Section 2 | Selective Dry Cow Therapy

Ontario Dairy Industry
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Defining Types of Mastitis

Important Definitions


Mastitis in cattle is an inflammation of the udder, normally caused by bacteria.


Clinical Mastitis

Clinical mastitis are those infections we can see — the milk is abnormal, and we may see signs of inflammation in the udder (redness, heat, pain, swelling) or in the cow (off-feed, down in milk, fever).


Subclinical Mastitis

Subclinical mastitis is inflammation in the udder that DOES NOT cause any change in the milk, udder, or cow — the only way we know a cow has subclinical mastitis is if we run tests. The most common tests that we run are the California mastitis test (CMT) and somatic cell count (SCC) measurements.




Internal Teat Sealants

These products are non-antimicrobial, sterile intramammary pastes containing bismuth subnitrate in an oil vehicle. Syringes containing internal teat sealants are delivered to the quarter and they fill the teat canal, acting as a physical barrier to prevent bacteria from gaining deeper access to the mammary gland. In Canada, these products go by the trade names Orbeseal®, Lockout®, and VetoSeal.