Systematic approach to keep mastitis at bay

Mastitis is an inflammation of the udder and teat in lactating cows, usually caused by an immune system reaction to a bacterial infection. This will cause a decrease in milk production and quality of milk. In extreme cases, mastitis can result in one or more quarters of the udder drying up, and can cause the cow to get very sick and die. 

There are two types of mastitis, sub-clinical and clinical.

With sub-clinical you will have animals getting a mild infection which can be difficult to detect and can present as mild inflammation of the udder or teat and slimy quality of milk. There may be no noticeable symptoms other than an elevated bulk SCC and it can be hard to isolate.  

Clinical mastitis is a serious infection which will present itself initially with hard or glutinous globules or clots in the milk and easily detected when stripped. The udder may be swollen and hot and she will not generally milk out fully.

With both clinical and sub-clinical you will see elevated SCC in the bulk milk testing and this indicates that the cow’s immune system is working away at something not quite right.

With clinical mastitis, a good operator will generally pick up cases as they present, but as herds and sheds get bigger and more automated it’s less likely there will always be an experienced person at cups-off where hard quarters and cows not fully milked out would be identified. In this instance the filter sock will be the first place where a problem is picked up. Sub-clinical is more likely to be picked up by a spike or gradual increase in the BSCC reading as shown on the daily docket.

In both cases the next step is to strip the herd and look for the low hanging fruit, i.e. the obvious clinical cases. Stripping can be done in stages over a couple of milkings, with back quarters stripped in the morning and front quarters in the evening. In my experience you seem to get more cases in the back quarters so start there.

If it’s sub-clinical you may need to CMT paddle test but also go back to the most recent herd test and look at any serial offenders with high cell counts. Once identified, treat as per vet recommendation.

So we know what to look for, but what is causing mastitis?

Disease causing bacteria are called pathogens. The most common mastitis pathogens are found in the udder tissues and spread from cow to cow (contagious pathogens) or in the herd’s surroundings (environmental pathogens). 

Contagious pathogens that cause mastitis tend to live on the cow’s udder and teat skin and transfer from affected cow or quarter to unaffected cow or quarter during milking. These pathogens can colonise and grow and end up in the teat canal where the infection occurs. 

Environmental mastitis pathogens are present in the environment as their name suggests. They will be affected to a greater or lesser degree by the conditions prevailing. The pathogen can enter the teat canal by force during milking, during the pre- and post-calving period and when conditions are muddy in paddocks and on tracks, yards or feed pads. 

The environmental pathogens do not possess the same ability as contagious pathogens to adhere to and colonise the teat. Therefore dry cow therapy (DCT) has little value in their control as these kinds of infections do not carry from one lactation to the next.  

Minimising the incidence of mastitis in your herd starts with a systematic approach across the season. 

Calving

• - Calve on clean pasture or a clean dry calving pad
• - Milk cows as soon as possible and check for mastitis; CMT paddle test before cows enter the herd
• - Focus on hygiene at this sensitive stage in the lactation

Lactation

• - Provide a stress-free environment for the cows; stressed cows will exhibit elevated cell counts
• - Maintain high levels of hygiene, wear gloves, be aware of splashing too much water around and potentially contaminating teats
• - Cups-on needs to be a calm and consistent routine
• - Check vacuum
• - Cups-off should be checking for obvious signs of mastitis -- teat end damage, and alert management to cup slip and monitor or execute teat spray system
• - Maintain and use correct liners  
• - Teat spray entire season
• - Herd test
• - Monitor BSCC and react by identifying and treating offenders

Drying off

• - Decide on rules for drying cows off, whole herd or partial, condition score, yield, etc.
• - What treatments will you use (Teatseal, short or long acting DCT or both Teatseal and DCT)? 
• - Who will deliver these treatments and training required?
• - What cows are to be culled based on mastitis and cell count history?
• - Maintain good records and be aware of withholding periods for early calvers. 

It has been widely flagged that blanket DCT will cease to be an option in future and this will mean either Teatseal for lower SCC cows – if any treatment is to be used – and DCT for cows above a certain threshold.   

Special care needs to be taken when administering anything into a cow’s teat canal and especially so with Teatseal. Use gloves and wipes supplied and follow the instructions set out with the product chosen.

Dry period

• - Cows are susceptible to new cases of mastitis immediately following dry-off 
• - Observe cows in the paddock for swollen quarters
• - Run cows through the shed every 14 days once you are satisfied cows are fully dry over the dry period
• - Use a lactation antibiotic on any clinical cases.
• - Mastitis is a complex issue and every situation is slightly different. There are plenty of resources available to help you get on top of a particular problem or maintain a satisfactory status.
• - Start with maintaining good animal husbandry and hygiene, teat spray all season and monitor your cow’s individual status by regularly herd testing. 
• - Train your staff well by using the resources available such as SmartSAMM  from DairyNZ and your vet and consultant.