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Efeito da suplementação com aminoácidos sobre a digestibilidade, balanço de nitrogênio e ácidos graxos de cadeia curta de equinos em trabalho leve

Wed, 01 Jan 2025 00:00:00 GMT

Título: Efeito da suplementação com aminoácidos sobre a digestibilidade, balanço de nitrogênio e ácidos graxos de cadeia curta de equinos em trabalho leve Abstract: This study aimed to evaluate the effects of amino acid supplementation from a liquid molasses-based product (Líquida Equinos®) on the digestibility, nitrogen balance and short-chain fatty acids of horses in light work, receiving a standard diet composed of commercial concentrate and Tifton 85 hay. Six male Pantaneiro horses, aged 10 ± 4 years and weighing 395 ± 41 kg, were used in a crossover design, receiving two treatments: control (simple molasses) and supplement. The diets were formulated based on the nutritional requirements of adult horses in light work. Apparent digestibility was calculated based on monitoring intake and fecal excretion of: dry matter (DM), crude protein (CP), mineral matter (MM), ether extract (EE), and neutral detergent fiber (NDF). Nitrogen balance (NB) and concentrations of short-chain fatty acids (SCFAs; acetate, propionate, and butyrate), and pH in fecal fluid were also evaluated. No differences (P > 0.05) were observed in nutrient intake, excretion, or digestibility. However, supplementation increased (P < 0.05) fecal concentrations of propionate (C3) (P = 0,01), butyrate (C4) (P = 0,005), and total SCFAs (P = 0,04), in addition to reducing fecal pH (P = 0,03). The relative proportions of SCFAs remained unchanged. An effect of supplementation was observed in the treatment x time interaction on the relative proportions of butyrate (NC4%) (P = 0,03) for the supplemented group in the period from 0 to 3 h (F1) after concentrate feeding. No significant differences were observed for excretion and nitrogen balance. There was a trend toward increased fecal N excretion and a significant reduction in urinary N excretion (P = 0,04) in the supplemented group. Amino acid supplementation had positive effects on SCFA production, demonstrating enhanced fermentative activity without compromising digestive stability, in addition to reducing urinary N excretion without affecting BN, indicating optimization in nitrogen metabolism. Tipo: Dissertação

TÉCNICAS DE COLETA DE LÍQUIDO RUMINAL PARA ANÁLISE DA DIGESTIBILIDADE in vitro DE ALIMENTOS

Wed, 01 Jan 2025 00:00:00 GMT

Título: TÉCNICAS DE COLETA DE LÍQUIDO RUMINAL PARA ANÁLISE DA DIGESTIBILIDADE in vitro DE ALIMENTOS Abstract: In vitro dry matter digestibility (IVDMD) is widely used in ruminant nutrition and depends directly on the quality of the ruminal inoculum employed, however, the literature is still inconclusive regarding the possible influence of the collection technique on this quality. This study aimed to compare the IVDMD of different forages using ruminal fluid obtained via ruminal fistula and esophageal probe. The experiment was conducted at the Experimental Farm of the Federal University of Mato Grosso do Sul, using four forages: BRS Capiaçu elephant grass silage, fresh BRS Capiaçu elephant grass, corn silage, and Marandu grass. Ruminal fluid was collected from three fistulated Nellore cattle by both collection methods, in two experimental runs conducted at one-week interval. After collection, the ruminal fluid was filtered, homogenized into a pooled sample for each collection technique, and transported to the Applied Nutrition Laboratory of the Faculty of Veterinary Medicine and Animal Science (FAMEZ/UFMS). The IVDMD was determined using the Tilley and Terry method, adapted to the Marconi® system, with the use of nonwoven fabric bags. The ruminal incubation period was 48 hours, followed by acid digestion with pepsin for 24 hours. Data were subjected to statistical analysis to compare collection methods, evaluating mean digestibility values as well as measures of variability (range, standard deviation, and coefficient of variation). The results indicated that, although differences in variability were observed between techniques depending on forage type, there was no significant effect (P > 0.05) of the collection technique on mean IVDMD values. It is concluded that ruminal fluid collection techniques using an esophageal probe or a ruminal fistula can be used in in vitro digestibility assays, considering their operational limitations and the characteristics of the evaluated feed. Keywords: Esophageal probe; feed analysis; fistula; inoculum; ruminants. Tipo: Dissertação

