This study aimed to evaluate urea excretion, nitrogen balance and microbial protein synthesis in lactating goats fed with diets containing different protein sources in the concentrate (soybean meal, cottonseed meal, aerial part of cassava hay and leucaena hay). Four Alpine goats whose mean body weight was 42.6±6.1 kg at the beginning of the experiment, a mean lactation period of 94.0±9.0 days and a production of 1.7±0.4 kg of milk were distributed in a 4×4 Latin square with four periods of 15 days. Diets were formulated to be isonitrogenous, containing 103.0 g/kg of CP, 400 g/kg of Tifton 85 hay and 600 g/kg of concentrate. Diet containing cottonseed meal provided (p<0.05) increased excretion of urea and urea nitrogen in the urine (g/d and mg/kg of BW) when compared with leucaena hay. The diets affected the concentrations of urea nitrogen in plasma (p<0.05) and excretion of urea nitrogen in milk, being that soybean meal and cottonseed meal showed (p<0.05) higher than the average aerial part of the cassava hay. The use of diets with cottonseed meal as protein source in the concentrate in feeding of lactating goats provides greater nitrogen excretion in urine and negative nitrogen balance, while the concentrate with leucaena hay as a source of protein, provides greater ruminal microbial protein synthesis.

ABSTRACT. Eight Santa Ines sheep were assigned to two 4 x 4 Latin squares, to evaluate the effects of replacing elephant grass silage with different levels of mesquite pod meal (MDM) (15, 30 and 45% DM) on intake, apparent digestibility of dry matter (DM), organic matter (OM), crude protein (CP), ether extract (EE), acid detergent fiber (ADF), neutral detergent fiber (NDF), total carbohydrates (TC) and non-fiber carbohydrates (NFC) and the nitrogen balance. There was a linear increase (p < 0.05) in the intake of DM, OM, CP, ADF, NDF, NFC and TC according to the addition of MPM to the diet. The digestibility of DM, OM and CP increased (p < 0.05) with the addition of MDM. We observed a positive linear effect (p < 0.05) for the nitrogen intake. The addition of mesquite pod meal up to 45% increased the intake of DM, NDF, ADF, CP, OM, NFC and TC but reduced the digestibility of EE and NDF. MPM at 30 and 45% propitiated a positive nitrogen balance.Keywords: forage conservation, Prosopis juliflora, silage.Farelo de vagem de algaroba em dietas de ovinos: consumo, digestibilidade aparente dos nutrientes e balanço de nitrogênio RESUMO. Foram utilizados oito ovinos da raça Santa Inês, distribuídos em dois quadrados latinos 4 x 4, com o objetivo é avaliar os efeitos da adição do farelo de vagem de algaroba -FVA (15, 30 e 45% da MS) em substituição à silagem de capim elefante sobre o consumo, digestibilidade aparente da matéria seca (MS), matéria orgânica (MO), proteína bruta (PB), extrato etéreo (EE), fibra de detergente ácido (FDA), fibra em detergente neutro (FDN), carboidratos totais (CT) e carboidratos não fibrosos (CNF) e balanço de nitrogênio. Foi observado efeito linear crescente (p < 0,05) dos níveis de FVA sobre os consumos de MS, MO, PB, FDA, FDN, CNF e CT. Os coeficientes de digestibilidade da MS, MO e PB aumentaram (p < 0,05) com a adição de FVA. Observou-se efeito linear positivo (p < 0,05) para a ingestão, excreção fecal e retenção de nitrogênio, enquanto que a excreção de N na urina não variou (p > 0,05) em função dos níveis de substituição. A adição de FVA em até 45% proporcionou o aumento do consumo de MS, FDN, FDA, PB, MO, CNF e CT, mas, reduziu o coeficiente de digestibilidade do EE e de FDN. Os níveis 30 e 45% de FVA proporcionaram balanço de nitrogênio positivo.Palavras-chave: conservação de forragem, Prosopis juliflora, silagem.

The objective of this study was to evaluate the effects of alkaloid extracts of Prosopis juliflora (Sw.) D.C. pods obtained by two extraction methods as compared with sodium monensin on the gas production kinetic, mitigation of methane, and rumen fermentation products using wheat bran or Tifton 85 hay as substrates, by the semi-automatic in vitro gas production technique. A completely randomized design was adopted, and two natural additives were tested made from mesquite pod (alkaloid extract I and alkaloid extract II) at three levels (3.9, 7.9, and 12 μg), sodium monensin 5 μM (positive control), and no inclusion of additives (negative control). The volume of gases produced by the degradation of the fibrous fraction of wheat bran was influenced by the concentration of the extract I added to the medium, and the amounts of 7.9 and 12 μg were equal to monensin at the lowest value. The degradation rate of the fibrous carbohydrates with additive extract I at 12 μg was lower in relation to monensin. When Tifton 85 hay was utilized, alkaloid extract I provided a shorter colonization time as compared with monensin at the added amounts of 7.9 and 12 μg and higher production of gases from the fibrous fraction but without interfering with the total volume of gases produced during 96 h of fermentation of carbohydrates. In the periods of 12 and 24 h of incubation, utilizing alkaloid extract I, the mean values of methane production with wheat bran and Tifton 85 hay were lower than monensin (p < 0.05) when the respective amounts of 7.9 and 12 μg were added. Alkaloid extract I has similar potential to sodium in reducing production of total gases, methane, and the acetate/propionate ratio.

