"Mastitis Costs" By Winston Ingalls, Ph.D.

"Winter Conditions, Skin Condition and Mastitis Management" By Winston Ingalls, Ph.D.

Practical farm management information.

1. Managing dry cows for good health and greater production. 

2. How to dry treat a cow.  

3. Producing milk with low P.I. counts.  

4. Keeping your pipeline clean. 

5. Checking your bulk tank.

6. Proper identification of teat lesions.  

7. Teat end lesions: Incidence and economic importance.

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Mastitis is a costly disease but the true costs often are significantly greater than what are routinely thought of. Significant effort is expended dealing with the obvious issues but it is important to also look at the other less obvious costs.

Mastitis is typically categorized as clinical or sub-clinical. Clinical generally refers to situations where there is need to take some action to limit the problem and prevent it from getting worse. It is often detected by noting abnormal milk containing flakes, clots or possibly it is very watery. Forestripping, when done properly, is a useful tool to help detect such abnormalities.

Swelling of a quarter, "hardness", is common and suggests mastitis, as do temperature elevations. A "hot" quarter is associated with an infection and in some cases it is more pronounced than in others. A temperature rise, in response to an active infection, is a normal body reaction. An experienced milker will look for these signs and be able to spot them. In severe cases the general well being of the animal may suffer and the symptoms will be obvious.

Clinical Mastitis Costs

A true clinical case of mastitis has some very definite costs associated with it including:

1. Cost of treatment products that may be used
2. Milk that is discarded in conjunction with use of the treatment products
3. Veterinary service fees involved with treating the animal

The total amount of these costs will depend on the drugs used, the amount of time spent by the veterinarian and the volume of milk discarded. It will differ from dairy to dairy and case to case but generally it is at least three days worth of milk after the last treatment (72 hours). If the discard time is significantly longer it raises a question regarding the efficacy of the treatment and this issue should be reviewed with the servicing veterinarian.

In addition to these obvious and direct costs are the less obvious issues. How much extra labor is involved dealing with problem cows and how much additional risk is associated with possible contamination of bulk milk if someone fails to withhold the milk from an antibiotic treated cow. It only has to happen one time and the costs convert from potential to real instantly.

Mastitis Treatment Limitations

Treatment products have limitations that need to be understood. Perhaps the treatment product is ineffective against the specific bacteria causing the problem. Culture results and antibiotic sensitivity screening may be helpful in determining the most effective treatment product. Veterinarians are capable of providing this service in most instances.

Possibly the treatment is not able to get to the actual infection site in sufficient quantity to eliminate the problem. Staph aureus infections, especially those that become chronic, tend to develop scar tissue around infection sites and these can form a physical barrier, which resists antibiotic penetration. In either case the treatment results will be disappointing and may require a change to something more suitable or it may be concluded that there is no product capable of satisfactory performance and the animal may have to be culled.

Non-Antibiotic Clinical Mastitis Treatment

Depending on the situation, there may be a decision made to not use antibiotics in managing clinical cases of mastitis. This is a decision to be made jointly involving the veterinarian and the farm management staff. Certain mastitis problems are unresponsive to most antibiotic treatments and the decision may be to not use them. Generally, coliform infections are quite unresponsive to antibiotics approved for use in lactating cows and veterinarians may prefer to not administer antibiotics in such cases and instead use frequent milkouts, to help rid the body of the toxins produced by these bacteria. Oxytocin may be used to get a more complete removal of milk. Also they may use anti-inflammatory compounds and provide fluid therapy to help flush out the toxins. There appears to be a reasonable level of success with this program in cases caused by these species of bacteria. It is important however to recognize that failure to treat certain types of mastitis with antibiotics may lead to rapid spread of the problem. Each situation has to be carefully evaluated.

Managing Contagious Mastitis

In instances where a problem appears related to contagious bacteria, such as Streptococcus agalactiae and Staphylococcus aureus, the non-antibiotic approach may be less effective due to the characteristics of these bacteria. Penicillin based treatment products offer reasonable cure rates, especially in the case of Strep ag mastitis. Cows near dry off may be best handled by drying them off a bit early and using a dry cow tube in each quarter. The higher antibiotic concentration of dry cow tubes and longer time in the gland tends to provide a better opportunity for cure than treating the lactating cow.

