New research presented at the American Dairy Science Association meeting in July indicates that periparturient activity and rumination time are associated with the dynamics of postpartum subclinical hypocalcemia (SCH).
Cornell University researchers conducted a study on 2 New York dairies with 89 multiparous Holstein cows. Starting at 10 days prior to calving, cows were monitored for urine pH, activity, rumination time and serum total calcium (tCa). Based on mean serum tCa at 1 and 4 days in milk (DIM) cows were classified into the following SCH groups: normocalcemic >1.89 mmol/L at 1 DIM and >2.25 mmol/L at 4 DIM; transient SCH <1.89 mmol/L at 1 DIM and >2.25 mmol/L at 4 DIM; delayed SCH >1.89 mmol/L at 1 DIM and <2.25 mmol/L at 4 DIM; and persistent SCH <1.89 mmol/L at 1 DIM and <2.25 mmol/L at 4 DIM. Cows were monitored through 10 DIM. Analysis of changes over time revealed the following differences between SCH groups:
- Delayed SCH cows had numerically lower prepartum urine pH, 6.15 compared to 6.44, 6.52 and 6.47 for normocalcemic, transient and persistent SCH cows, respectively.
- Prepartum rumination time was lowest in persistent SCH cows at 481.9 min/day compared to 513.6, 511.0 and 520.3 for normocalcemic, transient and delayed SCH cows, respectively.
- Postpartum rumination time was numerically lower in persistent SCH cows at 467.1 min/day compared to 499.8, 496.4 and 485.8 for normocalcemic, transient and delayed SCH cows, respectively.
- Postpartum activity was greatest in normocalcemic cows at 467.4 min/day compared to 429.9, 428.6 and 421.4 min/day for transient, delayed and persistent SCH cows, respectively.
These results indicate that low rumination time prepartum is associated with persistent SCH in cows, and this difference follows numerically into the postpartum period. More research is needed to determine if low urine pH prepartum is associated with delayed SCH in cows.
Seely et al., 2021. J. Dairy Sci. Vol. 104(Suppl. 1) p 73 Abstract 188