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The objective of this experiment was to determine the feed intake pattern and feed sorting of 30 Nelore males finished in a feedlot fed diets based on three different sources of corn: whole crop silage (WCS), high moisture corn (HMC) or corn grain (CG). Feed intake pattern and feed sorting were determined on days 13, 27, 41, 55, 69, and 83 days after the beginning of the experiment in three times relative to feed delivery (4, 10, and 24 hours). Diets were size-separated using the three-screen (19, 8, and 4 mm) and a bottom pan to yield long (>19 mm), medium (8 mm), short (4 mm) and fine (0.05) of corn source on feed intake pattern. Regardless of the source of corn, animals expressed a preferential consumption or sorting for the long (104.01% for WCS, 126.99% for HMC, and 132.58% for CG) and medium (116.66% for WCS, 109.95% for HMC, and 135.14% for CG) particles of the diets, which may be a beneficial aspect in terms of rumen motility as well as maintaining rumen pH in an adequate range.

BackgroundBeef tenderness is a complex trait of economic importance for the beef industry. Understanding the epigenetic mechanisms underlying this trait may help improve the accuracy of breeding programs. However, little is known about epigenetic effects on Bos taurus muscle and their implications in tenderness, and no studies have been conducted in Bos indicus.ResultsComparing methylation profile of Bos indicus skeletal muscle with contrasting beef tenderness at 14 days after slaughter, we identified differentially methylated cytosines and regions associated with this trait. Interestingly, muscle that became tender beef had higher levels of hypermethylation compared to the tough group. Enrichment analysis of predicted target genes suggested that differences in methylation between tender and tough beef may affect signal transduction pathways, among which G protein signaling was a key pathway. In addition, different methylation levels were found associated with expression levels of GNAS, PDE4B, EPCAM and EBF3 genes. The differentially methylated elements correlated with EBF3 and GNAS genes overlapped CpG islands and regulatory elements. GNAS, a complex imprinted gene, has a key role on G protein signaling pathways. Moreover, both G protein signaling pathway and the EBF3 gene regulate muscle homeostasis, relaxation, and muscle cell-specificity.ConclusionsWe present differentially methylated loci that may be of interest to decipher the epigenetic mechanisms affecting tenderness. Supported by the previous knowledge about regulatory elements and gene function, the methylation data suggests EBF3 and GNAS as potential candidate genes and G protein signaling as potential candidate pathway associated with beef tenderness via methylation.

Copyright of Revista Colombiana de Ciencia Animal - RECIA is the property of Revista Colombiana de Ciencia Animal - RECIA and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Ionóforos são adicionados em dietas para animais de alta produção para aumentar o ganho de peso, melhorar a eficiência alimentar e modular a fermentação ruminal. No entanto, existem vários compostos diferentes que podem ser utilizados em dietas de animais. Este trabalho foi realizado com o objetivo de avaliar o desempenho animal, ingestão de ração, rendimento de carcaça e sanidade do epitélio ruminal de tourinhos Nelore terminados em confinamento e alimentados com dieta suplementada com narasina ou monensina ou uma combinação desses dois compostos. Anteriormente, os animais foram alimentados com dietas suplementadas com narasina. Foram utilizados 96 animais da raça Nelore com peso médio inicial de 334,1 ± 27,0 kg. Os animais foram bloqueados por peso (total de seis blocos) e alocados aleatoriamente em 24 baias (n = 4 animais por baia). Os tratamentos foram distribuídos aleatoriamente em cada baia de acordo, primeiramente, com a fase de recria e depois com a fase de confinamento: CONT+MONE, sem adição de aditivo na recria e monensina (27 ppm) no confinamento; CONT+NARA, sem adição de aditivo na recria e narasina (13 ppm) no confinamento; NARA+MONE, inclusão de narasina (13 ppm) na recria e monensina (27 ppm) no confinamento e NARA+NARA, narasin (13 ppm) na recria e no confinamento. Assim, houve arranjo fatorial 2 x 2, com seis repetições por tratamento. A inclusão de monensina e narasina não afetaram o desempenho animal, consumo de ração, rendimento de carcaça quente e sanidade ruminal. Os animais apresentaram alto ganho de peso (1,70 kg/dia), alto consumo de matéria seca (mais de 2,50% do peso corporal), alto rendimento de carcaça (próximo a 56,0%) e nenhum efeito adverso sobre o epitélio ruminal. Em conclusão, a narasina pode substituir a monensina em touros terminados em confinamento. A inclusão de narasin na fase de recria não melhora o desempenho subsequente do confinamento de bovinos Nelore, independentemente de terem consumido narasina ou monensina durante o confinamento por um período de 117 dias.

Abstract Background Beef tenderness is a complex trait of economic importance for the beef industry. Understanding the epigenetic mechanisms underlying this trait may help improve the accuracy of breeding programs. However, little is known about epigenetic effects on Bos taurus muscle and their implications in tenderness, and no studies have been conducted in Bos indicus. Results Comparing methylation profile of Bos indicus skeletal muscle with contrasting beef tenderness at 14 days after slaughter, we identified differentially methylated cytosines and regions associated with this trait. Interestingly, muscle that became tender beef had higher levels of hypermethylation compared to the tough group. Enrichment analysis of predicted target genes suggested that differences in methylation between tender and tough beef may affect signal transduction pathways, among which G protein signaling was a key pathway. In addition, different methylation levels were found associated with expression levels of GNAS, PDE4B, EPCAM and EBF3 genes. The differentially methylated elements correlated with EBF3 and GNAS genes overlapped CpG islands and regulatory elements. GNAS, a complex imprinted gene, has a key role on G protein signaling pathways. Moreover, both G protein signaling pathway and the EBF3 gene regulate muscle homeostasis, relaxation, and muscle cell-specificity. Conclusions We present differentially methylated loci that may be of interest to decipher the epigenetic mechanisms affecting tenderness. Supported by the previous knowledge about regulatory elements and gene function, the methylation data suggests EBF3 and GNAS as potential candidate genes and G protein signaling as potential candidate pathway associated with beef tenderness via methylation.

Objetivou-se avaliar neste trabalho, o efeito da Promixalicina para o controle de ecto e endoparasitas em bovinos Nelore ou anelorados em sistemas de pastejo, na região de Presidente Prudente/SP. Avaliou-se durante 28 dias após a ingestão do produto, a eficiência da promixalicina na diminuição de comportamentos de estresse por animais da raça Nelore. Sendo assim, foram utilizados ao total de 367 animais em diversas categorias, garrotes, novilhas e vacas prenhes. Avaliou-se com este estudo, o fornecimento da Promixalicina misturada ao Sal proteinado e ao concentrado, na dosagem de 5 gramas por animal por dia. A época da avaliação foi nos meses de setembro e outubro de 2021. Para efeito dos animais, após trazidos em área de piquete delimitado, foram avaliados após 10 minutos de descanso, o comportamento dos animais, mensurando os seguintes eventos de estresse: abano de cauda; abano de orelha; levante de perna; inquietação; cabeçada; coice e agressão. Houve redução significativa de 70% dos efeitos comportamentais dos animais. Não houve influência na ingestão de alimento pelo animal, bem como reduziu significativamente a OPG dos animais. A partir do presente estudo, pode-se inferir efeitos positivos e satisfatórios em 21 dias com o uso da Promixalicina na dieta de bovinos Nelore em pastagem, para o controle de endo e ectoparasitas.

