In January 1998, an article by Dr. Leo Timms, extension dairy specialist, Iowa State University, was featured in Moomilk. It focused on the issue of winter teat lesions and some of his observations and recommendations. As we approach the upcoming winter season it is appropriate to re-visit that topic and highlight some of the important considerations in managing the potential problems.

Healthy Teat Skin-Mastitis Defense
Healthy teat skin is a critical component of the dairy cow's defense against mastitis but frequently it is given limited consideration. Skin condition can be directly influenced by many environmental factors but winter situations often pose the largest challenge. Certain things can be done to minimize problems and those need to be given consideration.

Skin that is healthy and free of cracks and sores etc. provides much less growth opportunity for certain mastitis causing bacteria than skin that suffers from such problems. Unfortunately winter conditions have the tendency to produce many of these problems and with them comes mastitis.

Teat Skin-Cold Weather
In areas of the country that experience severe winter cold, certain issues have to be dealt with. Severe cold can very quickly cause exposed flesh to freeze and a combination of wind and cold (wind chill factor) leads to an acceleration of this problem. This is often a concern is for humans, especially children. Alerting people to these conditions allows them to better protect themselves by covering exposed skin and limiting exposure time.

Dairy cows are subject to the same problem and frequently they experience the additional challenge of having wet teat skin as they exit into frigid conditions. This combination of wet teats, windy conditions and frigid temperatures can very quickly lead to frozen teat tissue and major problems. Frozen tissue is damaged tissue and damaged tissue is prone to many problems, including infections by bacteria that are adapted to colonizing these sites, Fox et al. (2). This especially is true for Staph aureus as well as some of the environmental Streptococci that are capable of attaching to skin tissue.

What is available to prevent this problem? Primarily understanding the potential for problems under these conditions. First, do everything possible to eliminate or minimize the direct exposure of teats to these conditions. This may be easier said than done, but it is still the best prevention. Traditionally, dairy cattle in cold climates were housed in facilities that provided shelter from wind and temperature extremes. Today, due to larger herds, costs associated with building facilities and the labor requirements, most cold weather areas are using freestall housing, where snowfall is significant, or a corral system and open lots in areas where it is dry and snowfall is limited. Such facilities perform well most of the time but under extreme conditions they may offer inadequate protection and problems may result.

During cold, windy conditions attempt to provide protection from the direct impact of the wind by providing some form of windbreak, even if it is temporary. Cows can tolerate cold, but cold coupled with windy conditions has the potential to cause serious damage quickly if cows can not gain some protection from the wind.

Consider what happens when the cows exit the milking center. Are they protected from wind or are they exposed and running the risk of frozen teats? Examine the feed bunk situation as well as the housing area. Young cows may be more vulnerable since they are often low in the herd pecking order and may be forced to locations that offer less protection than the more dominant, older cows. In the mid-west and the northern tier states during the winter months, it is common for cold fronts to move through very quickly and the temperatures can plunge to well below zero with very strong winds. This set of conditions can cause significant problems when cows are not adequately protected from these elements.

During these conditions examine carefully the teat dipping practices in view of the weather factors. Cows that are dipped are then immediately released into severe cold, can worsen the overall situation. As the moisture on the teat evaporates it accelerates cooling of skin and can hasten the freezing of tissue. It is comparable to having a rapidly evaporating fluid such as rubbing alcohol or gasoline on the skin. As it evaporates it cools the skin as it takes heat with it.

Teat dipping under such conditions needs to consider this. One way to lessen the risk is to dip the teats, allow the dip about 30 seconds of on time and then blot dry using a paper towel. Quality dips should provide much of their killing ability in the first 30 seconds of skin contact time and so the benefit of dipping is gained without increasing the risk of frozen tissue under these conditions.

During severe cold there is sometimes a tendency to want to stop dipping as a way of preventing tissue freezing. The concern with this approach is that the bacteria that grow well on skin, especially Staph aureus and Staph species, can proliferate during these periods of non-dipping and produce, in a fairly short period, an increase in infection potential as a result. Consider this approach carefully for this reason.

Teat Dips-Freezing Conditions
A practical concern during severe cold is frozen teat dips when stored in areas that have inadequate heat. Properly formulated and manufactured iodine teat dips are not damaged by freezing conditions, but if they are frozen and thawed, they may separate somewhat. They can be easily re-mixed by rolling or shaking the container, although this may be difficult with 55 gallon drums of material. The safest option is to store them in areas where there is no possibility of freezing.

Teat Chapping-Teat Dip Emollients
The combination of prolonged cold, windy conditions can create some additional problems. Cold conditions frequently are associated with low humidity and this can accelerate drying of skin as well as chapping and cracking. This condition is common during the colder winter months in certain areas and the skin problems may lead to increased mastitis. Any time skin condition is compromised it increases the risk of mastitis problems associated with bacteria that favor these sites and are adapted to growing in these locations.

