Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Grønnegårdsvej 8, DK-1870, Frederiksberg C, Denmark.
Department of Animal and Veterinary Sciences, Aarhus University, Blichers Allé 20, DK-8830, Tjele, Denmark.
Acta Vet Scand. 2023 Oct 12;65(1):45. doi: 10.1186/s13028-023-00708-8.
Rearing replacement heifers is pivotal for the dairy industry and is associated with high input costs for the preweaned calves, due to their higher susceptibility to diseases. Ensuring calf health and viability calls for systematic approaches in order to mitigate the costs induced by managing sick calves and to ensure animal welfare. The objective of this study was to develop a systematic and feasible health-monitoring tool for bovine dairy calves based on repeated clinical observations and diagnostic results of calves at three time points; the 1st (T0), the 3rd (T1) and the 12th (T3) week of age. The study included observations from 77 dairy heifer calves in nine Danish commercial dairy herds. Immunisation status was assessed by serum Brix% at T0. Clinical scoring included gastrointestinal disease (GD) and respiratory disease (RD). The average daily weight gain (ADWG) was estimated from heart-girth measurements. Pathogen detection from nasal swabs and faecal samples were analysed for 16 respiratory and enteric pathogens by means of high-throughput real time-PCR. All measures obtained in each herd were visualised in a panel to follow the health status of each calf over time.
The individual clinical observations combined with diagnostic information from immunisation and pathogen detection form each enrolled calf are presented in a herd dashboard illustrating the health status over the study period. This monitoring revealed failure of passive transfer (Brix% < 8.1) in 31% of the 77 enrolled calves, signs of severe GD peaked at T0 with 20% affected calves, while signs of severe RD peaked at T2 with 42% affected calves. ADWG over the first eight weeks was estimated to be 760 g (± 190 g). Pathogen profiles varied between herds.
The large variation in both clinical disease and pathogen occurrence across herds emphasizes the need for herd specific monitoring. Combining the results of the present study from measures of immunisation, health and growth from individual calves in one visualisation panel allowed for the detection of patterns across age groups in the specific herds, showing promising potential for early detection and interventions that can lead to enhanced calf health and welfare.
后备奶牛的饲养对于奶牛养殖业至关重要，由于犊牛对疾病的易感性较高，因此在犊牛断奶前需要投入大量成本。为了确保犊牛的健康和活力，需要采取系统的方法来降低管理患病犊牛的成本，并确保动物福利。本研究的目的是基于三头龄（T0）、三头龄（T1）和十二头龄（T3）的重复临床观察和犊牛诊断结果，为奶牛犊牛制定一种系统且可行的健康监测工具。该研究包括丹麦九个商业奶牛场的 77 头后备奶牛的观察。T0 时通过血清 Brix%评估免疫状态。临床评分包括胃肠道疾病（GD）和呼吸道疾病（RD）。从心围测量估计平均日增重（ADWG）。通过高通量实时 PCR 分析鼻拭子和粪便样本中 16 种呼吸道和肠道病原体的检测。每个牛群中获得的所有措施都在一个面板中可视化，以随时间跟踪每个犊牛的健康状况。
每个入组犊牛的个体临床观察结果结合免疫和病原体检测的诊断信息以图表形式呈现，说明研究期间的健康状况。该监测显示，31%的 77 头入组犊牛存在被动免疫失败（Brix%<8.1），严重 GD 症状在 T0 时达到高峰，20%的犊牛受影响，而严重 RD 症状在 T2 时达到高峰，42%的犊牛受影响。前八周的 ADWG 估计为 760 g（±190 g）。不同牛群之间的病原体谱存在差异。
不同牛群的临床疾病和病原体发生情况存在很大差异，这强调了需要针对特定牛群进行监测。将本研究中来自个体犊牛免疫、健康和生长的措施结果结合到一个可视化面板中，可以在特定牛群中检测到不同年龄组的模式，这为早期发现和干预提供了有希望的潜力，从而提高犊牛的健康和福利。
