Abstract #T4

# T4
Effects of postpartum uterine diseases on milk yield, milk components, and culling in dairy cows under certified organic management.
J. M. Piñeiro*1, M. G. Maquivar2, A. A. Barragan1, J. S. Velez3, H. Bothe3, G. M. Schuenemann1, 1The Ohio State University, Columbus, OH, 2Washington State University, Pullman, WA, 3Aurora Organic Farms, Boulder, CO.

The objective was to assess the effect of postpartum uterine diseases on milk yield (kg), milk components (SCC and percent fat and protein), and culling. Cows (n = 3,227) from 2 dairy herds were screened for retained placenta (RP; > 24 h after parturition), metritis (within 20 d in milk [DIM]), and purulent vaginal discharge (PVD) at 26 ± 3 DIM. Milk yield and components from the DHIA test-days and cows culled from farm records up to 300 DIM were collected. Weekly, a list of cows by DIM was obtained using on-farm computer records and screened for RP (presence of fetal membranes outside the vulva), metritis (fetid brown-red watery vaginal discharge and fever), and PVD (gloved hand technique). PVD was defined as any cow presenting a score of 2 or 3 (0–3 scale; mucopurulent or worse vaginal discharge) at the time of exam. Parity (lactations 1, 2 and ≥ 3) of cows was considered for milk yield, milk components, and culling. The statistical analyses were performed using MIXED (milk yield and components) and GLIMMIX (culling) procedures of SAS. Cows with metritis, RP or PVD had an additive effect on milk yield, milk components, and culling. Regardless of parity, lactating cows diagnosed with uterine diseases (all combined) had significantly reduced milk yield (by 2–3.9 kg/cow/d) for at least one of the first 4 DHIA test-days (P < 0.05), but was not different at later tests. For the first 2 DHIA test-days, lactating cows diagnosed with uterine disease (all combined) had significantly higher SCC (232 × 103 cells/mL) and fat content (3.7%) compared with cows without uterine diseases (164 × 103 cells/mL and 3.5%, respectively; P < 0.05). Milk protein content (%) was not different between cows with or without uterine diseases. Cows with uterine diseases had higher (P < 0.05) culling within 60 DIM and significantly lower (P < 0.05) pregnancy hazard up to 300 DIM compared with cows without uterine diseases, regardless of parity. Uterine diseases decreased milk yield and changed milk components (SCC and fat) early in lactation; and these diseases were a substantial risk factor within 60 DIM for culling.

Key Words: organic, dairy cattle, uterine disease