Evaluation of calving indicators measured by automated monitoring devices to predict the onset of calving in Holstein dairy XXXX .

@entity3685 @entity1266 @entity291
UNASSIGNED: Dystocias are common in dairy @entity291 and often adversely affect production, reproduction, animal welfare, labor, and economics within the dairy industry. An automated device that accurately predicts the onset of calving could potentially minimize the effect of @entity1266 by enabling producers to intervene early. Although many well-documented indicators can detect the imminence of calving, research is limited on their effectiveness to predict calving when measured by automated devices. The objective of this experiment was to determine if a decrease in vaginal temperature (VT), @entity3685 ( @entity3685 ), and lying time (LT), or an increase in lying bouts (LB), as measured by 3 automated devices, could accurately predict the onset of calving within 24, 12, and 6 h. The combination of these 4 calving indicators was also evaluated. Forty-two multiparous Holstein @entity291 housed in tie-stalls were fitted with a temperature logger inserted in the vaginal cavity 7    2 d before their expected calving date; VT was recorded at 1-min intervals. An ear-attached sensor recorded @entity3685 time every hour based on ear movement while an accelerometer fitted to the right hind leg recorded @entity291 position at 1-min intervals. On average, VT were 0.3    0.03  C lower, and @entity3685 and LT were 41    17 and 52    28 min lower, respectively, on the calving day compared with the previous 4 @entity291 had 2    1 more LB on the calving day. Of the 4 indicators, a decrease in VT >=  0.1  C was best able to predict calving within the next 24 h with a sensitivity of 74%, specificity of 74%, positive and negative predictive values of 51 and 89%, and area under the curve of 0.80. Combining the indicators enhanced the performance to predict calving within the next 24, 12, and 6 h with best overall results obtained by combining the 3 devices for prediction within the next 24 h (sensitivity: 77%, specificity: 77%, positive and negative predictive values: 56 and 90%, area under the curve: 0.82). These results indicate that a device that could simultaneously measure these 4 calving indicators could not precisely determine the onset of calving, but the information collected would assist dairy farmers in monitoring the onset of calving.
