Sealing strategies in corn silage and sheep performance in feedlots / Estratégias de vedação na ensilagem de milho e desempenho de ovinos em confinamento

The objective of this study was to evaluate the effects of different sealing strategies on aerobic stability and feed value of corn silage supplied to finishing lambs. The treatments were set up according to the silo sealing strategy: BP (black polyethylene film), BP + Bagasse (black polyethylene film + sugarcane bagasse) and BP + Silostop (Silostop® Orange oxygen barrier film + black polyethylene film). Six lambs per treatment were used, totaling 18 animals in an experimental period of 63 days. The silage from LP treatment presented the highest aerobic stability, however with lower dry matter digestibility coefficients. No significant differences were detected among treatments for intake and performance of lambs. But for final body weight, weight gain, daily average gain, feed efficiency and dry matter intake, the best results, in absolute value, were found for lambs fed with silage from LP + Bagasse treatment. The silage sealed exclusively with black polyethylene film showed greater aerobic stability. The different sealing strategies used in this experiment did not influence the performance of finishing Dorper x Santa Inês lambs.(AU)

Objetivou-se avaliar os efeitos de differentes estratégias de vedação sobre a estabilidade aeróbia e o valor alimentício da silagem de milho fornecida para cordeiros em terminação. Os tratamentos foram definidos de acordo com a estratégia de vedação do silo: LP (lona preta de polietileno), LP + Bagaço (lona preta de polietileno + bagaço de cana) e LP + Silostop (lona preta de polietileno + filme de barreira de oxigênio Silostop® Orange). Foram utilizados seis cordeiros por tratamento, totalizando 18 animais, em um período experimental de 63 dias. A silagem do tratamento LP apresentou maior estabilidade aeróbia, porém proporcionou menor coeficiente de digestibilidade da matéria seca. Não foi observada diferença significativa entre os tratamentos para o consumo e desempenho dos cordeiros. Todavia, para o peso corporal final, ganho de peso, ganho médio diário, eficiência alimentar e consumo de matéria seca, os melhores resultados, em valor absoluto, foram encontrados para os cordeiros alimentados com dieta à base da silagem coberta com LP + Bagaço. A silagem vedada exclusivamente com a lona preta de polietileno apresentou maior estabilidade aeróbia. As diferentes estratégias de vedação utilizadas nesse experimento não influenciaram o desempenho de cordeiros Dorper x Santa Inês em terminação.(AU)

Penile fractures in young bulls raised in feedlots in Southern Brazil

Background: Penile fracture is a pathology of young cattle that perform precocious and disordered breeding. The incompatibility of height between males and females and sodomy between males cause a great pressure on the sigmoid flexure and retractor muscle of the penis, which are the main causes and sites of organ injury. This study aimed to describe the epidemiological and pathological aspects of penile fractures observed in young bulls raised in pre-export feedlots (PEFs) in southern Brazil. Cases: In 2 PEFs located in the municipalities of Pelotas (property 1) and Capão do Leão (property 2), 3 male cattle [1 from property 1 and 2 from property 2] presented subcutaneous edema in the foreskin and perineum, associated with dysuria. The evolution of the clinical picture was approximately 20 days in all cases, with evolution to death. The bovine necropsied on property 1 had an increased volume and inguinal edema, involving the penis and scrotal sac. Necrosis of the subcutaneous tissue and local musculature was also observed. The testicles were surrounded by the necrotic tissue, and the right testis was swollen, with flaccid parenchyma adhering to the tunica albuginea. In the necropsy of 1 bull from property 2, an increase in the inguinal volume was observed, with an extensive area of necrosis and edema extending from the prepuce to the caudal musculature of the scrotal sac. There were also marked varicosis in the sigmoid flexure and necrosis of the adjacent region, without the involvement of the corpus cavernosum. During the necropsy of the 2 young bulls, fragments of organs from the abdominal, thoracic, and brain cavities were collected and fixed in 10% buffered formalin. From the bull of the property 2, an anatomical piece consisting of the penis, prepuce, and testicles was also collected and fixed in 10% buffered formalin. After 48 h, the tissue samples were cleaved, embedded in paraffin, cut into 3-µm-thick sections, and stained using hematoxylin and eosin (HE). A histological evaluation of the penile lesions in both cattle revealed intense hemorrhage, congestion, and necrosis of the muscles and tissues adjacent to the corpus cavernosum. In addition to areas of dystrophic calcification, neutrophil and macrophage infiltration was also observed. In the bull from the property 1, an intense edema and proliferation of fibrous tissue surrounding the urethra were noted. There were also marked tubular degeneration and intense infiltration of neutrophils, lymphocytes, and macrophages in the inner portion of the tunica albuginea. Discussion: In the present cases, the diagnosis was based on epidemiological data associated with clinical signs and pathology. The macroscopic lesions observed were probably due to the involvement of blood vessels adjacent to the penis, which suffered trauma during sodomy mating among cattle. These lesions have been described in other reports of this pathology and in diseases, such as acropostitis-phimosis, fibropapilloma of the glans, preputial abscess, and urolithiasis, and the differential diagnosis of these diseases must be carried out, as they have different etiologies. In the bulls of the present study, no lesions were observed in the corpus cavernosum, and this condition was attributed to the presence of varicosis and accumulation of urine in the prepuce, due to the difficulty in exposing the penis. Histologically, there were intense hemorrhage, congestion, and necrosis of the muscles and tissues adjacent to the corpus cavernosum, with the infiltration of neutrophils and macrophages, and areas of dystrophic calcification. The presence of necrotic lesions in tissues adjacent to the penis may be related to hypoxia, vascular lesions, or the action of chemical elements present in the urine. In both cases, vascular lesions were present, which were attributed to the main triggering factor for the disease.

Listeriosis outbreak in sheep raised in feedlots in the Southern Region of Rio Grande do Sul state, Brazil

Background: A listeriosis outbreak in a sheep fattening feedlot in the Southern Region of Rio Grande do Sul State, Brazilis described. This disease is caused by Listeria monocytogenes and represents a risk to public health since it affects notonly ruminants but also humans. This agent is widely spread in the environment, such as in the soil and water. It is alsofound in decaying vegetable matter and the feces and fluids of domestic animals. The aim of this study was to describe alisteriosis outbreak in sheep raised in feedlots, its epidemiology, and to establish the importance of this disease in this typeof sheep management system, evaluate the possible sources of infection, and suggest ways to control it.Cases: Sheep were kept in a 2-sector shed, one with east solar orientation and the other with west solar orientation, thelatter with free access to domestic birds. Sheep were fed silage and concentrate. Seven sheep were affected, 5 died and 2recovered. Clinically, the sheep displayed loss of balance, excessive drooling, and tremors; one exhibited circling, headdeviation, apathy, nystagmus, lateral recumbency, paddling, and labored breathing. At necropsy, macroscopic lesions werenot found, and histologically several micro-abscesses and perivascular cuffs with lymphocytes, macrophages, and neutrophils were present in the brain stem. Listeria monocytogenes suspected colonies were observed in the microbiologicalculture, and the bacteria was identified by biochemical analysis. The immunohistochemistry test in brain stem sectionswas positive for the antibody BD DifcoTM Listeria O Antiserum Poly Serotypes 1 and 4.Discussion: A listeriosis outbreak in a feedlot sheep was confirmed through epidemiological findings, histological lesions,bacterial culture, and immunohistochemistry analysis. This infection is frequent...

