Potential hazards include:

• Introducing environmental bacteria into the teat if the teat end is not disinfected properly, or it becomes contaminated before it has sealed. Infection with environmental bacteria can cause severe mastitis.
• Operators getting injured by cows during administration of DCT or ITS. It is important to take your time and have sufficient help.
• Antibiotic residues in milk and meat (including calves) are a risk from cows which are culled during the dry period, or calve earlier than expected. The specified minimum dry periods and withholding periods for each product after calving must be observed.

Guideline 17 and Technote 17 provide practical and technical information on:

• Choosing between whole herd and part herd antibiotic DCT
• Not using antibiotic DCT on cows which are going to be culled within the next 2-3 months
• The importance of only using antibiotic DCT at the cow’s last milking for the lactation
• Marking cows that have been treated especially if they are dried off before the rest of the herd
• Administering the treatments as recommended and partial insertion technique
• Thoroughly spraying teats with freshly made teat disinfectant after dry cow treatment
• Information to record at dry off
• Putting cows in clean areas after treatment
• Transporting cows after giving DCT or ITS