Is mastitis contagious in cattle

NO, it is NOT contagious. Mastitis is not a disease that is spread around by direct or indirect contact. It's an infection of the udder that is caused by bacteria entering the teat canal into the cavity of one or more quarters of the udder, or by injury when a full udder is bumped and bruised excessively. It cannot be spread from cow to cow like other illnesses can. Mastitis is not caused by a pathogen that spreads through contact from other cows or through other vectors like flies, airborne, or feed equipment. That is why cows with mastitis are not quarantined, because it is not necessary to quarantine them, particularly milk cows. Beef cows may need to be quarantined to have their infected quarter(s) milked out twice a day, but it is not because the illness is contagious.