Listeriosis outbreak in sheep raised in feedlots in the Southern Region of Rio Grande do Sul state, Brazil

Background: A listeriosis outbreak in a sheep fattening feedlot in the Southern Region of Rio Grande do Sul State, Brazilis described. This disease is caused by Listeria monocytogenes and represents a risk to public health since it affects notonly ruminants but also humans. This agent is widely spread in the environment, such as in the soil and water. It is alsofound in decaying vegetable matter and the feces and fluids of domestic animals. The aim of this study was to describe alisteriosis outbreak in sheep raised in feedlots, its epidemiology, and to establish the importance of this disease in this typeof sheep management system, evaluate the possible sources of infection, and suggest ways to control it.Cases: Sheep were kept in a 2-sector shed, one with east solar orientation and the other with west solar orientation, thelatter with free access to domestic birds. Sheep were fed silage and concentrate. Seven sheep were affected, 5 died and 2recovered. Clinically, the sheep displayed loss of balance, excessive drooling, and tremors; one exhibited circling, headdeviation, apathy, nystagmus, lateral recumbency, paddling, and labored breathing. At necropsy, macroscopic lesions werenot found, and histologically several micro-abscesses and perivascular cuffs with lymphocytes, macrophages, and neutrophils were present in the brain stem. Listeria monocytogenes suspected colonies were observed in the microbiologicalculture, and the bacteria was identified by biochemical analysis. The immunohistochemistry test in brain stem sectionswas positive for the antibody BD DifcoTM Listeria O Antiserum Poly Serotypes 1 and 4.Discussion: A listeriosis outbreak in a feedlot sheep was confirmed through epidemiological findings, histological lesions,bacterial culture, and immunohistochemistry analysis. This infection is frequent...(AU)

Physically effective fiber changes nutrient levels of total mixed ration and fecal parameters in beef feedlots / A fibra fisicamente efetiva altera os nutrientes da dieta e parâmetros fecais em confinamentos de bovinos de corte

This study evaluated the effects of the physically effective fiber (peNDF) content on nutrient composition of the total mixed ration (TMR), orts and fecal parameters in 15 commercial beef feedlots. The particle size distribution of TMR was measured adopting Penn State Particle Size Separator (PSPS). Samples were evaluated for dry matter (DM), ash, ether extract (EE), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF) and starch content. Fecal samples were also evaluated for pH and score. The feedlots were categorized into peNDF 20% and peNDF 20%. Data were analyzed by a model that included fixed effects of treatment and covariates (sex and genetic groups). Levels of DM, CP, EE and starch were lower in TMR with peNDF 20% (P 0.05). Fecal dry matter was higher and morning fecal pH was lower for TMR with peNDF 20% (P 0.05). Physically effective fiber changed nutrient levels in TMR, orts, fecal pH and DM. So, using PSPS and fecal parameters are practical and indirect tools for measuring fecal starch and assessing the effectiveness of the diet supplied to ruminants.(AU)

O objetivo desse estudo foi avaliar o teor de fibra fisicamente efetiva (FDNfe) de dietas totais e seus efeitos nos nutrientes da dieta, das sobras e nos parâmetros fecais de bovinos de corte em 15 confinamentos comerciais. As amostras da dieta foram separadas utilizando a peneira Penn State Particle Size Separator (PSPS). As amostras foram analisadas quanto aos teores de matéria seca (MS), matéria mineral (MM), extrato etéreo (EE), proteína bruta (PB), fibra em detergente neutro (FDN), fibra em detergente ácido (FDA) e amido. Nas amostras de fezes também foram avaliadas o escore e pH fecal. Os confinamentos foram categorizados em dois tratamentos: FDNfe 20% e FDNfe20%. Os dados foram analisados por um modelo que incluiu os efeitos de grupo e covariável (sexo e grupo genético). Os teores de MS, PB, EE e amido foram menores nas dietas com FDNfe20%(P 0,05). A MS fecal foi maior e pH fecal matinal foi menor nas dietas com FDNfe 20% (P 0,05). Sendo assim a efetividade da fibra alterou os nutrientes da dieta total e sobras, bem como as variáveis pH e MS fecal. Com isso, o uso de PSPS e parâmetros fecais são ferramentas práticas e indiretas para medir o amido fecal e a efetividade da dieta em confinamentos de bovinos comerciais.(AU)

Discrimination study between the carcass and noncarcass components for interaction between gender, age, and production system in indigenous sheep / Estudo de discriminação entre os componentes da carcaça e não da carcaça para interação entre gênero, idade e sistema de produção em ovinos indígenas

The objective of this work was to evaluate the yields, morphometric measures, carcass, and non-carcass components, and carcass regional and tissue composition of an indigenous sheep (Pantaneiro) of different physiological stages (gender, age, system production. Thirty sheep, eleven lambs, nine wethers, and ten cull ewes were used. The lambs were finished in feedlots, the wethers were maintained on pastures and supplementation, and the cull ewes were maintained on an extensive pasture system with mineral salt ad libitum. Slaughter ages were defined to simulate the most representative products and farming systems. Animals were slaughtered and classified as non- castrated lambs, wethers, and cull ewes. The criteria to slaughter lambs and wethers were the body condition, which ranged from 2.5 to 3.0. Cull ewes were slaughtered based on negative pregnancy diagnosis, regardless of their body condition, which ranged from 4.0 to 4.5. All animals were slaughtered after 16-hours of fasting (solids). The ewes presented the greatest fat thickness, differing significantly from the lambs. The morphometric measures were higher in ewes and lambs. The muscle to fat ratio of the animal's cuts from different physiological stages presented no significant differences. The indigenous Pantaneiro sheep have good potential for meat production regardless of their physiological stages. The ewes stood out, presenting carcasses with good performance considering their potential and longer permanence in the herd due to their reproductive function.(AU)

