Ammonia volatilization losses from urea coated with copper, boron, and selenium / Perdas por volatilização de amônia de ureia com cobre, boro e selênio

Urea coated with copper and boron may be a vehicle for selenium fertilization in grazing systems to improve both forage and animal productivity, and consequently, the nutritional quality of milk and meat. Urea is the most often used form of N fertilizer in Brazil; however, it can experience high losses by volatilization, primarily in pastures with high amounts of senescent biomass. The goal of this study was to evaluate losses by ammonia volatilization from urea coated with Cu, B, and Se. The fertilizer was applied to the soil surface under forage straw residues in cylindric glass chambers under controlled laboratory conditions. The treatments were urea (UR), urea coated with boric acid and copper sulfate (UBC), urea coated with boric acid, copper sulfate, and selenium (UBCS), and ammonium sulfate (AS). Measurements were recorded at regular intervals after fertilizer application for 27 days. High losses occurred from ammonia volatilization of amidic-N sources in the initial days after fertilizer application. The total loss of N by ammonia volatilization according to fertilizer treatment was UR > UBC = UBCS > AS. Urea lost by ammonia volatilization accounted for up to 50% of the N applied, although losses from coated urea treatments UBC and UBCS were 11.45% lower than that of urea. The Cu and B in the coated urea reduced losses by ammonia volatilization and the inclusion of Se had no effect. It is suggested that Se may be added to the Cu and B coating of urea to reduce ammonia volatilization.(AU)

O revestimento de ureia com Cu e B pode ser um veículo para a adubação com selênio (Se) em pastagens melhorando a produtividade da forragem e animal e, consequentemente a qualidade nutricional de leite e carne. A ureia é a fonte de N mais utilizada no Brasil, porém pode apresentar elevadas perdas por volatilização, principalmente em pastagens com altas quantidades de biomassa senescente. O objetivo foi avaliar as perdas por volatilização de amônia em ureia revestida com Cu, B e Se aplicado em superfície sob resíduos de palhada de forragem em câmaras cilíndricas de vidro sob condições controladas em laboratório. Os tratamentos foram ureia revestida com ácido bórico e sulfato de cobre (UBC), ureia revestida ácido bórico, sulfato de cobre e selênio (UBCS), e sulfato de amônio (AS) e medidas nos dias após aplicação dos fertilizantes. Altas perdas por volatilização de amônia a partir das fontes amídicas ocorreram nos primeiros dias após a aplicação dos fertilizantes. As perdas totais de N por volatilização de amônia comparando os fertilizantes foi de UR>UBC=UBCS>AS. A ureia perdeu amônia por volatilização em até 50% do N aplicado, enquanto as perdas com as ureias revestidas UBC e UBCS foram 11,45% menores que a ureia. O Cu e o B no revestimento da ureia reduzem as perdas por volatilização de amônia e a inclusão do Se não apresenta influência.(AU)

Trichostrongylus colubriformis infection in Santa Inês lambs: impact on feed digestibility, blood markers, and nitrogen balance / Infecção por Trichostrongylus colubriformis em cordeiros Santa Inês: impacto na digestibilidade dos alimentos, marcadores sanguíneos e balanço de nitrogênio

This study aimed to evaluate the effects of Trichostrongylus colubriformis infection on the hemato-biochemical parameters, feed digestibility, and nitrogen balance in Santa Inês lambs. Eighteen three-month-old Santa Ines castrated male lambs (16.9 ± 1.43 kg of body weight) were randomly distributed in two experimental treatments: infected with T. colubriformis (I, n = 9) and uninfected (U, n = 9). The I group received a total of 45,000 L3 larvae of T. colubriformis (5,000 infective larvae, three times per week, for three weeks). During the experimental period, blood, feed digestibility, and nitrogen balance were evaluated. The I lambs showed a reduction in erythrocytes, hemoglobin, hematocrit, mean corpuscular volume, and total proteins, as well as an increase in platelets and eosinophils compared to those in the U group (p < 0.05). With the exception of total protein content, these values were within the normal range for the species. Furthermore, lower dry matter and organic matter digestibility were observed in the I lambs (p = 0.08). The present findings highlight that T. colubriformis infection has the potential to impair some hemato-biochemical parameters as well as feed digestibility in lambs, which could affect their productivity.(AU)

