Violin Guilherme, Mochizuki Nanako, Warju Simon Stephen Abraham, Itoh Megumi, Aoki Takahiro
Department of Veterinary Medicine, Obihiro University of Agriculture and Veterinary Medicine, Obihiro 080-8555, Hokkaido, Japan.
Animals (Basel). 2025 Jul 11;15(14):2055. doi: 10.3390/ani15142055.
Hypocalcemia is common in dairy cows within the first 72 h post-calving, and can be either clinical or subclinical. Early detection is critical, but traditional laboratory tests are time-consuming and cow-side tests remain costly. A classic symptom of hypocalcemia is reduced ear skin temperature, which has been explored as a diagnostic tool in a previous study, but was not recommended at the end. Additionally, ambient temperature was found to strongly influence ear skin temperature, complicating diagnosis. The present study investigates infrared thermography of the ear as a potential non-invasive method for helping in the detection of hypocalcemia in Holstein cows. In order to differ from the previous study, with the goal of improving diagnosis accuracy, this research analyzed the entire ear temperature using infrared imaging software. Ambient temperature was factored in by categorizing samples into two groups based on air temperature: colder (-1.6 to 14.6 °C) and hotter (15.3 to 31.2 °C). Forty-two cows were monitored during the perinatal period, with blood samples and thermographic images taken twice a day until 48 h after calving. This study found that the median surface temperature of the ear correlated strongly with environmental temperature (r = 0.806, < 0.001) and weakly with blood ionized calcium levels (r = 0.310, < 0.01). In colder air temperatures, ear surface temperature was significantly different between healthy and hypocalcemic cows ( = 0.014). Logistic regression models were used to assess ionized calcium status based on different combinations of ear surface temperature, its difference from air temperature, and days in milk. In hotter air temperatures, only ear surface temperature, with no other covariates, was able to generate a valid model ( = 0.029). In colder air temperatures, multiple combinations of those variables generated valid models ( < 0.05), with the difference between ear and air temperature, together with days in milk, performing the best. Thus, this study concluded that ear surface temperature obtained through infrared thermography, while not promising for warmer environments, does show application potential for helping in the detection of hypocalcemia in colder environments.
低钙血症在奶牛产后72小时内很常见，可分为临床型和亚临床型。早期检测至关重要，但传统实验室检测耗时，而现场检测成本仍然很高。低钙血症的一个典型症状是耳部皮肤温度降低，此前一项研究曾探索将其作为一种诊断工具，但最终未被推荐。此外，发现环境温度对耳部皮肤温度有强烈影响，使诊断变得复杂。本研究调查了耳部红外热成像作为一种潜在的非侵入性方法，以帮助检测荷斯坦奶牛的低钙血症。为了与之前的研究不同，以提高诊断准确性为目标，本研究使用红外成像软件分析了整个耳部温度。通过根据气温将样本分为两组来考虑环境温度：较冷（-1.6至14.6°C）和较热（15.3至31.2°C）。在围产期对42头奶牛进行监测，每天采集两次血样和热成像图像，直至产后48小时。本研究发现，耳部表面温度中位数与环境温度密切相关（r = 0.806，P < 0.001），与血液离子钙水平弱相关（r = 0.310，P < 0.01）。在较冷的气温下，健康奶牛和低钙血症奶牛的耳部表面温度存在显著差异（P = 0.014）。使用逻辑回归模型根据耳部表面温度、其与气温的差值以及产奶天数的不同组合来评估离子钙状态。在较热的气温下，仅耳部表面温度（无其他协变量）就能生成有效模型（P = 0.029）。在较冷的气温下，这些变量的多种组合生成了有效模型（P < 0.05），其中耳部与气温的差值以及产奶天数表现最佳。因此，本研究得出结论，通过红外热成像获得的耳部表面温度，虽然在温暖环境中前景不佳，但确实显示出在较冷环境中帮助检测低钙血症的应用潜力。
