Mastitis is the most common disease of dairy cattle and is a significant cause of losses on the dairy farm, explains Dr Sean Daly, vet and technical adviser at MSD Animal Health.
In our previous article (click here to read), I discussed how to get the most out of a milk quality consultation and dry-cow therapy. Hopefully, many of you will have already started those discussions with your veterinarian.
This month we are discussing how best to manage your herd at dry-off.
As a reminder, the goals of dry-off are to cure existing subclinical mastitis infections and prevent new infections through the dry period and early lactation. To achieve this, not only do we need to select the right cows and product, but we need to adequately prepare cows to successfully dry them off.
Before we go into the specifics, it is critically important to remember to take your time, and to best achieve this aim select a smaller number of cows to dry-off each day, i.e. in batches, rather than the whole herd. This will reduce fatigue and lessen the chance of making a mistake or getting sloppy with your hygiene.
Prior to dry-off
Sort tags and decide on a marking and recording system.
Identify which cows you are drying off/treating using your herd test data or RMT (rapid mastitis test) results. Discuss with your vet how to decide which cows to treat and what with.
Cows should be dried off when milking 5-20L/day. If less than 5L then you risk getting an inhibitory substance grade at first collection and >20L/day you risk milk leaking from the teats after dry-off.
Changing the herd’s diet can help ‘shut down’ cows that are heavy milkers. Consult your vet to determine how best to do this for your farming system.
Consider training your staff in best practice administration of DCT and teat sealants. Your veterinarian can assist with this and you can watch our Insert Dry Cow Therapy video to recap on the basics.
Dry off during fine weather
Keep teat ends clean at drying off time
Dry off before cows go onto wet / muddy paddocks
Avoid hosing sheds / yards with cows nearby
Check for clinical mastitis; don’t dry off cows if they have clinical mastitis, but instead keep milking them and use a lactating cow therapy (antibiotic) according to your veterinarian’s advice.
Antibiotic or sealant (1 tube): 25 cows/person/hour
Antibiotic and sealant (2 tubes): 15 cows/person/hour
Stand cows on clean paddock with feed for 30 mins after dry-off
Don’t bring cows back into the shed for at least 10 days, ideally longer; this will help prevent leakage of milk.
Following drying off you should monitor the herd daily, especially for the first week after drying off; a walk through the herd and visual inspection is usually adequate.
Early identification of sick cows with black mastitis will give you the best chance to save the cow’s life. Always treat cows with mastitis with a lactating cow therapy according to your veterinarian’s advice; never ever use dry cow therapy to treat clinical cases of mastitis.
For helpful videos and fact sheets which expand on the information in this article visit www.topfarmers.co.nz , a reference library of industry best practice in some key animal health management areas.
• David Dymock is a livestock technical advisor with MSD Animal Health.