Estimation of the economic impact of heat stress on the Chilean dairy regions by using two comfort thermal indices.

The study aimed to estimate economic losses associated with heat stress in the eight dairy production regions (DPR), defined by the Dairy Chilean Consortium, using two comfort thermal indices, namely, the temperature-humidity index (THI) and the THI adjusted for solar radiation and wind speed (THIa). Hourly records from 19 weather stations (Nov - Mar 2017-2022) were collected to estimate the comfort thermal indices. The economic impact was estimated considering a critical threshold of 65 for both indices and the effect of higher values on loss in milk yield, days open, culling rate, and deaths. There were differences in the number of hours above the threshold among DPRs, independent of the thermal index used (P < 0.01). The greatest values were observed in DPRs I, II, and VIII, which concentrate most dairy cows. Average losses in milk yield were between 2.0 and 6.4 times higher when THIa was used instead of THI, which also depends on the DPR (P < 0.01). These estimations coincide with those observed empirically by producers. The lowest average economic losses per cow during the summer season (5 seasons average) occurred in DPR VI (US $ 91.5), and the highest losses were observed in DPR I (US $ 184.2) both using THIa. At the country level, economic losses fluctuate between US $ 29.0 and 108.4 million per summer season, depending on the comfort thermal index used. Finally, heat stress impacts negatively and significantly the Chilean dairy sector, which is highly dependent on the DPR.

Feeding strategies impact animal growth and beef color and tenderness.

The impact of growth rate (GR) and finishing regime (FR) on growth and meat quality traits of Angus x Nellore crossbred steers, harvested at a constant body weight (530 ± 20 kg) or time on feed (140 days), was evaluated. Treatments were: 1) feedlot, high GR; 2) feedlot, low GR; 3) pasture, high GR and 4) pasture, low GR. Live body composition, carcass and meat quality traits were evaluated. High GR had greater impact on muscle and fat deposition in feedlot-finished, but not in pasture-finished animals. Feedlot animals had higher Longissimus muscle area, backfat thickness, meat luminosity and tenderness when compared to pasture groups. Moreover, pasture- and feedlot-finished animals with similar GR did not differ in the chromatic attributes of non-aged meat, regardless of endpoint. Thus, GR appeared to be the main factor driving beef chromatic parameters, while FR had a major impact on achromatic attributes and tenderness of meat.

Reducing climate impacts of beef production: A synthesis of life cycle assessments across management systems and global regions.

The global demand for beef is rapidly increasing (FAO, 2019), raising concern about climate change impacts (Clark et al., 2020; Leip et al., 2015; Springmann et al., 2018). Beef and dairy contribute over 70% of livestock greenhouse gas emissions (GHG), which collectively contribute ~6.3 Gt CO2 -eq/year (Gerber et al., 2013; Herrero et al., 2016) and account for 14%-18% of human GHG emissions (Friedlingstein et al., 2019; Gerber et al., 2013). The utility of beef GHG mitigation strategies, such as land-based carbon (C) sequestration and increased production efficiency, are actively debated (Garnett et al., 2017). We compiled 292 local comparisons of "improved" versus "conventional" beef production systems across global regions, assessing net GHG emission data from Life Cycle Assessment (LCA) studies. Our results indicate that net beef GHG emissions could be reduced substantially via changes in management. Overall, a 46 % reduction in net GHG emissions per unit of beef was achieved at sites using carbon (C) sequestration management strategies on grazed lands, and an 8% reduction in net GHGs was achieved at sites using growth efficiency strategies. However, net-zero emissions were only achieved in 2% of studies. Among regions, studies from Brazil had the greatest improvement, with management strategies for C sequestration and efficiency reducing beef GHG emissions by 57%. In the United States, C sequestration strategies reduced beef GHG emissions by over 100% (net-zero emissions) in a few grazing systems, whereas efficiency strategies were not successful at reducing GHGs, possibly because of high baseline efficiency in the region. This meta-analysis offers insight into pathways to substantially reduce beef production's global GHG emissions. Nonetheless, even if these improved land-based and efficiency management strategies could be fully applied globally, the trajectory of growth in beef demand will likely more than offset GHG emissions reductions and lead to further warming unless there is also reduced beef consumption.

Fibrolytic enzymes improving in vitro rumen degradability of tropical forages.