O objetivo deste trabalho foi avaliar o rendimento, medidas morfométricas, componentes da carcaça e da não carcaça e a composição regional e tecidual da carcaça de ovelhas indígenas (Pantaneiro) de diferentes sistemas de produção, sexo e idade. Foram utilizadas trinta ovelhas, onze cordeiros, nove borregos e dez ovelhas de descarte. Os cordeiros foram terminados em confinamento, os borregos mantidos em pastagem e suplementação, e as ovelhas de descarte mantidas em sistema a pasto extensivo com sal mineral ad libitum. As idades ao abate foram definidas para simular os produtos e sistemas agrícolas mais representativos, cordeiros, borregos e ovelhas de descarte. Os animais foram abatidos e classificados como cordeiros não castrados, borregos e ovelhas de descarte. Os critérios para abate de cordeiros e borregos foram a condição corporal, que variou de 2,5 a 3,0. As ovelhas de descarte foram abatidas com base no diagnóstico de gestação negativo, independentemente da condição corporal, que variou de 4,0 a 4,5. Todos os animais foram abatidos após jejum de 16 horas (sólidos). As ovelhas apresentaram as maiores espessuras de gordura, diferindo significativamente dos cordeiros. As medidas morfométricas foram maiores em ovelhas e cordeiros. A relação músculo / gordura dos cortes dos animais nas diferentes fases fisiológicas não apresentou diferenças significativas. Os ovinos pantaneiros apresentam bom potencial para produção de carne, independentemente de seus estágios fisiológicos. As ovelhas se destacaram, apresentando carcaças com bom desempenho considerando seu potencial e maior permanência no rebanho devido à sua função reprodutiva.(AU)

Characterization and effects of DDG on the intake and digestibility of finishing bulls in feedlots

The aim of this study was to characterize four corn and sorghum co-products (DDG) in terms of their protein and carbohydrate fractions; we also evaluated the effects of substituting the protein source of the conventional supplement by DDG on consumption and nutrient digestibility in confined finishing cattle. Thirty-six male Nellore cattle with a mean age of 24 months were used. The treatments were: FA: concentrate with corn as an energy source and cottonseed meal as a protein source; DDG50: concentrate with a 50% substitution of the FA protein source by DDG; DDG100: concentrate with 100% substitution of the FA protein source by DDG. The experimental design was completely randomized with three treatments and three replicates (pens) containing four animals per pen. We found that the use of DDG in the finishing phase did not interfere with the animals food intake or the digestibility of the nutrients (p > 0.05). Nutrients were used by the animals; therefore, DDGs may be viable substitutes of cottonseed meal. We conclude that the bromatological composition of this co-product is influenced a lot during processing; therefore, the nutritional values of this co-product present in the composition tables may not be true.(AU)

Characterization and effects of DDG on the intake and digestibility of finishing bulls in feedlots

The aim of this study was to characterize four corn and sorghum co-products (DDG) in terms of their protein and carbohydrate fractions; we also evaluated the effects of substituting the protein source of the conventional supplement by DDG on consumption and nutrient digestibility in confined finishing cattle. Thirty-six male Nellore cattle with a mean age of 24 months were used. The treatments were: FA: concentrate with corn as an energy source and cottonseed meal as a protein source; DDG50: concentrate with a 50% substitution of the FA protein source by DDG; DDG100: concentrate with 100% substitution of the FA protein source by DDG. The experimental design was completely randomized with three treatments and three replicates (pens) containing four animals per pen. We found that the use of DDG in the finishing phase did not interfere with the animals’ food intake or the digestibility of the nutrients (p > 0.05). Nutrients were used by the animals; therefore, DDGs may be viable substitutes of cottonseed meal. We conclude that the bromatological composition of this co-product is influenced a lot during processing; therefore, the nutritional values of this co-product present in the composition tables may not be true.

Causes of death of beef cattle raised in feedlots / Causas de morte de bovinos de corte criados em confinamentos

The causes of death of cattle kept in pre-export feedlots (PEFs) and in feedlot for finishing for slaughter are described. Two studies were conducted: a retrospective study of mortality cases in feedlots from 2000 to 2017 registered at the "Laboratório Regional de Diagnóstico" of the "Faculdade de Veterinária" of the "Universidade Federal de Pelotas"; and a prospective study from January 2018 to August 2019, following up 22 feedlots for finishing and six PEFs for the export of live cattle. From January 2000 to August 2019 samples of 150 cases of diseases that affected feedlot cattle were received from 22 feedlots for finishing and 115 of the six PEFs followed. Mortality considering all diagnosed diseases was significantly higher in feedlots for finishing (p<0.05), than in PEFs for the export of live cattle, of 1% and 0.12%, respectively. Diseases of the digestive system were the most important causes, of death in feedlots regardless of its purpose. Acidosis presented the highest mortality rates both in feedlot for finishing (3.33%) as in PEFs for export (0.95%). In all cases the disease occurred due to failure in the adaptation of animals to the ingestion of concentrated foods. Bovine tick fever and pneumonia presented mortality rates of 0.13% and 0.09%, respectively in PEFs. In the feedlot for finishing seneciosis was the second cause of death due to cattle coming from areas with high infestation by the plant. In the present study, it was possible to identify the main diseases that occur in cattle feedlots for finishing or for the export of live animals in the southern region of Rio Grande do Sul. These diseases are known in other systems of cattle breeding and can be prevented or controlled through management, chemoprophylaxis or vaccination, minimizing losses due to mortality.(AU)

Descrevem-se as causas de morte de bovinos mantidos confinados em estabelecimentos pré-embarque (EPEs) para exportação de animais vivos e em estabelecimentos de terminação para abate. Foram realizados dois estudos: um retrospectivo dos casos de mortalidade em confinamentos de 2000 a 2017 registrados no Laboratório Regional de Diagnóstico da Faculdade de Veterinária da Universidade Federal de Pelotas; e um estudo prospectivo de janeiro de 2018 a agosto de 2019, acompanhando-se 22 confinamentos de terminação e seis EPEs para exportação de bovinos vivos. No total, de janeiro de 2000 a agosto de 2019 foram recebidos no LRD-UFPel amostras de 150 casos de enfermidades que afetaram bovinos confinados, 35 provenientes de 22 confinamentos de terminação e 115 dos seis EPEs acompanhados. A mortalidade considerando-se todas as enfermidades diagnosticadas foi significativamente maior nos confinamentos para terminação (p<0,05), do que nos EPEs para exportação de bovinos vivos, de 1% e 0,12%, respectivamente. As doenças do sistema digestivo foram as causas de morte mais importante nos confinamentos, independente da finalidade. Acidose apresentou as maiores taxas de mortalidade tanto nos confinamentos para terminação (3,33%) como nos EPEs para exportação (0,95%). Em todos os casos a doença ocorreu devido a falha na adaptação dos animais à ingestão de alimentos concentrados. Tristeza parasitária bovina e pneumonias apresentaram taxas de mortalidade de 0,13% e 0,09, respectivamente em EPEs de exportação. Nos confinamentos para terminação a seneciose foi a segunda causa de morte devido aos bovinos serem provenientes de áreas com alta infestação pela planta. Este estudo permitiu identificar as principais enfermidades diagnosticadas em confinamentos para terminação de bovinos ou para exportação de bovinos vivos na região Sul do Rio Grande do Sul. Observou-se que são doenças que ocorrem em outros sistemas de criação de bovinos e que podem ser prevenidas ou controladas por meio de manejo, quimioprofilaxia ou vacinação, minimizando prejuízos por mortalidade de animais.(AU)