A key point is to determine specifically what type of problem is ongoing and keep in mind there may be more than one type of bacteria at work in the herd. Contagious mastitis is best determined through culture work and the attending veterinarian is the person most capable of providing this service. Clinical cases due to the coliform type bacteria are not as easily picked up through bacteriology and observations, by the milkers and herd manager, of physical symptoms may provide the most useful information.

Sub-Clinical Mastitis Costs

Apart from the direct expenses associated with clinical cases there are a number of other costs that gradually reduce profits and frequently these are not considered. Sub-clinical mastitis is an infection that may go undetected by conventional observations. It may not cause any noticeable changes in the milk characteristics. The cow may not have any of the classic signs of mastitis. Due to this, the problem may go undetected for a period without any corrective action being taken.

Sub-clinical mastitis tends to reduce output and infected cows produce less than their full capability. Based on studies of the relationship between somatic cells/ml of milk and the loss of production, it has been determined that every time the somatic cell count doubles, starting at 200,000/ml, there is a daily loss of 1.5 pounds of milk. A cow with a SCC of 400,000 will lose twice as much production (3.0 pounds) when compared to output at 200,000/ml. Based on this understanding it is clear that sub-clinical mastitis can be a costly disease.

There are additional losses that may not always be considered but they are real. A certain percentage of cows that develop mastitis will have to be culled and this eliminates them from the genetic base of the herd. It is quite common for a good cow to have to be shipped and this means the herd genetic base is robbed of the potential. Exactly what that costs is tough to determine but it is a cost. A replacement animal will have to be purchased and it will cost money and the genetic potential may also be less.

A SCC level that is too high may result in a lost bonuses. That may be 10- 20 cents/CWT and is applied to all the milk produced by the herd. The reason for bonus payments is straightforward. High quality milk (low SCC, low bacteria count) is a better raw material for the processing industry. Milk that is processed and sold as fluid milk will taste better for a longer period when the original source is high quality raw milk. High quality milk that is processed into cheese will provide a better cheese curd and more total cheese yield than poor quality milk.

Mastitis Benchmarks

Dairymen need to establish a standard way to evaluate their mastitis situation and monitor it routinely to determine what trends may be occurring. Somatic cell data is readily available and can provide useful information in terms of spotting problems that may be occurring.

Clinical cases per month may be a helpful measure, especially in herds where the typical SCC is quite low (<200,000). There often is the observation in these herds that clinicals are the most damaging issue. Every clinical episode is costly and the impact can be significant in the short term. A sudden increase in clinicals needs to be viewed as an alarm that prompts all management programs to be questioned and changed as necessary.

Weather conditions, housing and bedding conditions, milking equipment, milking procedures, dry cow treatment and management programs, addition of recently purchased cows are some of the factors that may be involved. A general benchmark for clinicals is less than 2.0 cases per 100 milking cows per month. In a 100-cow herd that would mean no more than 2 clinical cases each month.

Another benchmark may be the discard time for milk from treated cows. The shorter the period the less loss is incurred and vice versa. Ideally a treatment should work quickly and leave no detectable residues in milk. A reasonable number is less than 4 days. Every milking that is dumped is money down the drain. It is partly for this reason that non-antibiotic approaches to treating mastitis problems have appeal.

The amount of milk loss (dollars/cow/year) is another measure that may be tracked over time. A reasonable goal is to discard less than $10 worth of milk/cow annually. This requires some record keeping but provides an indication of the economic losses that may be ongoing. It may also permit economic assessment of control programs. Expenditure in a program may not be justified if the current losses are very low while on the other hand if the losses or potential losses are high a program may be justifiable if the costs are reasonable.

The key is to maintain sufficient records to be able to determine whether or not mastitis control objectives are being met or not. Goals can and should be established for the appropriate indicators. Attempt to establish goals that are most meaningful to the dairy and are easily understood by all involved. Routine comparison of the actual results to the goals will provide a method of minimizing huge problems from occurring because corrective action can be taken as needed. Review these with the servicing veterinarian so that they can have input and also they can monitor the trends over time.

