Although many areas remain dry at present, some dairy areas have had significant wet weather. Wet muddy weather can lead to an increase in environmental mastitis cases, especially if cows are calving or lying in contaminated boggy areas.
The most common environmental mastitis bacteria are Escherichia coli and Streptococcus uberis. Others bacteria that can be responsible for mastitis at times are Klebsiella, Pseudomonas, Nocardia, Arcanobacterium, Bacillus, and Enterobacter. Nocardia and Pseudomonas rarely respond to treatment and culling is generally recommended. Strep uberis and E coli usually respond well to treatment, although E coli can sometimes cause sudden illness from toxin production (especially in downer cows) and Strep uberis occasionally becomes a chronic infection.
Although the reservoir of infection is the environment, it is still possible for these infections to be spread in the shed, so normal shed hygiene is vital.
Several management actions can aid in preventing wet weather environmental mastitis.
- Fill in puddles and boggy areas to prevent mud and 'splash', minimise faecal pats (less than two per square metre for calving pads is recommended).
- Maintain drainage from lanes, calving pads and around troughs.
- Encourage cows to stand (keeping their teats elevated off the ground) for the first hour after milking when their teat ends are still not yet closed. Providing feed as they exit the dairy is one way of achieving this, as they will stand and eat.
- Strip graze or fence off the worst of the contaminated boggy areas so they are kept off these -- this may require the use of portable troughs.
[crosshead]Udder preparation before milking
- Only wash teats if they are very dirty or wet. If teats are washed, then they must be dried -- never put the cups on wet teats. Dry with disposable paper towel not a communal towel.
- If teats are swollen with milk but the cow has not yet calved, start milking them to decrease their mastitis risk, do not under milk or over milk.
- If after milking the teats are dry, cracked or have sores then take action.
- May need to check liner lengths, vacuum, pulsation (machine testing)
- Ensure emollient is added into the teat spray being used.
- Post-milking the teat remains open and susceptible to infection for about an hour. Teat spray after milking to protect the teat during this time.
- Teat spray disinfectant must be made up as per instructions and should contain an emollient to maintain good teat condition.
- It must cover the entire teat and the opening of every teat.
- Pre-milking teat spray is rarely required, however, it is recommended in some cases - always speak to a veterinarian if this is believed to be necessary.
[crosshead]Identify and treat mastitis cases quickly
- These infections can still be spread during milking so early detection and treatment are important.
- Consider fore-striping milk to look for clots.
- Check the filter sock and individual cell counts.
- Take a milk sample before starting treatment. Keep this in the fridge for up to a week. If it needs to be kept for longer, then freeze the sample.
- Remember to label the sample with the cow's name/number, the date and the teat from which it was taken. This can be used for cultures to identify which bacteria is present to help with correct antibiotic selection.
- Review the mastitis protocol with the vet. If unsure when to call or if concerned that cases are failing to respond to treatment or case numbers are increasing, remember more than 2-3 new cases per 50 cows calved in the calving season is a commonly used trigger point to call the vet for a chat (or more than 5 cases per 100 cows generally).
Although most environmental mastitis cases respond well to therapy it is still a significant loss of milk from the vat and prevention and preparedness is always better than 'cure'. Happy milking.
*Sherri Jaques is a practising veterinarian and reproduction adviser in the West Gippsland region of Victoria.
All comments and information discussed in this article are intended to be of a general nature only. Please consult a veterinarian for herd health advice, protocols and/or treatments that are tailored to a herd's particular needs.