Predicting dyscalcemia at 4 days in milk using activity and rumination data in multiparous Holstein cows
C. R. Seely* and J. A. A. McArt
Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY
Dyscalcemia (DYS), reduced blood Ca at 4 DIM, is associated with reduced milk production and reproduction and increased risk for negative health events. Cowside testing of blood Ca to diagnose DYS is difficult and alternative methods to identify DYS are needed. Our objectives were to use activity and rumination data to predict DYS. Data were collected from multiparous Holstein cows (n = 182) from 2 herds in NY. Cows were affixed with ear or neck loggers to record daily activity (AT; arbitrary units (AU)/d, defined by manufacturer) and rumination (RT; min/d) times. Daily AT and RT were collected from 14 d prior to calving until 14 DIM. No cows received supplemental Ca or experienced clinical hypocalcemia. A blood sample was collected at 4 DIM and analyzed for total Ca (tCa); cows were classified as DYS if tCa ≤ 2.2 mmol/L (n = 57), or eucalcemic (EUC) if tCa > 2.2 mmol/L (n = 125). We used linear mixed models to analyze differences in AT and RT between calcemic groups. Logistic models were used to predict the probability of DYS from AT and RT variables. Prepartum AT was similar between EUC and DYS cows (402.0 ± 10.4 AU/d and 395.1 ± 14.5 AU/d, respectively; P = 0.5). Postpartum, EUC cows had greater AT than DYS cows (436.1 ± 10.7 vs. 407.8 ± 14.7 AU/d, respectively; P = 0.004). Prepartum RT was similar between EUC and DYS cows (512.6 ± 9.8 min/d and 504.2 ± 14 min/d, respectively; P = 0.3). Postpartum, EUC cows had greater RT than DYS cows (512.3 ± 10.5 min/d vs 480.5 ± 15 min/d, respectively; P < 0.001). The prediction model including daily changes in RT between 0 and 4 DIM and raw AT for 1 to 4 DIM yielded the greatest predictive capacity (AUC = 80%, sensitivity = 45%, specificity = 94%, negative predictive value = 79%, positive predictive value = 76%, accuracy = 78%). Our findings suggest that differences exist in postpartum AT and RT between cows that experience DYS and those that remain EUC. Utilizing AT and RT data in the immediate postpartum period shows utility in identifying cows with DYS at 4 DIM which could be beneficial to aid in management decisions that may ameliorate the associated negative outcomes.
Key words: dyscalcemia, activity time, rumination time
Loading...
Reload document 
Open in new tab