Traumatic and Structural Disorders of the Udder
Superficial wounds to the udder and teats may be cleaned with suitable antiseptic solutions and treated as open wounds with frequent application of antiseptic powders or sprays. If the teats are involved, adhesive tape may hasten healing. Wounds involving the teat orifice should be dressed with antiseptic creams and bandaged after milking. Affected quarters are at very high risk of infection, and prophylactic treatment with intramammary antibiotics is recommended to prevent development of mastitis.
Lacerations of the large milk vein should be considered an emergency because of the potential for severe hemorrhage; prompt compression and ligation of these lacerations is recommended.
Deeper wounds of the udder and teats should be promptly (within 6 hr) cleansed and sutured or stapled under local anesthesia with appropriate sedation and restraint. When the wound involves the teat cistern, it may be necessary to insert a self-retaining teat cannula with removable cap into the teat for the first 24 hr to prevent milk seeping through the wound (which would delay or prevent healing) and to aid in milking. The affected quarter should be infused with antibiotic preparations.
Acquired teat obstructions are usually the result of proliferation of granulation tissue after the occurrence of an observed or unobserved teat injury. Teat obstructions are usually recognized when they interfere with milk flow. They can range from diffuse, tightly adherent lesions to highly mobile discrete lesions that float throughout the gland cistern. Some “floaters” are caused by formation of small masses from butterfat, minerals, and tissue in mammary ducts during the dry period. These can be recognized by intermittent disruptions in milk flow. They may be removed by forced pressure downward on the teat cistern or by use of specialized instruments inserted through the teat canal. Membranous obstructions in the area of the annular fold at the base of the gland cistern are sometimes seen in heifers. Treatment of these obstructions is generally unsuccessful.
Complete teat obstruction may result when adhesions fill the teat cistern after severe trauma. Treatment is similar to that for stenosis (see below), but the prognosis usually is more guarded. In instances of severe injury, milking of the quarter should be permanently discontinued.
Teat stenosis is characterized by a marked narrowing of the teat orifice or streak canal, which makes milking difficult. It usually results from a contusion or wound that produces swelling or formation of a blood clot or scab or from mastitis infections (especially in prelactating heifers). Teat obstructions can be diagnosed initially by careful palpation of the affected gland. Complex teat obstructions or obstructions in valuable animals may require diagnostic imaging such as ultrasonography, contrast radiography, or theloscopy (endoscopy).
Treatment varies depending on severity. Conservative treatment includes the use of teat cannulas and external pressure to remove obstructions, whereas serious cases may require prompt referral to specialists for thelotomy or theloscopy (endoscopic surgery). All injuries to, or surgical procedures on, the teat should be handled carefully to prevent infection. Prophylactic antibiotic infusions of the quarter are indicated when the teat or teat orifice is involved. Permanent fistulas into the teat or gland cisterns are best repaired during the dry period.
Rupture of the suspensory ligaments of the udder (usually the medial suspensory ligament) occurs gradually in some older cows and leads to a dropping of the udder floor, resulting in lateral deviation of the teats. Occasionally, acute rupture can occur at or just after parturition. Animals with this condition are at high risk of developing mastitis. There is no successful treatment; supportive trusses generally are not satisfactory. The condition is suspected to have a genetic basis, and these animals are often removed from the milking herd.
Trauma (often related to inadequate housing) can result in contusions and hematomas of the udder. Hematomas usually appear as soft-tissue swellings located anterior to the foreudder or caudodorsal to the rear udder. They may be difficult to differentiate from abscesses. Severe hematomas can result in anemia if not treated. In most instances, hematomas resolve after conservative treatment consisting of pressure wraps and rest. Hematomas should not be incised or drained unless they become infected. Milking should be performed cautiously during the convalescent period. Hematomas that continue to enlarge should be considered an emergency because of the possibility of excessive blood loss and shock.
Subcutaneous abscesses of the udder (not involving the milk-producing tissue) can develop between the skin and the supporting connective tissue of the udder. Diagnosis is by needle aspiration. Abscesses usually develop secondary to wounds, chronic mastitis, infected hematomas, or severe contusions. They should be incised and drained when chronic and near the surface of the udder. The wound should be flushed daily with an antiseptic solution or water under pressure until healing is complete.
The occurrence of pink- or red-tinged milk is common after calving and can be attributed to rupture of tiny mammary blood vessels. Udder swelling from edema or trauma is a potential underlying cause. Bloody milk is not fit for consumption. In most cases, it resolves without treatment in 4–14 days, provided the gland is milked out regularly. The occurrence of frank blood in a single quarter is likely the result of severe, acute mastitis (see Mastitis in Large Animals) or trauma, and milking should be discontinued until hemorrhage is controlled. Intramammary antibiotics should be administered if mastitis is suspected.
High levels of intramammary pressure in high-producing dairy cows may result in milk dripping from teats. Risk factors for milk leakage include high peak milk flow rates, short teats, and inverted teat ends. Shorter intervals or more frequent milking may be recommended when a large proportion of the herd is affected. Occasionally, cows are observed to leak milk continuously. These cows usually have sustained a severe teat injury or have an abnormal streak canal. In general, little can be done to correct this condition, and most of these cows will develop mastitis; it is recommended that persistent leakers be designated for removal from the herd.