Treating cows with antibiotic at drying-off is the basis of all mastitis control plans. But, at the same time, it is important that antibiotic residues in milk and meat are avoided. The way in which Dry Cow Treatment of herds is applied on the farm determines the risk of antibiotic residue in farm’s produce.

The Countdown Downunder Farm Guidelines for Mastitis Control recommend several practices to minimise antibiotic residue in vat milk:

1.   Administer the intramammary tubes immediately after the last milking

Dry Cow Treatment is only registered for use straight after a cow’s last milking for a lactation. Delayed treatment may result in the uneven distribution of antibiotic through the udder tissue – reducing cure rates and increasing the risk of antibiotic residue. Don’t use the drug off-label. If a delay in treatment has been unavoidable, consult your vet before proceeding.

2.   Ensure cows don’t drop to less than 5 litres per day before drying-off

Cows producing less than 5 litres per day are already starting to dry themselves off and parts of their udder tissue will be shutting down. Antibiotic may not be evenly distributed through the udder tissue of these cows.

3.   Don’t treat quarters that have already dried-off

When treating a 3-teater, don’t put antibiotic into the quarter that has not been milking. Application of Dry Cow Treatment to a dry quarter is effectively an “off-label” use, because of the way absorption of antibiotic is altered.

4.   Use safeguards to prevent accidental milking of treated cows

Put the treated, dry cows in a paddock where they cannot accidentally rejoin the milking herd. Clearly mark the udder (eg with a spray paint) so that cows that have received Dry Cow Treatment are easily recognisable. Some farms use distinct colours and symbols, such as an ‘X’, known by all milking staff, whether regular or relief milkers.

5.   Don’t mistakenly use Dry Cow tubes to treat a lactating cow!  

To reduce the chance of using Dry Cow Treatment in milking cows, do not store Dry Cow Treatment near tubes of Lactating Cow antibiotic. For some products, the Lactating Cow and Dry Cow Treatment products can look very similar!

6.   Withhold milk from the vat for cows that have not reached the Minimum Dry Period

The Minimum Dry Period is the minimum number of days that should elapse between giving the intramammary tubes and when the cow calves. It varies from one Dry Cow Treatment product to the next.

For each batch of cows treated, record the date when they will pass the Minimum Dry Period for the Dry Cow Treatment product that you used. If a cow calves BEFORE completing her Minimum Dry Period, then her milk must be withheld from the vat for considerably longer.

7.   Know the Withholding Period for the Dry Cow Treatment product you are using

Keep the milk from freshly calved cows out of the vat for the Withholding Period specified on the label. Withholding Periods are the number of days or hours after calving that milk must be kept out of the vat. NOTE that the Withholding Period assumes that each quarter is fully milked out at each milking. If this doesn’t happen, you may need to extend the Withholding Period. Ask your vet if you have any doubts or queries about Withholding Periods.

8.   Do not treat cows that will be culled after drying-off

This helps others in the industry to avoid errors.

If there is the slightest suspicion that vat milk may contain antibiotic residue, talk with the field officers from your factory. And help keep Australia’s milk supply clean and white!

Image and caption
“Clearly mark the udders of all cows given Dry Cow Treatment”

“Check the cow has passed the Minimum Dry Period and the Withholding Period”

Countdown Downunder Farm Guideline or Technote
Farm Guideline 14.4, 14.5, 14.6, 17.4, 17.6, 17.8, 17.9, Fact Sheet D

Keywords
Dry Cow Treatment, antibiotic residue, risk

Word length
604