During specific times of the year, especially dry seasons, tropical forages typically have poor nutritional value due to high contents of neutral and acid detergent fibres, and low crude protein in their composition, which may reduce productivity of ruminant livestock production and lead to increased enteric methane (CH4 ) emissions per unit of generated product in forage-bases systems. In order to increase fibre degradability and the efficiency of energy utilisation from low-quality forages, exogenous fibrolytic enzymes have been studied. In this assay, we evaluated the effects of increasing dose levels of fibrolytic enzymes extract (FEE) produced by Trichoderma reesei on in vitro rumen organic matter degradability, fermentation parameters, total gas and CH4 production of tropical forages. Forage samples were analysed for their bromatological composition, and enzyme activity from FEE was performed for xylanase and endoglucanase. The in vitro gas production technique was used in a 5 × 3 factorial arrangement with five FEE dose levels (0, 5, 50, 500 and 5,000 µl) and three substrates (Cynodon spp., Panicum maximum and Cenchrus ciliaris L.). The highest dose level of FEE increased degradability, total gas and CH4 production in all substrates (p < .05). Butyrate concentration also increased while acetate:propionate ratio and pH decreased with the addition of FEE (p < .05). These results indicated that the use of fibrolytic enzymes can be a reliable strategy to improve degradability of low-quality forages, contributing to the sustainability and intensification of livestock production in tropical countries.

Grain supplementation of calves as an alternative beef production system to pasture-finished steers in Chilean Patagonia: meat quality and fatty acid composition.

Beef production in Chilean Patagonia is based on steer finishing on pastures with low nutritive value. Grain supplementation for finishing calves on pasture arises as an attractive alternative to shorten the finishing phase and improve the production efficiency of the traditional system. The aim of this study was to compare meat quality and fatty acid (FA) composition of beef from steers and calves. Forty Angus cross steers were raised on pasture and slaughtered at 18 to 20 mo of age (448 ±â€…31.7 kg body weight). An additional group of 10 calves from similar genetics was weaned at 9 mo of age (303 ±â€…8.0 kg) and subsequently supplemented with 2.5 kg corn plus 1.0 kg commercial concentrate daily while on pasture during 47 d, until they reached slaughter weight (316 ±â€…13.9 kg). All animals were slaughtered on the same day and the Longissimus thoracis muscle was removed from each carcass for meat quality and FA profile analysis. Hot carcass weight from calves was lighter than steers (174 ±â€…7.9 vs. 224 ±â€…17.5 kg, P ≤ 0.001). Meat from calves was lighter (higher L*) and less red (lower a*). In addition, meat from calves showed lower level of yellow pigments in subcutaneous fat (lower b*) compared with meat from steers (P ≤ 0.001). Meat from calves was more tender than meat from steers (P ≤ 0.05), although both shear force values were low and within recommendations for high consumer acceptability. Meat from both production systems showed fat content and FA profiles within dietary recommendations for a healthy diet. However, meat from calves was leaner (1.10 ±â€…0.29 vs. 2.00 ±â€…0.72% fat, P ≤ 0.001). Meat from calves showed lower percentages of saturated (P ≤ 0.05) and monounsaturated (P ≤ 0.001) FAs and higher percentages of polyunsaturated and n-3 (P ≤ 0.001) FAs and conjugated linoleic acid (total and 9c,11t-18:2 isomer, P ≤ 0.001) than meat from steers. Grain supplementation of calves on pasture can reduce the finishing period by 8 to 10 mo at the expense of lighter carcasses with similar or improved meat quality characteristics compared with the traditional finishing of steers on pasture. Implementation of the alternative production system will depend mainly on feed costs and target carcass weights for specific markets.

Growth, Carcass and Meat Characteristics of Grass-Fed Lambs Weaned from Extensive Rangeland and Grazed on Permanent Pastures or Alfalfa.

Western Patagonia lamb production systems are based on extensive rangeland. The harsh climate limits the adoption of more intensive systems. Therefore, producers must focus on developing differentiated products. The aim of this study was to evaluate growth patterns, carcasses and nutritive value of meat from 45 lambs. Lambs were divided into three groups: 15 lambs were slaughtered at weaning (W), with the remaining 30 weaned lambs being allocated to grazing either alfalfa (AG) or permanent pasture (PPG). AG lambs were significantly heavier and had higher condition scores than PPG lambs. Further, AG lambs showed higher carcass weight and larger tissue depth and commercial cuts. Moreover, W lambs had lower shear force and more tender meat than either AG or PPG lambs. The three systems showed a low shear force and acceptable sensory traits. Low levels of cholesterol, with low levels of saturated fat, classified these cuts of meat as extra lean. W lambs had higher omega-3 fatty acid content than AG or PPG lambs. Overall, results showed that meat from the three lamb production systems showed health claimable levels of omega-3 fatty acids and were low in fat and thereby, can be classified as lean meat.