The application of Fixed Time Artificial Insemination (FTAI) protocols has strongly boosted artificial insemination in Brazilian bovine herds. The control of the estrous cycle with protocols based on progesterone and estrogen involves synchronizing the emergence of a follicular wave, controlling the progesterone phase, and inducing ovulation in a synchronized manner. The increase in pregnancy rates starts with the preparation of the breeding season and the choice of protocols and females. Thereafter, based on the characteristics of the property and the lots of animals, small adjustments can be made to the hormonal protocols as needed. Finally, resynchronization can increase usability by allowing multiple inseminations within short periods. The search for new strategies is of paramount importance for the development of the FTAI protocol and the increase in final pregnancy rates. Thus, this review sought to highlight the main critical points and adjustments of the FTAI protocols and their applicability in the reproduction of beef cattle.

RESUMO A ultrassonografia é um exame complementar não invasivo ainda pouco utilizado na avaliação prepucial e sem descrições detalhadas da parte livre do pênis (PLP) de bovinos. Este estudo objetivou padronizar a ultrassonografia prepucial em bovinos hígidos da raça Nelore com um ano de idade e, para tanto, descreveu o aspecto da lâmina interna prepucial (LIP) e da PLP, determinando as principais janelas acústicas, a viabilidade da utilização de contraste no lúmen da cavidade prepucial (LCP) e o melhor posicionamento do animal para a realização do exame. O escaneamento foi realizado com os animais na posição quadrupedal e em decúbito lateral direito. Foram determinadas cinco janelas acústicas a partir do óstio até a identificação do recesso prepucial. Os escaneamentos foram realizados nos planos longitudinais, transversais e dorsais, antes e após a infiltração de solução fisiológica a 0,9% no LCP. Como conclusões, o exame ultrassonográfico permitiu identificar a LIP e a PLP em todos os planos e em todas as janelas acústicas propostas. O melhor ponto de referência é a identificação da glande. O posicionamento quadrupedal é mais adequado para a realização do exame e o uso de contraste é recomendado para delimitação topográfica das estruturas.

Foi avaliado o desempenho de touros Nelore em cobertura a campo por 4 dias com alta pressão de cios sincronizados, quanto a sua classificação andrológica por pontos(CAP) e teste de libido e testados em 4 tratamentos: T1 = CAP > 75 pontos e alta libido; T2 = CAP < 75 pontos e alta libido; T3 = CAP > 75 e baixa libido; T4 = CAP < 75 pontos e baixa libido. Os cios foram observados de 18 a 78 horas após a sincronização com os maiores percentuais registrados às 42 (40,1%) e às 54 (30,4%) horas. Foram registrados, em média, 24,62 ± 2,11 fêmeas em cio por lote com pico de 9,87 ± 1,55 fêmeas/touro/dia. O número médio de fêmeas gestante por touro foi de 9,25 ± 3,2. A taxa média de gestação foi de 33,33%, variando de 22,44 no T4 a 47,82% no T1 (p

Objective. Evaluate the effects of supplementation with different protein sources (soybean meal and wheat bran with urea) on the productive performance, intake, digestibility, microbial protein synthesis, and metabolic profile of grazing beef heifers. Materials and methods. Were used twenty Nellore heifers at 8.5±0.06 months of age, with an initial average body weight of 241.5±4.71 kg. The animals were distributed in a completely randomized deseing with two treatments and ten replicates. Two protein sources in the supplements were evaluated: 1) Soybean meal (SBM), and 2) Soybean meal + Wheat bran + Urea (SBM+WB+U). Results. Crude protein (CP) and organic matter intakes were higher (p<0.05) for heifers from SBM compared with SBM+WB+U. The CP digestibility was increased (p<0.05) with SBM supplementation. Mean blood concentrations of glucose, cholesterol, serum urea nitrogen, and total proteins were not affected (p>0.10) by protein sources. In the same way, daily weight gain and final body weight were not influenced (p>0.10) by protein sources. Conclusions. The supplementation with soybean meal or wheat bran with urea in association with soybean meal in multiple supplements for grazing cattle provides similar productive and nutritional performance and metabolic profile in beef heifers. [ABSTRACT FROM AUTHOR]

Background: the use of creep-feeding combined with the correct management of pastures has been one of the main tools of nutritional management in cattle. Objective: to evaluate the effects of supplementation with different protein regimes on the metabolic profile in grazing suckling male calves. Methods: fifty suckling Nellore male calves with average initial body weight (BW) of 114 ± 2.4 kg and 105 ± 3.0 days age were used and distributed in a completely randomized design in two treatments and 25 replicates. The protein regimens evaluated were low protein (LOW)-supplement with 150 g CP/kg DM and; High protein (HIGH) - supplement with 300 g CP/kg DM. The supplements were composed of soybean meal‚ cornmeal‚ wheat meal‚ mineral mixture‚ and molasses‚ and provided in amounts of 6 g/kg BW. The animals were subjected to 78 experimental days and kept in eight 5 hectares paddocks each‚ formed by Brachiaria decumbens and equipped with drinkers and feeders. All animals had unrestricted access to water. Blood samples were collected to quantify levels of urea‚ albumin‚ globulins‚ total protein‚ glucose‚ triglycerides‚ and insulinlike growth factor 1 (IGF-1). Globulin concentrations were calculated by the difference between total protein and albumin concentration. Results: no treatment effect was observed (p > 0.10) on concentrations of glucose (77.6 vs 81.6 mg/mL)‚ triglycerides (32.8 vs 39.2 mg/mL)‚ total proteins (6.52 vs 6.67 g/dL)‚ globulin (3.28 vs 3.25 g/dL) and IGF-1 (424 vs 441 nm/ mL); while the albumin (3.24 vs 3.42 g/dL) and SUN (10.2 vs 15.7 mg/dL) concentrations did show significant differences (p < 0.05)‚ being higher in the calves supplemented with higher level of crude protein. Conclusions: supplementation with 150 g CP/kg DM in the amount of 6 g/kg PC is recommended for lactating beef calves during the rainy season and rainy-dry transition. [ABSTRACT FROM AUTHOR]

