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Este trabalho foi conduzido com o objetivo de avaliar o desempenho produtivo de vacas de corte. Foram utilizadas 30 vacas da raça Aberdeen Angus e 32 da raça Charolês primíparas, prenhes no início do experimento, com bezerros puros ou mestiços Nelore. As vacas foram submetidas a diferentes tratamentos alimentares durante o inverno e a primavera: T1 - pastagem natural, T2 - pastagem cultivada por 60 dias (24 horas/dia), do início de setembro ao início de novembro, T3 - acesso à pastagem cultivada por duas horas diárias, por um período de 60 dias (de início de julho ao início de setembro), T4 - acesso à pastagem cultivada por duas horas diárias, por um período de 60 dias (de início de julho ao início de setembro), e mais 60 dias (24 horas/dia) de pastagem cultivada do início de setembro ao início de novembro. As medidas de eficiência produtiva foram: EPPARTO = (P205/PVP)*100; EPDESMAME = (P205/PVD)*100; EPMBPARTO = (P205/PVP0,75); EPMBDESMAME = (P205/PVD0,75); e EPNDT = NDTTOTAL/P205, em que P205 é o peso ao desmame dos bezerros; PVP e PVD, os pesos das vacas ao parto e ao desmame, respectivamente; e NDTTOTAL, a exigência em energia para manutenção e produção de leite das vacas. As vacas Aberdeen Angus, com bezerros machos e aquelas com bezerros mestiços, foram mais eficientes. Vacas que utilizaram a pastagem cultivada por um período de tempo maior (T4) tiveram melhor desempenho do que aquelas que permaneceram apenas em pastagem natural(T1); as vacas dos outros tratamentos tiveram desempenhos intermediários.

This study was carried out to evaluate the effect of a luteinizing hormone-releasing hormone (LHRH) fusion protein vaccine vs. surgical castration on the chemical composition and fatty acid profile of beef cattle (Bos indicus) slaughtered at three years of age. Thirty bulls (Nellore-cross) were divided into three groups: immunized against LHRH fusion protein, castrated or left intact (control). These animals were 24 months old at the initiation of the study and ranged on Brachiaria grass in Mato Grosso, Brazil. Meat of intact bulls presented a lower fat content compared to castrated or surgically castrated animals. For the immunized and surgically castrated animals there were differences in fat and cholesterol concentrations. Although the fatty acid profiles of the three treatments were similar in composition, there were differences in the concentrations of some fatty acids (miristic, C14:0; stearic, C18:0; linolenic, C18:3n-3; and eicosapentaenoic, C22:5n-3). Meat samples of surgically castrated animals had less polyunsaturated (PUFA) and monounsaturated (MUFA) fatty acids (8.2 and 37.7%, respectively), higher saturated (SFA) fatty acids (52.2%) and a lower PUFA/SFA ratio (0.16) and were different compared to intact and immunized bulls. The PUFA/SFA ratio increased as the fat content decreased. On the other hand, surgically castrated bulls had a higher lipid and lower cholesterol contents. It is concluded that immunization against LHRH using new recombinant LHRH fusion proteins could be an alternative to physical castration to improve carcass quality in cattle production.

* Bolsista Produtividade do CNPq.RESUMO -O objetivo neste estudo foi avaliar os efeitos de dietas com diferentes níveis de bagaço de laranja em substituição à silagem de sorgo sobre o comportamento ingestivo de ovinos (alimentação, ruminação e ócio) em ovinos. Dezesseis ovinos machos mestiços, com peso médio de 28,27 kg (±2,41) foram distribuídos em delineamento experimental em blocos casualizados com quatro tratamentos (0, 25, 50 e 75%), dois blocos e duas repetições por bloco. Os animais foram submetidos à observação visual durante dois dias consecutivos. No primeiro dia, os animais foram avaliados durante três períodos (8 às 10 h, 14 às 16 h e 18 às 20 h), estimando-se a média do número de mastigações merícicas por bolo ruminal e a média do tempo despendido de mastigação merícica por bolo ruminal, utilizando-se cronômetro digital. No segundo dia, o comportamento ingestivo de cada ovino foi determinado visualmente, a intervalos de cinco minutos, durante 24 horas, para determinação do tempo despendido em ócio, alimentação e ruminação. Não houve diferença entre os tratamentos, para o tempo despendido em alimentação, em min/dia e min/kg de MS e FDN. Os tempos despendidos em ruminação e ócio apresentaram efeitos quadráticos em função da inclusão de bagaço de laranja nas dietas. O tempo de ruminação em min/kg de MS apresentou efeito linear decrescente, logo, o tempo de ruminação em min/kg FDN não apresentou diferença significativa. Não se observou diferença para o número de refeições/dia, o tempo de mastigação total, os números de bolos ruminais, o número de mastigações por bolo e o tempo de mastigação por bolo. Os números de períodos ruminais e de mastigações merícicas por dia apresentaram comportamento linear decrescente. Palavras-chave: alimentação, ócio, ruminaçãoIngestive behaviour of sheep fed with different levels of fresh orange pulp replacing sorghum silage in the diet ABSTRACT -The objective of this study was to evaluate the effects of diets with different levels of fresh orange pulp in substitution to sorghum silage on eating behavior (feeding, rumination and idle)in sheep. Sixteen wethers, crossbred breeds averaging 28.27 kg BW (±2.41) were allotted to a randomized blocks design, with four treatments (0, 25, 50, and 75%), two blocks and two replicates per block. Animals were evaluated by observation during two consecutive days. In the first day, the average number of chewing per ruminal bolus and the average time spending in the chewing per ruminal bolus were evaluated during three periods (8 to 10 hours, 14 to 16 hours and 18 to 20 hours). In the second day, the behaviour was visually determined during 24 hours with five minutes intervals to determine the times spent in idle, feeding, rumination. There was not difference for the time spent with feeding in minutes day and in minutes/kg of DM and NDF. The time spent in rumination and idle in minutes day showed a quadratic effect in function of increased levels of fresh citrus pulp in the diets. The time spent in rumination, in minutes for kg MS, presente...