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 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, Burmeister et al. (1). 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 cannot 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 Midwest 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 and 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. (2), 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 January 1998, MooMilk.com 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.

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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These management decisions include areas such as nutrition, parasite control, vaccinations and housing, as well as a dry cow udder health program that includes Stronghold™ Teat Sealant. 

In addition, Dr. Austin Belschner, technical services program manager for Pharmacia & Upjohn, offers the following suggestions on how to best manage the health and nutrition of dairy cows during the dry period. 

Mastitis Control Management Tips:  

• Bring down production as quickly as possible at dry off. 
• Dry treat every quarter of every cow with antibiotic tubes such as Quartermaster^® or Albadry Plus^®. 
• Incorporate good sanitation practices when dry treating. 
• Administer J-5 Bacterin at dry off, 30 days later and at calving. 
• Keep the environment clean and dry. 
• Monitor SCC scores at dry off and again at freshening to measure mastitis control effectiveness. 
• Administer lactating-cow antibiotic tubes such as Pharmacia & Upjohn's Pirsue^® or Albacillin^® to infected quarters. 

Nutrition Management Tips:  

• Separate dry from lactating cows, then divide dry cow groups according to an early dry group and a close-up group. 
• Incorporate body condition scoring into nutritional management. 
• Provide an adequate supply of fresh, clean water to dry cows. 
• Feed a low-energy, high-fiber ration to early dry cows.
• Adjust the ration to accommodate added nutritional demands of close-up dry cows. 
• Consult a veterinarian or nutritionist for help with dry cow rations. 

Preventive Health Management Tips:  

• Keep dry-cow housing clean and dry. 
• Provide a sanitizing footbath for all cows. 
• Administer routine vaccinations and parasite control treatment during the dry period. 
• Follow all label directions on medications and health care products. 

Calving Management Tips:  

• Maintain a sanitary environment. 
• Avoid excessive build-up of bedding material, especially if wet. 
• Separate cows close to calving from other cows. 
• Clip udder hair prior to calving. 
• Apply Stronghold Teat Sealant 10 days prior to calving. Re-apply as needed until calving. 
• Ensure adequate high quality colostrum intake of newborn calves. 
• Use properly functioning milking equipment on fresh cows. 
• Do not sell milk from fresh cows until 72 to 96 hours post-freshening.

  
   

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A) Wipe each teat and teat end with a separate alcohol pad. 

B) Treat each teat with dry cow antibiotic. Again, wipe each teat end with separate alcohol pad. Allow teats to dry completely.

C) Fill Stronghold product applicator cup to directed level. 

D) For maximum adherence, apply Stronghold to the entire length of teat. Allow to dry completely before releasing cow. 

E) Immediately dispose of unused product and applicator cup after each use. 

F) Vaccinate with J-5 Bacterin according to manufacturer's recommendations. 

G) Move cows to a clean, dry environment. Feed dry cows according to their nutritional needs.

H) 10 days prior to calving, wipe each teat and teat end with separate alcohol pad. Allow teats to dry completely. Apply Stronghold. Reapply if needed before calving. 

I) Freshen cows in a clean, dry environment. Remove any remaining Stronghold film at calving. 

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Before Milking  

• Clip hair from cow's udder and flanks and keep them clean. 
• Clean teats only. (Do not wash the udder unless you intend to thoroughly dry it. If you don't dry the udder, the water will run down the teat into the inflation, carrying with it loads of bacteria.) 
• Thoroughly dry teats with a clean single-service paper towel or properly cleaned cloth towels. 
• Forestrip using a strip cup to check each quarter for abnormal milk. Do not squirt the milk on the floor. This promotes rapid bacteria growth, which can contaminate the milk through improper handling or operation of the milking cluster. 
• Pre-dip or spray the entire teat to the base of the udder using a proven pre-dip. A proven pre-dip is one that has been University tested and is labeled for pre-dipping. 

After Milking  

• Immediately after removing the inflations, dip each teat as far as possible in a teat dip cup containing an approved teat dip. An approved teat dip is one that has been University tested using the National Mastitis Council Experimental Challenge or Naturally Occurring protocol guidelines.

