Seasonal semen quality of a local and commercial taurine cattle breeds, raised in a subtropical climate: Relationship between external morphology of the animals and climate.

Livestock production is considered an important factor influencing global warming; however, climate change has also been considered one of the major factors affecting livestock production and reproduction. The present study was carried out in the Southern region of Brazil and aimed to assess the seasonal influence of climatic factors and external morphology of the animals on the semen quality. Three ejaculates were obtained from each bull (Crioulo Lageano and Angus) in summer and winter seasons. Motile cells, sperm vigor, sperm concentration, sperm membrane status, and sperm abnormalities were analyzed in fresh and post-thawed semen. In addition, the sperm kinetics using CASA was assessed on post-thawed semen. Environmental data such as air temperature (AT), relative humidity (RH), mean radiant temperature (MRT) and temperature-humidity index (THI) were measured. Furthermore, body and testicular metrics, as well as hair coat characteristics, were recorded in each season on all bulls. Environmental traits differed significantly between seasons. Results of the PLS regression and Spearman's correlations confirmed a negative relationship between climatic variables and sperm traits in both seasons. Semen quality between breeds and seasons was similar, satisfactory, and heat stress was not sufficient to impair spermatozoa viability. External morphological traits were considered non-important in the final model. The findings of this study suggest that AT, MRT, and THI were the most important factors that could affect seminal characteristics of bulls raised in a subtropical climate.

Modulating the lipid profile of beef using cottonseed and crude glycerin.

The search for healthy food leads to demand for functional foods that do not harm the health of the consumers. The objective was to evaluate the impact of the supply of cottonseed and crude glycerin as modulators of the lipid profile of the beef produced on pasture. The concentrated supplement was formulated with two levels of cottonseed (0 and 25%) and/or two levels of crude glycerin (0 and 15%), totaling four experimental groups. Two experiments were conducted; the first experiment was outlined in a 5 × 5 Latin square design, contrasting the protein-energy supplementation with the mineral supplementation. The concentrate supplementation allowed the increase in intake and digestibility of the dry matter (P = 0.03), ether extract, crude protein, and non-fibrous carbohydrate (P < 0.01). However, the results showed no effect of crude glycerin or cottonseed inclusion on intake or nutrients digestibility. The second experiment evaluated the protein-energy supplementation and its impact on the lipid profile of meat produced, carcass characteristics, and animal performance. There was no influence of cottonseed or crude glycerin in performance or carcass characteristics. However, the use of the cottonseed reduced the content of short-chain fatty acids, omega 3 linolenic acid, conjugated linoleic acid (CLA) C18: 2 cis 9 trans 11 (P < 0.01), and the inclusion of crude glycerin led to increased conjugated linoleic acid (CLA) C18: 2 cis 9 trans 11 (P = 0.04). An important result is given by illustrating the impact of these fatty acids in the nutritional quality of the meat. Thus, it is possible to manipulate the lipid profile of meat produced by cottonseed or crude glycerin supplementation, without affecting the animal performance.

Seasonal differences in seminal plasma proteins from two bovine breeds adapted to a subtropical climate.

This study was designed to evaluate the seasonal expression of seminal plasma proteins from two bovine breeds adapted to a subtropical climate and their associations with post-thawing sperm and environmental characteristics. Semen samples were obtained three times in summer and three times in winter from four Crioulo Lageano and four Angus bulls. Seminal plasma was obtained by centrifugation, and the other portion of the semen was cryopreserved. Seminal plasma proteins were identified by 2D-nanoUPLC-MSE. Post-thawing assessments of sperm kinetics, morphology and membrane integrity were performed. Environmental data such as air temperature, air humidity and black globe temperature (BGT) were recorded, and the temperature-humidity index (THI) was calculated in summer and winter. Results showed that the climate varied significantly between seasons. Although no statistical differences were observed in semen quality between breeds, the protein profiles varied within and between seasons. We suggest that the most critical proteins in summer affecting sperm characteristics were TIMP-2, DNase, Clusterin, CFAH and GPx6. TIMP-2 and DNase showed a higher abundance in Crioulo Lageano in comparison with Angus, while Clusterin, CFAH and GPx6 presented a lower abundance. To the best of our knowledge, this is the first report of a recently evolved type of glutathione peroxidase, GPx6, in seminal plasma of bovines. In winter, five proteins were considered to be more critical: BSP1, BSP3, CCL2, Sulfhydryl oxidase and TIMP-2. BSP1 and TIMP-2 showed a lower abundance while BSP3, CCL2 and Sulfhydryl oxidase presented a higher abundance in this season in Crioulo Lageano in comparison with Angus.

RESUMO: Este estudo foi desenvolvido para avaliar a expressão sazonal de proteínas plasmáticas seminais de duas raças bovinas adaptadas ao clima subtropical e suas associações com espermatozóides pós-descongelamento e características ambientais. Amostras de sêmen foram obtidas três vezes no verão e três no inverno de quatro touros Crioulo Lageano e quatro Angus. O plasma seminal foi obtido por centrifugação e outra porção do sêmen foi criopreservada. As proteínas plasmáticas seminais foram identificadas por 2D-nanoUPLC-MSE. Foram realizadas avaliações pós-descongelamento da cinética espermática, morfologia e integridade da membrana. Dados ambientais como temperatura do ar, umidade do ar e temperatura do globo negro (BGT) foram registrados, e o índice temperatura-umidade (THI) foi calculado no verão e no inverno. Os resultados mostraram que o clima variou significativamente entre as estações. Embora não tenham sido observadas diferenças estatísticas na qualidade do sêmen entre as raças, os perfis proteicos variaram dentro e entre as estações. Sugerimos que as proteínas mais críticas no verão que afetam as características espermáticas foram TIMP-2, DNase, Clusterin, CFAH e GPx6. TIMP-2 e DNase apresentaram maior abundância em Crioulo Lageano em comparação com Angus, enquanto Clusterin, CFAH e GPx6 apresentaram menor abundância. Até onde sabemos, este é o primeiro relato de um tipo recentemente desenvolvido de glutationa peroxidase, GPx6, no plasma seminal de bovinos. No inverno, cinco proteínas foram consideradas mais críticas: BSP1, BSP3, CCL2, sulfidril oxidase e TIMP-2. BSP1 e TIMP-2 apresentaram menor abundância, enquanto BSP3, CCL2 e Sulfidril oxidase apresentaram maior abundância nesta temporada em Crioulo Lageano em comparação com Angus.

