Grad Student Competition
Differential effects of early lactation metabolic disruption on periparturient rumination and activity time in organic Jersey cows
| Date/Time: |
8/28/2026
08:15
|
| Author: |
Kayla Young |
| Clinic: |
University of New Hampshire |
| City, State, ZIP: |
Durham, NH 03824 |
K.A. Young, BS
1
;
F.C. Pharo, BS, MS
1
;
C.R. Seely, BS, MS, PhD
1
;
1Department of Agriculture, Nutrition, and Food Systems, University of New Hampshire, Durham, New Hampshire, 03824
Introduction:
In early lactation, dairy cows are at a higher risk of developing metabolic disorders compared to other periods of lactation. While many metabolic disorders present subclinically, rumination time (RT) and activity time (AT) may offer utility in identifying cows with subclinical metabolic disruptions. However, little work has been done to explore these effects in organically managed dairy cows. Our objective was to explore the association of metabolic disruption and patterns of RT and AT during the periparturient period in organic dairy cows.
Materials and methods:
Multiparous organic Jersey cows (n = 36) were enrolled at 1 DIM, serum was collected at 1 – 4, 7, and 14 DIM and was analyzed for BHB and total calcium (tCa). From 2 wk prepartum (PRE) to 3 wk postpartum (POST), daily RT (min/d) and AT (arbitrary units [AU]/d) data was recorded by SmaXtec boluses. Cows were subsequently classified as ketotic (HYK) if BHB was 1.2 mmol/L (n = 9) or non-ketotic (nHYK) if BHB was 1.2 mmol/L (n = 28) at any point from 1 to 14 DIM, and dyscalcemic (DYS) if tCa ≤ 2.2 mmol/L (n = 15) or eucalcemic (EUC) if tCa was > 2.2 mmol/L (n = 23) at 4 DIM. Separate linear mixed models were used to analyze differences in PRE and POST RT and AT between HYK and nHYK and DYS and EUC cows.
Results:
During the PRE period, RT was similar between HYK and nHYK cows (P = 0.9) and between DYS and EUC cows (P >0.5). There was a day×HYK group interaction PRE for AT (P = 0.008) with HYK cows being less active compared to nHYK cows. Postpartum, there was a tendency for HYK cows to have lower RT and AT compared to nHYK cows through 3 wk POST (both P = 0.1). Similarly, there was a tendency for DYS cows to have reduced RT compared to EUC cows POST (P = 0.1) where mean DYS RT = 467 (95% CI = 440, 495) min/d and EUC RT = 494 (473, 516) min/d. Postpartum AT tended to be higher in DYS (8.73 [7.26, 10.2] AU/d) compared to EUC (7.72 [6.57, 8.87] AU/d; P = 0.09).
Significance:
Our findings suggest that utility exists in utilizing AT and RT during the periparturient period to identify cows with HYK and DYS in organically managed systems. Further investigations are needed to optimize the capability of RT and AT.
