Department of Veterinary Medicine, Obihiro University of Agriculture and Veterinary Medicine, Inada, Obihiro, Hokkaido 080-8555, Japan.
Industrial Research Center, Hokkaido Research Organization, Kita 19, Nishi 11, Kita-ku, Sapporo, Hokkaido 060-0819, Japan.
J Vet Med Sci. 2022 Feb 10;84(2):193-198. doi: 10.1292/jvms.21-0320. Epub 2021 Dec 10.
We previously reported the possibility of using the electrocardiogram variable to estimate blood calcium (Ca) concentration in dairy cows based on the strong positive correlation between the blood Ca concentration and the inverse of the corrected ST peak interval (STc). To improve the accuracy of the estimation of blood Ca concentration, we investigated the relationship between blood Ca concentration and STc for each postpartum day and available variables other than STc. We measured multiple variables (milk yield, calving number, age, body temperature, etc.), including serum total Ca concentration (tCa), blood ionized Ca concentration (iCa) and STc in 462 Holstein cows on days 0, 1, 2, 3, 5, and 7 postpartum. A very high correlation was observed between iCa and tCa. The association between tCa and STc for each postpartum day had a high coefficient of determination of 0.61-0.79 postpartum 0-2 days but decreased after the third day. In the investigation using the data from postpartum days 0-2, STc, heart rate interval, calving number, and age were highly correlated with tCa. In addition, a multiple regression equation was obtained with tCa as the objective variable and STc and calving number as explanatory variables. The estimation accuracy was improved as compared with the simple regression equation using only STc as the explanatory variable. This multiple regression equation was used for 11 cows suspected of having hypocalcemia, and it was able to correctly detect cows requiring early treatment, except for one cow.
我们之前曾报道过，基于血钙（Ca）浓度与校正后 ST 峰值间隔（STc）倒数之间的强正相关，使用心电图变量来估计奶牛血钙浓度的可能性。为了提高血钙浓度估计的准确性，我们研究了不同产后天数与 STc 相关的血液 Ca 浓度和可用变量之间的关系。我们测量了包括血清总钙浓度（tCa）、离子钙浓度（iCa）和 STc 在内的多个变量，在产后 0、1、2、3、5 和 7 天，对 462 头荷斯坦奶牛进行了检测。iCa 与 tCa 之间存在非常高的相关性。在产后 0-2 天，tCa 与 STc 的关联具有非常高的决定系数（0.61-0.79），但第三天之后，该系数下降。在对产后 0-2 天数据的调查中，STc、心率间隔、产犊数和年龄与 tCa 高度相关。此外，还获得了一个以 tCa 为目标变量、以 STc 和产犊数为解释变量的多元回归方程。与仅使用 STc 作为解释变量的简单回归方程相比，该方程的估计准确性有所提高。该多元回归方程用于 11 头疑似低钙血症的奶牛，除了一头奶牛外，其余奶牛均能正确检测出需要早期治疗的奶牛。