Influence of season and external morphology on thermal comfort and physiological responses in bulls from two breeds adapted to a subtropical climate / Influência da estação e da morfologia externa no conforto térmico e respostas fisiológicas em touros de duas raças adaptadas a um clima subtropical

Animals in subtropical regions can be exposed to periods of thermal stress. Locally adapted breeds are especially important in this context, but these have little information available in their natural environments. The aim of this study was to assess whether season affects thermal comfort and physiological responses to increased temperatures of two breeds of bulls in a subtropical climate. Four Angus and four Crioulo Lageano bulls were used in this study. Body and testicles measurements, skin pigmentation and thickness, hair number, length and pigmentation, respiratory rate, panting score, rectal temperature and haematological profile were recorded on three occasions in summer and winter, morning and afternoon. The surface temperature of the flank, eye and scrotum were obtained by infrared thermography. Hair coat colour was determined by CIELAB method. Thermal comfort indexes were calculated from meteorological data. Statistical analysis included analyses of variance, correlations and a partial least squares regression in determining which traits were the most important in thermal adaptability. External morphology of the bulls was important for explaining physiological changes in both seasons, but their contribution was greater in summer. Bulls experienced moderate heat stress in summer, which led to significant physiological responses, which were more pronounced in Angus bulls. The main differences in thermal adaptation found between breeds were the hair coat characteristics and respiratory rate. Despite using different mechanisms to cope with environmental challenges, all bulls were able to maintain optimal testicular thermoregulation as well as systemic normothermia throughout the seasons, showing good adaptation to the climate conditions.

Animais em regiões subtropicais podem ser expostos ao estresse térmico. As raças localmente adaptadas são especialmente importantes nesse contexto, mas possuem pouca informação disponível em seus ambientes naturais. O objetivo deste estudo foi avaliar se a estação afeta o conforto térmico e as respostas fisiológicas ao aumento da temperatura de duas raças de touros em clima subtropical. Quatro touros Angus e quatro Crioulo Lageano foram utilizados neste estudo. As medidas do corpo e testículos, pigmentação e espessura da pele, número, comprimento e pigmentação de pêlos, frequência respiratória, escore ofegante, temperatura retal e perfil hematológico foram registradas no verão e inverno, manhã e tarde. A temperatura da superfície do flanco, olho e escroto foi obtida por termografia infravermelho. Os índices de conforto térmico foram calculados a partir de dados meteorológicos. A análise estatística incluiu análises de variância, correlações e uma regressão parcial de mínimos quadrados para determinar quais características foram as mais importantes na adaptabilidade térmica. A morfologia externa dos touros foi importante para explicar as mudanças fisiológicas nas duas estações, mas sua contribuição foi maior no verão. Os touros sofreram estresse térmico moderado no verão, o que levou a respostas fisiológicas significativas, que foram mais pronunciadas na Angus. As principais diferenças de adaptação térmica encontradas entre as raças foram as características do pêlo e a frequência respiratória. Apesar de usar diferentes mecanismos para lidar com os desafios ambientais, todos os touros foram capazes de manter a termorregulação testicular ideal e a normotermia, mostrando boa adaptação às condições climáticas.

Influence of season and external morphology on thermal comfort and physiological responses in bulls from two breeds adapted to a subtropical climate

ABSTRACT Animals in subtropical regions can be exposed to periods of thermal stress. Locally adapted breeds are especially important in this context, but these have little information available in their natural environments. The aim of this study was to assess whether season affects thermal comfort and physiological responses to increased temperatures of two breeds of bulls in a subtropical climate. Four Angus and four Crioulo Lageano bulls were used in this study. Body and testicles measurements, skin pigmentation and thickness, hair number, length and pigmentation, respiratory rate, panting score, rectal temperature and haematological profile were recorded on three occasions in summer and winter, morning and afternoon. The surface temperature of the flank, eye and scrotum were obtained by infrared thermography. Hair coat colour was determined by CIELAB method. Thermal comfort indexes were calculated from meteorological data. Statistical analysis included analyses of variance, correlations and a partial least squares regression in determining which traits were the most important in thermal adaptability. External morphology of the bulls was important for explaining physiological changes in both seasons, but their contribution was greater in summer. Bulls experienced moderate heat stress in summer, which led to significant physiological responses, which were more pronounced in Angus bulls. The main differences in thermal adaptation found between breeds were the hair coat characteristics and respiratory rate. Despite using different mechanisms to cope with environmental challenges, all bulls were able to maintain optimal testicular thermoregulation as well as systemic normothermia throughout the seasons, showing good adaptation to the climate conditions.

RESUMO Animais em regiões subtropicais podem ser expostos ao estresse térmico. As raças localmente adaptadas são especialmente importantes nesse contexto, mas possuem pouca informação disponível em seus ambientes naturais. O objetivo deste estudo foi avaliar se a estação afeta o conforto térmico e as respostas fisiológicas ao aumento da temperatura de duas raças de touros em clima subtropical. Quatro touros Angus e quatro Crioulo Lageano foram utilizados neste estudo. As medidas do corpo e testículos, pigmentação e espessura da pele, número, comprimento e pigmentação de pêlos, frequência respiratória, escore ofegante, temperatura retal e perfil hematológico foram registradas no verão e inverno, manhã e tarde. A temperatura da superfície do flanco, olho e escroto foi obtida por termografia infravermelho. Os índices de conforto térmico foram calculados a partir de dados meteorológicos. A análise estatística incluiu análises de variância, correlações e uma regressão parcial de mínimos quadrados para determinar quais características foram as mais importantes na adaptabilidade térmica. A morfologia externa dos touros foi importante para explicar as mudanças fisiológicas nas duas estações, mas sua contribuição foi maior no verão. Os touros sofreram estresse térmico moderado no verão, o que levou a respostas fisiológicas significativas, que foram mais pronunciadas na Angus. As principais diferenças de adaptação térmica encontradas entre as raças foram as características do pêlo e a frequência respiratória. Apesar de usar diferentes mecanismos para lidar com os desafios ambientais, todos os touros foram capazes de manter a termorregulação testicular ideal e a normotermia, mostrando boa adaptação às condições climáticas.