O objetivo deste estudo foi avaliar os efeitos da infecção por Trichostrongylus colubriformis nos parâmetros hemato-bioquímicos, digestibilidade aparente dos nutrientes e balanço de nitrogênio de cordeiros Santa Inês. Dezoito cordeiros Santa Inês, de três meses de idade e castrados (16,9 ± 1,43 kg de peso corporal), foram distribuídos aleatoriamente em dois tratamentos experimentais: infectados com T. colubriformis (I, n = 9) e não infectados (U, n = 9). O grupo I recebeu um total de 45.000 larvas L3 de T. colubriformis (5.000 larvas infectantes, três vezes por semana, durante três semanas). Durante o período experimental, foram avaliadas as variáveis sanguíneas, digestibilidade e balanço de nitrogênio. Os cordeiros I apresentaram redução de eritrócitos, hemoglobina, hematócrito, volume corpuscular médio e proteínas totais, além de aumento de plaquetas e eosinófilos, quando comparados ao grupo U (p< 0,05). Contudo, exceto para proteínas totais, os valores estavam dentro do intervalo normal para a espécie. Além disso, a digestibilidade da matéria seca e da matéria orgânica foi menor no grupo I de cordeiros (p = 0,08). Os presentes achados destacam que a infecção por T. colubriformis teve potencial para prejudicar alguns parâmetros hemato-bioquímicos, bem como a digestibilidade aparente da dieta, o que poderia afetar a produtividade dos cordeiros.(AU)

Determination of methanol residues in crude glycerol for animal feed by gas chromatography

Crude glycerol is a major by-product of biodiesel production and is an economical additive feed for ruminants. However, residual methanol in crude glycerol can be harmful to animal health. Several methods exist for quantifying methanol residues in biodiesel, yet few have been described that identify the methanol level in crude glycerol. We propose a method for determining the methanol level in crude glycerol destined for animal feed. Crude glycerol was extracted from the headspace and quantified by gas chromatography using a flame ionization detector (GC-FID). The method was linear up to 0.5 % of methanol. The limits of detection (LOD) and quantification (LOQ) were 0.015 and 0.031 %, respectively. No significant matrix effects were observed. Precision was 2 % at the 0.05 and 0.5 % levels. The average percentage of recovery was 90 %. Three analyzed samples of crude glycerol had methanol residues of 0.027-7.802 %. Furthermore, this methanol quantification method may be externally or internally calibrated using a GC manual injector. A reduction of at least 20 % in running time was obtained with good resolution between the peaks. Thus, this method can be applied to determine the methanol level in crude glycerol according to the upper limits for animal feed (5,000 ppm) and for human consumption (150 ppm). Finally, this method is useful for the quality control of crude glycerol intended for use in animal feed, enabling the alternative use of this by-product to add value to the biodiesel production chain.

Determination of methanol residues in crude glycerol for animal feed by gas chromatography

Crude glycerol is a major by-product of biodiesel production and is an economical additive feed for ruminants. However, residual methanol in crude glycerol can be harmful to animal health. Several methods exist for quantifying methanol residues in biodiesel, yet few have been described that identify the methanol level in crude glycerol. We propose a method for determining the methanol level in crude glycerol destined for animal feed. Crude glycerol was extracted from the headspace and quantified by gas chromatography using a flame ionization detector (GC-FID). The method was linear up to 0.5 % of methanol. The limits of detection (LOD) and quantification (LOQ) were 0.015 and 0.031 %, respectively. No significant matrix effects were observed. Precision was 2 % at the 0.05 and 0.5 % levels. The average percentage of recovery was 90 %. Three analyzed samples of crude glycerol had methanol residues of 0.027-7.802 %. Furthermore, this methanol quantification method may be externally or internally calibrated using a GC manual injector. A reduction of at least 20 % in running time was obtained with good resolution between the peaks. Thus, this method can be applied to determine the methanol level in crude glycerol according to the upper limits for animal feed (5,000 ppm) and for human consumption (150 ppm). Finally, this method is useful for the quality control of crude glycerol intended for use in animal feed, enabling the alternative use of this by-product to add value to the biodiesel production chain.(AU)

Feeding effects of cottonseed and its co-products on the meat proteome from ram lambs