Background: to ensure continuous calves' growth, the supply of supplements is necessary to impact the animals' tissue response. Objective: the aim of this study was to evaluate the effects of supplementation with different protein regimens on performance in suckling beef calves. Methods: fifty suckling Nellore calves with average initial body weight (BW) of 114 ± 2.4 kg and 105 ± 3.0 days age were used and distributed in a completely randomized design with two supplementation treatments: Low protein (LOW) and High protein (HIGH). The supplements were composed of soybean meal, cornmeal, wheat meal, mineral mixture, and molasses, containing 150 g CP/kg dry matter (DM) and 300 g CP/kg DM for LOW and HIGH respectively, and provided in amounts of 6 g/kg BW. The animals underwent 78 experimental days, and were kept in eight 5 hectares paddocks each, formed by Brachiaria decumbens and equipped with drinkers and feeders. For productive performance evaluation, all calves were weighed at the beginning and end of the experiment after 14 h for solids fasting. Also, on the 78th-day experimental carcass images were obtained by ultrasound between the 12th and 13th ribs over the longissimus muscle to measure the ribeye area and backfatthickness on the Longissimus muscle (FAT-L), and between the ischium and pubis to the backfat-thickness on the rump (FAT-R). Biopsies of Longissimus dorsi muscle were performed at 75 days to measure the number and diameter of muscle fibers. Results: no difference (p > 0.05) was observed for average daily gain (LOW = 0.98 vs HIGH = 1.00 kg/d) or final BW (LOW = 191 vs HIGH = 193 kg) throughout the experiment. Likewise, no effect (p > 0.05) of the amounts of protein supplementation was verified on ribeye area (LOW = 36.7 vs HIGH = 38.8 cm2), FAT-L (LOW = 1.38 vs HIGH = 1.54 mm), FAT-R (LOW = 2.06 vs HIGH = 2.30 mm), or number (LOW = 141 vs HIGH = 142) and diameter (LOW = 29.2 vs HIGH = 30.9) of muscle fibers. Conclusions: supplementation with 150 g CP/kg DM in the amount of 6 g/kg BW is recommended for suckling beef calves in grazing. [ABSTRACT FROM AUTHOR]

O presente estudo teve como objetivo avaliar o uso de dispositivos intravaginais contendo doses altas ou baixas de progesterona (P4) na taxa de prenhez de novilhas zebuínas submetidas à inseminação artificial em tempo fixo (IATF). Novilhas Bos indicus (Nelore) receberam, no dia 0, uma injeção im de 2 mg de benzoato de estradiol (BE) e, em seguida, foram divididas aleatoriamente em três grupos. Nos grupos 1 (n = 80) e 2 (n = 79) foi colocado um dispositivo intravaginal contendo 1,9 g (grupo 1) e 0,75 g ( grupo 2) de P4, enquanto que o grupo 3 (n = 76) não recebeu dispositivo. Os dispositivos intravaginais foram removidos no dia 8, juntamente com a aplicação im de uma dose luteolítica de cloprostenol. Metade dos animais de cada grupo recebeu adicionalmente um injeção im de 300 UI de eCG. Vinte e quatro horas depois, todos animais receberam uma segunda aplicação im de 1 mg de BE e foram inseminados 54-56 horas após a aplicação de cloprostenol. O diagnostico de prenhez foi realizado 40 dias após a IATF, por meio de ultrassonografia transretal. Os dados foram analisados ​​por regressão logística. As taxas de prenhez foram de 27,5% , 30,4% e 28,9% para os grupos 1, 2 e 3, respectivamente (P> 0,05). A injeção de eCG, bem como outras variáveis tais como escore corporal, fazenda e presença de CL no início dos tratamentos não influenciaram esse resultado. Em conclusão, o uso de dispositivos intravaginas contendo alto (1,9 g) ou baixo (0,75 g) teor de P4 resultou em semelhantes taxas de prenhez após IATF de novilhas Nelore púberes.

Objective. Evaluate the effects of supplementation with different protein sources (soybean meal and wheat bran with urea) on the productive performance, intake, digestibility, microbial protein synthesis, and metabolic profile of grazing beef heifers. Materials and methods. Were used twenty Nellore heifers at 8.5±0.06 months of age, with an initial average body weight of 241.5±4.71 kg. The animals were distributed in a completely randomized deseing with two treatments and ten replicates. Two protein sources in the supplements were evaluated: 1) Soybean meal (SBM), and 2) Soybean meal + Wheat bran + Urea (SBM+WB+U). Results. Crude protein (CP) and organic matter intakes were higher (p0.10) by protein sources. In the same way, daily weight gain and final body weight were not influenced (p>0.10) by protein sources. Conclusions. The supplementation with soybean meal or wheat bran with urea in association with soybean meal in multiple supplements for grazing cattle provides similar productive and nutritional performance and metabolic profile in beef heifers.

Abstract: The objective of this work was to evaluate the potential of the stable isotope technique to characterize beef cattle production systems in tropical conditions. For this, carbon and nitrogen stable isotopes were identified in non-defatted and defatted bovine muscles. A total of 45 cattle were evaluated in three production systems: pasture, conventional feedlot, and young beef bull feedlot (n = 15 per system). Samples from the Trapezius cervicis, Longissimus dorsi, and Semitendinosus muscles were collected to determine the isotopic composition of δ13C and δ15N. The isotopic data of the δ13C and δ15N of non-defatted and defatted muscles were subjected to the principal component analysis (PCA) and to the discriminant analysis (DA). The PCA allowed separating the three production systems based on the results obtained for the non-defatted and defatted muscles. A correct global classification rate of 100% and a cross-validation rate of 100% were obtained with the DA. The carbon and nitrogen isotopic ratio of non-defatted and defatted muscles allows for the precise identification of beef cattle production systems in tropical conditions.

O objetivo do estudo foi avaliar o desempenho produtivo, produção de leite e os parâmetros da curva de lactação de vacas de corte e bezerros de três diferentes grupos genéticos no período pós-parto. Foram usadas 15 vacas paridas divididas em três grupos genéticos: cinco vacas ½Angus ½Nelore (F1), cinco ¼Angus ¼Nelore ½Tabapuã (F2) e cinco Nelore (NE). Avaliou-se a produção de leite, curva de lactação, peso corporal (PC), condição corporal (CC) e eficiência produtiva das vacas além do ganho de peso diário médio (GPDMB) e peso corporal no pós-parto e ao desmame (PCB) dos bezerros. As vacas F2 apresentaram maior PC comparado às F1 e NE que não diferiram entre si. O PCB do F2 e F1 não diferiram e, foram superiores aos NE dos 125 até 183 dias pós-parto. A CC das vacas F1 e F2 reduziu no período pós-parto, ao contrário das NE que mantiveram. Os bezerros mestiços tiveram melhor desempenho produtivo que o Nelore. A curva de lactação teve comportamento quadrático e parecido entre os grupos genéticos, assim como suas eficiências produtivas. As vacas F2 e F1 apresentaram maior produção de leite total e produção de leite diária em relação às vacas NE. Vacas mestiças, apesar das características produtivas superiores, tiveram eficiência produtiva parecida à raça Nelore, justificando o seu uso como matriz em sistemas de cruzamento com outras raças bovinas.

ABSTRACT: Cuts of muscle (biceps femoris) from three crossbreeds between the Nelore, Angus and Wagyu breeds of cattle (Crossbreed 1 (C1): ½ Angus and ½ Nelore; Crossbreed 2 (C2): ¾ Angus and ¼ Nelore; Crossbreed 3 (C3): ½ Wagyu, ¼ Nelore and ¼ Angus) were characterized by their chemical composition, pH, water activity and lipid oxidation. The cuts were submitted to wet brining in a 5 % NaCl concentration at 5 °C with either static brine (SB) or brine assisted with ultrasound (US). Samples of the treatments were taken after 30, 60, and 120 min of wet brining for later analysis. The experimental data were adjusted using the Peleg and Page models, and the Page template best described the experimental data. The crossbreeding did not affect the water and ash content; however, it significantly affected the levels of lipids and proteins. C3 presented higher fat content than C2, which, in turn, was higher than C1. C1 had higher protein content than C2, which had more protein than C3. When ultrasound was applied, crossbreeding influenced the water content and the water absorption rate during brining, which had the highest values for the highest protein content. The crossbreeding and ultrasound application also affected the NaCl content of the cuts. However, only ultrasound application increased the rate of NaCl absorption during wet brining. The results demonstrate that ultrasound accelerates the mass transfer in wet brining of the cuts of beef, regardless of the crossbreeds studied.