Influence of season and external morphology on thermal comfort and physiological responses in bulls from two breeds adapted to a subtropical climate / Influência da estação e da morfologia externa no conforto térmico e respostas fisiológicas em touros de duas raças adaptadas a um clima subtropical

Animals in subtropical regions can be exposed to periods of thermal stress. Locally adapted breeds are especially important in this context, but these have little information available in their natural environments. The aim of this study was to assess whether season affects thermal comfort and physiological responses to increased temperatures of two breeds of bulls in a subtropical climate. Four Angus and four Crioulo Lageano bulls were used in this study. Body and testicles measurements, skin pigmentation and thickness, hair number, length and pigmentation, respiratory rate, panting score, rectal temperature and haematological profile were recorded on three occasions in summer and winter, morning and afternoon. The surface temperature of the flank, eye and scrotum were obtained by infrared thermography. Hair coat colour was determined by CIELAB method. Thermal comfort indexes were calculated from meteorological data. Statistical analysis included analyses of variance, correlations and a partial least squares regression in determining which traits were the most important in thermal adaptability. External morphology of the bulls was important for explaining physiological changes in both seasons, but their contribution was greater in summer. Bulls experienced moderate heat stress in summer, which led to significant physiological responses, which were more pronounced in Angus bulls. The main differences in thermal adaptation found between breeds were the hair coat characteristics and respiratory rate. Despite using different mechanisms to cope with environmental challenges, all bulls were able to maintain optimal testicular thermoregulation as well as systemic normothermia throughout the seasons, showing good adaptation to the climate conditions.(AU)

Animais em regiões subtropicais podem ser expostos ao estresse térmico. As raças localmente adaptadas são especialmente importantes nesse contexto, mas possuem pouca informação disponível em seus ambientes naturais. O objetivo deste estudo foi avaliar se a estação afeta o conforto térmico e as respostas fisiológicas ao aumento da temperatura de duas raças de touros em clima subtropical. Quatro touros Angus e quatro Crioulo Lageano foram utilizados neste estudo. As medidas do corpo e testículos, pigmentação e espessura da pele, número, comprimento e pigmentação de pêlos, frequência respiratória, escore ofegante, temperatura retal e perfil hematológico foram registradas no verão e inverno, manhã e tarde. A temperatura da superfície do flanco, olho e escroto foi obtida por termografia infravermelho. Os índices de conforto térmico foram calculados a partir de dados meteorológicos. A análise estatística incluiu análises de variância, correlações e uma regressão parcial de mínimos quadrados para determinar quais características foram as mais importantes na adaptabilidade térmica. A morfologia externa dos touros foi importante para explicar as mudanças fisiológicas nas duas estações, mas sua contribuição foi maior no verão. Os touros sofreram estresse térmico moderado no verão, o que levou a respostas fisiológicas significativas, que foram mais pronunciadas na Angus. As principais diferenças de adaptação térmica encontradas entre as raças foram as características do pêlo e a frequência respiratória. Apesar de usar diferentes mecanismos para lidar com os desafios ambientais, todos os touros foram capazes de manter a termorregulação testicular ideal e a normotermia, mostrando boa adaptação às condições climáticas.(AU)

Supplementation with different protein profiles for grazing beef cattle supplemented in tropical grass during the rainy-dry transition season.

The objective of this study was to evaluate increasing levels of inclusion of dry distillery grains (DDGs) in substitution of corn and urea in multiple supplements for beef cattle of Urochloa brizantha cv. Marandu on the consumption, digestibility, and efficiency of microbial synthesis and use of nitrogen. We used four Nellore bulls cannulated in the rumen with an average age of 24 months and 445.12 ± 34.4 kg of body weight (BW), in a 4 × 4 Latin square design. Supplements differed by the inclusion level of DDG (0%, 31.5%, 63.0%, and 94.5%). Increasing levels of DDG inclusion decreased dry matter intake (DMI) (P = 0.002), forage (P = 0.002), organic matter (OM) (P = 0.001), crude protein (CP) (P = 0.037), and total digestible nutrients (TDN) (P < 0.001) and had a quadratic effect on the intake of non-fibrous carbohydrates (NFC) (P = 0.002). It was observed an increase in the digestibility of ether extract (EE) (P = 0.005), however a decrease in the digestibility of NFC (P = 0.001). Inclusion of DDG did not influence ruminal pH. There was a quadratic effect at collection times for ruminal ammoniacal nitrogen (P < 0.05), except for the supplement with 94.5% DDG where the effect was linear (P = 0.002). Nitrogen intake was 10.9% higher when there was no DDG in the supplement, compared with the supplement with 94.5% DDG (P = 0.039). The excretion of N by feces was greater when there was a greater amount of DDG in the supplement (P = 0.027), the opposite occurred with urine excretion of N, being higher when there was less amount of DDG in the supplement (P = 0.027). Increasing levels of DDG did not affect ruminal microbial protein yield (P > 0.05). Replacing corn and urea with up to 94.5% DDGs in multiple supplements resulted in no adverse effect efficiency of microbial synthesis, although nutrient intake, total digestible nutrients, and use of nitrogen were reduced at 94.5% DDG inclusion.

Effects of rumen-protected oil supplementation on finishing grazing beef cattle.

