Drying-off - dos and don'ts
Budgetary decisions made at the end of last season saw expenditure on dry-cow therapy (DCT) pruned in many herds. By the end of last season, the forecast payout for this season was back to what most would have liked - how quickly things change! Some of you have paid for this decision with increased mastitis problems this season.
The dry period remains the best window of opportunity for reducing udder infections in your herd. Dry cow therapy achieves better cure rates than treatment during lactation. It also protects cows from new infection during the dry period and early lactation.
Early dry-off
There are a number of cows that would benefit from early dry-off:
- Cows producing less than five litres - these cows are trying to dry off anyway, so let them
- Cows that have a persistently high individual somatic cell count (ISCC) i.e. >500,000
- Cows with teat-end lesions
- Low body-condition cows
Early dry-off obviously depends on other factors like feed supply, cow condition and bulk tank somatic cell count (BTSCC).
Cows to cull
There are cows for which culling is the only way to deal with the problem. The chances of curing infected cows using DCT reduce with increasing age, multiple mastitis cases, mastitis involving multiple quarters and the presence of Staph aureus infections.
Whole herd or selective therapy
Take the chance to discuss this with your vet at dry-off consult time.
Consider selective DCT for herds with less than 50% of the herd with an ISCC greater than 150,000 cells/ml and where clinical cases in the first month of calving are less than 10%.
The Australian "Countdown Downunder" suggestion is that if you answer yes to any of the following then you should blanket DCT:
- Is your average BTSCC for the past six months above 250,000 cells/ml?
- Did more than 30% of your cows have peak ISCCs above 250,000?
- Did you have more than five clinical cases per 100 cows in the first month of lactation?
- Did you have more than an average of two clinical cases per 100 cows after the first month of lactation?
For those of you who adopt the selective DCT option, the SAMM plan suggestion of treating cows with an ISCC above 150,000 and heifers with an ISCC above 120,000, plus all clinical cases is a good starting point.
Preparing for dry-off
Cows that are producing less than 10-12 litres per day should need no special preparation for drying-off. Cows producing more than this pose a slight problem. Herds that reduce feed intake around dry-off show an increase in clinical mastitis during the dry period and also a higher BTSCC during the following lactation. These higher-producing cows show increased risk of dry-season mastitis. A sensible reduction in protein intake for a week leading up to drying-off and for a week afterwards is probably beneficial. Hay and maize silage could be utilised. Water should not be withheld.
Dry-cow treatment
Guidelines for treatment are:
- Dry off abruptly, don't skip days and preferably don't skip milkings
- Treat immediately after the last milking and clearly mark treated cows if the rest of the herd is still being milked
- Treat every quarter of each cow
- Sanitise teat ends properly: use a swab moistened with methylated spirits, or medicated teat wipes, before treatment
- Insert the nozzle of the dry-cow antibiotic tube no more than 3mm into the teat canal
- Spray teats after treatment
- Put cows in a dry, clean paddock
- Complete full treatment record
Drying off can entail the use of several veterinary medicines that require the authorisation of your vet. Avoid delays by ensuring your vet puts these authorisations in place before you need the product.
