DSpace Coleção:

Influência dos níveis de suplementação na fase de recria no comportamento ingestivo e características das carcaças de novilhos Nelore terminados em confinamento

2026-05-13T20:52:22Z

Título: Influência dos níveis de suplementação na fase de recria no comportamento ingestivo e características das carcaças de novilhos Nelore terminados em confinamento Autor(es): Matos, Victória Leite de Abstract: Cattle’s farming in Brazil plays an important role in this movement, being inseparable from the social and natural factors that shaped the development of Brazil's rural landscape. Intensification techniques that enable increased productivity in pasture-based cattle farming should be considered, as they become a tool for maximizing the rational use of available resources, enabling efficient increases in final revenue. The study was conducted from July 2023 to December 2023 at São Geraldo Farm (Km06), in the Cattle Farming sector of the Federal Institute of Education, Science, and Technology of Northern Minas Gerais (IFNMG), in the city of Januária. The study lasted 158 days in two phases: phase one, pasture-rearing (56 days) and phase two, where the study was conducted during feedlot finishing (102 days).Twenty Nellore steers (mean BW = 330 kg; age of 18 months) were confined in an intensive system and equally distributed into two groups to evaluate the impact of supplementation levels during the rearing phase on the performance and carcass components of animals finished in conventional confinement. During the rearing phase, group 1 received protein-energy supplementation with 0.25% of live weight, and group 2 received protein-energy supplementation with 0.25% of live weight. During the finishing phase, the animals remained in the same groups and received the same diet, with a roughage:concentrate ratio of 50:50. A completely randomized design was applied, and when the results were significant, the t-test was applied at 5% probability. There was no difference between the levels studied for body weight and average daily gain. There was a significant effect on dry matter intake (% BW) and hot carcass yield (%) data for group 1. Supplementation levels did not influence ingestive behavior. The use of a supplementation level of 0.25% of live weight improves hot carcass yield and increases dry matter intake (% BW), being a beneficial practice in feeding confined Nellore steers during finishing.

Predição do rendimento de carcaça de bovinos de corte

2026-05-13T19:19:48Z

Título: Predição do rendimento de carcaça de bovinos de corte Autor(es): Silva, Rafaela Mendes Abstract: The aim of this study was to evaluate whether carcass yield can be predicted by body measurements in a multivariate manner. Carcass yield is obtained after slaughter, considering the ratio of carcass weight to live weight of the animal. An alternative would be to attempt to measure carcass yield using simple and accessible methods, using morphometric and ultrasound measurements, combining variables that are easily measurable in multivariate analyses. Path analysis provides estimates of the magnitude and significance of the connections between sets of variables, decomposing them into direct and indirect effects in the model, helping to quantify the relationships between carcass composition and the consequences found. The database used was obtained using 160 Nellore cattle, divided into two groups (119 and 41 animals). Biometric measurements (live weight, body length, thoracic perimeter, withers height and rump height) and ultrasonographic measurements were performed before slaughter (loin eye area and subcutaneous fat thickness), and the loin eye area per 100 kg of body weight, carcass weight and adjusted per 450 kg of body weight were calculated. Statistical analyses included descriptive statistics, Pearson's explanatory and path analysis (p < 0.05). The relationship between the variables of withers height and hot carcass yield was significant and positive (p < 0.05). There is a significant and positive relationship between the variables loin eye area adjusted for 450 kg of body weight and hot carcass yield (p < 0.05). The path model revealed the complexity involved in predicting carcass yield with low predictive power ranging from R2 = 8.5 to 22%. Carcass yield cannot be predicted through the joint analysis of the evaluated body measurements.