The objective of this study was to evaluate the effects of rumen-protected oil (soybean and palm oil) in supplements for beef cattle during the fattening phase in pastures on the intake and digestibility of nutrients, animal performance, and carcass characteristics. Forty-eight noncastrated male Nellore cattle (15 ± 2 months and 389.5 ± 20 kg of body weight) were used in a completely randomized design to evaluate the following treatments: protein-energy supplement (PES) without rumen-protected oil (control: CO), PES containing palm rumen-protected oil (PRPO), PES containing soybean rumen-protected oil (SRPO), and PES containing a mixture of soybean and palm rumen-protected oil (SPRPO). The study lasted 112 days, and there was a decrease in crude protein intake (P < 0.05) and an increase in ether extract intake (P < 0.05) when rumen-protected oil was included in the supplements. In comparison to the palm rumen-protected oil supplement, the soybean rumen-protected oil supplement promoted a lower average daily gain (ADG) (P < 0.05); however, regardless of the rumen-protected oil source, an increase in the fat thickness of the subcutaneous tissue was observed. In addition, there was no difference in carcass gain (P > 0.05) regardless of oil source. Rumen-protected oil is a tool to increase the finishing of pasture-finished young beef cattle in the dry season.

Suplementação de selênio na dieta e qualidade espermática do sêmen de touros Brangus / Dietary selenium supplementation and sperm quality in Brangus bulls semen

Objetivou-se avaliar a qualidade espermática do sêmen de touros suplementados com selênio (Se) na dieta. Foram utilizados 16 touros Brangus, igualmente distribuídos em grupo controle (GC) e grupo Se (GSe − 0,1mg de Se/kg de MS de dieta). O experimento teve duração de 75 dias, e os animais foram suplementados por 60 dias. Foram realizadas quatro coletas de sêmen durante o período (0, 30, 60 e 75 dias) por animal. As amostras foram avaliadas quanto a motilidade e vigor espermáticos, integridade e funcionalidade da membrana plasmática (teste de expansão hiposmótico - HIPO) e viabilidade espermática e reação acrossomal (coloração tripla - TRI). Após avaliação, estas foram diluídas em meio Tris-gema com 5% de glicerol, envasadas (40x106 espermatozoides/palheta), resfriadas, congeladas e armazenadas em nitrogênio líquido até a análise. Após descongelação, foram submetidas às mesmas avaliações descritas para o sêmen fresco. Não houve interferência da suplementação com Se nas variáveis vigor espermático, HIPO e TRI do sêmen fresco e descongelado. Porém, constatou-se queda na motilidade espermática do GSe comparativamente ao GC no sêmen fresco (P=0,0035) e descongelado (P=0,0067) após 60 dias de suplementação. Portanto, a suplementação de Se na dieta não foi efetiva na promoção de melhorias dos parâmetros espermáticos de touros Brangus.(AU)

The aim of the present study was to evaluate sperm quality of bulls supplemented with selenium (Se) in the diet. Sixteen Brangus bulls were randomly divided in two groups: control (GC) and Se (GSe - 0.1mg Se/kg dietary DM). The experiment lasted 75 days and the animals were supplemented for 60 days. Four semen collections (0, 30, 60 and 75 days) per animal, were performed during the experimental period. Sperm motility and vigor, plasma membrane integrity and functionality (hyposmotic swelling test - HOST) and sperm viability and acrosome reaction (triple staining -TRI) were assessed. After immediate analysis, samples were diluted in Tris-egg yolk extender with 5% glycerol, packed (40x106 spermatozoa / straw), chilled, frozen and stored in liquid nitrogen until analysis. After thawing, sperm motility and vigor, HOST and TRI were performed. No significance was noticed on sperm vigor, HOST and TRI of fresh and post-thawed semen after dietary selenium supplementation. However, sperm motility decreased in GSe compared to GC in fresh (P = 0.0035) and post- thawed (P = 0.0067) semen samples after 60 days of supplementation. Therefore, dietary selenium supplementation was ineffective to improve semen parameters of fresh and post-thawed semen of Brangus bulls.(AU)

Ruminal Microbial Populations and Fermentation Characteristics in Beef Cattle Grazing Tropical Forage in Dry Season and Supplemented with Different Protein Levels.

We tested the hypothesis that supplementation with protein improves fermentation parameters without damaging the rumen microbial populations of beef cattle grazing Urochloa brizantha cv. Marandu during the dry season. Four rumen-cannulated Nellore bulls (571 ± 31 kg of body weight) were used in a 4 × 4 Latin square design. The treatments were not supplemented with concentrate (only free-choice mineral salt ad libitum) and supplemented (supplements with low-LPSU, medium-MPS, and high protein supplement-HPS), supplying 155, 515, and 875 g/animal/day of crude protein (CP), respectively. The abundance of each target taxon was calculated as a fraction of the total 16S rRNA gene copies in the samples, using taxon-specific and domain bacteria primers. There was no difference (P > 0.05) across treatments for intakes of dry matter (DM), forage and neutral detergent fiber (NDF), digestibility of DM and NDF, and ruminal pH. Animals supplemented with concentrate had greater (P < 0.05) intakes and digestibility of CP, ether extract and non-fibrous carbohydrate contents of the substrates (EE + NFC), and ruminal ammonia nitrogen (RAN) compared to control. Bulls that received only mineral salt had lower proportions of Butyrivibrio fibrisolvens and had greater (P < 0.05) proportions of Fibrobacter succinogenes, Ruminococcus albus, Ruminococcus flavefaciens, Methanogen archaea than bulls supplemented with concentrate. The MPS animals had greater (P < 0.05) intake and digestibility of CP, RAN concentration, and had lower (P < 0.05) proportions of Fibrobacter succinogenes, Ruminococcus flavefaciens, and Selenomonas ruminantium than LPSU animals. The HPS provided higher (P < 0.05) intake of CP, RAN and proportion of Ruminococcus albus when compared with MPS. In conclusion, supply of 515 g/animal/day of protein via supplement provides better ruminal conditions for the growth of cellulolytic bacteria of bulls on pasture during dry season.