The cottonseed cake is a co-product obtained after extraction of oil cottonseed, and because of their bromatological characteristics has potential use in ruminant feed, can increase the economy efficiency of animal production systems. The objective of this study was to evaluate diets with cottonseed cake in substitution of soybean meal through nitrogen balance, microbial protein synthesis and the ingestive behavior of lambs. Forty crossbred Santa Inês × Dorper non-castrated rams with average initial weight of 20.9 ± 2.5 kg were distributed into a completely randomized design with four treatments and ten replicates, and fed diets containing cottonseed cake in substitution of 0, 33, 66 and 100% of soybean meal. The diets were composed of corn, soybean meal, cottonseed meal and hay, with forage:concentrate reason of 50:50, isonitrogenous, with 14% crude protein. The animals were confined individually in pens with slatted floor, the evaluations of ingestive behavior, which included observations of the feeding, rumination and idle times were performed in a period of 24 hours, in 5-minute intervals. At 82 days of experiment, a spot urine sample was collected from all animals to quantify the concentrations of nitrogen, creatinine, allantoin, uric acid, xanthine and hypoxanthine in the urine. The data were subjected to variance analysis and regression, adopting α= 0.05. There was no significant difference between treatments for nitrogen balance, the synthesis of nitrogen compounds, and microbial efficiency. In addition, there was no effect of replacing soybean meal by cottonseed meal on feeding behavior of animals. Cottonseed cake can replace soybean meal up to 100% in diets for lambs. ResumoA torta de algodão é um coproduto obtido após a extração do oléo do caroço de algodão, e devido às suas características bromatológicas apresenta potencial de uso na alimentação de ruminantes, podendo aumentar a economicidade dos sistemas de produção animal. O objetivo com este estudo foi avaliar dietas com torta de algodão em substituição ao farelo de soja sobre o balanço de nitrogênio, a síntese de proteína microbiana e o comportamento ingestivo de cordeiros. Foram utilizados quarenta cordeiros mestiços Santa Inês x Dorper não castrados, com peso médio inicial de 20,9±2,5 kg, distribuídos em um delineamento experimental inteiramente casualizado, com quatro tratamentos e dez repetições, alimentados com dietas contendo torta de algodão em substituição à 0, 33, 66 e 100% do farelo de soja. As dietas foram compostas de milho, farelo de soja, torta de algodão e feno, com razão volumoso:concentrado de 50:50, isonitrogenadas, com aproximadamente14% de proteína bruta. Os animais foram confinados em baias individuais com piso ripado, as avaliações do comportamento ingestivo, que incluíram observações dos tempos de alimentação, ruminação e ócio foram realizadas em um período de 24 horas, em intervalos de 5 minutos. No 82º dia do período experimental, foram coletadas amostras de urina de todos os animais para quantificar as concentra...

-This study was conducted with the objective of evaluating the effect of concentrate supplementation, formulated with different ingredients (Mesquite pod meal, sorghum meal or wheat meal and mineral supplementation) on performance, intake and digestibility of nutrients in Santa Inês lambs grazing on urochloa grass during the dry season. Twentyfour uncastrated weaned Santa Inês sheep, with average body weight (BW) 20±2 kg with an average of 120 days of age were used in the assay. The experiment lasted 75 days. The animals grazing deferred Urochloa grass (Urochloa mosambicensis (Hack) Daudy) were distributed into four treatments consisting of mineral supplementation provided ad libitum and concentrated supplements containing mesquite pod meal, sorghum meal or wheat meal, supplied 10 g /kg BW on dry matter basis. The intakes of dry matter (DM) and crude protein (CP) were affected by the intake of concentrate supplement, regardless of the ingredients used in the supplements, compared with the mineral supplementation treatment, since the consumption of forage was reduced in 30% with mesquite pod meal supplement, and neutral detergent fiber (NDF) intake was not affected in relation to treatments. The digestibility of DM and CP were higher for treatments with supplements, and NDF digestibility did not differ between treatments. A significant difference was observed in the values of average daily gain for the treatments with concentrate supplementation compared with the one of mineral supplementation. The supplementation with concentrate in grazing enables improvement of performance, intake and digestibility of nutrients regardless of the ingredient used in the supplement.

