Tang Minfeng, Lhermie Guillaume
Simpson Centre for Food and Agricultural Policy, The School of Public Policy, Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada.
Simpson Centre for Food and Agricultural Policy, The School of Public Policy, Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada.
Prev Vet Med. 2023 Sep;218:105989. doi: 10.1016/j.prevetmed.2023.105989. Epub 2023 Aug 4.
This study examined the influence of management practices and herd demographics on calf mortality proportions in Western Canadian cow-calf operations, utilizing data from the second Western Canadian Cow-calf Survey. The survey was conducted between October 23, 2017, and February 28, 2018. The survey, which was open to all cow-calf producers across Western Canada, provided producer-reported data regarding calf death loss and corresponding herd-level factors. A fractional logit model was employed to identify significant factors associated with calf mortality proportions. The findings revealed that shorter breeding seasons (<63 days), calves born within the same season, and regular pregnancy checks for breeding females were negatively associated with calf mortality proportions. Conversely, regular breeding soundness evaluations for breeding bulls, traditional weaning methods, and vaccinating heifers for scours showed positive associations with increased calf mortality proportions. Herd operations where dams were vaccinated against clostridial and bovine respiratory diseases had lower calf mortality proportions. Notably, operations with experienced primary decision-makers holding off-farm jobs had lower predicted calf mortality proportions compared to those managed by full-time cattle producers. Higher predicted calf mortality proportions were observed in operations employing a backgrounding system. The study's limitations included potential biases due to its cross-sectional nature and reliance on producer-reported data, which might lead to an underestimation of calf mortality proportions. Also, the limited sample size and missing data might have affected the statistical significance of some variables. This study contributed to the research on cow-calf operation by using a fractional logit model to analyze the correlation between risk factors and calf mortality proportions, and by identifying novel herd-level risk factors. It provided a basis for future research aimed at developing empirically-based management strategies to optimize calf health outcomes.
本研究利用第二次加拿大西部母牛-犊牛调查的数据，考察了管理实践和畜群特征对加拿大西部母牛-犊牛养殖场犊牛死亡率的影响。该调查于2017年10月23日至2018年2月28日进行。该调查面向加拿大西部所有母牛-犊牛生产者，提供了生产者报告的犊牛死亡损失及相应畜群水平因素的数据。采用分数对数模型来识别与犊牛死亡率相关的显著因素。研究结果显示，较短的繁殖季节（<63天）、同一季节出生的犊牛以及对繁殖母牛进行定期妊娠检查与犊牛死亡率呈负相关。相反，对种公牛进行定期繁殖健全性评估、采用传统断奶方法以及给后备母牛接种腹泻疫苗与犊牛死亡率增加呈正相关。对母畜接种梭菌病和牛呼吸道疾病疫苗的畜群养殖场犊牛死亡率较低。值得注意的是，与由全职养牛生产者管理的养殖场相比，由有经验的非农场工作主要决策者管理的养殖场预测的犊牛死亡率较低。采用育肥系统的养殖场预测的犊牛死亡率较高。该研究的局限性包括由于其横断面性质和依赖生产者报告的数据可能存在的潜在偏差，这可能导致犊牛死亡率被低估。此外，样本量有限和数据缺失可能影响了一些变量的统计显著性。本研究通过使用分数对数模型分析风险因素与犊牛死亡率之间的相关性，并识别新的畜群水平风险因素，为母牛-犊牛养殖研究做出了贡献。它为未来旨在制定基于经验的管理策略以优化犊牛健康结果的研究提供了基础。