Suplementação de selênio na dieta e qualidade espermática do sêmen de touros Brangus / Dietary selenium supplementation and sperm quality in Brangus bulls semen

Objetivou-se avaliar a qualidade espermática do sêmen de touros suplementados com selênio (Se) na dieta. Foram utilizados 16 touros Brangus, igualmente distribuídos em grupo controle (GC) e grupo Se (GSe − 0,1mg de Se/kg de MS de dieta). O experimento teve duração de 75 dias, e os animais foram suplementados por 60 dias. Foram realizadas quatro coletas de sêmen durante o período (0, 30, 60 e 75 dias) por animal. As amostras foram avaliadas quanto a motilidade e vigor espermáticos, integridade e funcionalidade da membrana plasmática (teste de expansão hiposmótico - HIPO) e viabilidade espermática e reação acrossomal (coloração tripla - TRI). Após avaliação, estas foram diluídas em meio Tris-gema com 5% de glicerol, envasadas (40x106 espermatozoides/palheta), resfriadas, congeladas e armazenadas em nitrogênio líquido até a análise. Após descongelação, foram submetidas às mesmas avaliações descritas para o sêmen fresco. Não houve interferência da suplementação com Se nas variáveis vigor espermático, HIPO e TRI do sêmen fresco e descongelado. Porém, constatou-se queda na motilidade espermática do GSe comparativamente ao GC no sêmen fresco (P=0,0035) e descongelado (P=0,0067) após 60 dias de suplementação. Portanto, a suplementação de Se na dieta não foi efetiva na promoção de melhorias dos parâmetros espermáticos de touros Brangus.

The aim of the present study was to evaluate sperm quality of bulls supplemented with selenium (Se) in the diet. Sixteen Brangus bulls were randomly divided in two groups: control (GC) and Se (GSe - 0.1mg Se/kg dietary DM). The experiment lasted 75 days and the animals were supplemented for 60 days. Four semen collections (0, 30, 60 and 75 days) per animal, were performed during the experimental period. Sperm motility and vigor, plasma membrane integrity and functionality (hyposmotic swelling test - HOST) and sperm viability and acrosome reaction (triple staining -TRI) were assessed. After immediate analysis, samples were diluted in Tris-egg yolk extender with 5% glycerol, packed (40x106 spermatozoa / straw), chilled, frozen and stored in liquid nitrogen until analysis. After thawing, sperm motility and vigor, HOST and TRI were performed. No significance was noticed on sperm vigor, HOST and TRI of fresh and post-thawed semen after dietary selenium supplementation. However, sperm motility decreased in GSe compared to GC in fresh (P = 0.0035) and post- thawed (P = 0.0067) semen samples after 60 days of supplementation. Therefore, dietary selenium supplementation was ineffective to improve semen parameters of fresh and post-thawed semen of Brangus bulls.

Quantitative qPCR Analysis of Ruminal Microorganisms in Beef Cattle Grazing in Pastures in the Rainy Season and Supplemented with Different Protein Levels.

We tested the hypothesis that supplementation with three protein levels improves fermentation parameters without changing the rumen microbial population of grazing beef cattle in the rainy season. Four rumen-cannulated Nellore bulls (432 ± 21 kg of body weight) were used in a 4 × 4 Latin square design with four supplements and four experimental periods of 21 days each. The treatments were mineral supplement (ad libitum) and supplements with low, medium (MPS), and high protein supplement (HPS), supplying 106, 408, and 601 g/day of CP, respectively. The abundance of each target taxon was calculated as a fraction of the total 16S rRNA gene copies in the samples, using taxon-specific and domain bacteria primers. Supplemented animals showed lower (P < 0.05) proportions of Ruminococcus flavefaciens and greater (P < 0.05) proportions of Ruminococcus albus and Butyrivibrio fibrisolvens than animals that received only the mineral supplement. The HPS supplement resulted in higher (P < 0.05) proportions of Fibrobacter succinogenes, R. flavefaciens, and B. fibrisolvens and lower (P < 0.05) proportions of R. albus than the MPS supplement. Based on our results, high protein supplementation improves the ruminal conditions and facilitates the growth of cellulolytic bacteria in the rumen of bulls on pastures during the rainy season.

Effects of protein-energetic supplementation frequency on growth performance and nutritional characteristics of grazing beef cattle.

Two experiments were conducted to evaluate reduced supplementation frequencies for grazing beef cattle in rainy season. In experiment 1, evaluating the nutritional parameters, four rumen-cannulated Nellore bulls (BW = 410 kg) were used. In experiment 2, evaluating animal performance, 48 Nellore bulls (BW = 358 kg) were used. The treatments were as follows: mineral supplement (MS) alone and MS plus protein-energy supplement provided 3×, 5× and 7×/week. Supplementation frequency did not affect (P > 0.05) intake and digestibility. Average daily gain was greater (P < 0.001) to supplementation compared with MS. The supplementation 5×/week resulted in greater weight gain per hectare (9.24) and higher economic returns during the study period (1.64%) compared to other supplementations. Supplementation 5×/week increased animal performance and positively influenced economic returns.

Efficiency of nitrogen metabolism in beef cattle grazing pasture and supplemented with different protein levels in the rainy season.

Supplementation of animals in the rainy season is essential to maximise weight gain. Thus, the objective was to evaluate the effects of supplementation with low-, medium- and high-protein levels on nutritional parameters of grazing beef cattle in the rainy season. Eight rumen-cannulated Nellore bulls (437 kg body weight) were used in a 4 × 4 double Latin square design with four supplements and four experimental periods. The treatments were mineral supplement (ad libitum) and supplements with low-protein (LPSU), medium-protein (MPS) and high-protein (HPS) levels, providing 106, 408 and 601 g/day of crude protein (CP), respectively. There was no difference (P > 0.05) between treatments for dry matter and forage intake, ruminal pH, ruminal ammonia nitrogen (RAN) at time 0 (before supplementation) and microbial protein yield. Animals on MPS had a higher (P > 0.05) intake and digestibility of CP, higher RAN levels (3 and 6 h after supplementation), increased nitrogen intake and a better nitrogen balance than animals on LPSU. The HPS provided higher (P > 0.05) RAN at time 6 and a better nitrogen balance when compared with MPS. We therefore infer that the high-protein supplement positively impacts nitrogen metabolism and efficiency in grazing beef cattle during the rainy season.

