From the NMC Newsletter "Udder Topics", June, 1999

Teat lesions can be caused by a variety of events, including trauma, chemical injury, environmental conditions, insects and the milking machine.

Traumatic lesions of the teat are most commonly the result of the cow stepping on her teats or wire cuts. They are a troublesome problem for the veterinarian as well as the dairy producer.

Histologically, the teat wall contains an abundance of elastic connective tissue which provides for expansion and contraction of the teat as it fills and evacuates milk in the lactating cow. The near constant movement associated with these physical dynamics of the teat combined with milking preparation procedures, and milk collection complicate the normal healing process.

The producer's challenge is in getting cows with teat lesions milked. Because these lesions are generally painful and cows resist preparation and milking procedures, they are difficult if not hazardous to milk.

A further complication is mastitis. Teat lesions are readily colonized by bacteria and thus serve as an important reservoir of infection. Udder preparation cloths, hands of the milker and milking machine components facilitate the transfer of infectious organisms between quarters of the same cow and can be responsible for cow to cow transmission as well. Emphasis on milking hygiene procedures becomes crucial for controlling new infections whenever teat lesions are present.

Depending on severity and the period of time prior to discovery, teat lacerations may be repaired surgically. Fresh superficial lacerations of the teat skin (within 12 hours of occurrence) in which the vascular supply has not been significantly damaged have the best prognosis. These are generally amenable to surgical closure. If, on the other hand, such lesions go unnoticed for a couple of days and become heavily contaminated, cleansing in mild disinfectant solution and removal of the skin flap tissue are likely the best therapeutic approach.

Teat lacerations which extend into the teat cistern are of greater concern and generally carry a more guarded prognosis. The exposed edges of the cistern lining must be sutured using a suture pattern that will turn the edges inward creating an impervious seal. If this is not achieved healing cannot occur and draining fistulas develop. The teat wall muscle layers and the skin may be closed separately or individually. Most advise intramammary and/or systemic therapy for 4 to 5 days as a precaution against the development of mastitis. A protective bandage allowing access to the teat end for milking is recommended. Milk should be retrieved from the gland through the use of teat cannulas.

Pastured cattle have a lower incidence of teat trauma than confined cattle. Housing factors of primary importance are associated with the amount of space available to the cow for resting and rising. Further, individual cow characteristics and conformation increase the potential for teat trauma in some cows.

Source: "Non-Infectious Lesions of the Bovine Teat", J.K. Shearer, University of Florida
http://gnv.ifas.ufl.edu/~fairsweb/text/ds/3061.html