ResumoO presente estudo objetivou avaliar a influência de rações com diferentes níveis de energia metabolizável sobre o teor de lipídeos totais, colesterol e perfil de ácidos graxos no músculo Longissimus dorsi de cordeiros Santa Inês. Foram utilizados 20 cordeiros, com idade e peso de 50 dias e 13,0 ± 0,56 kg, respectivamente, alimentados com rações contendo diferentes níveis energéticos: 2,08; 2,28; 2,47 e 2,69 Mcal/kgMS. Os animais foram pesados semanalmente para acompanhamento do ganho de peso vivo, quando a média do peso vivo do tratamento atingiu 28 kg, os animais foram abatidos. A análise do perfil lipídico do músculo Longissimus dorsi apresentou efeito linear crescente e decrescente para os ácidos Cis-10 heptadecanóico (C17:1) e eicosatrienóico (C20:3), respectivamente, com o aumento nos níveis de energia dietéticos (P<0,05). Os níveis de colesterol (mg/100g) decresceram em relação ao aumento nos níveis de energia das rações. As relações ácidos graxos poliinsaturados (AGPI):ácidos graxos saturados (AGS); AGPI:ácidos graxos monoinsaturados (AGM); AGM:AGS; ácidos graxos desejáveis, w-6:w-3, índice de aterogenicidade, índice de trombogenicidade, relação entre os ácidos graxos hipercolesterolêmicos e hipocolesterolêmicos e a relação (C18:0 + C18:1):C16:0 não foram influenciadas pelos níveis energéticos (P>0,05). A manipulação dietética influencia o perfil lipídico no Longissimus dorsi de cordeiros Santa Inês. Palavras-chave: Ácidos graxos insaturados, carne de cordeiro, índice de aterogenicidade AbstractThis study evaluated the influence of rations with different levels of metabolizable energy on the content of total lipids, cholesterol and fatty acid profile of the longissimus dorsi of Santa Ines lambs. Twenty Santa Ines lambs were used, with age and body weight of 50 days and 13.0 ± 0.56 kg, respectively, fed rations with different energy levels: 2.08; 2.28; 2.47 e 2.69 Mcal/kgDM. Animals were weighed weekly

-The objectives of this study were to evaluate the environmental effects (age of dam at lambing, type of birth and sex of lamb) and genetic groups (Santa Inês and ½ Santa Inês) on weight and morphometric measurements (heart girth, body length and height) of lambs; to test linear and allometric regressions to predict the weight through the measurements; and to describe the type of growth of the measurements from weight. Weight and morphometric measurements were sampled from birth to 154 days of age, at every 14 days. For the evaluation of the environmental factors and to predict the regressions the data of birth, weaning and 154 days of age were used; and to determine the type of growth all the data collected were used. The lambs derived from younger (two-tooth) ewes recorded lower averages than the ones from eighttooth ewes for weight, heart girth and body length at birth and length at weaning. The animals born from single births presented higher average weight from birth to weaning, as well as of all the measurements from birth to 154 days of age than those from twin births. There was no difference between the genetic groups Santa Inês and ½ Santa Inês. The correlations between the weight and measurements were significant, and it was possible to predict the weight from the morphometric measurements through regressions. The type of weight gain with heart girth was isometric, while with length it was positive allometric, and with height it was negative allometric. Thereby, in the absence of a scale it is possible to predict the weight from the morphometric measurements, and the type of birth is the most important factor that affects the development of lambs from birth to weaning.

The main objective of this study was to evaluate the influence of the energy levels in the diet of ewes in the last third of gestation and lactation on body measurements and weights of lambs from birth to weaning. As secondary objectives were also evaluated the effects of year of birth, sex of the lamb, type of birth and age of the ewe at lambing on the same characteristics. Forty-five Santa Inês lambs were evaluated. They were born from 40 ewes distributed randomly to three treatments: 2.0, 2.2 and 2.4 Mcal of metabolizable energy/kg of dry matter). Ewes were subjected to the experimental diets during the last third of gestation and lactation. Lambs were kept with their mothers until weaning, which occurred at 70 days. Feeding energy level did not affect traits measured on the lambs at birth. Regression analysis showed a linear increasing in all traits at weaning and in average daily gain until weaning as the energy level increased. Male lambs were heavier at birth and at weaning. All morphometric measurements performed were similar between males and females, except for thoracic perimeter at 70 days, which was higher in male lambs. Single lambs were larger and heavier than twin lambs. Lambs born from ewes of intermediate age (4 and 6 teeth) showed higher means for average daily weight gain. Among morphometric measurements, thoracic perimeter showed the best correlation to body weight at birth and at weaning. Besides the nutrition of the ewe, it is important to consider other environmental factors that affect animal's growth characteristics by acting on the expression of genetic potential.

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