Intake, digestibility, and ruminal parameters of Nellore bulls supplemented with increasing levels of crude glycerin in Brachiaria Brizantha pastures / Consumo, digestibilidade e parâmetros ruminais de machos Nelore não castrados suplementados com níveis crescentes de glicerina bruta em pastagens de “Brachiaria brizantha”

We evaluated the effects of increasing levels of crude glycerin in multiple supplements for grazing beef cattle on intake, nutrient digestibility, pH, ruminal ammoniacal nitrogen, and serum glucose. Five Nellore steers (initial BW of 480 kg [SD 15]), grazing a tropical pasture, were used in a 5 × 5 Latin square design. The treatments used were control (no supplementation; only a mineral mixture ad libitum) and four levels of crude glycerin (0, 80, 160, 240 g/kg of supplements). Supplementation type had no impact (P > 0.05) on pH at 0 and 4 h after supplementation. Animals supplemented with different levels of crude glycerin showed higher N-NH3 values (P 0.05), increasing dry matter intake (P > 0.05) due to increased organic matter digestibility (P > 0.05). Supplementation of 4 kg/animal with crude glycerin (240 g/kg supplement) did not reduce pasture intake and organic matter digestibility.

Objetivou-se avaliar o efeito de níveis crescentes de glicerina bruta em suplementos múltiplos, sobre consumo, digestibilidade dos nutrientes, pH, nitrogênio amoniacal ruminal e glicose sérica. Foram utilizados cinco novilhos, Nelore (peso inicial de 480 kg ± 15), em pastejo de forragem tropical, em delineamento experimental Quadrado Latino 5X5. Os tratamentos utilizados foram controle (apenas suplementação mineral) e quatro níveis de glicerina bruta (0, 80, 160, 240 g/kg de suplemento). Não houve influencia do tipo de suplementação (P>0,05) para pH no tempo zero ou quatro horas após a suplementação. Os animais suplementados com níveis de glicerina bruta apresentaram maior N-NH3 (P>0,05) quatro horas após a suplementação, e o consumo de pasto não foi afetado (P>0,05), com incremento no consumo de matéria seca total (P<0,05), devido o aumento da digestibilidade da matéria orgânica (P<0,05). Os suplementos concentrados fornecidos na quantidade de 4 kg por animal a inclusão de glicerina bruta (240 g/kg de suplemento) não altera o consumo de pasto, suplemento e matéria orgânica digerida.

Intake, digestibility, and ruminal parameters of Nellore bulls supplemented with increasing levels of crude glycerin in Brachiaria Brizantha pastures / Consumo, digestibilidade e parâmetros ruminais de machos Nelore não castrados suplementados com níveis crescentes de glicerina bruta em pastagens de “Brachiaria brizantha”

We evaluated the effects of increasing levels of crude glycerin in multiple supplements for grazing beef cattle on intake, nutrient digestibility, pH, ruminal ammoniacal nitrogen, and serum glucose. Five Nellore steers (initial BW of 480 kg [SD 15]), grazing a tropical pasture, were used in a 5 × 5 Latin square design. The treatments used were control (no supplementation; only a mineral mixture ad libitum) and four levels of crude glycerin (0, 80, 160, 240 g/kg of supplements). Supplementation type had no impact (P > 0.05) on pH at 0 and 4 h after supplementation. Animals supplemented with different levels of crude glycerin showed higher N-NH3 values (P < 0.05) at 4 h after supplementation. Crude glycerin supplementation did not reduce pasture intake (P > 0.05), increasing dry matter intake (P > 0.05) due to increased organic matter digestibility (P > 0.05). Supplementation of 4 kg/animal with crude glycerin (240 g/kg supplement) did not reduce pasture intake and organic matter digestibility.(AU)

Objetivou-se avaliar o efeito de níveis crescentes de glicerina bruta em suplementos múltiplos, sobre consumo, digestibilidade dos nutrientes, pH, nitrogênio amoniacal ruminal e glicose sérica. Foram utilizados cinco novilhos, Nelore (peso inicial de 480 kg ± 15), em pastejo de forragem tropical, em delineamento experimental Quadrado Latino 5X5. Os tratamentos utilizados foram controle (apenas suplementação mineral) e quatro níveis de glicerina bruta (0, 80, 160, 240 g/kg de suplemento). Não houve influencia do tipo de suplementação (P>0,05) para pH no tempo zero ou quatro horas após a suplementação. Os animais suplementados com níveis de glicerina bruta apresentaram maior N-NH3 (P>0,05) quatro horas após a suplementação, e o consumo de pasto não foi afetado (P>0,05), com incremento no consumo de matéria seca total (P<0,05), devido o aumento da digestibilidade da matéria orgânica (P<0,05). Os suplementos concentrados fornecidos na quantidade de 4 kg por animal a inclusão de glicerina bruta (240 g/kg de suplemento) não altera o consumo de pasto, suplemento e matéria orgânica digerida.(AU)

Sazonalidade e qualidade do sêmen fresco e criopreservado de touros Pantaneiro e Nelore / Seasonality and quality of fresh and cryopreserved semen of Pantaneiroand Nellore bulls