Teat dips, incorporating significant amounts of emollients, primarily glycerin (5-10%), are recommended for these conditions and are helpful in minimizing these problems. The emollients help accomplish two things. They tend to reduce the loss of skin moisture and help prevent the skin from drying out and cracking. This allows skin condition to be improved and this lessens the opportunity for Staph aureus and other bacteria that tend to colonize skin sores.

Teat Skin Viruses
Temperature drops also appear to be associated with outbreaks of teat skin virus problems. Work by Farnsworth et al.(1), has described species of viruses that tend to cause teat skin lesions that may range from mild to severe. They appear to emerge and are more likely to cause problems as the ambient temperature drops and yet it is not clear why this is the case. Bovine herpes mammilitis and pseudocowpox are two viruses that can produce severe ulcerated type lesions that may be on the side of the teat but they also can extend down to the teat end. Obviously, any time tissue damage occurs near the teat end, there is an increased risk of new infections. In addition, such cows can be very sore and difficult to milk and this may lead to problems at milking time.

Presently there is no prevention for these viral outbreaks and herd immunity after infection may not be long lived. If this problem is suspected, involve the herd veterinarian promptly and attempt to determine if the teat skin problems are due to virus infections or possibly some other factor. Often these problems, especially at the outset, are thought to be related to the teat dip being used or problems with the milking system. It is important to quickly determine the nature of the lesions so that time is not wasted pursuing the wrong issue.

The standard recommendation, when these lesions occur, is to continue dipping all teats with a high quality teat dip containing emollients. The objective is to use the germicidal agent to minimize secondary bacterial infections that can develop in and around the lesions while the emollients help promote skin healing. These two recommendations in combination offer the best approach that is available presently. Unfortunately this can be a significant problem, especially during the winter months.

Teat End Rings-Cold Weather
An associated issue, during the colder periods, is the appearance of teat end rings that may range from quite mild to very pronounced, Timms et al. (4). While these may be present at all times, the colder conditions seems to make them transition from mild to more pronounced quite rapidly. So long as there are no significant skin breaks they likely will not increase the incident rate of mastitis but cold weather will make them appear more prominently. The January1998, Moomilk article by Dr. Leo Timms, Iowa State University, should be reviewed for further information on this issue.

Mastitis-Wet/Muddy Conditions
In certain areas of the country, winter may mean prolonged periods of wet, muddy conditions, which can also be a significant problem. Dirty, wet cows are at risk of increased mastitis due to the teats being coated with soils that increase the exposure of the teat ends to large numbers of environmental bacteria such as the coliforms and environmental Streptococci. Such conditions force milkers to spend extra time and effort attending to the cleanliness and dryness of the teats and teat ends.

From a milking management and mastitis control viewpoint the most critical factor is to milk a clean, dry teat. The pre-milking work routine has to focus on accomplishing this objective and there are times when doing the job effectively will take some extra time. It is critical however that the job be done properly rather than allowing the pre-milking routine to be determined primarily by the need for milking center throughput. Both are important but minimizing mastitis and working with the cow to maximize the yield of milk is likely to provide a bigger benefit than strictly moving a lot of cows through the parlor.

The practice or pre-dipping with a fast acting teat dip has been documented as helpful in reducing the number of new infections due to environmental bacteria and is a practice that should be seriously considered, Pankey et al. (3).

Winter is about to set in most parts of the US. Winter conditions frequently pose serious challenges for dairymen and cows due to some of the extremes that occur. Knowing in advance what factors can lead to problems should allow preparations to be made that can reduce the impact of these issues.

1. Burmeister J.E., L.K. Fox, J.K. Hillers and D.D. Hancock. 1998. A Comparison of Two Methods of Evaluation of Teat Skin Pathology. J. Dairy Sci. 81: 1904-1909.

2. Farnsworth, R.J. 1996. Observations on Teat Lesions. Proceedings of the Annual Meeting of the National Mastitis Council. 93-98.

3. Pankey, J.W., E.E.Wildman, P.A.Dreschler, and J.S. Hogan. 1987. Field Trial Evaluation of Premilking Teat Disinfection. J. Dairy Sci. 70: 867-872.

4. Timms, L.L., M.J. Van Der Maaten, M.E. Kehrli, Jr., and M.R. Ackermann. 1998. Histologic Features and Results of Virus Isolation Tests of Tissues Obtained From Teat Lesions That Developed in Dairy Cattle During Winter. J. American Veterinary Medical Assoc. 6: 862- 865.

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