Winter's Coming! What Changes are needed for Mastitis Control?
by Winston Ingalls, Ph.D.
West Agro Inc., Kansas City, Mo.

Mastitis discussions generally indicate that mastitis problems are directly related to three inter-related factors: cows, the environment and bacteria. When some aspect of these three components gets out of line, problems are more likely to develop. Cows for example may be more susceptible to problems under periods of stress such as around calving and early lactation. Bacteria levels may increase when warm moist conditions develop and this increases exposure of the cow to potential problems. Winter conditions, in many areas of the US, bring significant environmental challenge and may be a major mastitis risk factor for extended periods. That period is now upon us.

Winter means different conditions for different areas. In much of the northern US, winter tends to mean cold and snow with occasional periods of extremely windy, cold conditions. In other regions it means cool temperatures and increased amounts of rain and lots of muddy, wet conditions. Both situations provide challenges in terms of mastitis control which managers must attempt to minimize.

Certain winter conditions may actually provide some relief for mastitis issues only to be offset by other issues that increase mastitis risks. Very cold conditions for example may slow the growth rate of environmental bacteria in cold housing areas which helps but cold may lead to teat skin problems which hurts in the battle against mastitis.

Winter Skin Problems
Winter, in areas where it gets very cold and sometimes quite dry, poses serious problems for teat skin. Skin protects the body against bacterial infection so long as it is intact. When damaged, for whatever reason, the situation changes and risk of infection quickly rises.

As cold weather sets in several different issues often arise. Two different viral conditions, Pseudocowpox and Herpes mammilitis, frequently appear as temperatures fall. Cold somehow acts as a trigger mechanism causing them to show-up on certain cows. They express themselves on teat skin tissue as sores or lesions that are often quite large and may extend down to the teat end. The net result can be very sore teated cows that are hard to milk and prone to secondary bacterial infections with Staph aureus bacteria, which have a special affinity for skin tissue, especially damaged skin.

When the lesions appear there is no available remedy that quickly reverses it and heals up the skin. Therefore, afflicted cows are likely to exhibit problems for several weeks and the problem may gradually progress through a herd over a period of weeks or months. It becomes crucial during these periods that everything possible is done to limit secondary Staph infections and promote skin healing.

These conditions require use of the best teat dip product available. That means products that have been NMC protocol tested and have demonstrated efficacy against Staph aureus. Consider using a dip with large amounts of emollient along with the germicide. The germicide kills the bacteria and the emollient helps maintain skin condition and helps repair damaged skin. Emollient in US teat dip products is primarily glycerin, which is widely used as a skin-conditioning agent.

When using iodine products consider a 1% -10% product meaning 1% available iodine and 10% glycerin. The iodine kills bacteria and the glycerin helps improve sin condition. It is common during such problems for iodine users to consider switching to some other germicide and chlorhexidine is frequently suggested. There is no evidence that the mastitis causing organisms develop resistance to iodine. The kill mechanism of iodine prevents this. Also, there is no evidence that iodine is less effective against these viruses than other germicides. Such discussions are irrelevant also because once lesions develop the problem becomes controlling secondary infections caused by bacteria, not viruses. The use of products with large amounts of glycerin helps skin repair itself and that is critical with such problems.

Sores or open lesions on the teat skin often leads to questions about using salves. It is a concern because most salves are non-germicidal. This means they are not going to control the growth of bacteria in the lesions and there are reports indicating that salves can become contaminated with viruses as hands are used to scoop product out of the containers. They then become a source of contamination and can potentially spread the problem. Salves are suitable for use on udder sores but they do not belong on the teats.

Chapped Skin
Apart from virus induced lesions it is common for teat skin to become dry, chapped and cracked during winter conditions. Cold, dry air accelerates skin loss of moisture and the result can be chapping. Windy conditions accelerate the process. As the skin dries out it may then crack which again provides an opportunity for Staph aureus and Staph species buildup. Use of teat dips capable of controlling Staph infections along with providing large amounts of emollient are necessary during this period.

Make sure the teat dip used is not a cause of skin irritation. Many dips are manufactured using aggressive components, which further accelerate the removal of natural oils from skin and aggravate teat skin condition problems. Ask your supplier and make sure that the dip you are using incorporates the mildest ingredients available and no, they are not all alike.

Handling Severe Cold
What to do when the weather becomes extremely cold? Under severe cold, exposed skin can freeze quite quickly, especially if moist. Once frozen the teat tissue dies and this can lead to serious secondary infections. Windy conditions accelerate the condition. Teat dip products should not be used and left on the skin when it is extremely cold. Two options are available. The first is to dip the teats as usual, allowing the dip to stay on for as long as possible and then just before release from the milking center blot each teat dry. Based on research evidence this is the best approach during cold weather.

Stopping dipping altogether is an option occasionally selected. The problem with this approach is that Staph aureus and other Staph species continue to grow on
un-dipped skin and soon they can become a mastitis threat.

Teat End Rings
Another observation, common during cold weather is the accelerated progression of teat end rings. These are quite common on teat ends of cows but as the weather gets cold it appears that they develop quicker and may be more pronounced than during warmer periods. The degree of ring thickness is not related to mastitis so long as there is no skin damage but the observation of these rings causes people to question the reason for their development.

Wet Winter Conditions
In regions where winter means wet, muddy conditions the challenge is the exposure of the teat end to increased concentrations of environmental bacteria which increases the risk of environmental mastitis. Procedures have to be implemented that help reduce the threat. It obviously forces more attention and time to be paid to corral area maintenance and cleanliness of teats at milking time. The requirement is that teats still have to be clean and dry at milking but extra effort has to be made to assure this. Wet cows often means increased bacteria counts and risk of more mastitis and elevated cell counts.

Sloppy wet conditions make it tougher to clean and dry teats prior to unit attachment. This is a time when consideration needs to be given to using pre-dips products with elevated levels of free iodine so that maximum bacteria kill can be exerted in a short period. The application of a fast acting pre-dip kills maximum numbers of bacteria and subsequently wiping the teats clean and dry removes teat dip residues and removes a great percentage of the moisture and bacteria that may be attached to the teat skin. Study after study has demonstrated this procedure to be effective at reducing bacteria numbers on the skin prior to milking.

Consideration should also be given to use of a barrier teat dip at this time. The barrier products tend to cling better to the teat skin and around the teat opening helping prevent bacterial entry. Select a product that can provide a flexible film and extended killing action for maximum protection. This allows extended protection for the teat under these challenging conditions.