Causes of death of beef cattle raised in feedlots / Causas de morte de bovinos de corte criados em confinamentos

The causes of death of cattle kept in pre-export feedlots (PEFs) and in feedlot for finishing for slaughter are described. Two studies were conducted: a retrospective study of mortality cases in feedlots from 2000 to 2017 registered at the "Laboratório Regional de Diagnóstico" of the "Faculdade de Veterinária" of the "Universidade Federal de Pelotas"; and a prospective study from January 2018 to August 2019, following up 22 feedlots for finishing and six PEFs for the export of live cattle. From January 2000 to August 2019 samples of 150 cases of diseases that affected feedlot cattle were received from 22 feedlots for finishing and 115 of the six PEFs followed. Mortality considering all diagnosed diseases was significantly higher in feedlots for finishing (p<0.05), than in PEFs for the export of live cattle, of 1% and 0.12%, respectively. Diseases of the digestive system were the most important causes, of death in feedlots regardless of its purpose. Acidosis presented the highest mortality rates both in feedlot for finishing (3.33%) as in PEFs for export (0.95%). In all cases the disease occurred due to failure in the adaptation of animals to the ingestion of concentrated foods. Bovine tick fever and pneumonia presented mortality rates of 0.13% and 0.09%, respectively in PEFs. In the feedlot for finishing seneciosis was the second cause of death due to cattle coming from areas with high infestation by the plant. In the present study, it was possible to identify the main diseases that occur in cattle feedlots for finishing or for the export of live animals in the southern region of Rio Grande do Sul. These diseases are known in other systems of cattle breeding and can be prevented or controlled through management, chemoprophylaxis or vaccination, minimizing losses due to mortality.(AU)

Descrevem-se as causas de morte de bovinos mantidos confinados em estabelecimentos pré-embarque (EPEs) para exportação de animais vivos e em estabelecimentos de terminação para abate. Foram realizados dois estudos: um retrospectivo dos casos de mortalidade em confinamentos de 2000 a 2017 registrados no Laboratório Regional de Diagnóstico da Faculdade de Veterinária da Universidade Federal de Pelotas; e um estudo prospectivo de janeiro de 2018 a agosto de 2019, acompanhando-se 22 confinamentos de terminação e seis EPEs para exportação de bovinos vivos. No total, de janeiro de 2000 a agosto de 2019 foram recebidos no LRD-UFPel amostras de 150 casos de enfermidades que afetaram bovinos confinados, 35 provenientes de 22 confinamentos de terminação e 115 dos seis EPEs acompanhados. A mortalidade considerando-se todas as enfermidades diagnosticadas foi significativamente maior nos confinamentos para terminação (p<0,05), do que nos EPEs para exportação de bovinos vivos, de 1% e 0,12%, respectivamente. As doenças do sistema digestivo foram as causas de morte mais importante nos confinamentos, independente da finalidade. Acidose apresentou as maiores taxas de mortalidade tanto nos confinamentos para terminação (3,33%) como nos EPEs para exportação (0,95%). Em todos os casos a doença ocorreu devido a falha na adaptação dos animais à ingestão de alimentos concentrados. Tristeza parasitária bovina e pneumonias apresentaram taxas de mortalidade de 0,13% e 0,09, respectivamente em EPEs de exportação. Nos confinamentos para terminação a seneciose foi a segunda causa de morte devido aos bovinos serem provenientes de áreas com alta infestação pela planta. Este estudo permitiu identificar as principais enfermidades diagnosticadas em confinamentos para terminação de bovinos ou para exportação de bovinos vivos na região Sul do Rio Grande do Sul. Observou-se que são doenças que ocorrem em outros sistemas de criação de bovinos e que podem ser prevenidas ou controladas por meio de manejo, quimioprofilaxia ou vacinação, minimizando prejuízos por mortalidade de animais.(AU)

Fresh yeast additives improve immune parameters and reduce respiratory disease in heifers finished in feedlots / Aditivos de levedura viva melhoram parâmetros imunes e reduzem doenças respiratórias em novilhos terminados em confinamento

Although cattle feedlot presents productive advantages, this management generates stress, which may impact immunity and increase the incidence of respiratory diseases. Because the immunostimulatory potential of yeasts, this study aimed to verify whether supplementation of cattle with fresh yeast promotes an increase in innate immunity and, consequently, reduces the occurrence of respiratory diseases in heifers finished in feedlots. A total of 32 heifers, finished in feedlots, were randomly divided into two treatments and 16 repetitions: A control group (n=16; 7 g day-¹ per animal of corn kernel) and a yeast group (n=16, 7 g day-¹ per animal of the commercial product with fresh yeast additive). At day 0, 16 days after acclimatisation to the feedlot, and at days 28, 56 and 84, leukogram, serum haptoglobin, oxidative metabolism neutrophil, and indicators of respiratory diseases (nasal temperatures, nasal secretion score, and histopathological examination of lung) were evaluated. The yeast group had lower blood neutrophil counts (P = 0.02), higher neutrophil oxidative metabolism (P = 0.04) than the control group after 56 days of confinement. There was a lower frequency of animals from the yeast group with purulent nasal secretion on days 28 and 84 (P = 0.0001 and 0.008) and with histopathological lesion of pneumonia at slaughter day (P = 0.0001). The yeast group also presented lower nasal temperatures than the control group on days 28 and 84 (P = 0.02 and P= 0.08). Thus, fresh yeast additives attenuated the effects of the feedlot system in the heifer immune system and contributed to a reduction of respiratory diseases.