ABSTRACT. This study evaluated the effect of using fresh sugar cane, sugar cane silage with or without Lactobacillus buchneri, and burnt sugar cane silage with or without L. buchneri on ingestive behavior, nitrogen balance and synthesis of microbial nitrogen compounds of dairy cows. Five ¾ Holstein x Gir crossbred cows, assigned to a 5 x 5 Latin square design, were given diets with a 60:40 forage: concentrate ratio on a dry matter basis, to meet an average body weight of 550 kg and production of 15 kg of milk per day. The treatment with fresh sugar cane showed higher values (p < 0.05) for dry matter feed efficiency (3,133.3 vs 2,234.47 g DM h -1 ) and rumination (1,642.3 vs 1,222.93 g DM h -1 ) compared to the silages. There was a shorter total chewing time (58.7 vs 81.5 min. kg -1 DM) for fresh sugar cane when compared to silages without inoculum. The addition of microbial additive during ensiling of sugar cane did not alter (p > 0.05) the nitrogen intake and balance, but led to a greater (p < 0.05) synthesis of microbial nitrogen. Microbial efficiency was not affected (p > 0.05), and showed an average value of 204.32 g microbial crude protein kg -1 total digestible nutrients.Keywords: Lactobacillus buchneri, microbial synthesis, nitrogen balance, Saccharum officinarum.Cana-de-açúcar in natura e ensilada com ou sem aditivo bacteriano em dietas para vacas lactantes RESUMO. Objetivou-se avaliar o efeito da utilização de cana-de-açúcar in natura, silagem de cana sem ou com Lactobacillus buchneri e cana queimada sem ou com L. buchneri sobre o comportamento ingestivo, balanço de nitrogênio e síntese de compostos nitrogenados microbianos em vacas lactantes. Foram utilizadas cinco vacas mestiças, ¾ Holandês x Gir, distribuídas em um quadrado latino 5 x 5 e alimentadas com dietas compostas por 60% de volumoso e 40% de concentrado na base da matéria seca, para atender um peso corporal médio de 550 kg e produção média de 15 kg de leite por dia. A cana-de-açúcar in natura proporcionou maiores valores (p < 0,05) para eficiência de alimentação da matéria seca (3.133,3 vs 2.234,47 g MS h -1 ) e de ruminação (1.642,3 vs 1.222,93 g MS h -1 ) em relação às silagens. Observou-se menor tempo de mastigação total (58,7 vs 81,5 min. kg -1 de MS) para cana-de-açúcar in natura quando comparada às silagens sem inóculo. A utilização do aditivo microbiano na ensilagem da cana-de-açúcar não alterou (p > 0,05) o consumo e o balanço de nitrogênio, porém propiciou maior (p < 0,05) síntese de nitrogênio microbiano. Não houve diferença entre as dietas (p > 0,05) para eficiência microbiana, cujo valor médio foi de 204,32 g PB microbiana kg -1 de TDN. Palavras-chave:Lactobacillus buchneri, síntese microbiana, balance de nitrogenio, Saccharum officinarum.

This study aimed to evaluate the impact of the use of chemically treated tropical forage in nutritional profile of bovine milk. We evaluated four cane sugar silages: without additive (control); with 1% urea; with 0.5% urea + 0.5% calcium oxide (CaO); with 1% CaO, with base on natural matter, the feeding of dairy cows. There was no difference in the physical‐chemical milk characteristics. The sum of polyunsaturated fatty acids (PUFA) was higher for diet with sugar cane silage with 1% CaO. The activity of the enzyme Δ9‐desaturase in the mammary gland was greatest for myristoleic acid (C14:1 c9) and palmitoleic acid (C16:1 c9) with the diet with sugar cane silage with 1% urea. Among the evaluated diets, the best one was that used 1% CaO in sugar cane silage because it provided higher proportions of PUFA, Omega‐3 fatty acids and conjugated linoleic acid and its isomers. Practical Applications There is considerable interest in altering the fatty acid composition of milk with the overall aim of improving the long‐term health of consumers. In general, milk fat synthesis directly responds to changes in ruminal fermentation pattern, given that in this process both precursors and metabolites of regulatory synthesis in the mammary gland are produced. The use of additives in the diet also changes the pattern of rumen fermentation and consequently the fat synthesis in milk. There are very few studies that seek to evaluate the effect of additives in the ensiling process on rumen environment and milk characteristics. More than that, study the safety and quality of the product for consumers.