Gossypol easily pairs with lysine side chains and enzymes involved in the cellular growth process. The effect of gossypol (a compound present in cotton co-products) in ruminant metabolism and meat quality is not yet clear. This study was undertaken in order to evaluate the effects of cotton co-products in lamb muscle proteome. Twenty-four Santa Inês ram lambs, 5-months old (20.6 ± 1.9 kg), were randomly assigned to four treatments: control (without cottonseed), whole cottonseed, cottonseed meal and high oil cottonseed meal. At 95 days into the experiment, lambs were slaughtered and samples from Longissimus dorsi were collected. Proteins were extracted and analyzed by 2-D electrophoresis. Spots showing a significant effect from the treatment (the “treatment effect”) and present in more than 90 % of the samples were identified using mass spectrometry. Cotton co-products decreased the abundance of aldehyde and malate dehydrogenases, creatine kinase M-type and Adenosine triphosphate (ATP) synthase. They also increased four proteins related to muscle contraction. Thus, feeding cotton co-products to lambs changed the abundance of important muscle proteins. A cotton co-product diet induced a negative impact on the energy supply of muscle cells and, consequently, the abundance of ATP dependent proteins (contractile apparatus) increased, probably in order to offset and maintain muscle function. These proteomic changes can promote our understanding of alterations in the sensorial properties of meat due to cotton co-product diets in further investigations.

Feeding effects of cottonseed and its co-products on the meat proteome from ram lambs

Gossypol easily pairs with lysine side chains and enzymes involved in the cellular growth process. The effect of gossypol (a compound present in cotton co-products) in ruminant metabolism and meat quality is not yet clear. This study was undertaken in order to evaluate the effects of cotton co-products in lamb muscle proteome. Twenty-four Santa Inês ram lambs, 5-months old (20.6 ± 1.9 kg), were randomly assigned to four treatments: control (without cottonseed), whole cottonseed, cottonseed meal and high oil cottonseed meal. At 95 days into the experiment, lambs were slaughtered and samples from Longissimus dorsi were collected. Proteins were extracted and analyzed by 2-D electrophoresis. Spots showing a significant effect from the treatment (the “treatment effect”) and present in more than 90 % of the samples were identified using mass spectrometry. Cotton co-products decreased the abundance of aldehyde and malate dehydrogenases, creatine kinase M-type and Adenosine triphosphate (ATP) synthase. They also increased four proteins related to muscle contraction. Thus, feeding cotton co-products to lambs changed the abundance of important muscle proteins. A cotton co-product diet induced a negative impact on the energy supply of muscle cells and, consequently, the abundance of ATP dependent proteins (contractile apparatus) increased, probably in order to offset and maintain muscle function. These proteomic changes can promote our understanding of alterations in the sensorial properties of meat due to cotton co-product diets in further investigations.(AU)

Phosphorus utilization in broilers fed with diets supplemented with different feed ingredients

A reliable determination of endogenous phosphorus (P) excretion is required to measure P utilization in chickens accurately. The objective of this study was to investigate phosphorus (P) retention in broilers fed diets formulated with different feed ingredients. Sixty-four 15-d old broiler chicks were fed diets in which part of the dietary P was provided from dicalcium phosphate, maize, barley or soybean. Level of supplementation of each ingredient was calculated to provide two levels of total P (4.5 or 5.0 g kg1 feed). Birds received a single injection of 3 MBq of 32P to determine endogenous P excretion using the isotope dilution technique. Four days after injection, blood and excreta were collected for analysis of inorganic and radioactive P. There were no differences among diets in total (p = 0.37) or endogenous (p = 0.65) P excretion or in P retention (p = 0.37) regardless of the supplemental feed material used in each diet. Daily P retention was increased (p = 0.004) as P intake increased, but the proportion of P ingested that was retained was not affected (p = 0.23) by the level of dietary P. The use of an isotopic tracer allows for accurate estimation of endogenous P in excreta, ranging from 0.24 to 0.42 mg P g1 dry matter intake. The retention of P in growing chickens was not changed when 10-20 % of total P was provided by maize, barley or soybean.

Phosphorus utilization in broilers fed with diets supplemented with different feed ingredients

A reliable determination of endogenous phosphorus (P) excretion is required to measure P utilization in chickens accurately. The objective of this study was to investigate phosphorus (P) retention in broilers fed diets formulated with different feed ingredients. Sixty-four 15-d old broiler chicks were fed diets in which part of the dietary P was provided from dicalcium phosphate, maize, barley or soybean. Level of supplementation of each ingredient was calculated to provide two levels of total P (4.5 or 5.0 g kg1 feed). Birds received a single injection of 3 MBq of 32P to determine endogenous P excretion using the isotope dilution technique. Four days after injection, blood and excreta were collected for analysis of inorganic and radioactive P. There were no differences among diets in total (p = 0.37) or endogenous (p = 0.65) P excretion or in P retention (p = 0.37) regardless of the supplemental feed material used in each diet. Daily P retention was increased (p = 0.004) as P intake increased, but the proportion of P ingested that was retained was not affected (p = 0.23) by the level of dietary P. The use of an isotopic tracer allows for accurate estimation of endogenous P in excreta, ranging from 0.24 to 0.42 mg P g1 dry matter intake. The retention of P in growing chickens was not changed when 10-20 % of total P was provided by maize, barley or soybean.(AU)