Embora confinamento de bovinos apresente vantagens produtivas, este manejo gera estresse, podendo impactar a imunidade e aumentar a incidência de doenças respiratórias. Tendo em vista o potencial imunoestimulante das leveduras, este trabalho objetivou verificar se a suplementação de bovinos com levedura fresca promove incremento da imunidade inata e consequentemente, diminui a ocorrência de afecções respiratórias de novilhas terminados em confinamento. Para tanto 32 novilhas terminadas em confinamento, foram divididas aleatoriamente em dois tratamentos, com 16 repetições cada, formando o grupo controle (n = 16; 7 g dia-¹ por animal de caroço de milho) e o grupo levedura (n = 16, 7 g dia-¹ por animal do produto comercial com aditivo de levedura fresca). No dia 0, 16 dias após a aclimatação ao confinamento, e nos dias 28, 56 e 84, avaliou-se o leucograma, haptoglobina sérica, metabolismo oxidativo de leucócitos e indicadores de doenças respiratórias (temperatura nasal, escore de secreção nasal e exame histopatológico do pulmão). O grupo levedura apresentou menor contagem de neutrófilos no sangue (P = 0.02), maior metabolismo oxidativo dos neutrófilos (P = 0.02) e menores níveis séricos de haptoglobina (P = 0.04) do que o grupo controle após 56 dias de confinamento. Houve menor frequência de animais do grupo levedura com secreção nasal purulenta nos dias 28 e 84 (P = 0.0001 e 0,008) e com lesão histopatológica de pneumonia no dia do abate (P = 0.0001). O grupo levedura também apresentou temperaturas nasais mais baixas do que o grupo controle nos dias 28 e 84 (P = 0.02 e P =0.08). Assim conclui-se que o aditivo de levedura fresca atenuou os efeitos do sistema de confinamento no sistema imunológico de novilhas e contribuíram para a redução de doenças respiratórias, o que traz impactos importantes na pecuária seja por reduzir custos com tratamento, evitar resistência bacteriana a antibióticos, como diminuir a morbidade de doenças respiratórias entre os animais.

Fresh yeast additives improve immune parameters and reduce respiratory disease in heifers finished in feedlots / Aditivos de levedura viva melhoram parâmetros imunes e reduzem doenças respiratórias em novilhos terminados em confinamento

Although cattle feedlot presents productive advantages, this management generates stress, which may impact immunity and increase the incidence of respiratory diseases. Because the immunostimulatory potential of yeasts, this study aimed to verify whether supplementation of cattle with fresh yeast promotes an increase in innate immunity and, consequently, reduces the occurrence of respiratory diseases in heifers finished in feedlots. A total of 32 heifers, finished in feedlots, were randomly divided into two treatments and 16 repetitions: A control group (n=16; 7 g day-¹ per animal of corn kernel) and a yeast group (n=16, 7 g day-¹ per animal of the commercial product with fresh yeast additive). At day 0, 16 days after acclimatisation to the feedlot, and at days 28, 56 and 84, leukogram, serum haptoglobin, oxidative metabolism neutrophil, and indicators of respiratory diseases (nasal temperatures, nasal secretion score, and histopathological examination of lung) were evaluated. The yeast group had lower blood neutrophil counts (P = 0.02), higher neutrophil oxidative metabolism (P = 0.04) than the control group after 56 days of confinement. There was a lower frequency of animals from the yeast group with purulent nasal secretion on days 28 and 84 (P = 0.0001 and 0.008) and with histopathological lesion of pneumonia at slaughter day (P = 0.0001). The yeast group also presented lower nasal temperatures than the control group on days 28 and 84 (P = 0.02 and P= 0.08). Thus, fresh yeast additives attenuated the effects of the feedlot system in the heifer immune system and contributed to a reduction of respiratory diseases.(AU)

Embora confinamento de bovinos apresente vantagens produtivas, este manejo gera estresse, podendo impactar a imunidade e aumentar a incidência de doenças respiratórias. Tendo em vista o potencial imunoestimulante das leveduras, este trabalho objetivou verificar se a suplementação de bovinos com levedura fresca promove incremento da imunidade inata e consequentemente, diminui a ocorrência de afecções respiratórias de novilhas terminados em confinamento. Para tanto 32 novilhas terminadas em confinamento, foram divididas aleatoriamente em dois tratamentos, com 16 repetições cada, formando o grupo controle (n = 16; 7 g dia-¹ por animal de caroço de milho) e o grupo levedura (n = 16, 7 g dia-¹ por animal do produto comercial com aditivo de levedura fresca). No dia 0, 16 dias após a aclimatação ao confinamento, e nos dias 28, 56 e 84, avaliou-se o leucograma, haptoglobina sérica, metabolismo oxidativo de leucócitos e indicadores de doenças respiratórias (temperatura nasal, escore de secreção nasal e exame histopatológico do pulmão). O grupo levedura apresentou menor contagem de neutrófilos no sangue (P = 0.02), maior metabolismo oxidativo dos neutrófilos (P = 0.02) e menores níveis séricos de haptoglobina (P = 0.04) do que o grupo controle após 56 dias de confinamento. Houve menor frequência de animais do grupo levedura com secreção nasal purulenta nos dias 28 e 84 (P = 0.0001 e 0,008) e com lesão histopatológica de pneumonia no dia do abate (P = 0.0001). O grupo levedura também apresentou temperaturas nasais mais baixas do que o grupo controle nos dias 28 e 84 (P = 0.02 e P =0.08). Assim conclui-se que o aditivo de levedura fresca atenuou os efeitos do sistema de confinamento no sistema imunológico de novilhas e contribuíram para a redução de doenças respiratórias, o que traz impactos importantes na pecuária seja por reduzir custos com tratamento, evitar resistência bacteriana a antibióticos, como diminuir a morbidade de doenças respiratórias entre os animais.(AU)

Slaughter body weights of Jersey young bulls finished on feedlot

The objective of this study was to investigate the effects of slaughter body weight (SW) on the performance, carcass characteristics, and meat quality of Jersey bulls in feedlots from weaning to slaughter. Eighteen Jersey bulls (125.7±15.9 kg; 5±0.6 months old) were used in the study. The treatments corresponded to three slaughter-weights: L360 ­ light weight, SW of 360 kg, M390 ­ medium weight, SW of 390 kg, and H420 ­ heavy weight, SW of 420 kg (n = 6/treatment); the animals were slaughtered at 368, 392, and 422 kg, respectively. The average daily gain was not influenced by SW. The M390 and H420 groups remained in feedlot, on average, 6 and 51 d longer, respectively, to reach a similar SW in relation to the L360 group. The increase in SW did not influence dry matter intake. However, the L360 group exhibited greater dry matter intake relative to body weight compared with the other two groups (29 vs. 26 g/kg). The increase in SW resulted in heavier and longer carcasses, with higher hot carcass yields. However, animals with greater SW had lower fat thickness. In addition, the increase in SW led to greater pistol cut, bone, and muscle weight for the carcasses. Although the meat color of Jersey bulls was darker in the H420 group, the meat was considered softer and more palatable by the consumer panel compared with the meat from the L360 group. The L360 group exhibited less fluid loss during thawing and cooking. Shear force measured by Warner Blatzer Shear was lower for H420. Animals slaughtered in the L390 group had an intermediate carcass weight, similar carcass yield, better cover fat and meat quality (color and shear) than animals slaughtered in the H420. Combining these factors with a shorter feedlot time compared with that of heavier animals, the SW of feedlot Jersey bulls is recommended at 390 kg.(AU)