Objetivou-se avaliar o efeito da estação do ano sobre a qualidade do sêmen fresco e criopreservado de reprodutores Pantaneiros(Bos taurus) criados em condições tropicais. Foram utilizados 7 touros Pantaneiros e 3 Nelores (controle), dos quais foi aferidocircunferência escrotal, consistência testicular e após a coleta e congelamento do sêmen realizada análise de motilidade, vigor,defeitos menores, maiores e totais, concentração, integridade de membrana plasmática e acrossomal para sêmen fresco e alémdestas, estresse oxidativo para sêmen criopreservado. O experimento foi conduzido em delineamento inteiramente casualizado, earranjo fatorial 2x2 (2 raças e 2 estações do ano). A raça, estação do ano ou a interação entre eles, não alteraram significativamenteas médias de circunferência escrotal, consistência testicular, motilidade, vigor, concentração, integridade de membrana acrossomale porcentagem de defeitos menores. A integridade da membrana plasmática no sêmen fresco sofreu efeito da estação do ano efoi menor no inverno em ambas raças (95,76 ± 1,77% vs. 87,07 ± 4,78% P=0,03). A estação do inverno aumentou a porcentagemde defeitos maiores (29,15% vs. 16,44%, P<0,01) e totais (17,49% vs. 30,45%, P<0,01). Os parâmetros do sêmen congeladonão foram influenciados pela raça, estação do ano ou interação entre elas. Portanto, nas condições edafoclimáticas estudadas,os reprodutores Pantaneiros apresentaram redução na sua qualidade seminal na estação do inverno.(AU)

The aim of the present study was to evaluate the effect of seasonality on the quality of fresh and cryopreserved semen of Pantaneirobreed (Bos taurus) bulls raised under tropical conditions. Scrotal circumference and testicular consistency were performed inseven Pantaneiro and three Nellore (control) bulls. Sperm motility, vigor, minor, major and total defects, concentration, plasmaand acrosomal membrane integrity were assessed in fresh and post-thawed semen. Additionally, oxidative stress was determinedin post-thawed semen samples. The experiment was done in a complete randomized design, with a 2x2 factorial arrangement (2breeds and 2 seasons). Breed, season of the year or the interaction of both did not alter scrotal circumference, testicular consistency,motility, vigor, concentration, acrosomal membrane integrity and percentage of minor defects (P<0.05). Plasma membrane integrityof fresh semen was affected by the season and was smaller in winter in both breeds (95.76 ± 1.77% vs 87.07 ± 4.78%, P=0.03).Nevertheless, also in the winter there was an increase in the percentage of major (29.15% vs 16.44%, P<0.01) and total defects(17.49% vs. 30.45%, P<0.01) in fresh semen samples. Breed, season or interaction of both did not influence the sperm parametersof cryopreserved semen. Thus, in the studied climatic conditions, the Pantaneiro breed bulls present decrease in semen qualitymainly in the winter season.(AU)

Sazonalidade e qualidade do sêmen fresco e criopreservado de touros Pantaneiro e Nelore / Seasonality and quality of fresh and cryopreserved semen of Pantaneiro and Nellore bulls

Objetivou-se avaliar o efeito da estação do ano sobre a qualidade do sêmen fresco e criopreservado de reprodutores Pantaneiros (Bos taurus) criados em condições tropicais. Foram utilizados 7 touros Pantaneiros e 3 Nelores (controle), dos quais foi aferido circunferência escrotal, consistência testicular e após a coleta e congelamento do sêmen realizada análise de motilidade, vigor, defeitos menores, maiores e totais, concentração, integridade de membrana plasmática e acrossomal para sêmen fresco e além destas, estresse oxidativo para sêmen criopreservado. O experimento foi conduzido em delineamento inteiramente casualizado, e arranjo fatorial 2x2 (2 raças e 2 estações do ano). A raça, estação do ano ou a interação entre eles, não alteraram significativamente as médias de circunferência escrotal, consistência testicular, motilidade, vigor, concentração, integridade de membrana acrossomal e porcentagem de defeitos menores. A integridade da membrana plasmática no sêmen fresco sofreu efeito da estação do ano e foi menor no inverno em ambas raças (95,76 ± 1,77% vs. 87,07 ± 4,78% P=0,03). A estação do inverno aumentou a porcentagem de defeitos maiores (29,15% vs. 16,44%, P<0,01) e totais (17,49% vs. 30,45%, P<0,01). Os parâmetros do sêmen congelado não foram influenciados pela raça, estação do ano ou interação entre elas. Portanto, nas condições edafoclimáticas estudadas, os reprodutores Pantaneiros apresentaram redução na sua qualidade seminal na estação do inverno.

The aim of the present study was to evaluate the effect of seasonality on the quality of fresh and cryopreserved semen of Pantaneiro breed (Bos taurus) bulls raised under tropical conditions. Scrotal circumference and testicular consistency were performed in seven Pantaneiro and three Nellore (control) bulls. Sperm motility, vigor, minor, major and total defects, concentration, plasma and acrosomal membrane integrity were assessed in fresh and post-thawed semen. Additionally, oxidative stress was determined in post-thawed semen samples. The experiment was done in a complete randomized design, with a 2x2 factorial arrangement (2 breeds and 2 seasons). Breed, season of the year or the interaction of both did not alter scrotal circumference, testicular consistency, motility, vigor, concentration, acrosomal membrane integrity and percentage of minor defects (P<0.05). Plasma membrane integrity of fresh semen was affected by the season and was smaller in winter in both breeds (95.76 ± 1.77% vs 87.07 ± 4.78%, P=0.03). Nevertheless, also in the winter there was an increase in the percentage of major (29.15% vs 16.44%, P<0.01) and total defects (17.49% vs. 30.45%, P<0.01) in fresh semen samples. Breed, season or interaction of both did not influence the sperm parameters of cryopreserved semen. Thus, in the studied climatic conditions, the Pantaneiro breed bulls present decrease in semen quality mainly in the winter season

Performance and economic viability of protein supplementation for grazing cattle steers in the wet and dry-wet transition season / Desempenho e viabilidade econômica da suplementação proteica de novilhos de corte em pasto no período das águas e transição águas-seca