O objetivo com este estudo foi avaliar os resultados econômicos de confinamento de bovinos com três espaços disponíveis por animal (6, 12 e 24 m2 por animal). Para as simulações considerou-se confinamentos com capacidade estática de 5.000 animais por ciclo e dois ciclos de 86 dias por ano. Os dados de desempenho foram obtidos de 1.350 bovinos não castrados. O aumento no espaço elevou o custo fixo por animal. Os custos fixos e variáveis representaram 3% e 93% do custo operacional total, respectivamente. Dos custos variáveis, cerca de 70% foi utilizado para a compra de gado e 17% para a compra de alimentos. O lucro operacional por animal foi crescente com o aumento na disponibilidade de espaço (R$ 80,90; R$ 102,00 e R$ 109,00 para 6, 12 e 24 m2 por animal, respectivamente). Os três sistemas de confinamento recuperaram o investimento inicial e apresentaram valor presente líquido positivo. Além disso, as taxas internas de retorno foram de 22%, 27% e 25%, e as probabilidades de perdas financeiras foram de 33%, 29% e 26% para as dimensões de 6, 12 e 24 m2 por animal, respectivamente. Portanto, maior concessão de espaço nos currais de confinamento melhora a rentabilidade e reduz o risco de perda financeira.

Knowledge of animal behavior can be indicative of the well-being, health, productivity, and reproduction of animals. The use of accelerometers to classify and predict animal behavior can be a tool for continuous animal monitoring. Therefore, the aim of this study was to provide strategies for predicting more and less frequent beef cattle grazing behaviors. The behavior activities observed were grazing, ruminating, idle, water consumption frequency (WCF), feeding (supplementation) and walking. Three Machine Learning algorithms: Random Forest (RF), Support Vector Machine (SVM) and Naïve Bayes Classifier (NBC) and two resample methods: under and over-sampling, were tested. Overall accuracy was higher for RF models trained with the over-sampled dataset. The greatest sensitivity (0.808) for the less frequent behavior (WCF) was observed in the RF algorithm trained with the under-sampled data. The SVM models only performed efficiently when classifying the most frequent behavior (idle). The greatest predictor in the NBC algorithm was for ruminating behavior, with the over-sampled training dataset. The results showed that the behaviors of the studied animals were classified with high accuracy and specificity when the RF algorithm trained with the resampling methods was used. Resampling training datasets is a strategy to be considered, especially when less frequent behaviors are of interest.

Background: Rehydration of grains, such as corn and sorghum, is used to increase nutrient absorption. However, the effect of this practice on meat quality is poorly understood. Objective: To evaluate the effects of type of grain and processing on the meat quality of Nellore steers in a feedlot. Methods: Twenty-four non-castrated Nellore steers (270 ± 53 kg initial body weight) were distributed in a completely randomized 2×2 factorial design, with six replicates. The first factor was cereal type (corn or sorghum), and the second was the grain processing (dry or rehydrated and ensiled). The diets were composed of 28.44% corn silage and 71.56% concentrate. Sixty days before the beginning of the experiment, corn and sorghum grains were rehydrated and ensiled. The animals were slaughtered after 140 days of confinement. Meat quality analyses were determined in samples of fresh and aged meat (7 days) from the Longissimus lumborum muscle. Results: no difference between treatments was observed for carcass pH and L* (lightness), a* (redness), and b* (yellowness) values, shear force, thawing and cooking losses, and chemical composition of meat (p>0.05). The b* (yellowness) value of subcutaneous fat was higher in steers fed corn, regardless of grain processing (p=0.03). Sarcomere length was higher in aged meat of steers fed sorghum, regardless of processing method (p=0.01). Conclusions: the grain processing method does not affect beef quality; however, grain type can affect subcutaneous fat color and sarcomere length of aged beef. [ABSTRACT FROM AUTHOR]

Copyright of Revista Ciência Agronômica is the property of Revista Ciencia Agronomica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: Rumen microorganisms have developed a series of complex interactions, representing one of the best examples of symbiosis between microorganisms in nature. Conventional taxonomic methods based on culture techniques are being replaced by molecular techniques that are faster and more accurate. Objective: To characterize rumen bacterial diversity of Nellore steers grazing on tropical pastures by sequencing the 16S rRNA gene using Illumina sequencing. Methods: Three rumen-cannulated Nellore steers were used. The liquid and solid fractions of the rumen contents were processed to extract metagenomic DNA, and the V1 and V2 hypervariable regions of the 16S rRNA gene were sequenced using Illumina sequencing. Results: A total of 11,407,000 reads of adequate quality were generated, and 812 operational taxonomic units (OTUs) were found at the species level. Twenty-seven phyla were identified, and the predominant phyla were Firmicutes (23%), Bacteroidetes (14%), Proteobacteria (10%), Spirochaetes (9%), Fibrobacteres (7%), Tenericutes (5%), and Actinobacteria (2%), which represented 70% of the total phyla identified in the rumen content. Conclusion: Rumen environment in grazing Nellore steers showed high bacterial diversity, with Firmicutes, Bacteroidetes, Proteobacteria, Spirochaetes, and Fibrobacteres as the predominant phyla. [ABSTRACT FROM AUTHOR]

A neosporose é uma doença parasitária ocasionada pelo protozoário intracelular obrigatório Neospora caninum, responsável por quadros de abortos em bovinos em várias regiões do país. A principal forma de transmissão entre os bovinos é a via vertical ou transplacentária com abortos prevalentes entre 3 a 6 meses de gestação. Este trabalho teve como objetivo pesquisar a presença de anticorpos anti-N.caninum em fêmeas e fetos bovinos da raça Nelore (Bos indicus), do município de Nossa Senhora do Livramento-MT. Durante o abate dos animais foram coletadas amostras de sangue de 489 fêmeas e de 128 fetos acima de três meses de gestação. A pesquisa de anticorpos anti N. caninum nas fêmeas e fetos foi determinada pela Reação de Imunofluorescência Indireta (RIFI). A ocorrência foi de 2,45% para as fêmeas e de 3,91% para os fetos.

