What is Mastitis ?
Mastitis is the inflammation of the mammary gland and udder tissue, and is a major endemic disease of dairy cattle. Mastitis occurs when the udder becomes inflamed because leukocytes are released into the mammary gland in response to invasion of the teat canal, usually by bacteria. These bacteria multiply and produce toxins that cause injury to milk secreting tissue and various ducts throughout the mammary gland. Elevated leukocytes, or somatic cells, cause a reduction in milk production and alter milk composition. These changes in turn adversely affect quality and quantity of raw milk and dairy products.
Mastitis infects dairy cattle world-wide and is regarded as a serious impediment to the successful functioning of any dairy . The National Mastitis Council (USA) considers mastitis as an inflammation of the mammary gland in response to injury for the purpose of “destroying or neutralizing the infectious agents and to prepare the way for healing and return to normal function. Inflammation can be caused by many types of injury including infectious agents and their toxins, physical trauma or chemical irritants. In the dairy cow, mastitis is nearly always caused by micro-organisms, usually bacteria, that invade the udder, multiply in the milk-producing tissues, and produce toxins that are the immediate cause of injury.”
The teat end serves as the body’s first line of defence against infection. A smooth muscled sphincter, which surrounds the teat canal, functions to keep the teat canal closed, prevents milk from escaping, and prevents bacteria from entering the teat. The cells lining the teat canal produce keratin, a fibrous protein with lipid components (long chain fatty acids) that have bacteria-static properties. This keratin forms a barrier against bacteria. After milking, the sphincter muscle in the teat canal remains dilated for 1-2 hours and bacteria present during this time can enter the teat canal. Examples would be dirty housing or environment, or failure to use teat dipping properly.
Disease causing bacteria are often referred to as pathogens. The most common mastitis pathogens are found either in the udder (con- tagious pathogens) or the cow’s surroundings (environmental pathogens), such as bedding, manure, soil, etc.Read more →
Mastitis resulting from major presence of pathogens causes considerable compositional changes in milk. The types of proteins present change dramatically. Casein, the major milk protein of high nutritional quality, declines and lower quality whey proteins increase which adversely impacts dairy product quality, such as cheese yield, flavour and quality.Read more →
Mastitis treatment and control is one of the largest costs to the dairy industry and is also a significant factor in dairy cow welfare. Losses arise from reduction in yields due to illness and any permanent damage to udder tissue, Read more →
Typically when clinical mastitis is detected, the cow is milked out and then given an intra-mammary infusion of antibiotic, i.e. infused directly into the infected gland. Prior to intra-mammary infusion, the teat is cleaned well and the tip of the teat is swabbed with an alcohol swab and allowed to dry for a number of seconds.Read more →
Somatic cell count (SCC) is the number of somatic cells found in a millilitre of milk. Somatic cells (or “body” cells) are a mixture of milk-producing cells shed from the udder tissue (about 2%) and cells from the immune system (the other 98%), known as leukocytes (also called white blood cells).Read more →