Silagem mista de palma forrageira e sorgo biomassa na alimentação de vacas mestiças em lactação

2026-05-11T21:29:28Z

Título: Silagem mista de palma forrageira e sorgo biomassa na alimentação de vacas mestiças em lactação Autor(es): Oliveira, Pedro Henrique Alves de Abstract: Forage cactus stands out as a feeding strategy for ruminants in semiarid regions due to its high water content, adaptability to arid environments, and favorable nutritional composition. However, its exclusive use is limited by its low effective fiber and crude protein content. Ensiling with fibrous forages, such as biomass sorghum, emerges as a viable alternative to maximize its use in diets for dairy cow. The study aimed to identify the best proportion of forage cactus in silage with biomass sorghum BRS 716 for crossbred cows, evaluating the silage's nutritional quality, nutrient intake and digestibility, ingestive behavior, nitrogen balance, microbial synthesis, ruminal fermentation, and milk production and composition. The experiment was carried out at Experimental Farm of the Unimontes (Janaúba/MG), using 10 lactating cows (471.5 ± 52.8 kg) in a 5 × 5 simultaneous Latin square design, over 90 days. Five diets with increasing levels of inclusion of cactus (0%, 15%, 30%, 45%, and 60%) in silage with biomass sorghum (based on natural matter) were tested. The roughage:concentrate ratio of the diets was approximately 75:25. Data were subjected to analysis of variance and regression at 5% significance level. Increasing levels of cactus in the silage decreased intake (P = 0.01) and digestibility (P < 0.05) of NDFap, respectively, by 12.03 g/day and 2.14% for each additional 1% of inclusion of cactus in the silage. In contrast, there was increase in the intake (P < 0.05) and digestibility (P = 0.01) of non-fibrous carbohydrates (14.87 g/day and 0.0008% for each 1% of inclusion, respectively), besides reducing the intake of ether extract (0.67 g/day per percentage point). The lactic acid content increased (P = 0.05) by 0.8 g/L for each 1% increase in cactus, while the other ruminal parameters and microbial production remained similar between the inclusion levels. The increase in cactus extended the feeding time per kg of NDFap (P = 0.01) by 0.298 min/kg NDFap and reduced water intake (P < 0.01), decreasing approximately 0.26 L/day for each additional 1% of cactus. The difference in body weight showed a quadratic effect (P = 0.05) with maximum weight point at 31.4% of cactus, while milk production and composition remained similar between treatments, with the exception of UNM, which decreased with cactus inclusion. It is concluded that cactus can be included in silage at levels of up to 60% of the natural matter of silage with biomass sorghum, without compromising ruminal fermentation parameters and the productive performance of crossbred lactating cows.

Histórico das mudanças climáticas na região semiárida e impacto sobre a produção de leite e carne

2026-05-08T20:25:23Z

Título: Histórico das mudanças climáticas na região semiárida e impacto sobre a produção de leite e carne Autor(es): Nhalumba, Oferência Albino Abstract: Climate change has affected both plant and animal production in severalregions of the world. However, knowledge gapsstill remainregarding itseffectsin semi-aridregions, particularly on cattle production. Therefore, this study aimed to evaluate the historical influence of climate on milk and beef production in the region through a multivariate approach. The climatic variables - air temperature, relative humidity, global solar radiation, and wind speed - were obtained from the Brazilian National Institute of Meteorology (INMET) for the period from 2014 to 2024. From these variables,thermal comfort indicators were calculated, including the Temperature-Humidity Index (THI) and the specific air enthalpy. Milk production data were obtained from EMBRAPA’s Anuário do Leite, and beef cattle production data were estimated using statistics from IBGE and SEAPA-MG. Statistical analysis, performed using Principal Component Analysis (PCA) and Cluster Analysis (grouping), revealed that the first two components explained 76.36% of the total variance in the data. The first principal component (PC1), which accounted for 51.36% of the variance, was strongly associated with air temperature and relative humidity, reflecting the direct effect of heat load and thermal stress on animals. The second component (PC2), which explained 25.00%, was relatedto global solar radiation and wind speed, representing the environmental energy balance and ventilation conditions. During El Ninho years (2015 - 2016), higher mean THI (>78) and enthalpy (>85 kJ kg−1) values were observed, accompanied by reductions in milk (−14%) and beef (−16.7%) production. Conversely, during LaNinha years(2020 - 2021), milder thermal conditionsfavored productive recovery, with increases of 23% in milkand 44% in beef production. These findings highlight the greater vulnerability of dairy cattle to heat stress and reinforce the importance of adaptive and sustainable management strategies, as well as continuous monitoring of climatic variables, to strengthen productive resilience in the semi-arid region of Minas Gerais.