How to prevent environmental mastitis
Presuming the outside is a cleaner environment than inside is wrong and could lead to mastitis problems in both cows and heifers, warns vet Ben Brearley, The Livestock Partnership.
“The dry period consistently throws up issues with environmental mastitis, with as many, if not more cases identified from cows kept outdoors,” he says.
Pasture Management
These patterns of infection can be linked to Strep uberis’s ability to survive in soil and pastures, with bad pasture management increasing the likelihood of new infections.
“Poor pasture rotation, where animals are kept on the same ground for extended periods, can pose an environmental mastitis risk – ideally paddocks should be grazed for two weeks and then rested for four.”
Where stock are fed at grass, feeders should also be moved regularly or semi-permanent feed areas constructed to prevent animals from lying on spilled feed. Gate management is also crucial to limit foot and leg contamination.
“When a cow lies, the lower leg sits right under the udder, so the teats are only ever as clean as the feet,” warns Mr Brearley. And this applies to both dry and milking cows.
“I regularly see an increase in new infection rates at turnout, which remain high throughout the grazing period. On many farms a lot of attention is paid to getting the housed environment right only for the hard work to be undone at grazing,” he adds.
Heifers
And although it may be easy to presume heifers are less susceptible to new infections, more and more are calving in for the first time with high somatic cell counts and either calve in with blind quarters or develop mastitis in early lactation.
“More producers are noticing how open the teat end is prior to first calving – a factor that could be a result of selecting for higher yields and faster milking cows,” Mr Brearley explains.
Bedding
Anything that creates a moist, warm environment will also provide an ideal setting for mastitis-causing bacteria, and as such, providing dry, well-ventilated housing is essential, says Mr Brearley.
Milk leakage can encourage bacterial growth, emphasising the need for good bed management. “As yields go above 9500 litres, bed management becomes increasingly difficult on twice-a-day milking, and a decision should be made over whether to move to milking three times a day.”
Soiled bedding should be removed regularly and fresh bedding provided to create adequate cushioning. Ventilation and drainage must also be sufficient to remove the large quantity of moisture produced by cattle every day.
And where no improvements to environmental mastitis rates have been made through addressing bedding material, using a drying agent such as lime or gypsum could be an option. However, to work effectively, soiled bedding must be removed first.
Loafing area
Insufficient loafing area can also result in increased environmental contamination, leading to dirtier legs and thus dirtier teats. And according to Mr Brearley, loafing space is an issue for almost all herds.
“Providing enough loafing space not only helps keep stock clean, but also takes the pressure off other areas on farm, potentially reducing overall problems.” Ideally cows should be provided with 3m2 of loafing space a head, with this measurement excluding passageways, feed area and walking areas.
Milkiing routine
Although good environmental management should aim to limit udder contamination, the pre-milking routine provides a good opportunity to remove a good proportion of the bacteria already present on the teats by disinfecting and wiping.
And to ensure open teats are not contaminated on exit from the parlour, it is crucial cows walk in a calm, controlled manner through any footbath.
Ensuring a period of standing post-milking can also be considered, however, there is a delicate balance between increased length of standing and reduced lying times.
“Increased standing times will have an impact on lameness levels, so it is important to weigh up the pros and cons.”
Take home messages:
• Pastures can create as much of an environmental mastitis risk as housing, particularly for dry cows
• Insufficient loafing area will increase the level of contamination and the chance of mastitis
• Heifers are as much at risk as cows
Case study: Parkwood Farm, East Sussex
For the farm team at Parkwood Farm, East Sussex, undertaking an independent review of mastitis influencers has helped drop the number of clinical cases from about nine cases a month to three cases a month in under a year.
As part of the DairyCo Mastitis Plan (DCMP), the environment was identified as one of the main causes of high infection rates in lactating cows, along with rolling SCC of 250,000 cells a ml – something which was pushing the farm dangerously close to losing their milk premium.
Dairy farmer, Peter Appleton, says frequency of topping up the deep bed sand cubicles was one of the main areas flagged up in the report.
“We were bedding up twice a week, but our vet, Ben Brearley suggested moving to three times a week – sand is great, but you still need to manage it and ensure beds are provided with a decent amount.”
Lighting has also been significantly improved in the cubicle shed, so muck can be easily seen and removed in the mornings.
“The report didn’t flag up anything dramatic – it was just a matter of addressing the little things and doing them better,” says Mr Appleton.
“We all know loose straw yards should be bedded up daily, but it’s simply a matter of ensuring it actually happens and moving on from the mentality of just topping up when they look dirty.”
The trailing side of one of the sheds has also been opened up to improve air flow – something which Mr Appleton views as being crucial for overall cow health.
The report also recommended relocating the water troughs in the loose calving yards so they could be accessed from the concrete feed passage, rather than bedded area. This is something which will be implanted next summer to reduce bed contamination.
The DCMP also highlighted pre milking teat preparation as an area for improvement, however, it is hoped through addressing environmental influencers it will be unnecessary to introduce pre dipping into the milking routine.
According to herdswomen, Wendy Bowsher, the 345 Holstein Friesians in milk are already presenting themselves cleaner in the parlour.
“We are seeing a lot less cases of mastitis during lactation – part of this has been a result of adjusting some cubicle neck rails so cows are not lying too far forward and mucking on the back of the beds.”
However, autumn calving flagged up a higher than desirable level of new infections post calving, something which could be linked to high infection rates in the dry period and particularly pre-calving.
We will review this area in isolation to see whether there are any environmental improvements to be made, says Mr Appleton. “Our cure rates are good, so it is more a matter of stopping cows from getting mastitis in the first place.”
“The DCMP has helped us better understand where are challenges lie – we were considering installing cluster flushing in the parlour, but the report showed cross infection was not our main issue. We were then able to direct our energies towards specific areas.”
By working with their vet, the farm team were able to take a rational approach to the causes of mastitis and measure the effects of changing parts of the farming system.