This study evaluated the pregnancy rate in Nelore cows (Bos indicus) that were subjected to fixed-time artificial insemination (FTAI) using different protocols consisting of injectable progesterone (P4) or an intravaginal device (impregnated with P4). Multiparous cows 72-84 months in age, 30-45 days postpartum, were selected on the basis of the absence of a corpus luteum (CL) and follicles < 8 mm after transrectal palpation and ultrasound examinations. On a random day of the estrus cycle (D0), the selected animals (n = 135) were randomly assigned to one of three experimental groups (n = 45 each). Group I (injectable P4/FTAI 36 hours) received 250 mg of injectable P4 and 2 mg EB on D0; on D7, they received 500 µg of cloprostenol; on D8, 300 IU of eCG and 1 mg of EB were administered; and finally, FTAI was performed 36 hours after the application of EB. Group II (injectable P4/FTAI 48 hours) received the same protocol as Group I, except that the FTAI was performed 48 hours after ovulation induction. The animals of Group III (Control/CIDR) received a conventional protocol for FTAI using an intravaginal device (D0: P4 and 2 mg EB; D8: device removal, 500 µg cloprostenol, 300 IU eCG, 1 mg EB; and FTAI performed 48 hours after removal of the device). The results showed that cows synchronized with the conventional protocol for FTAI (Control/CIDR) had a higher pregnancy rate (60 %, 27/45) than those synchronized with an injectable P4/FTAI 36 hours (33.33 %; 15/45, P = 0.010). However, the group receiving injectable P4 group/FTAI 48 hours had a similar pregnancy rate (48.9 %; 22/45; P = 0.290) when compared to both the group receiving the conventional protocol and that receiving injectable P4/FTAI 36 hours (P = 0.134). Although the injectable P4 may affect pregnancy rate with the FTAI performed in 36 hours, we found similar pregnancy rates from cows inseminated 48 hours after induction ovulation, considering injectable or intravaginal P4. Therefore, we suggest that injectable P4 represents an alternative source of progesterone for synchronization of cattle for FTAI.

The expansion of the biodiesel industry has created opportunities for crude glycerol use in beef cattle diets. The objective of this study was to determine the effects of substituting sorghum grain with crude glycerol on dry matter intake (DMI), weight gain and feed intake pattern of 28 non-castrated Nelore males with initial body weight (BW) of 441 ± 40.2 kg and 21.5 ± 0.5 months of age housed in individual or collective pens. The experiment lasted 98 days (June 29 through October 5, 2015), with a 14 day-period of adaptation and 84 days for data collection. Crude glycerol was included at 15% of the ration dry matter as a replacement for sorghum grain. Orts were collected and weighed daily, and DMI was calculated by difference between feed offered and feed refused. Feed intake pattern was determined every two weeks after the beginning of the study in three intervals relative to feed delivery (0-4, 4-10, and 10-24 hours post-feeding). Animals' BW was obtained on days 1, 13, 27, 41, 55, 69, and 83 days of the trial after a 12-hour solid fasting. Crude glycerol did not alter (P>0.05) DMI, weight gain, hot carcass weight and dressing percentage compared with the control diet. A treatment × days of experiment response (P<0.05) occurred due to a decreased DMI in animals fed crude glycerol during the first 14 days of the trial. Crude glycerol-fed animals decreased (P<0.05) the neutral detergent fiber (NDF) intake pattern in individual and collective pens. Crude glycerol can be recommended at 15% of the total DM ration as a sorghum grain replacement in diets fed to Nelore animals finished in feedlot. [ABSTRACT FROM AUTHOR]

The expansion of the biodiesel industry has created opportunities for crude glycerol use in beef cattle diets. The objective of this study was to determine the effects of substituting sorghum grain with crude glycerol on dry matter intake (DMI), weight gain and feed intake pattern of 28 non-castrated Nelore males with initial body weight (BW) of 441 ± 40.2 kg and 21.5 ± 0.5 months of age housed in individual or collective pens. The experiment lasted 98 days (June 29 through October 5, 2015), with a 14 day-period of adaptation and 84 days for data collection. Crude glycerol was included at 15% of the ration dry matter as a replacement for sorghum grain. Orts were collected and weighed daily, and DMI was calculated by difference between feed offered and feed refused. Feed intake pattern was determined every two weeks after the beginning of the study in three intervals relative to feed delivery (0-4, 4-10, and 10-24 hours post-feeding). Animals' BW was obtained on days 1, 13, 27, 41, 55, 69, and 83 days of the trial after a 12-hour solid fasting. Crude glycerol did not alter (P>0.05) DMI, weight gain, hot carcass weight and dressing percentage compared with the control diet. A treatment × days of experiment response (P<0.05) occurred due to a decreased DMI in animals fed crude glycerol during the first 14 days of the trial. Crude glycerol-fed animals decreased (P<0.05) the neutral detergent fiber (NDF) intake pattern in individual and collective pens. Crude glycerol can be recommended at 15% of the total DM ration as a sorghum grain replacement in diets fed to Nelore animals finished in feedlot. [ABSTRACT FROM AUTHOR]

We evaluated the clinical aspects and feeding behavior of cattle with subacute ruminal acidosis (SARA) caused by short-chain fatty acids (SCFAs). Ten healthy Nelore heifers were subjected to an adjusted SARA induction protocol using citrus pulp (CP). Clinical examinations were performed at baseline and at 3, 6, 9, 12, 15, 18, and 24 h intervals after induction, with ruminal fluid, blood, and feces sampling. The animals’ feeding behavior was evaluated on, before, and for 3 days after SARA by observing the animals every 5 min for 24 h. The dry matter intake (DMI) was recorded daily. The ruminal pH during SARA was always lower than baseline, with an acidotic duration of 547 ± 215 min, a minimum pH of 5.38 ± 0.16, and an average pH of 5.62 ± 0.1. SARA was mainly caused by SCFAs (maximum 118.4 ± 9.3 mmol/L), with the production of l-lactic acids (7.17 mmol/L) and d-lactic acids (0.56 mmol/L) 6 h after the experiment began. The DMI was reduced by 66% and 48% on days 1 and 2, respectively, and returned to normal levels on day 3. SARA caused a reduction in feed intake and rumination time, as well as an increase in the time spent in decubitus on days 1 and 2. These results were influenced by the ruminal pH, ruminal movement, and osmolarity. Furthermore, SARA caused different degrees of depression, which became more pronounced with higher ruminal lactic acid concentrations.

In order to evaluate the performance and carcass characteristics of cattle cross breeds ½ Aberdeen Angus x ½Nelore and Nelore confined submitted to immunocastration 218 male animals were used, feedlot, averaging 342 kg, divided into three experimental groups, T1: 117 steers ½ Angus x ½ Nelore no castrated (ANC), T2: 51 Nelore steers uncastrated (NNC) and T3: 50 Nellore steers immunocastrated (NIC). The experiment lasted 144 days of confinement. The selection of animals for group formation was according to the individual weight, breed, sex condition and age. For immunocastration it wasused Bopriva® vaccine. The rating was finished according to the parameter used by the meatpacking industry ranging from 1 to 5. The experimental design was completely randomized in three groups. For the analyzes the variables studied statistics were submitted to analysis of variance (ANOVA) and Tukey test both at the 5% level of significance. The results showed differences (p