The objective was to evaluate performance and economic viability of protein supplementation of grazing beef cattle in the wet and dry-wet transition season. Eighty non-castrated Nellore steers, body weight of 371 ± 11.3 kg were used in the experiment. The treatments were the following: SM Mineral supplement; Protein mineral supplements (SMP 20% FS - soybean meal: 410 g/animal; SMP 40% UR - urea: 223 g/animal; and SMP 40% UP - protect urea: 236 g/animal). It was used a complete random design with 20 replicates per treatment. There was a difference in the results (P<0.05) of PMS 40% UP compared with SM, with average daily gain (ADG) of 1.06 kg/animal for SMP 40% UP and 0.95 kg/ animal for SM, respectively. There was difference (P<0.10) in the fat accumulation rate in longissimus dorsi muscle (Tx.EGLD) between treatments. The PMS 40% UP supplement showed an accumulation of fat 0.018 mm/day while the SMP 40% UR had a lower rate of fat 0.011 mm/day. There was no effect (P> 0.10) of treatments on the rate of accumulation of fat in the rump region. All treatments presented a positive net margin. The best net margin was observed for treatment PMS 40% UP, that is, R$123.92 per animal/period, whereas the smallest was observed in treatment PMS 20% FS, that is, R$98.91 per animal/period. Protein supplementation with a source of protected nitrogen can be used as a strategy to increase the performance of beef cattle on pasture of Brachiaria brizantha cv. Xaraés during the wetand dry-wet transition.(AU)

Objetivou avaliar o desempenho e viabilidade econômica da suplementação proteica de bovinos de corte em pasto no período das águas e transição águas-seca. Foram utilizados 80 novilhos Nelore, não castrados, peso corporal médio de 371 ± 11,3 kg. Os tratamentos foram: SM - Suplemento Mineral; Suplementos mineral proteico (SMP 20% FS -farelo soja: 410 g/animal; SMP 40% UR-ureia: 223 g/animal; e SMP 40% UP-ureia protegida: 236 g/animal. O delineamento utilizado foi inteiramente casualizado com 20 repetições por tratamento. Houve diferença nos resultados (P<0,05) do SMP 40% UP, comparado com o SM, com ganho médio diário (GMD) de 1,06 kg/animal para SMP 40% UP e 0,95 kg/animal para SM. Houve diferença (P<0,10) na taxa de acúmulo de gordura no músculo Longissimus dorsi (Tx.EGLD) entre os tratamentos, sendo que o suplemento SMP 40% UP apresentou um acúmulo de 0,018 mm de gordura/dia, enquanto o SMP 40% UR teve uma taxa inferior de 0,011 mm de gordura/dia). Não houve efeito (P>0,10) dos tratamentos sobre a taxa de acúmulo de gordura na região da garupa. Todos os tratamentos apresentaram margem líquida positiva. A melhor margem líquida foi observada no tratamento SMP 40% UP, ou seja, R$123,92 por animal/período, enquanto a menor, no tratamento SMP 20% FS, ou seja, R$98,91 por animal/período. A suplementação proteica com uma fonte de nitrogênio protegido pode ser utilizada como uma ferramenta para aumentar o desempenho de bovinos de corte sob pastejo de Brachiaria brizantha cv. Xaraés no período das águas e transição águas-seca.(AU)

Seminal characteristics and sperm membrane bulls supplemented with tocopherol / Características seminais e de membrana espermática em touros suplementados com tocoferol

This study had objective to evaluate the integrity of the plasma membrane and semen quality of bulls supplemented with tocopherol. Bulls were used 16 with an average age of 24 months and average weight of 462.2 kg in two treatments: control group (CG) and group supplemented with tocopherol (GE-400 IU of tocoferol/animal / day) added to the concentrate supplement. The groups were kept in pasture supplemented with 4.5 kg / animal / day concentrate. Tocopherol supplementation was provided for 60 days. 4 semen samples were carried out: on days 0 , 30, 60 and 15 days after the end of supplementation. Semen was collected by electroejaculation , it has measured up the physical and morphological sperm characteristics. To assess the integrity of membrane used the hyposmotic test, eosin / nigrosine, Pope and trypan blue. The experiment was conducted in a completely randomized design with repeated measurements over time. Data were analyzed using ANOVA and SNK test with a 5% significance level with assistance from the SAS statistical program. It found effect of supplementation  force (p = 0.0183) (CG = 2.71 ± 0.095 and GE = 2.23 ± 0.16) ;. There were no differences (p > 0.05) for the other variables: motility, concentration, morphology, acrosome integrity, sperm viability and membrane integrity. With the results obtained in the experimental conditions of this study, it is concluded that

O trabalho teve como objetivo avaliar a integridade da membrana plasmática e qualidade seminal de touros suplementados com tocoferol. Foram utilizados 16 touros  com idade média de 24 meses e peso médio de 462,2kg, em dois tratamentos: grupo controle (GC) e grupo suplementado com tocoferol (GE- 400 UI de tocoferol/ animal/dia) adicionados ao suplemento concentrado. Os grupos foram mantidos em pastejo com suplementação de 4,5kg/ animal/ dia de concentrado. A suplementação com tocoferol foi fornecida por 60 dias. Foram realizadas 4 coletas de sêmen, sendo: nos dias 0, 30, 60 e 15 dias após o término da suplementação. O sêmen foi coletado por eletroejaculação, aferiu-se as características físicas e morfológicas. Para avaliar a integridade de membrana utilizou-se o teste hiposmótico, coloração eosina/ nigrosina,  coloração Pope e trypan blue. Os dados foram analisados através da ANOVA e do teste SNK com um nível de significância de 5%. Foi encontrado efeito da suplementação para vigor (p = 0,0183) (GC = 2,71±0,095 e GE = 2,23±0,16). Não foram encontradas diferenças (p > 0,05) para as demais variáveis: volume, motilidade, concentração, morfologia, integridade acrossomal, viabilidade espermática e integridade de membrana. Com os resultados obtidos, nas condições experimentais do presente trabalho, conclui-se que a suplementação oral com tocoferol de 400UI/dia não apresenta melhori