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The Procedure  

• Rinse thoroughly all milk contact surfaces with warm water (100°F - 110°F) to remove milk residues. Do not use hot water to rinse the pipeline. Hot water will set the protein making the pipeline more difficult to clean. Drain water. Do not re-use it for wash water. 
• Wash all milk contact surfaces manually and/or automatically with a good chlorinated alkaline cleaner. The beginning temperature of the C.I.P. solution should be 165°F and should not drop below 120°F during the wash cycle. Drain. 
• Rinse all milk contact surfaces with an acidified rinse to prevent mineral films. Acidified rinse solution must be a 3.0 pH to be effective. Drain.

  OR
  Rinse all milk contact surfaces with an EPA-registered acid sanitizer to prevent mineral film build-up and perform the sanitizing rinse at the same time. Acidified rinse should be pH 3.0 to be effective. Drain. Do not perform additional rinse. 

• Sanitize all milk contact surfaces with an approved sanitizer immediately before milking. Drain. Check inflations daily. Replace cracked or rough inflations. Replace all inflations every 1,000 - 1,200 milkings.

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An effective method of determining the presence of a "milk protein film" is to squeegee an area about one square foot, to remove moisture. Then direct a 150 watt flood lamp on the surface about 12" - 18" from the tank. The heat from the flood lamp will dry the protein film and cause it to turn grayish so it can be seen with the naked eye. 

These films provide ideal places for psychrotrophs (cold-loving organisms) to hide, even when the tank is empty. They have everything they need to grow--food, moisture and temperature. 

Hot water (165°F) and a good chlorinated alkaline C.I.P. cleaner are musts for spray cleaning bulk tanks. The following four-step cleaning procedure will produce sparkling film-free tanks, provided the procedure is followed every time the tank is emptied. 

Bulk Tank Cleaning Procedures  

• Rinse the tank thoroughly immediately after the tank is empty with warm (100 - 110°F) water to remove milk residue. (Do not use hot water to rinse the tank. Hot water will set the protein and make the tank more difficult to clean.) Drain--do not re-use for wash. 
• Wash all milk contact surfaces manually and/or automatically with a good chlorinated cleaner. Pay particular attention to the valve, lid and agitator cover. The beginning temperature of the C.I.P. solution should be 165°F and should not drop below 120°F during the wash cycle. Drain. 
• Rinse tank thoroughly with an acid rinse to prevent mineral deposits.

  OR
  Rinse all milk contact surfaces with an EPA-registered acid sanitizer to prevent mineral film build-up and perform the sanitizing rinse at the same time. Acidified rinse should be pH 3.0 to be effective. Drain. Do not perform additional rinse.  

• Sanitize just prior to reuse with an approved sanitizer. The sanitizing solution should be circulated through the tank for two minutes. Acidified rinse should be a pH 3.0 to be effective. Drain.

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Upon seeing an "epidemic" of teat lesions in the herd, dairymen usually first suspect or blame the milking equipment. 

Next, many suspect or blame the particular teat dip or udder wash product they are using as responsible for teat lesion problems. However, rarely is this a correct conclusion if the product is being used as recommended. 

With a serious teat lesion problem in the herd, typically it falls to the herd veterinarian to accurately diagnose the cause of teat lesions and provide professional advice. 

First, lesions which cause pain or discomfort to the cow make the cow hard to milk and may result in interference with milk letdown. And the lesions may block the flow of milk from the gland. Incomplete milking can result in subclinical mastitis infections progressing to clinical mastitis. 

Second, teat lesions can result in removal of healthy skin, or epithelium, which serves as a barrier to bacteria. The chance for bacteria to enter the teat canal is increased if the lesions occur on the teat end, or if improper management techniques allow colonized bacteria to travel to the teat end--failure to dry teats and udder prior to milking, liner slippage, etc. 

Teat lesions are a commonplace, frequent problem in day to day dairy management. Almost every dairy farmer has an occasional problem with teat lesions caused by trauma, or injury to the teat. This type of teat lesion problem normally is limited to one or two animals in the herd at any one time. But in addition to these occasional teat lesions, a more severe problem can develop where much of the herd exhibits lesions resulting from viral infections, for example. 

Teat lesion research has revealed that certain teat lesions are highly significant in terms of mastitis and milk production whereas other teat lesions have not proven to be economically important. 

