Drying-off practices and cell count –based new infection and cure risk over the dry period on 765 German dairy farms

This observational study with voluntary participation investigated drying-off practices and dry period-related udder health key performance indicators (KPIs) in 3 important dairy production regions in Germany (the North (N), the East (E), and the South (S)). Data from dairy herd improvement testing (DHI) and information about drying-off practices were collected during a single herd visit between 2016 and 2019 from 253, 252, and 260 farms in N, E, and S, respectively. Abrupt cessation of lactation was most common in N and E, but only practiced on about half of the farms in S (N: 79%, E: 75%, S: 56%). Blanket dry cow therapy (BDCT, the use of antibiotic agents for all cows) dominated in N and E (63% and 65%), while in S, primarily selective dry cow therapy (SDCT, targeted use of antibiotic agents at drying-off for individual cows according to farm-specific criteria) (56%), or even no use of antibiotic dry cow therapy (20%) was adopted. The use of teat sealants (TS) with or without the use of antibiotics was most common in E (66%), followed by farms in N (54%), and least common in S (30%). The median new infection risk (using a somatic cell count (SCC) threshold of 100,000 cells/ mL milk) during the dry period (NIRD; cows with SCC ≤100.000 before dry period and SCC > 100.000 at first test day post dry period) in N, E, and S was 24% (interquartile range (IQR): 13–35%), 25% (18–35), and 24% (8–37), and the cure risk during the dry period (CRD; cows with SCC >100.000 before dry period and SCC ≤100.000 at first test day post dry period) in N, E, and S was 63% (51–72), 57% (47–65), and 60% (42–75), respectively. NIRD and CRD varied greatly between farms indicating improvement potential on many dairy farms.