heifers, benefiting the animal performance indexes in the first mating at 25-27 months of age.

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.

Avaliaram-se as características de carcaça e da carne de novilhos Devon terminados em confinamento, em pastagem temperada (pastagem de azevém -Lolium multiflorum Lam) ou em pastagem tropical (milheto, Pennisetum americanum (L.) Leeke + capim-papuã, Bracharia plantaginea). No início da terminação, os novilhos apresentaram em média 320 kg e 15 meses de idade. Os animais em confinamento foram alimentados com relação volumoso:concentrado de 60:40 e abatidos com pesos semelhantes, de 388,3; 391,5 e 375,8 kg, respectivamente. A terminação em pastagem tropical elevou a idade ao abate de 17 para 19 meses, como resultado do menor ganho de peso médio diário observado em relação ao confinamento e à pastagem temperada. O sistema de alimentação não influenciou os pesos de carcaça quente e fria, nem seus rendimentos, mesmo que as carcaças dos animais terminados em pastagem tropical tenham apresentado maior quebra ao resfriamento em comparação aos da pastagem temperada. A espessura de gordura subcutânea e a conformação nos animais terminados em pastagem temperada foram maiores que naqueles terminados em pastagem tropical, enquanto os animais terminados em confinamento mantiveram-se em posição intermediária. Animais terminados em pastagem tropical apresentaram carcaças com maior porcentagem de ossos e menor porção comestível/osso. Os animais terminados em pastagem temperada apresentaram carcaças com maior espessura de coxão em relação àqueles do confinamento. A carne dos animais terminados em pastagem temperada foi mais escura, apresentou maior força ao cisalhamento e textura mais grosseira, com menor maciez, avaliada pelo painel de degustadores, em comparação à carne daqueles terminados em confinamento ou em pastagem tropicale. Animais terminados em pastagem tropical apresentam carne menos palatável que a de animais terminados em confinamento.

The carcass and meat characteristics were assessed of Devon steers finished in feedlot (CONF), temperate pasture ( ryegrass pasture - Lolium multiflorum Lam -PTEM), or tropical pasture (association of millet pasture - Pennisetum americanum (L.) Leeke and Alexander grass - Brachiaria plantaginea -PTRO). At the beginning of finishing the average weight of the steers was 320 kg and the age was 15 months. The animals in feedlot were fed feeds with 60:40 roughage:concentrate and slaughtered with similar weights of 388.3; 391.5 and 375.8, respectively. Finishing on tropical pasture increased the slaughter age from 17 to 19 months, due to lower average daily weight gain compared to the feedlot and the temperate pasture. The feeding system did not influence the hot and cold carcass weight, nor the hot and cold carcass dressing percentage, even though the carcasses of the animals finished on tropical pasture showed greater chilling loss compared to the temperate pastures. Subcutaneous fat thickness and carcass conformation were higher for the animals finished on temperate pastures than those finished on temperate pasture, while the animals finished in feedlot maintained an intermediary position. The animals finished on tropical pasture presented carcasses with higher bone percentage and lower muscle plus fat/bone ratio. The animals finished on temperate pasture presented carcasses with greater cushion thickness compared to the animals in feedlot. Meat from the animals finished on temperate pasture was darker, had a coarser texture, higher shear force and lower tenderness assessed by a panel of tasters compared to meat from animals finished in feedlot or on tropical pasture. Animals finished on tropical pasture present less palatable meat compared to animals finished in feedlot.

O experimento foi conduzido no Departamento de Zootecnia da Universidade Federal de Santa Maria, para avaliar produtiva e qualitativamente a pastagem de capim elefante e o desempenho animal sob pastejo. A área experimental foi composta de oito piquetes de 0,443ha cada de capim-elefante (Pennisetun purpureum, Schum. cv. "Tawian"), onde pastejaram 36 novilhos das raças Charolês, Nelore e suas cruzas, com três animais "testers" por piquete, em duas repetições. Foram estudadas as variáveis relacionadas à produtividade e à qualidade da pastagem e ao desempenho animal. As massas reais de lâminas foliares (MLF) de capim-elefante foram: 1.167; 1.543; 1.926 e 2.248kg MS LF/ha, o que constitui os tratamentos. A carga animal suportada pela pastagem, pode ser descrita pela equação y=2.243,14 - 0,32MLF (R2=0,4). O peso vivo final em kg apresentou resposta quadrática (PF=103,41 + 0,114x - 0,00003x², R2=0,5) com o acréscimo da MLF. O ganho de peso diário médio apresentou comportamento linear positivo (GMD = 0,25 + 0,0002MLF, R2=0,2). O aumento na massa de lâminas foliares de capim-elefante acarreta diminuição na carga animal suportada pela pastagem e aumenta o ganho de peso médio diário.

The experiment was conducted at the animal science department of Universidade Federal de Santa Maria, to evaluate productive and qualitative characteristics of elephantgrass pasture and animal performance under grazing. The experimental area consisted of eight paddocks of 0.443 ha of elephantgrass (Pennisetun purpureum, Schum. cv. Taiwam), where 36 Charolais, Nelore and crossbred were kept, with three tester animals per paddock, with two repetitions. Variables related to pasture production and quality and animal performance were studied. Real leaf lamina masses (LLM) of elephantgrass were: 1.167; 1.543; 1.926 and 2.248kg of dry matter of leaf lamina/ha, constituting the treatments. Stocking rate (y=2.243.14 - .32LLM, R2=.4), showed a negative linear relationship. The final liveweight is kg, presented a quadratic effect (y = 103,41 + .114LLM - .00003LLm², R2=.5) with the LLM increase. The average daily weight gain showed positive linear effect (y = .25 + .0002LLM, R2=.2). The increase of the elephantgrass leaf lamina mass proportioned a decrease of stocking rate supported by the pasture and increased the average weight gain.