This study aimed to evaluate the effects of gonadorelin (GnRH), used both at the outset of a timed artificial insemination (TAI) protocol to synchronize follicular wave recruitment and at the end to synchronize ovulation, on the conception rate (CR) in Nellore cows. The experiment was conducted on two beef cattle farms in the Vale do Araguaia, MT. The body condition score (BCS) evaluation and ultrasound examination to determine ovarian status [follicle diameter < 10 mm, ? 10 mm or presence of corpus luteum (CL)] were performed at the beginning (Day 0) of the TAI protocol. Multiparous cows (n = 494) were subjected to the following protocol: Day 0 – insertion of intravaginal progesterone device (P4 DIB®, MSD) previously used for 8 or 16 days and IM administration of 2.0 mg of estradiol benzoate (EB, Gonadiol®, MSD); Day 8 – P4 device withdrawal, IM injection of 300 IU of equine chorionic gonadotropin (eCG, Folligon®, MSD), 1.0 mg of estradiol cypionate (ECP®, Zoetis) and 0.265 mg of Sodium cloprostenol (PGF2?, Ciosin®, MSD); Day 10 – TAI, performed by a single inseminator. Animals were randomly assigned to one of four groups: control (n = 126), GnRH D0 (n = 123), GnRH D10 (n = 123) and GnRH D0 + D10 (n = 122). Animals treated with GnRH received 50 mcg of gonadorelin (GnRH, Cystorelin®, Merial). Pregnancy was diagnosed by ultrasound 39 ± 10 days after TAI. Data were analyzed using the GLIMMIX procedure of SAS program (P < 0.05). The overall CR was 42.71%. Effect of treatment was not detected (P = 0.2482) on CR, which was 36.89% ± 0.19 (47/126) for the control group, 46.08% ± 0.19 (56/123) for GnRH D0, 48.30% ± 0.18 (61/123) for GnRH D10 and 38.48% ± 0.19 (47/122) for GnRH D0 + D10. An effect of farm was detected; the CR was 47.32% ± 0.13 at Farm A and was 38.24% ± 0.13 at Farm B (P = 0.0249). No effects of the interaction between farm and treatment were observed (P = 0.7662), nor of those among ovarian condition and treatment (P = 0.1225) on CR. Cows with follicles < 10 mm had lower CR (16.44% ± 0.08; P = 0.0001) than cows with follicles ? 10 mm (46.15% ± 0.07) and cows with CL (48.35% ± 0.07). It was concluded that GnRH used to both synchronize the follicular wave recruitment and synchronize ovulation as part of a TAI protocol, did not improve the conception rate in Nellore beef cows.

The squamous cell carcinoma (SCC) is a malignant tumor arising from the squamous cells (keratinocytes) and can development in humans and animals. In cattle, the SCC occur mainly in the periocular region of taurine breeds. A Nelore cow presented a proliferative mass in the vulvar region. The histopathological examination showed a proliferation of neoplastic squamous epithelial cells arranged in islands with keratinized center. The definitive diagnosis was SCC well-differentiated. Despite not be a predisposed breed, the prolonged solar exposition associated to the vulvar partial depigmentation, contribute to the tumor development in this case.

The objective of this study was to characterize oligofructose-induced acute rumen lactic acidosis and its consequences in zebu cattle. We used 29 Nellore heifers which were submitted to experimental induction of laminitis by oligofructose excess. During the induction period, the animals underwent clinical examination, including laminitis diagnosis (hoof pressure testing and locomotion score) and blood and ruminal fluid sampling every six hours (over the initial 24 h) and every 12 h (up to 72 h), after the highest dose. Almost half of the animals (48.1%) required treatment with bicarbonate and saline to correct metabolic acidosis and dehydration. Due to this treatment, the animals were analyzed in treated (n = 13) and non-treated (n = 14) groups. The induction model promoted marked reduction in rumen pH, rumen anaerobiosis, carbon dioxide pressure, and increase in rumen lactate, blood osmolarity, and cortisol concentration. The animals treated had lower values of rumen pH and marked dehydration, evidenced by the increase in globular volume and serum urea. The clinical condition caused by excess oligofructose is severe, with the differential of the appearance of ephemeral fever and respiratory compensation against systemic acidosis, in addition to the frequent appearance of laminitis.

Foram utilizados cinco novilhos nelore com peso inicial médio de 335±12kg, mantidos em baias individuais, para determinação do consumo e da digestibilidade, e 40 novilhos com peso corporal médio de 345±14kg, mantidos em baias coletivas, para avaliação do desempenho. A dieta definitiva foi constituída de 82% de concentrado e 18,2% de silagem de sorgo na base da matéria seca, e os níveis de inclusão da torta de crambe foram 0 (controle), 5, 10, 15 e 20%. Os ingredientes do concentrado foram sorgo moído, casca de soja, caroço de algodão, resíduo da colheita de soja, torta de crambe e núcleo mineral proteico. Houve efeito linear decrescente de nível de inclusão de torta de crambe sobre o peso corporal, e crescente, sobre o consumo de extrato etéreo, e houve efeito cúbico sobre o consumo de fibra em detergente neutro corrigido para cinzas e proteína (CFDNcp), em que o maior valor foi observado da dieta controle e o menor na dieta contendo 20% de torta de crambe. Os consumos de MS, PB, ureia, PB de ureia e CNFcp, bem como as digestibilidades e os ganhos de peso, não foram afetados pelos tratamentos. Conclui-se que a torta de crambe pode ser utilizada em até 20% de inclusão na matéria seca de dietas de bovinos de corte em confinamento.

Avaliaram-se a proporção volumétrica dos constituintes do corpo lúteo e a distribuição de células lúteas com grânulos citoplasmáticos no corpo lúteo de animais Nelore ao longo da gestação e em animais não gestantes. Foram coletados ovários com corpos lúteos de 24 animais abatidos em frigorífico. Os animais foram distribuídos em dois grupos: gestantes e não gestantes. A idade gestacional foi determinada pela medição do comprimento apicocaudal do feto. Os ovários foram distribuídos segundo o trimestre gestacional: primeiro - gestação de até 90 dias; segundo - de 91 a 180 dias; e terceiro - de 181 a 270 dias. Os corpos lúteos, processados para inclusão em paraplast, foram avaliados em microscópio de luz. Na proporção volumétrica do corpo lúteo, os constituintes avaliados foram citoplasma e núcleo de células lúteas, tecido conjuntivo e fibroblastos, células endoteliais e pericitos e vasos sanguíneos. A proporção volumétrica de citoplasma de células lúteas reduziu de 46,1±2,8% para 37,9±3,5% e a de núcleo de células lúteas reduziu de 9,2±1,0% para 6,2±1,0%, do primeiro para o segundo trimestre. A proporção de tecido conjuntivo e fibroblastos aumentou de 20,9±5,4%, no primeiro trimestre, para 34,0±4,2%, no segundo trimestre. Grânulos citoplasmáticos foram evidenciados pelas técnicas histoquímicas xylidine ponceau e azul de bromofenol, que indicam sua provável composição proteica. A quantidade de células maiores com grânulos aumentou significativamente de 2,3±1,9%, no primeiro trimestre, para 25,5±20,3%, no segundo. A proporção volumétrica de citoplasma e núcleo de células lúteas diminuiu ao longo da gestação, e a de tecido conjuntivo aumentou. A quantidade de células lúteas maiores contendo grânulos também aumentou ao longo da gestação.