Brazilian beef produced on pastures: sustainable and healthy.

With a herd of 209 million cattle, Brazilian beef production estimate for 2023 is 10,935 million tons, representing an increase of 28.9% and accounting for 20% of the world trade. Beef cattle production is constantly evolving; however, there are extremes, ranging from simple existing farm ranges to intensive forage systems, strategic supplementation, updated health and genetic improvement programs for the production of quality beef. This modern production is based on scientific research carried out at universities and other research institutions. A new generation of professionals with multidisciplinary knowledge and a holistic vision of the productive chain-proposed management practices to reduce greenhouse gas emissions in the production of grass-fed beef cattle, whose meat has high omega-3 and CLA contents. Age at slaughter of steers and of heifers at first mating, significant increases in the ratio calves/100 cows, adequate traceability for pastoral systems with hundreds or thousands of animals per farm and a more intense transference of technology are required.

Composición nutritiva de la carne de ganado tropical venezolano / Nutritional composition of tropical venezuelan beef

Actualmente, existe cada vez, más preocupación por la salud del consumidor y los productores de carne e investigadores, están dando mayor importancia a su calidad nutritiva. Así, en su interés por erradicar falsas creencias, en relación al contenido nutricional de la carne bovina, derivadas de la utilización de datos foráneos provenientes de animales de otras razas alimentados con granos o feedlot con alto contenido lipídico, se ha estudiado la composición nutritiva de la carne bovina venezolana, considerando factores como la especie (la carne vacuna se comparó con bufalina, cerdo y pollo) y la condición sexual, utilizando muestras del músculo longissimus dorsi thoracis libre de grasa de cobertura. Se encontró bajo nivel de marmoleo y baja concentración lipídica y de colesterol. Además, buena cantidad de proteínas de alto valor biológico y cierta cantidad de ácido linoleico conjugado (CLA); que constituye una fuente excelente de minerales como P, Fe y Zn, y un buen balance AGPI/AGS, ω6/ω3, favorables para el individuo. Presenta índices H/h, IA e IT (relación ácidos grasos hipercolesterolémicos/hipocolesterolémicos, índice aterogénico y trombogénico, respectivamente), comparables o más bajos que los reportados en la literatura internacional. La castración favorece la acumulación de lípidos. Presenta menor tenor lipídico que los cortes norteamericanos. Cuando elija un alimento, la carne bovina libre de grasa no tiene nada que envidiar a la de otras especies como la carne de pollo y cerdo y es una buena opción nutricional. La carne de bóvidos jóvenes a pastoreo es una buena opción en regímenes dietéticos saludables(AU)

Currently, there is growing interest about the health of the consumer, so, meat producers and researchers are giving more importance to the nutritional quality of this food. Thus, in their interest to eradicate false beliefs about the nutritional content of beef, derived of the use of foreign data from animals of other breeds or feedlot grain-fed with high lipid content, for this reason it has conducted studies about the nutritional composition in Venezuelan beef considering factors, such as, the species (stablishing comparisons between beef, buffalo, pork and chicken), and sexual condition, using samples of longissimus dorsi thoracis without fat coverage. The results showed a low marbling level of meat bovids, a low of cholesterol and lipid concentration. In addition, it provides a good amount of protein with high biological quality and a certain amount of conjugated linoleic acid (CLA). Is an excellent source of minerals such as P, Fe and Zn, and a good balance of PUFA / SFA, n6/n3 favorable to the individual. Presents indices H/h, IA and IT (hypercholesterolemic / hypocholesterolemic fatty acid ratio, atherogenic and thrombogenic index, respectively), comparable to or lower than those reported in the international literature. Castration promotes lipid accumulation. When compared to U.S. meat with similar Venezuelan cut, it presents lower lipid tenor. When choosing a food, the fat-free meat of bovids has nothing to envy to the meat of other species such as chicken and pork, so it seems to become a good nutritional option. Is conclude, that meat of young bovids fed to grazing appears to be a good option for healthy dietary regimens(AU)