Despite our very best intentions to limit the number of cows with clinical mastitis and limit the spread of mastitis in our herds, an inevitable fact is we will never eliminate mastitis completely.
The past few months have certainly been challenging with all the wet, muddy and cold weather testing even the best mastitis plans.
Managing milk quality begins with understanding the risk factors on your farm and knowing what tools you have at your disposal to mitigate those risks.
A great place to start is Dairy Australia’s Milking Mastitis Management program.
This is the revamped working of the Cups On Cups Off workshop that has been running for a number of years. This course covers several key areas.
Understanding mastitis infection
Some bacteria in the cow’s environment can invade the teat and cause inflammation of the udder (aka mastitis). The number of white blood cells in the milk increase as the cow fights the mastitis infection.
When stripping the quarter if there are clots and a cheesy appearance for more than three squirts, the infection is called ‘clinical mastitis’.
Signs of clinical mastitis may range from mild with flecks and/or discolouration of milk; moderate with swollen quarters; to severe cases where the infection spreads from the udder to the cow causing signs of sickness (reduced appetite, rumen tucked, eyes sunken, head/ears drooping or cow sitting down not grazing in paddock).
When the infection only causes an increase in the cell count but no change in the appearance of the milk, the infection is known as ‘subclinical mastitis’.
Both types of infection will cause an increase in Somatic Cell Count (SCC) and decrease the volume of milk a cow produces. The SCC of an infected quarter can be 250,000 to many million cells per ml.
Treatment of mastitis
The cost to treat a case of mastitis is estimated at $400 per cow in 2023. The key to any treatment program is understanding if you have an issue.
Dairy Australia’s triggers for action for mastitis control are:
- If you have more than five per cent of cows affected by clinical mastitis in the first 14 days after calving.
- More than two per cent of cows affected by clinical mastitis in each month of lactation.
Appropriate antibiotic and anti-inflammatory treatment are most likely to be of benefit in cows with a newly acquired mastitis infection during lactation.
If the cow has a previous history of mastitis infection or the infection remains untreated for a while, then the chance of clearing the infection with lactating cow antibiotics is reduced.
Hence the merit of treating the cow must be considered against the type and level of infection, time taken to identify the issue and using her health, production and fertility records.
A written treatment protocol ensures consistency in treatment and reduces the risk of antibiotic residues reaching the vat.
Eighty per cent of residues occur as a result of not separating treated cows from the herd and off-label use of medication.
Things that should be written down in mastitis treatment protocol include:
- When a cow needs treatment.
- What treatments to be given and how to be given.
- How to administer.
- How to mark the cow and separate from main milking herd.
- How and what to record.
- When a cow should be culled.
Collecting a useful milk sample
A sample needs to be collected from the affected quarter before the cow receives antibiotic treatment.
Wearing clean disposable gloves and thoroughly cleaning the teat end with 70 per cent methylated spirits before collecting a milk sample will reduce the chance of contaminating the milk sample with dirt or dung. Contaminated milk samples may obscure identification of the bacteria causing the mastitis infection.
After cleaning the teat end, the first few squirts of foremilk should be discarded and then a 5ml sample of milk should be collected into a sterile container. To reduce the risk of contaminating the milk sample during collection, the teat end must not touch the sample container, and nothing should touch the inside surface of the container lid.
The cow’s number, quarter sampled and date of sampling are useful to record on the sample container before delivery to the testing site (many veterinary clinics offer rapid mastitis testing service).
Even when the likely cause of infection has been established and an effective treatment protocol is put in place it is prudent to collect a milk sample before treatment in case of treatment failure.
Some bugs can protect themselves from antibiotic treatment by producing a special slime coating over their surface or may even have genes for antibiotic resistance.
If your initial treatment is unsuccessful, contact your veterinarian for further advice. The stored milk sample can be used up to six months from collection date.
Prevention of new infections
Understanding the types of infection is the first step in preventing infection.
If the cause of the mastitis in your cows is infection by bugs living in the environment (environmental mastitis), the focus of prevention must be to either decrease the exposure of your cow’s teats to dung and dirt or increase the protection in your cow’s teats.
Clean calving paddocks and avoiding calving cows on feedpads will reduce teat-end contamination.
If you are getting several cows coming in with mastitis on day one of milking, the use of teat-sealant products should be considered. Teat-seal forms a physical barrier to udder invasion from environmental bugs.
Some bugs are difficult to culture as they hide inside cells in the udder and are not shed in the milk all the time, but the bugs can cause great damage to the udder tissue (cow associated mastitis).
Such bugs are found on the skin of the udder and their presence inside the udder suggests that there is a problem with cow hygiene or milking plant function allowing skin bugs to invade the udder. This may occur with uneven cup removal, high vacuum or short milk liners damaging teat ends.
Unless the cause of teat-end damage is stopped you will continue to have new mastitis infections occurring in your cows.
Milking practices begins with understanding how to implement effective, efficient stockmanship and care in milking processes on farm.
These include careful movement of stock to and from the paddock, thorough application of teat spray (two litres per 100 cows, per milking applied over the whole teat after milking), gentle even cup removal, avoiding over-milking and regular timely changing of rubber-ware.
These will all assist in reducing the incidence of new mastitis infections.
Good-conditioned cows with supple teats that have clean teat ends are more resistant to mastitis infection than cows in poor condition with low immunity, cracked teats and damaged teat-ends.
Having a good consistent milking routine, healthy cows and clean calving environment will minimise the incidence of new mastitis infections in your herd.
MMM program can help
The Dairy Australia Milking Mastitis Management program will help your farm team understand how to achieve good milking practices.
The MMM program is valuable for induction of farm staff entering the dairy industry as foundation for good milking practices while more experienced employees and farm mangers/owners will often gain practical useful information to improve operations, attention to detail and in turn milk quality.
For more information about the MMM program, contact Ross Read on 0438 906 613 or rread@murraydairy.com.au
– Ross Read, Murray Dairy regional extension officer animal performance