Avaliação econômica da produção de carne bovina em sistemas integrados submetidos a protocolos ambientais

Wed, 01 Jan 2025 00:00:00 GMT

Título: Avaliação econômica da produção de carne bovina em sistemas integrados submetidos a protocolos ambientais Abstract: Studies were conducted at the Experimental Farm of the Brazilian Association of Zebu Breeders (ABCZ), in Uberaba-MG, aiming to study the economic evaluation of beef production in production systems subjected to environmental protocols, focusing on the sustainability and productive efficiency of Brazilian livestock farming. The work is structured in two main sections and presents a multidisciplinary approach that integrates silvicultural, zootechnical, and economic aspects. For the study simulating the profitability of wood and carbon stock through growth and production, four timber species were analyzed: Tectona grandis, Azadirachta indica, Khaya spp., and Acacia mangium, cultivated in an Integrated Crop-Livestock-Forestry (ICLF) system. Based on non-destructive methods, forest inventory data, allometry, and growth models were used to estimate the commercial volume of wood and accumulated carbon, associating these estimates with the economic potential of the wood and carbon credits. To estimate the profitability of timber production in Integrated Crop-Livestock-Forestry (ICLF) systems, the average market prices of logs (values updated to 2025) were considered, as follows: Tectona grandis (teak) at US$350.00/m³; Acacia mangium at US$120.00/m³; Azadirachta indica (neem) at US$150.00/m³; and Khaya spp (African Mahogany) at US$ 500.00/m³. African Mahogany presented the highest profitability (US$23,026.00) considering the 10-year net present value (NPV) and the best technical-economic performance, with an estimated investment payback period of 6 years, highlighting the market value of the wood. For the analysis, technical and economic data generated by animals produced at the Brazilian Association of Zebu Breeders (ABCZ) were used, in the Zebu Quality Meat programs, following environmental protocols, Low Carbon Beef (CBC) and Carbon Neutral Beef (CCN). Zootechnical and economic indicators of the participating genetic groups were evaluated, considering animal performance, feed efficiency, greenhouse gas emissions, and financial return per arroba produced. The average cost per arroba produced was R$ 259.52; on average, the overall production cost is closer to that of certified meats. The CBC and CCN projects presented lower average costs per arroba of R$ 252.44 and R$ 255.48, respectively, when compared to the herd of the Quality Meat Program (R$ 261.08). The comparative approach between the programs allowed the identification of the productive and economic advantages of the environmentally certified systems, highlighting the positive impacts on the beef production chain. Tipo: Tese

Efeitos do estresse por calor no desempenho e contagem de células somáticas de vacas leiteiras

Wed, 01 Jan 2025 00:00:00 GMT

Título: Efeitos do estresse por calor no desempenho e contagem de células somáticas de vacas leiteiras Abstract: Heat stress in dairy cows is one of the main factors affecting the welfare and productive performance of these animals, especially in tropical and subtropical regions. The objective was to evaluate the effects of thermal stress on physiological, immunological (SCC), productive, and qualitative variables in dairy cows of different breeds and production systems. The first chapter aimed to synthesize, through a narrative review, the main factors that influence heat stress in dairy cows. The second chapter focused on conducting a systematic review with meta- analysis. To formulate the guiding research question, the PICOS strategy was used, where the population (P): dairy cows; intervention (I): heat stress; comparison (C): thermal comfort; and expected outcomes (O): milk yield and composition, and somatic cell count. Only well- designed experimental studies were accepted as the study type (S). The databases SCOPUS (Elsevier), CAB Direct, Science Direct (Elsevier), and Wiley Online Library were used for the search. The review initially identified 1,835 articles, of which 24 were considered eligible for data extraction due to their methodological robustness. Articles were included when they addressed the influence of the Temperature–Humidity Index (THI) on thermoregulation, milk yield and composition, and when they provided different strategies for mitigating heat stress. The results confirmed that an increase in THI above 68 triggers heat-dissipation mechanisms, leading to negative impacts mainly on milk production. A reduction in milk protein and fat contents was also observed, along with changes in somatic cell count (SCC). It is concluded that heat stress has negative effects on the metabolism and immunity of dairy cows, making the adoption of mitigation strategies—such as natural or artificial shading and cooling—essential to ensure cow welfare and productivity. Keywords: dairy cattles; heat stress; milk production; systematic review; thermal comfort. Tipo: Tese