The objective of this study was to evaluate the effects of feeding primiparous Nellore cows supplements rich in protected or unprotected linoleic (n-6) and linolenic (n-3) acids before and after calving on the number of follicles, total number of cumulus-oocyte complexes (COCs) collected by aspiration (OPU) and oocytes suitable for culture (grades I, II and III), and in vitro embryo production (IVEP). The donor cows were randomly divided into three groups: control (n=7), Megalac-E® (n=8; 100 g/donor/day), and flaxseed (n=7; 1.0 kg/donor/day). The diets were offered at least 30 days precalving and 75 days postcalving. The animals were submitted to OPU on postcalving days 30, 45, 60 and 75. Recovered oocytes were selected and those considered suitable for culture were submitted to the IVEP procedures. The data were analyzed using a completely randomized design with repeated measures over time. There was no effect of supplementation on the number of follicles, the number of recovered COCs and those suitable for culture, or IVEP. However, the rate of oocytes suitable for culture recovered by OPU was higher on postcalving days 60 and 75 when compared to days 30 and 45. Additionally, the rate of embryos produced in vitro increased after postcalving day 45. In conclusion, pre- and postcalving supplementation with 100 g/day Megalac-E® or 1.0 kg/day flaxseed does not alter the number of oocytes obtained in vivo or IVEP rates of lactating primiparous Nellore donor cows. However, IVEP improves when the programs are carried out 45 days after calving.

The individual experimental results of 1,393 feedlot-finished cattle of different genetic groups obtained at different research institutions were collected. Exploratory multivariate hierarchical analysis was applied, which permitted the division of cattle into seven groups containing animals with similar performance patterns. The following variables were studied: weight of the animal at feedlot entry and exit, concentrate percentage, time spent in the feedlot, dry matter intake, weight gain, and feed efficiency. The data were submitted to non-hierarchical k-means cluster analysis, which revealed that all traits should be considered. In addition to the variables used in the previous analysis, the following variables were included: dietary nutrient content, crude protein and total digestible nutrient intake, hot carcass weight and yield, fat coverage, and loin eye area. Using all of these data, structures of 3 to 14 groups were formed which were analyzed using Kohonen self-organizing maps. Specimens of the Nellore breed, either intact or castrated, were diluted among groups in hierarchical and non-hierarchical analysis, as well as in the analysis of artificial neural networks. Nellore animals therefore cannot be characterized as having a single behavior when finished in feedlots, since they participate in groups formed with animals of other Zebu breeds (Gyr, Guzerá) and with animals of European breeds (Hereford, Aberdeen Angus, Caracu) that exhibit different performance potentials.

A study was conducted to evaluate the associations among testis size, testosterone concentrations, semen parameters and aspects of spermatogenesis in Nelore bulls (n = 28). Testis size was measured from 10 to 29 months of age. Bulls were treated with GnRH (12 to 21 months) and semen samples also collected from 25 to 29 months. At 30 months, animals were slaughtered. Correlations were significant when p < 0.05. Basal testosterone was highest at 18 months, suggesting that bulls reached puberty at this age. At 30 months, seminiferous tubules represented 77.9 ± 3.8 % of the testicular parenchyma and there were 33.6 ± 8.4 round spermatids/A1 spermatogonium/tubule section, indicating a 47.5% degeneration rate during spermatogenesis. At 30 months, heavier testis correlated with Sertoli cell numbers/testis (r = 0.77), and round spermatids/tubule section, Sertoli cell and A1 spermatogonium (r = 0.50 – 0.60). Scrotal circumference (SC) taken between 10 and 29 months correlated with the percentage of tubules with spermatids (r = 0.42 – 0.59) and number of A1 spermatogonium and round spermatids/Sertoli cell (r = 0.49 – 0.68). Epididymal weight was related to Sertoli cell numbers/testis, and round spermatids/ Sertoli cell and A1 spermatogonium (r = 0.51 – 0.61). GnRH-stimulated testosterone from 17 to 21 months correlated with SC between 14 and 29 months (r = 0.48 – 0.60), testis and epididymal weights (r = 0.41 – 0.64) and with parameters of spermatogenesis (r = 0.44 – 0.58). Additionally, sperm motility and vigor from 25 to 29 months correlated with the number of tubules with spermatids (r = 0.42 – 0.59) and GnRH-stimulated testosterone at 12, 13 and 18 months (r = 0.46 – 0.57). In conclusion, testis size during and after the period of pronounced increases in testosterone is an indicator of quantitative parameters of spermatogenesis of post-pubertal bulls.

The main of the study was to compare the quality of frozen bull semen processed with three different commercially extenders (Tryladil®, Botu-Bov® and OptiXcell®). For this, eight Nelore bulls (two ejaculate per bull). Sperm samples were analyzed fresh, diluted and frozen-thawed. The parameters analyzed were total motility, sperm vigor, functional integrity of sperm plasma membrane (HOST) and plasma membrane integrity (eosin). Date were expressed as mean and standard deviation. The variables were subjected to ANOVA (Tukey test) or Friedman (Dunn's test) test according to normality (p< 0,05). The results indicate that there was no difference (p>0,005) among all treatments in the parameters evaluated (except plasma membrane integrity) at dilution moment. However, Tryladil extender promoted an increase (p<0,005) in functional and integrity of sperm plasma membrane compared with others extenders at the post-thawing analyze. After thawing, there was no difference (p>0,005) among all treatments in the kinetic parameters. In conclusion, the Tryladil® extender promoted an increase in functional and integrity of frozen-thawed sperm plasma membrane. Therefore, the Tryladil® extender is recommended to be use as an extender for Nelore bull sperm cryopreservation. [ABSTRACT FROM AUTHOR]

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Gestation length, birth weight, and weaning weight of F2 Nelore-Angus calves (n = 737) with designed extensive full-sibling and half-sibling relatedness were evaluated for association with 34,957 SNP markers. In analyses of birth weight, random relatedness was modeled three ways: 1) none, 2) random animal, pedigree-based relationship matrix, or 3) random animal, genomic relationship matrix. Detected birth weight-SNP associations were 1,200, 735, and 31 for those parameterizations respectively; each additional model refinement removed associations that apparently were a result of the built-in stratification by relatedness. Subsequent analyses of gestation length and weaning weight modeled genomic relatedness; there were 40 and 26 trait-marker associations detected for those traits, respectively. Birth weight associations were on BTA14 except for a single marker on BTA5. Gestation length associations included 37 SNP on BTA21, 2 on BTA27 and one on BTA3. Weaning weight associations were on BTA14 except for a single marker on BTA10. Twenty-one SNP markers on BTA14 were detected in both birth and weaning weight analyses.

Avaliou-se a produção de oócitos e embriões de vacas Nelore in vitro e a resistência à vitrificação. Foram utilizadas 12 vacas Nelore, distribuídas aleatoriamente em dois tratamentos: T1-tratados com canola em grão (2,0kg/animal/dia) e T2-controle. Cada animal foi aspirado quatro vezes para obtenção de óocitos para fecundação in vitro. Os oócitos foram quantificados e classificados em viáveis ou inviáveis. Os zigotos foram cultivados in vitro e, sete dias após, os embriões foram avaliados quanto à qualidade e grau de desenvolvimento e vitrificados em hastes próprias. Na sequência, foram descongelados e cultivados em 6, 12 e 24 horas, observando-se a taxa de expansão e eclosão. Não houve diferenças (P>0,05) no número total de oócitos viáveis, T1=12,7% e T2=11,0%, na taxa de clivagem, T1=60,6% e T2=61,4%, e taxa de blastocistos, T1=23,7% e T2=27,0%, em função do tratamento. Também não houve influência na taxa de re-expansão, T1=70,5 e T2=59,6%, após a vitrificação e descongelamento. Todavia houve diferença (P