Selectivity and feeding behavior of Saanen goats subjected to three nutritional levels

This study was conducted to investigate the effect of selective feeding habits on the quality of the ingested diet and the effect of feed restriction on the selectivity and behavior of goats in feedlots. Differences were found only in the amount of feed given to the animals, with a difference in the amount of feed rejected as a function of the nutritional level. Higher levels of orts were measured for those animals that received the ad libitum diet. For the composition of orts, differences were measured only in the ether extract fraction. Animals fed the ad libitum diet increased their intake of ether extract and energy, crude fiber, neutral detergent fiber, and acid detergent fiber. Thus, they had a preference for consuming the fibrous and energetic portions of the diet to the detriment of the mineral matter. The granulometry influenced the leftovers for the male and female treatments only in the diet that contained the 2.00- and 0.063-mm sized particles, with larger leftovers for the females. There were statistical differences as a function of feeding level for time spent in rumination, with stereotypical behavior, and in time spent standing up or lying down. As a function of sex, the differences were the same variables, including the time spent with agonistic behavior. Animals that received the ad libitum diet had a greater gain and final weight, whereas the animals that received the 60% restricted diet had the lowest performance, as did the females. Feed restriction changed the natural feeding behavior of goats, with smaller feed particles preferred. The feed restriction and sex also influenced the time spent on nonproductive activities, and the animals became more restless, with females having a higher social behavior than males.(AU)

Terminação de cordeiros, com e sem suplementação na fase de cria, confinados ou semiconfinados em Brachiaria brizantha diferida: parasitismo gastrintestinal e eficiência bioeconômica / Performance of creep feed lambs, finished under feedlot or Brachiaria brizantha deferred pasture: gastrintestinal parasitism and bioeconomic efficiency

Objetivou-se avaliar os efeitos da suplementação na fase de aleitamento sobre o desempenho ponderal, o grau de infecção por nematódeos gastrintestinais e a viabilidade econômica na terminação de cordeiros em confinamento ou semiconfinamento. Na fase de aleitamento, os cordeiros de seis lotes de 30 ovelhas foram pesados ao nascimento e ao desmame. Três lotes foram suplementados em cochos individuais e o consumo de alimento foi mensurado. Na segunda fase, pós-desmame, os cordeiros foram distribuídos em dois grupos, considerando sexo, peso ao desmame e suplementação durante o aleitamento, para terminação em confinamento ou semiconfinamento. Todos os animais foram everminados no início da terminação. Os animais foram pesados a cada 14 dias e arraçoados com concentrado na proporção de 2% do peso vivo. Os animais confinados receberam silagem de sorgo, e os semiconfinados foram mantidos em pastagem de Braquiaria brizantha cv Piatã. A suplementação na fase de cria teve efeito no peso e no ganho em peso na desmama e na terminação, mas com retorno econômico favorável somente na terminação. O diferimento do pasto no sistema de semiconfinamento controlou a verminose, evitando mortes, e não houve diferenças no peso e no ganho em peso entre os cordeiros confinados ou semiconfinados. Os dois sistemas foram viáveis, mas o lucro no semiconfinamento foi 2,3 vezes superior ao do confinamento.

The objectives of this study were to evaluate the effect of creep feeding and drylots or semi confined raised lambs on weight gain, gastrointestinal nematodes infection and economic viability. Lambs from six lots of 30 ewes were weighed at birth and at weaning and the offspring of three lots were supplemented in private troughs and their food intake was measured. In the second phase, after weaning, lambs were divided into two finishing groups, feedlot or semi confinement considering gender, weaning weight and creep feeding. All animals were dewormed at early termination, weighed every 14 days and supplemented with 2% of body weight. Feedlot animals received sorghum silage while semi confined animals were kept at pasture on Brachiaria brizantha cv Piata. Creep feeding had effect on weight and weight gain at weaning and finishing, but favorable economic returns were only observed at termination. Pasture deferred in the semi-confinement system controlled verminosis, preventing deaths with no differences in weight and weight gain among feedlots or semi-confined lambs. Both systems were economically viable, but profit in semi confinement was 2.3 times higher than the feedlots.

Terminação de cordeiros, com e sem suplementação na fase de cria, confinados ou semiconfinados em Brachiaria brizantha diferida: parasitismo gastrintestinal e eficiência bioeconômica / Performance of creep feed lambs, finished under feedlot or Brachiaria brizantha deferred pasture: gastrintestinal parasitism and bioeconomic efficiency

Objetivou-se avaliar os efeitos da suplementação na fase de aleitamento sobre o desempenho ponderal, o grau de infecção por nematódeos gastrintestinais e a viabilidade econômica na terminação de cordeiros em confinamento ou semiconfinamento. Na fase de aleitamento, os cordeiros de seis lotes de 30 ovelhas foram pesados ao nascimento e ao desmame. Três lotes foram suplementados em cochos individuais e o consumo de alimento foi mensurado. Na segunda fase, pós-desmame, os cordeiros foram distribuídos em dois grupos, considerando sexo, peso ao desmame e suplementação durante o aleitamento, para terminação em confinamento ou semiconfinamento. Todos os animais foram everminados no início da terminação. Os animais foram pesados a cada 14 dias e arraçoados com concentrado na proporção de 2% do peso vivo. Os animais confinados receberam silagem de sorgo, e os semiconfinados foram mantidos em pastagem de Braquiaria brizantha cv Piatã. A suplementação na fase de cria teve efeito no peso e no ganho em peso na desmama e na terminação, mas com retorno econômico favorável somente na terminação. O diferimento do pasto no sistema de semiconfinamento controlou a verminose, evitando mortes, e não houve diferenças no peso e no ganho em peso entre os cordeiros confinados ou semiconfinados. Os dois sistemas foram viáveis, mas o lucro no semiconfinamento foi 2,3 vezes superior ao do confinamento.(AU)