Crossbreeding locally adapted hair sheep to improve productivity and meat quality

The use of lambs from crossing of local with specialized sheep breeds for meat production may lead to higher meat deposition and a smaller fat amount in the carcass, with a more adequate nutritional profile for human consumption. This study investigated the performance, carcass and meat characteristics of lambs from the Morada Nova and Santa Inês locally adapted hair breeds and crosses between Dorper × Morada Nova and Dorper × Santa Inês slaughtered at approximately 35 kg. Morada Nova lambs showed lower (p < 0.05) performance compared to the other genetic groups resulting in a higher age at slaughter (p < 0.05). Crossbred Dorper × Santa Inês and Dorper × Morada Nova lambs showed better characteristics for meat production with better (p < 0.05) conformation as well as leg and carcass compacteness index. Dorper × Santa Inês have a fatty acid profile that is more suitable for human consumption than Dorper × Morada Nova lambs do (p < 0.05); however, both had lower (p < 0.05) intramuscular lipid content (as measured by ether extract levels from Longíssimus lumborum) compared with purebred lambs. Therefore, when the objective is to obtain lean meat, with improved nutritional profile to reduce risks of cardiovascular disease, the use of breeds and crosses that reduce animal slaughter age, such as the ½ Dorper × ½ Santa Inês crossbred, is an interesting alternative.(AU)

Brachiaria enrichment with selenium-coated urea / Enriquecimento de Brachiaria com ureia revestida com selênio

Selenium (Se) fertilization in grazing to biofortification of animal products have been carried out in low Se soils. The objective of this study was to increase the Se content in the biomass of Brachiaria spp.with urea coated with Se. The experiment was performed in a typical Hapludox soil under greenhouse conditions. A completely randomized block design with four replicates in a factorial structure with two cuts and six Se doses (0, 10, 20, 40, 80, and 160gha-1) was used. The Brachiaria brizantha demonstrated the absence of changes in higher harmful doses without modifying the activity of glutathione peroxidase enzyme. We concluded that enrichment of Brachiaria brizantha with coated urea is obtained with 34.5gha-1of Se.(AU)

A adubação com Selênio (Se) em pastagem para a biofortificação de alimentos de origem animal tem sido realizada em solos com baixo Se. O objetivo foi avaliar o aumento no conteúdo de Se na biomassa de Brachiaria spp. com aplicação de ureia revestida com Se. O experimento foi conduzido em casa de vegetação em Latossolo Amarelo. O delineamento foi em blocos casualizados com quatro repetições em esquema fatorial com dois cortes e seis doses de Se (0, 10, 20, 40, 80 e 160gha-1). A Brachiaria brizantha demonstrou ausência de mudanças em altas e perigosas doses de Se sem alterar a atividade da enzima antioxidante glutationa peroxidase. Com isso, concluiu-se que seu enriquecimento com ureia revestida é obtida com 34,5gha-1 de Se.(AU)

Optimization of the national livestock sustainably / Otimização da pecuária nacional de forma sustentável

O objetivo deste trabalho foi avaliar o uso de nitrato de cálcio em substituição ao farelo de soja em dieta de ruminantes sobre a mitigação do metano entérico visando determinar os custos com a dieta do animal e os custos marginais de abatimento de carbono. O estudo foi realizado em duas fases, na primeira foi avaliado o potencial de mitigação de metano do nitrato por produção de gases in vitro. Os dados de mitigação de metano foram utilizados na segunda fase, que simulou uma propriedade leiteira com três sistemas de alimentação controle, sem nitrato, e sistemas com inclusão de 1,5 e 3% de nitrato na dieta. Foram utilizadas planilhas de cálculo para avaliar os custos e receitas de cada sistema com vendas de crédito de carbono resultantes da redução de metano ao final de 10 anos. O valor presente líquido (VPL) e a taxa interna de retorno (TIR) foram os índices utilizados na avaliação financeira. A venda de crédito de carbono não alterou o VPL, no entanto a inclusão de nitrato a 1,5 e 3% na dieta animal mostrou-se economicamente viável, pois reduziu o valor das dietas (R$ 5,89 e 5,81/vaca/dia, respectivamente) em comparação com a dieta controle (R$ 6,13 /vaca/dia), além de contribuir para redução de gases de efeito estufa. Portanto, a suplementação de nitrato,como fonte de nitrogênio não protéico, em dietas para ruminantes, além de reduz a produção de metano possibilitou uma sens(AU)