Experience has shown that it is not uncommon for a dairyman to conclude his herd has a serious teat lesion problem when in fact it does not. This emphasizes the importance of correct identification or diagnosis of the type of teat lesions that have developed. 

In professional circles and research literature it is generally agreed that there are five distinct types of bovine teat lesions, as follows: 

1. Traumatic
2. Infectious 
3. Chemical
4. Environmental 
5. Teat end or orifice 

Traumatic lesions are typical injury lesions such as can result from a cow stepping on her teats or from wire cuts. 

Infectious lesions result from viral agents such as pseudocowpox or bovine herpes mammillitis or DN-599, to cite the three most common causes. 

Chemical lesions (burn) can result from harsh teat dip irritation or the improper use of concentrated sanitizing solutions as a teat dip. 

Environmental teat lesions can result from exposure of teats to the elements with resultant freezing, chapping, sunburn, windburn, etc. 

Teat End or Orifice are also called eversions or erosions. They are a proliferative band or ring of tissue surrounding the teat orifice. An acute form is seen where there is an actual loss of skin or epithelium which in turn results in a scab over the teat orifice. 

Perspective on the incidence of various types of teat lesions is provided by a special study at the University of Minnesota. In the study, 27 dairy herds were referred to researchers by veterinary practices in Minnesota, Wisconsin and Kentucky. Approximately 50 veterinary practices were asked to notify the University when they encountered herds with teat lesion problems. (Only herds were referred where the milking equipment had already been checked by local equipment dealers to assure the lesions were not due to equipment malfunction.) The research was conducted by Dr. R.J. Farnsworth and Dr. R.L. Sieber. Results of the special 27-herd study are summarized as follows, according to type of teat lesions experienced. 

Environmental Lesions 
Three of the 27 herds which were reported had lesions which could be attributed to environmental causes, specifically typical freeze lesions...discoloration and peeling of skin from sides and ends of teats, leaving a raw denuded area; a slight reddening of the teat end with serum extravasation and loss of epithelium in the proximity of the teat orifice. Possible cause was the cow being sent outside immediately after milking with a drop of milk or teat dip hanging on the teat end, which then froze. 

Chemical Lesions–Teat Dip Suspected 
Five of the herds reported as having a teat lesion problem were suspected of reacting to the iodophor teat dip being used. This actually was not a correct diagnosis. The lesions seen in these herds appeared as dry, roughened proliferative bands of tissue around the teat orifice that were frequently mistaken for scabbing. The bands of tissue were usually dark brown or black. Microscopic examination of the proliferative material from the teat orifice showed that this material was not a true crust or scab but rather a callous-like buildup of epithelium typical of rough teat end lesions with the material stained by the iodine in the teat dip. This condition was usually associated with the use of low cost iodophor teat dips that were apparently lacking in skin softening or moisturizing agents. 

In one problem herd it was determined that there were true black scab-like proliferations over the teat orifice. Further examination of the iodophor teat dip being used showed that the product actually was a concentrated iodophor udder wash being wrongly used as a teat dip. It had a pH of 2.9 and an iodine concentration of 1.9%. 

Viral Lesions 
In nine of the reported problem herds, viral lesions were apparent. There were lesions on the udder as well as on the teats.

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Extensive research on teat end lesions by Dr. R.L.Sieber and Dr. R.J. Farnsworth has shown that teat end lesions or rings are commonplace in dairy herds. And while they are more prevalent in herds which are machine milked, teat end lesions can be found on cows that have never been machine milked, on cows that have been milked by hand and even on beef cows. 

A special study was conducted involving 22 dairy herds. Importantly, these were no-problem herds (herds not having a particular problem with teat lesions.) The study focused on the prevalence of teat end lesions related to milking equipment, milking procedures, genetically inherited factors and the effects of lactation. Also, the relationship of the presence of teat end lesions to intrammary infection and mastitis was examined. 