The production of grazing cattle has been very interesting, due to the low cost to produce fodder, compared to other sources of forage used to feed these animals, but the adequate management pasture has high influence on the success and profitability of cattle production systems. Thus, the objective of this study was to determine the optimum grazing height of Brachiaria brizantha cv. Xaraés, which provides the highest individual weight gain and gain per area. The stocking rate was continuous, with variable stocking rate. The experimental period was from January to December 2010. Three Nellore males were used in each experimental plot, and, when needed, additional animals were used for adjusting the desired heights. Monthly sampling was obtained to estimate forage mass (kg.ha-1 of DM) and the structural characteristics of the pastures, such as, leaf: stem ratio. The animals were weighed at the beginning of the experiment and every 28 days, after 12 hours of fasting, to measure the average daily gain (ADG) After weighings were performed adjustments stocking rate to desired heights. Throughout the experimental period the animals received mineral supplementation. The desired sward heights were 15, 30, 45 and 60 cm, with three replicates each. The experimental design was completely randomized with four treatments and three replications. To body weight gain (BWG) and average daily gain (ADG), each animal was considered an experimental unit. To gain per area and stocking rate, the paddock was considered the experimental unit. The leaf: stem ratio showed a linear increasing behavior in the spring and summer seasons. The smaller grazing heights provided higher gain per unit area (812.15 kg ha-1), while the highest grazing heights promoted high individual weight gain (0.790 kg.dia-1). The results suggest that Xaraés grass pastures should be grazed between 30 and 45 cm to allow reasonable performances by area and individual performances.

Vinte e quatro touros jovens da raça Nelore foram distribuídos em grupo 1 (G1, à puberdade) e grupo 2 (G2, pós-puberdade), segundo a concentração seminal e motilidade progressiva dos espermatozoides. Características de produção, seminais e endócrinas foram avaliadas à puberdade e pós-puberdade, aos 12, 14, 16 e 18 meses de idade. A média de idade, de peso e de perímetro escrotal à puberdade foram, respectivamente, de 15,37±1,58 meses, 391,35±55,64 kg e 26,41±2,35cm, e na pós-puberdade foram, respectivamente, de 17,49±1,73 meses; 451,75±35,44kg e 29,93±2,59cm. As características seminais na pós-puberdade aumentaram em relação à puberdade. Pode-se inferir que os tourinhos da raça Nelore submetidos a um programa de seleção para precocidade sexual manifestaram a puberdade em torno de 15 meses de idade e que touros jovens com maior perímetro escrotal apresentaram menor idade à puberdade.

Estudaram-se o desempenho produtivo e a viabilidade econômica no confinamento de 24 bovinos, inteiros, com idade média de 23 meses, sendo 12 Nelore (NEL) e 12 F1 Nelore x Brahman (NBR), divididos em três dietas: SIL - silagem de milho e ração concentrada; PEL - exclusiva de pellets; GRN - milho grão inteiro e pellets. O experimento foi realizado em um delineamento inteiramente ao acaso, em esquema fatorial 2x3, com quatro repetições. Os animais NBR apresentaram resultados semelhantes aos da raça NEL quanto aos desempenhos alimentar e econômico, para todas as variáveis analisadas durante o confinamento. Entre as três dietas, a dieta PEL, apesar de não ser a de maior custo em R$/kg, obteve o menor desempenho, com maior COT/kg, menor RT e menores margens líquidas. A dieta SIL apresentou os menores COT/kg e custo/kg de carcaça, com maiores receitas e margens líquidas. A dieta GRN obteve resultados econômicos semelhantes à SIL, porém obteve menor GMD em relação à SIL, além de ter o custo de dieta (R$/kg) mais oneroso em relação aos três tratamentos. Todas as dietas foram economicamente viáveis ao final do experimento, com ML/Kg de carcaça médios de 2,12, 0,35 e 1,09 para SIL, PEL e GRN, respectivamente, no entanto a dieta SIL foi a de melhor desempenho produtivo e econômico.

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Thepurpose of thisreview isto show the increase in number of researches on covariance components and genetic evaluation using random regression models (RRM) for growth traits of Nellore cattle. Random regression models (RRM), also known as infinite-dimension models have been used to estimate variance components and genetic parameters for weight of beef cattle. In addition, those models are a standard alternative for genetic analyses of longitudinal data, however, the availibility of computational resources for performing genetic evaluations widely is an obstacle. Traits related to animal growth are adopted as selection criteria in beef cattle breeding programs, because the remuneration of cattle breeders is made based on the weight of carcasses. In recent years, RRM have been adopted as standard procedure in relation to the analysis of longitudinal data in animal breeding. [ABSTRACT FROM AUTHOR]

Avaliou-se a eficiência de um protocolo de inseminação artificial em tempo fixo (IATF), para melhorar o desempenho reprodutivo de vacas Nelore primíparas, lactantes e acíclicas. Utilizaram-se 350 vacas com escore de condição corporal médio de 2,65±0,01 e média de dias pós-parto de 67,35±1,0 dias. A estação de monta (EM) foi de 180 dias. Os animais foram distribuídos em: G1(n=61) e G3(n=116) - vacas com presença de folículos ovarianos ≤8mm de diâmetro e sem corpo lúteo (CL); G2(n=57) e G4(n=116) - vacas com folículos ≥8mm e sem CL. As vacas do G1 e do G2 permaneceram em monta natural (MN) a partir do dia zero da EM. G3 e G4 foram tratados (dia zero) com 2mg de benzoato de estradiol (BE), IM, e dispositivo com 1,0g de P4 por oito dias. Retirou-se a P4, administraram-se 400UI de eCG e 75µg de cloprostenol, IM, 24h após, e 1mg BE, IM. A IATF foi realizada 51-54h após retirar P4. Aos cinco dias após término da IATF, as vacas do G3 e do G4 também foram mantidas em MN. Avaliou-se, por ultrassonografia, a presença de CL e realizou-se o diagnóstico de gestação, aos 45 e 210 dias após início da EM. Aos 45 dias, mais animais do G3, 42,2%, e do G4, 51,7%, estavam gestantes (P

Foram obtidas estimativas de variância fenotípica, genética e residual, herdabilidades e correlações genéticas para as características reprodutivas em 5.903 animais da raça Nelore. O modelo experimental utilizado foi o método de máxima verossimilhança restrita livre de derivadas. Os valores de herdabilidade foram de 0,24±0,05 para perímetro escrotal aos 450 dias de idade e de 0,37±0,05 aos 21 meses de idade, na ocasião do exame andrológico; de 0,24±0,05 e 0,26±0,05 para comprimento dos testículos esquerdo e direito; de 0,29±0,05 e 0,31±0,05 para largura dos testículos esquerdo e direito; de 0,12±0,04 para formato testicular; de 0,33±0,06 para volume testicular; de 0,11±0,03 para turbilhonamento; de 0,08±0,03 para motilidade e de 0,05±0,02 para vigor espermático; de 0,20±0,04, 0,03±0,02 e 0,19±0,04 para defeitos espermáticos maiores, menores e totais, respectivamente. As características biométricas testiculares apresentaram valores de herdabilidade moderados a altos, enquanto as características seminais valores baixos. Correlações genéticas entre perímetro escrotal com todas as características reprodutivas foram favoráveis, o que sugere o perímetro escrotal como característica de escolha na seleção de touros.