The objective of this work was to evaluate the calcium nitrate utilization in replacing to the soybean meal for ruminants diets under the mitigation of enteric methane aiming to determine the animal diet cost and the marginal costs for carbon rebates. The study was conducted in two stages, the first stage was in vitro gas production were performed in order to measure the enteric methane mitigation potential of the nitrate. The methane mitigation data were used in the second stage, which simulated a dairy farm with three feed systems: control system without nitrate, and systems with inclusion of 1.5 to 3% nitrate in the diet. The spreadsheets were used to evaluate the costs and revenues of each system resulting carbon credit sales of methane reduction in 10 years. The net present value (NPV) and the internal rate of return (IRR) were the indexes used in the financial evaluation.The carbon credit sale did not change the NPV significantly, however the inclusion of nitrate to 1.5 and 3% in animal feed showed economically feasible, because it reduced the diet value (R$5.89 e R$5.81/cow/day, respectively) in comparison to control diet (R$6.13/cow/day) besides contributing to the reduction and greenhouse gases. Therefore, the nitrate supplementation beside reduced the methane production, has the positive effect on the variable cost of the activity.(AU)

Optimization of the national livestock sustainably / Otimização da pecuária nacional de forma sustentável

O objetivo deste trabalho foi avaliar o uso de nitrato de cálcio em substituição ao farelo de soja em dieta de ruminantes sobre a mitigação do metano entérico visando determinar os custos com a dieta do animal e os custos marginais de abatimento de carbono. O estudo foi realizado em duas fases, na primeira foi avaliado o potencial de mitigação de metano do nitrato por produção de gases in vitro. Os dados de mitigação de metano foram utilizados na segunda fase, que simulou uma propriedade leiteira com três sistemas de alimentação controle, sem nitrato, e sistemas com inclusão de 1,5 e 3% de nitrato na dieta. Foram utilizadas planilhas de cálculo para avaliar os custos e receitas de cada sistema com vendas de crédito de carbono resultantes da redução de metano ao final de 10 anos. O valor presente líquido (VPL) e a taxa interna de retorno (TIR) foram os índices utilizados na avaliação financeira. A venda de crédito de carbono não alterou o VPL, no entanto a inclusão de nitrato a 1,5 e 3% na dieta animal mostrou-se economicamente viável, pois reduziu o valor das dietas (R$ 5,89 e 5,81/vaca/dia, respectivamente) em comparação com a dieta controle (R$ 6,13 /vaca/dia), além de contribuir para redução de gases de efeito estufa. Portanto, a suplementação de nitrato,como fonte de nitrogênio não protéico, em dietas para ruminantes, além de reduz a produção de metano possibilitou uma sens

The objective of this work was to evaluate the calcium nitrate utilization in replacing to the soybean meal for ruminants diets under the mitigation of enteric methane aiming to determine the animal diet cost and the marginal costs for carbon rebates. The study was conducted in two stages, the first stage was in vitro gas production were performed in order to measure the enteric methane mitigation potential of the nitrate. The methane mitigation data were used in the second stage, which simulated a dairy farm with three feed systems: control system without nitrate, and systems with inclusion of 1.5 to 3% nitrate in the diet. The spreadsheets were used to evaluate the costs and revenues of each system resulting carbon credit sales of methane reduction in 10 years. The net present value (NPV) and the internal rate of return (IRR) were the indexes used in the financial evaluation.The carbon credit sale did not change the NPV significantly, however the inclusion of nitrate to 1.5 and 3% in animal feed showed economically feasible, because it reduced the diet value (R$5.89 e R$5.81/cow/day, respectively) in comparison to control diet (R$6.13/cow/day) besides contributing to the reduction and greenhouse gases. Therefore, the nitrate supplementation beside reduced the methane production, has the positive effect on the variable cost of the activity.

