Abstract #T31

# T31
Advancement of Dairying in Austria (ADDA): Antimicrobial dry cow therapy on conventional dairy farms—Farmers’ management decisions.
C. L. Firth*1, C. Schleicher2, A. Käsbohrer1, W. Obritzhauser1, 1University of Veterinary Medicine, Institute of Veterinary Public Health, Vienna, Austria, 2Austrian Agency for Health and Food Safety (AGES), Integrated Risk Assessment, Data and Statistics, Graz, Styria, Austria.

Advancement of Dairying in Austria (ADDA) is a 3-year research project encouraging cooperation between academic institutions and the dairy industry in Austria. The study presented here investigated how farmers dried their cows off and their use of antimicrobial substances at this time. Veterinary practices in Austria were asked to contact their dairy clients and inquire whether they would participate in the study. Livestock treatment records were collected and an online survey was sent via email to all participating farmers. A total of 251 farmers provided consent; of these, 211 responded to the survey (response rate: 84%). With respect to production system, 165 (78%) of respondents managed their farms conventionally and are included in this analysis. Herd size ranged from 8 to 94 cows (mean 29). One-third of conventional farmers kept their cows in tie-stalls, while the remaining farms had cubicle housing or straw/compost yards. The majority (69%) of farmers stated that they sent milk samples from symptomatic animals for bacteriology before drying off, while only 13% regularly ordered this precautionary investigation for all cows, regardless of history. Drying off was primarily carried out abruptly (74% of farms) and the most common drying off period was 56–60d antepartum (58%). When asked whether they used antibiotics at drying off, 55.8% of farmers responded “yes, in all cows” (i.e., blanket dry cow therapy [DCT]), whereas 27.9% used antimicrobial DCT only in cows with symptoms and 15.2% only in cows where a milk sample returned a positive bacterial culture. Preliminary results showed that the farmers’ level of agricultural education did not significantly affect whether they dried off cows with antibiotics (P = 0.264, Chi2 test). The correlation between the use of antibiotics at dry off and whether the CMT was regularly used was not significant (P = 0.807, 2-sided Fisher’s exact test). More targeted antimicrobial use could lead to further reductions in blanket dry cow therapy and it is vital that vets and farmers work together to achieve this goal. The influence of farm management data regarding DCT (survey responses) on the incidence of mastitis on farm is to be analyzed using a generalized linear mixed model (GLMM).

Key Words: dry cow therapy, mastitis, antibiotics