McAtee T B, Renter D G, Betts N B, Cernicchiaro N
Center for Outcomes Research and Epidemiology, Department of Diagnostic Medicine and Pathobiology, Kansas State University, College of Veterinary Medicine, Manhattan, KS 66506, USA.
Elanco Animal Health, Greenfield, IN 46140, USA.
Transl Anim Sci. 2025 Jun 27;9:txaf087. doi: 10.1093/tas/txaf087. eCollection 2025.
With increasing emphasis on sustainability, beef producers are evaluating potential environmental impacts of production practices. However, gaps remain in understanding how cattle health and performance metrics align with environmental impacts and global protein needs. This study quantified how feedlot performance and health metrics for beef-breed steers and heifers are associated with total greenhouse gas (GHG) emissions and emissions per unit of production. Using data on 9,436 single-lot pens in nine U.S. commercial feedlots (2017 to 2021), we fit mixed-effects multivariable models, based on directed acyclic graphs, to evaluate four key explanatory variables: average daily gain (ADG), feed efficiency (G:F), medicine costs per pen (proxy for disease burden), and cumulative mortality. Sex, season of arrival, days on feed, and arrival body weight were assessed as potential confounders. The primary outcome was estimated carbon dioxide equivalent emissions per kg of final body weight (emissions intensity), derived from Uplook 1.0 (Elanco Animal Health). Across all study pens, 19.2% of estimated lifetime emissions occurred during the feedlot phase, while 41.8% of total body weight gain occurred at the feedlot; demonstrating how feedlots reduce emissions intensity and enhance production efficiency. Higher ADG and G:F were associated with lower emissions intensity, while higher mortality and disease burden were linked to increased emissions intensity. Significant interactions were observed in all models, with effects of ADG and G:F modified by sex and season ( values < 0.01). Improved growth and feed efficiency were consistently associated with lower emissions, but the magnitude of effects differed between steers and heifers and varied by season. Disease burden and mortality impacts also varied by season and arrival weight, with significant three-way interactions ( values < 0.01). Pens with poorer health consistently had higher emissions intensity, with the largest effects in lighter-weight pens during certain seasons. This study quantifies how improving health, G:F, and ADG can reduce emissions intensity. For example, reducing mortality from 5% to 0% lowers lifetime emissions by nearly 6%. Findings highlight the importance of health and performance in sustainability and help quantify potential impacts of strategies for improving health and performance to reduce GHG emissions intensity and improve production efficiency.
随着对可持续性的日益重视，牛肉生产商正在评估生产方式对环境的潜在影响。然而，在理解牛的健康和生产性能指标如何与环境影响及全球蛋白质需求相匹配方面，仍存在差距。本研究量化了肉牛育肥期的性能和健康指标与温室气体（GHG）总排放量及单位产量排放量之间的关系。利用美国九个商业育肥场（2017年至2021年）9436个单栏的数据，我们基于有向无环图拟合了混合效应多变量模型，以评估四个关键解释变量：平均日增重（ADG）、饲料效率（G:F）、每栏药品成本（疾病负担的代理指标）和累计死亡率。将性别、到达季节、饲养天数和到达体重作为潜在混杂因素进行评估。主要结果是根据Uplook 1.0（礼蓝动保）得出的每千克最终体重的估计二氧化碳当量排放量（排放强度）。在所有研究栏中，育肥期估计的终身排放量占19.2%，而总增重的41.8%发生在育肥期；这表明育肥场如何降低排放强度并提高生产效率。较高的ADG和G:F与较低的排放强度相关，而较高的死亡率和疾病负担与较高排放强度相关。在所有模型中均观察到显著的交互作用，ADG和G:F的效应因性别和季节而改变（ 值<0.01）。生长和饲料效率的提高始终与较低的排放相关，但阉牛和小母牛的效应大小不同，且随季节变化。疾病负担和死亡率的影响也因季节和到达体重而异，存在显著的三向交互作用（ 值<0.01）。健康状况较差的栏始终具有较高的排放强度，并在某些季节对较轻体重的栏影响最大。本研究量化了改善健康、G:F和ADG如何降低排放强度。例如，将死亡率从5%降至0%可使终身排放量降低近6%。研究结果突出了健康和生产性能在可持续性方面的重要性，并有助于量化改善健康和生产性能以降低温室气体排放强度及提高生产效率的策略的潜在影响。