Impact of feeding cottonseed coproducts on reproductive system of male sheep during peripubertal period

Cottonseed coproducts contain gossypol which can have specific effects upon the male reproductive system. We evaluated the reproductive development of male lambs close to puberty fed on three cotton coproducts. Twenty-four 5-month old male lambs received four diets: 20 % of dry matter intake of whole cottonseed (WCS), high oil cottonseed meal (CSC), cottonseed meal (CSM), and a control group (CTL) without any cottonseed coproducts. Free gossypol intake was 16.32, 6.98, 5.47 and 0 mg kg1 BW1 d1 for WCS, CSC, CSM and CTL, respectively. Every 15 days, the animals were weighted and serum and semen samples were collected. After 95 days, testis samples were collected for analysis under light and transmission electron microscopes. The CTL group had higher testosterone concentrations than CSC at the end of the trial and lower total sperm defects, higher mass movement and higher scores for seminiferous epithelium than other treatments. The WCS and CSC groups showed higher levels of segmental aplasia lesion in sperm than other diets, which showed that high levels of gossypol led to higher occurrence of this lesion. Cottonseed coproducts had a negative impact on the reproductive system of pubertal lambs regardless of gossypol concentration. Therefore, the use of cottonseed coproducts to feed lambs earmarked for reproduction is not safe.

Impact of feeding cottonseed coproducts on reproductive system of male sheep during peripubertal period

Cottonseed coproducts contain gossypol which can have specific effects upon the male reproductive system. We evaluated the reproductive development of male lambs close to puberty fed on three cotton coproducts. Twenty-four 5-month old male lambs received four diets: 20 % of dry matter intake of whole cottonseed (WCS), high oil cottonseed meal (CSC), cottonseed meal (CSM), and a control group (CTL) without any cottonseed coproducts. Free gossypol intake was 16.32, 6.98, 5.47 and 0 mg kg1 BW1 d1 for WCS, CSC, CSM and CTL, respectively. Every 15 days, the animals were weighted and serum and semen samples were collected. After 95 days, testis samples were collected for analysis under light and transmission electron microscopes. The CTL group had higher testosterone concentrations than CSC at the end of the trial and lower total sperm defects, higher mass movement and higher scores for seminiferous epithelium than other treatments. The WCS and CSC groups showed higher levels of segmental aplasia lesion in sperm than other diets, which showed that high levels of gossypol led to higher occurrence of this lesion. Cottonseed coproducts had a negative impact on the reproductive system of pubertal lambs regardless of gossypol concentration. Therefore, the use of cottonseed coproducts to feed lambs earmarked for reproduction is not safe.(AU)

Uso de subprodutos do algodão na nutrição de ruminantes / Use of cotton byproducts in ruminant nutrition

O caroço, o farelo e a torta de algodão destacam-se como fonte alternativa de proteina e energia, que pode diminuir o custo da dieta dos animais. Estes produtos apresentam elevada quantidade de ácidos graxos, o que pode propiciar maior deposição de gordura na carcaça e maior ganho em peso, além de uma carne de melhor qualidade. Uma das grandes limitações para o uso desses produtos na nutrição animal é a presença de quantidades elevadas de gossipol (Gp). Esta substância é tóxica para os animais, sendo bastante conhecidos os seus efeitos deletérios no sistema reprodutivo de machos, principalmente em animais jovens. Esta caracteristica tem criado alguma resistência ao uso desses produtos na nutrição de ruminantes. Entretanto, apesar do potencial tóxico do Gp e de fatores de risco associados com a diminuição da fertilidade, os subprodutos de algodão oferecem uma alternativa que pode ser segura para a alimentação de ruminantes quando o teor desta substância no alimento é conhecido e utilizado em níveis recomendados. Dessa forma, realizou-se a presente revisão objetivando esclarecer dúvidas quanto ao uso dos subprodutos do algodão na alimentação de ruminantes, evidenciando resultados de efeitos no sistema reprodutivo e de desempenho dos animais.

The whole cotton seed, the bran and pie stands out as an alternative source of protein and energy, which can decrease the cost of the animal diet. These products feature high amounts of fatty acids, which may provide greater deposition of carcass fat and increased weight gain, and better meat quality. A major limitation for using these products in animal nutrition is the presence of high amounts of gossypol. This substance is toxic to animals and their harmful effects are well known on the reproductive system of males, especially in young animals. This feature has created some resistance in using these products in ruminant nutrition. Despite the potential toxic effects of Gp and risk factors associated with declining fertility, the byproducts of cotton offer an alternative that can be safely fed to ruminants if the level of Gp in the food is known and used at recommended levels. Thus, we carried out this review aiming to clarify the doubts regarding the use of cotton byproducts in ruminant feeding, presenting results of effects on the reproductive system and in the performance of animals.