Relationship between dry-matter intake and subclinical endometritis in healthy postpartum dairy cows
The main objective was to study the relationship between dry matter intake (DMI) and subclinical endometritis of postpartum dairy cows. A secondary objective was to evaluate whether colostrum quality at calving was associated with subclinical endometritis. Postpartum Holstein cows (n=70 total; primiparous=28; multiparous=42), were milked twice daily and housed and fed individually in tie-stalls. Dry matter intake was measured daily from individual cows from calving to 10thweek postpartum. Four cows that were evidently sick in the first week after calving with depressed DMI for over 3 days and/or detected with fever were removed from further analysis. Colostrum was collected from the 1st milking and frozen for later quality analysis (digital Brix refractometer, 0 to 53% scale). To measure level of subclinical endometritis, uterine swabs were performed at 40±3d postpartum and a single treatment-blind technician evaluated all the slides by counting a minimum of 100 cells at 400x magnification and determined the number and percentage of polymorphonuclear cells (PMN) in the endometrial smear. The statistical analyses were performed with proc CORR and proc GLIMMIX of SAS®. Dry matter intake averaged 18.5±0.3 kg/day and 23.6±0.4 kg/day, for primiparous and multiparous respectively. There was no significant association between proportion of uterine PMN cells and average DMI (r=0.16; P=0.20), with no significant interactions with parity. In a further retrospective analysis, cows were divided in three classes of subclinical endometritis (0% PMN (n=22); 1 to 20% PMN (n=32); or >20% PMN (n=16)). Similarly, the repeated measures comparison indicated no effects (P=0.42) of subclinical endometritis on DMI. Interestingly, greater colostrum quality at calving was associated with greater DMI in multiparous (r=0.40; P=0.01), but not in primiparous cows (r=-0.08; P=0.69). Further, colostrum quality was not associated with subclinical endometritis in older cows (r=0.19; P=0.25); but surprisingly, greater colostrum quality was associated with lower subclinical endometritis in primiparous cows (r=-0.37; P=0.05). In conclusion, healthy postpartum cows with lower DMI had similar incidence of subclinical endometritis as compared to cows with greater intake levels. Associations between colostrum quality at calving and DMI and/or proportion of subclinical endometritis need further examination, but could represent an interesting tool to predict postpartum performance. Support: USDA Grant 2010-85122-20612.
Dry Matter Intake