Chronic ring teat end lesions are proliferative bands of tissue around the teat orifice. In this described study, the teat and teat end lesions were classified as follows: 

1. Normal--a teat with a smooth, non-raised and well-closed orfice.
2. Smooth Chronic Ring--the appearance of a smooth, raised ring of tissue around the teat orifice. This lesion may be further classified as very mild, mild, moderate or severe. 
3. Rough Chronic Ring--a rough proliferative appearance to the raised ring of tissue around the teat orifice. This lesion may be further classified as very mild, mild, moderate or severe. 
4. Acute--an ulcerative or hemorrhagic appearance to the teat orifice. A scab may be present around the teat orifice. 

(In the study there were a number of teats that were unclassified from photographs because of disfiguration due to injury, warts, milk leakage, dirt, etc. This affects number of teats included in the study and numbers not totalling 100%.) 

In this particular study, 1,213 animals were included--1,055 were lactating cows; 126 were dry cows; and 32 were springing heifers. Of the 22 herds, 20 were Holsteins and 2 were Guernseys. 

The 1,213 animals studied resulted in the classification of 4,824 teats on the basis of observed teat end lesions. These were the results: 

• Only 762 or 15.8% of the teats were normal. 
• 3,044 or 63% of the teats exhibited smooth chronic rings. 
• 667 or 13.9% exhibited rough chronic rings. 
• Only 16 of the 4,824 teats, or 0.3% exhibited lesions with scabs or loss of epithelium around the orifice (not trauma related), and were classified as acute teat lesions.

In brief, the research study revealed the following important points relating to teat end rings or lesions. 

• The prevalence of teat end rings varied between herds and within the cow. Only 15.3% of the animals had the same teat end classification for all four teats. There was a tendency for front quarters to have more severe forms of lesions than the rear quarters. 
• The prevalence and severity of teat end rings increased as the length of milking time increased. Milking on a dry teat is a factor, whether it is milking on an improperly stimulated teat or overmilking the cow (front quarters are more likely to be overmilked.) 
• There was a definite relationship between teat end rings and the volume of milk passing through the teat orifice. Heavy producers are more likely to have teat end rings. 
• The shape of the teat end appeared to be related to the prevalence of teat end rings. Only 10.7% of the teats with flat ends were "normal" whereas almost half...49.1%...of the conical shaped teat ends were normal. 
• There were significant differences between sires and breeds, in relation to the prevalence of teat end rings. Only 15% of the Holstein teats were normal compared to 33.5% of the Guernsey teats. A study of sires indicated a genetic link to teat end lesions. 

Summarized, this research study emphasizes these important points: 

• Relative to milking equipment, no relationship was seen between the level of severity or the prevalence of chronic teat end rings with vacuum level, vacuum reserve per unit, pulsation rate, pulsation ratio, milk rest ratio or length of liner usage.
• Milking procedures were shown to have a marked effect on the prevalence of teat end rings. Dairy farmers who spend more time stimulating the udder have better teat end condition. Milking on the teat prior to complete milk letdown and over milking (milking on a dry teat) increases the prevalence and severity of chronic ring lesions. 
• Based on milk samples from 3,982 quarters, the test showed a non-significant relationship between teat end rings and infected and uninfected quarters. This leads to the conclusion that chronic teat end ring lesions are economically unimportant...not related to the incidence of intramammary infection (mastitis) except under certain conditions. 

It is important to note that teat end rings appear histologically (microscopically) as a callus. The acute lesions with breaks in epithelium (plus traumatically injured teats, and milk dripping from teats which indicates an open sphincter) did show, in this special study, an increase in infection rates. 

On examining teats for lesions, it is important to identify correctly the lesion involved. When the diagnosis is chronic ring teat end or orifice lesions, then a careful differentiation must be made between acute type lesions with epithelium breaks and scabs versus the rough form of chronic rings where there is considerable sloughing of keratin. This can be stained brown, by a teat dip for example, and confused with a true crust or scab of acute lesions. 

From the professional veterinary standpoint, it is important to note that among all classifications of chronic ring teat end lesions, it is only the "acute" teat end lesion that has significance. This ulcerative or hemorrhagic teat end lesion, involving broken epithelium and scabs, compromises a healthy teat's barrier to bacterial colonization. Intramammary infection and mastitis can result. Less than 1% of 4,824 teats in this study with chronic teat end lesions were classified as acute, and therefore presenting an increased risk of intramammary infection and mastitis.

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