The objectives of this study were to evaluate the effect of creep feeding and drylots or semi confined raised lambs on weight gain, gastrointestinal nematodes infection and economic viability. Lambs from six lots of 30 ewes were weighed at birth and at weaning and the offspring of three lots were supplemented in private troughs and their food intake was measured. In the second phase, after weaning, lambs were divided into two finishing groups, feedlot or semi confinement considering gender, weaning weight and creep feeding. All animals were dewormed at early termination, weighed every 14 days and supplemented with 2% of body weight. Feedlot animals received sorghum silage while semi confined animals were kept at pasture on Brachiaria brizantha cv Piata. Creep feeding had effect on weight and weight gain at weaning and finishing, but favorable economic returns were only observed at termination. Pasture deferred in the semi-confinement system controlled verminosis, preventing deaths with no differences in weight and weight gain among feedlots or semi-confined lambs. Both systems were economically viable, but profit in semi confinement was 2.3 times higher than the feedlots.(AU)

The effect of combinations of dried or ensiled corn and sorghum on the performance of feedlot lambs / Combinações de milho e sorgo secos e ensilados nas características de carcaça de cordeiros terminados em confinamento

The objective of this study was to evaluate the effects of combinations of dry and moist corn and sorghum grain on the carcass and cut characteristics of crossbred lambs Suffolk x Santa Inês produced in feedlots. The experimental design was a randomized block with four treatments and three replicates. Sixty uncastrated male lambs with an initial average weight of 15.5 kg were used in this experiment. Four combinations of grain were evaluated: dry sorghum milled + silage of high-moisture sorghum grain (DS: MS); dry corn milled + silage of high-moisture sorghum grain (DC:MS); dry corn milled + silage of high-moisture corn grain (DC:MC); dry sorghum milled + silage of high-moisture corn grain (DS:MC). There was no difference between treatments for carcass yield, warm and cold carcass weight and for cooling loss. The slaughtering weights of lambs fed DC:MS associations were higher (29.46 kg) than lambs fed DC: MC (24.17 kg), but both did not differ DS:MS (26.18 kg) and DS:MC (25.21 kg). There was influence of the grain associations on the yield of commercial cuts palette and shank. Combinations of corn and sorghum grain, dried and ensiled, can be used to feed lambs in confinement for meat production without affecting the quality of the carcass.(AU)

O objetivo deste estudo foi avaliar o efeito das associações de grãos secos e úmidos de milho e sorgo nas características de carcaça de cordeiros mestiços Suffolk x Santa Inês terminados em confinamento. O delineamento experimental foi em blocos casualizado com quatro tratamentos e três repetições. Foram utilizados 60 cordeiros machos não castrados, com média de 15,5 kg de peso corporal. Quatro associações de grãos na dieta foram avaliadas: sorgo seco triturado + silagem de grãos úmidos de sorgo (SS:SU); milho seco triturado + silagem de grãos úmidos de sorgo (MS:SU); milho seco triturado + silagem de grãos úmidos de milho (MS:MU); sorgo seco triturado + silagem de grãos úmidos de milho (SS:MU). Não houve diferença entre os tratamentos para rendimento, peso de carcaça quente e fria e para perda por resfriamento. Os pesos de abate dos cordeiros alimentados com associações MS:SU foram superiores (29,46 kg) aos dos cordeiros alimentados com MS:MU (24,17 kg) porém, ambos não diferiram SS:SU (26,18 kg) e SS:MU (25,21 kg). Houve influência das associações de grãos sobre rendimento dos cortes comerciais paleta e pernil. As associações de grãos de milho e sorgo, secos e ensilados, podem ser utilizadas na alimentação de cordeiros em confinamento para produção de carne.(AU)

The effect of combinations of dried or ensiled corn and sorghum on the performance of feedlot lambs / Combinações de milho e sorgo secos e ensilados nas características de carcaça de cordeiros terminados em confinamento

The objective of this study was to evaluate the effects of combinations of dry and moist corn and sorghum grain on the carcass and cut characteristics of crossbred lambs Suffolk x Santa Inês produced in feedlots. The experimental design was a randomized block with four treatments and three replicates. Sixty uncastrated male lambs with an initial average weight of 15.5 kg were used in this experiment. Four combinations of grain were evaluated: dry sorghum milled + silage of high-moisture sorghum grain (DS: MS); dry corn milled + silage of high-moisture sorghum grain (DC:MS); dry corn milled + silage of high-moisture corn grain (DC:MC); dry sorghum milled + silage of high-moisture corn grain (DS:MC). There was no difference between treatments for carcass yield, warm and cold carcass weight and for cooling loss. The slaughtering weights of lambs fed DC:MS associations were higher (29.46 kg) than lambs fed DC: MC (24.17 kg), but both did not differ DS:MS (26.18 kg) and DS:MC (25.21 kg). There was influence of the grain associations on the yield of commercial cuts palette and shank. Combinations of corn and sorghum grain, dried and ensiled, can be used to feed lambs in confinement for meat production without affecting the quality of the carcass.

O objetivo deste estudo foi avaliar o efeito das associações de grãos secos e úmidos de milho e sorgo nas características de carcaça de cordeiros mestiços Suffolk x Santa Inês terminados em confinamento. O delineamento experimental foi em blocos casualizado com quatro tratamentos e três repetições. Foram utilizados 60 cordeiros machos não castrados, com média de 15,5 kg de peso corporal. Quatro associações de grãos na dieta foram avaliadas: sorgo seco triturado + silagem de grãos úmidos de sorgo (SS:SU); milho seco triturado + silagem de grãos úmidos de sorgo (MS:SU); milho seco triturado + silagem de grãos úmidos de milho (MS:MU); sorgo seco triturado + silagem de grãos úmidos de milho (SS:MU). Não houve diferença entre os tratamentos para rendimento, peso de carcaça quente e fria e para perda por resfriamento. Os pesos de abate dos cordeiros alimentados com associações MS:SU foram superiores (29,46 kg) aos dos cordeiros alimentados com MS:MU (24,17 kg) porém, ambos não diferiram SS:SU (26,18 kg) e SS:MU (25,21 kg). Houve influência das associações de grãos sobre rendimento dos cortes comerciais paleta e pernil. As associações de grãos de milho e sorgo, secos e ensilados, podem ser utilizadas na alimentação de cordeiros em confinamento para produção de carne.

Dry matter intake observed and predicted by the nutritional systems NRC and BR-Corte for feedlot nelore heifers fed with human feed products / Consumo de matéria seca observado e predito pelo NRC e BR-Corte de novilhas nelore em confinamento alimentadas com produtos oriundos da alimentação humana

We aimed to evaluate the effects of using a concentrated ration containing industrialised human food on the productive parameters of Nellore heifers in confinement, in addition to comparing the dry matter intake (DMI) observed with that predicted by the nutritional systems BR-Corte and NRC, in order to determine which system makes the most accurate predictions for heifers of the breed Nelore in feedlots. Twenty-four Nelore heifers, with an average age of 24 months and average body weight (BW) of 350 kg, were used over the 70 days of the experiment. They were randomly assigned to two treatments and housed in partially covered stalls equipped with an automatic Growsafe® Systems feeding system. Animals in the control group (CONT) received a concentrated ration containing ground corn, soybean meal, urea, and mineral nucleus. In the residual treatment (RES) group, heifers received concentrated feed containing products from the human diet. The difference between the treatments was the concentrated ration; in the control treatment, the energy source used was maize, whereas in the residue treatment, the energy sources were corn chips, coconut candies, and ground coffee. Corn silage was included as forage for both treatments. The forage:concentrate (F:C) ratio was 84:16. The predicted intake was estimated according to the nutritional systems NRC (2000, 2016) and BR-Corte (VALADARES FILHO et al., 2010, 2016). The average DMI observed of the heifers was 7.46 kg day-1. Heifers fed with human feed residue had a higher dry matter intake (DMI) and higher ether extract intake (EEI) than animals fed with the control feed. In addition, heifers that received human feed products showed a lower average daily weight gain (DWG) of 1.08 kg day-1 than animals fed the control treatment with an average DWG of 1.24 kg day-1. The predicted dry matter intake by NRC 2000 was an overestimate by 9.78 % and by BR-Corte 2010 was an overestimate by 5.5 %...

Objetivou-se avaliar os efeitos da utilização de ração concentrada contendo produtos industrializados da alimentação humana sobre os parâmetros produtivos de novilhas Nelore em confinamento, além de comparar o consumo de matéria seca observado com o predito pelos sistemas nutricionais BR-Corte e NRC e encontrar qual sistema faz melhores predições para novilhas de corte da raça Nelore em confinamento. Foram utilizadas 24 novilhas da raça Nelore, durante 70 dias de experimento, com idade média de 24 meses e peso corporal (PC) médio de 350 kg, na qual foram distribuídas aleatoriamente em dois tratamentos e alojadas em baias equipadas com sistema automático de alimentação Growsafe®. No tratamento controle (CONT), os animais receberam ração concentrada contendo milho moído, farelo de soja, ureia, núcleo mineral. No tratamento resíduo (RES), as novilhas receberam ração concentrada contendo produtos oriundos da alimentação humana. A diferença entre os tratamentos se encontra na ração concentrada, onde no tratamento controle a fonte de energia usada foi o milho, enquanto que no tratamento resíduo, as fontes de energias foram salgadinho de milho, balas de côco e café moído. Silagem de milho foi oferecido como volumoso para ambos os tratamentos, sendo adotado a relação volumoso:concentrado de 84:16. Os consumos preditos foram obtidos utilizando os sistemas nutricionais NRC (2000, 2016) e BR-Corte (VALADARES FILHO et al., 2010, 2016). O CMS médio observado nas novilhas foi de 7,46 kg dia-1. As novilhas alimentadas com ração resíduo tiveram maior consumo de matéria seca (CMS) e maior consumo de extrato etéreo (CEE) em comparação aos animais alimentados com a ração controle. Além disso, os animais que receberam ração resíduo apresentaram menor ganho médio diário (GMD), 1,08 kg dia-1 em relação as do tratamento controle com 1,24 kg dia-1...

The economic viability of the inclusion of ureain the ration for feedlot lambs / Viabilidade econômica da inclusão de ureia na ração para cordeiros confinados

The aim of this study was to evaluate the economic viability of the inclusion of urea in the ration provided to feedlot lambs. Twenty-four non-castrated male lambs, crossbred Dorper, with 2-5 months of age and a body weight (BW) of 25.0 ± 4.3 kg were used. A completely randomized design with four treatments and six replicates was adopted, in which the treatments were urea levels of 0.0, 0.5, 1.0 and 1.5% in the ration, on a dry matter (DM) basis. Lambs were fed ad libitum for 56 days and slaughtered at a BW of37.9 ± 5.1 kg. The analyzed economic indexes were the cost of the rations, cost of marginal factor (CMF), revenue of marginal factor (RMF), net revenue (NR) and benefit: cost ratio (BCR). The ration without urea presented the highest cost (0.30 US$/kg DM) and the ration with 1.0% DM of urea had the lowest cost (0.23 US$/kg DM). The CMF had a quadratic response to the urea level, reaching the lowest value (0.28 US$/day) with the addition of 0.9 to 1.0% DM of urea. The lowest and the highest NR values were obtained from the rations without and with 1.5% DM of urea, respectively (0.26 and 0.34 US$/day). The ration without urea had a worse BCR (1.74), whereas the ration with 1.0% DM of urea resulted in a better BCR (2.09). A better economic return for lambs finishing in feedlots is obtained with rations containing 1.0 to 1.5% DM of urea.(AU)

Objetivou-se com este estudo avaliar a viabilidade econômica da inclusão de ureia na ração fornecida para cordeiros terminados em confinamento. Foram utilizados 24 cordeiros machos não castrados, mestiços Dorper, com 2 a 5 meses de idade e 25,0 ± 4,3 kg de peso corporal (PC). O delineamento experimental foi inteiramente casualizado com quatro tratamentos e seis repetições, onde os tratamentos foram os teores de 0,0; 0,5; 1,0 e 1,5% de ureia na ração, com base na matéria seca (MS). Os cordeiros foram alimentados ad libitum por 56 dias e abatidos com 37,9 ± 5,1 kg de PC. Os índices econômicos analisados foram custo das rações, custo do fator marginal (CFM), receita do fator marginal (RFM), receita líquida (RL) e relação benefício:custo (RBC). A ração sem ureia apresentou o maior custo (0,30 US$/kg MS) e a ração com 1,0% MS de ureia teve o menor custo (0,23 US$/kg MS). O CFM apresentou resposta quadrática aos níveis de ureia, alcançando o menor valor (0,28 US$/dia) com a inclusão de 0,9 a 1,0% MS de ureia na ração. O menor e o maior valor de RL foram obtidos a partir das rações sem e com 1,5% MS de ureia, respectivamente (0,26 e 0,34 US$/dia). A ração sem ureia apresentou a pior RBC (1,74), enquanto a ração com 1,0% MS de ureia resultou na melhor RBC (2,09). O melhor retorno econômico na terminação de cordeiros em confinamento é obtido com rações contendo 1,0 a 1,5% MS de ureia.(AU)