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Canadian Bovine Mastitis Research Network

Mastitis Dictionary

Acute mastitis: Udder inflammation characterized by sudden onset, redness, swelling, hardness, pain, grossly abnormal milk, and reduced milk yield.
Alpha toxin: A poison produced by Staphylococcus aureus that causes blood vessal constriction and blood clotting.
Alveolus: Microscopic, spherical milk-producing unit of the udder composed of epithelial cells.
Anaerobic (bacteria): Bacteria that grow in the absence of oxygen.
Antibodies: Proteins synthesized by organs of the cows' immune system that aid in the elimination of foreign substances such as microorganisms.
Backflushing: An automated system for sanitizing teat cup liners between cows.
Bacteremia: Presence of bacteria in the blood stream.
Casein: The major protein found in milk.
Chronic mastitis: Udder inflammation that continues over a long period of time, with progressive development of scar tissue and simultaneous reduction in milk yield.
Clinical mastitis: Udder inflammation characterized by visible abnormalities in the udder or milk.
Cluster: The milking unit assembly containing teat cup shells and liners, short milk and pulsation tubes, claw, and long milk and pulsation tubes.
Coliform(s): Rod-shaped bacteria originating from the intestinal tract.
Complement: An antibacterial protein found in milk that inhibits bacterial growth.
Contagious (microorganisms): Bacteria growing in the udder that are spread from cow to cow by hands, milking machine, etc.
Corticosteroid: An anti-inflammatory hormone.
Cytokine: A protein produced by leukocytes, which regulates the antibacterial activity of other leukocytes.
Droplet impact: Microscopic droplets of milk, possibly containing microorganisms, that impact against the teat orifice near the end of milking, which may initiate a new udder infection.
Edema (of the udder): Swelling of the udder or teats caused by the accumulation of fluid below the skin.
Endotoxin: A poison produced by Escherichia coli that causes systemic response (fever, diarrhea, appetite loss) to coliform mastitis in cows.
Enterococci: Gram-positive, catalase-negative cocci.
Enterotoxin: A poison produced by Staphylococcus aureus that causes illness when ingested by humans.
Environmental (microorganisms): Bacteria growing in the cows' environment that contact the udder and teats causing infection.
Epidemiology: A study of the relationships of various factors determining the incidence and prevalence of mastitis in a herd.
Epithelial cells: Cells in the udder comprising an alveolus that synthesize and secrete milk.
Fibrosis: The replacement of infected tissue areas with fibrous connective or scar tissue.
Foremilk: The first streams of milk stripped from the udder prior to milking.
Forestrip: Process by which the first few streams of the milk are expressed from the teat prior to milking to observe for abnormalities and to flush the teat canal.
Immunoglobulin: See Antibodies.
Incidence (of mastitis): Rate at which mastitis cases occur.
Infection: The presence of microorganisms growing in the udder.
Inflammation: A condition in which the cow's body seeks to eliminate or neutralize invading microorganisms and repair damaged tissue.
Involution: The process by which udder tissue reverts to a non-milk-producing state after drying off.
Keratin: A waxy substance produced by cells lining the teat canal that serves as a plug between milkings and aids in reducing penetration by microorganisms.
Lactoferrrin: An antibacterial protein found in milk that inhibits bacterial growth.
Lactoperoxidase/thiocyanate/hydrogen peroxide system: An enzyme complex in milk that inhibits bacterial growth.
Lactose: The sugar present in milk.
Let-down: A process through which milk is squeezed out of milk-producing tissue by the action of the hormone, oxytocin.
Leukocyte: White blood cell.
Leukotriene: Arachidonic acid metabolites having potent pharmacological effects.
Liner slip: Condition whereby the teat cups slide down the surface of the teat, often accompanied by a squawk, caused by improper liner design, cluster weight, vacuum fluctuations, and milking wet teats.
Lipase: An enzyme that breaks down butterfat, leading to rancidity of milk.
Lymphocyte: A type of white blood cell involved in udder immunity.
Macrophage: A type of white blood cell that engulfs and destroys microorganisms in milk.
Major histocompatibility complex: A genetic region of chromosomes responsible for the production of products that function in cell to cell communication.
Mastitis: Inflammation of the udder, most commonly caused by infecting microorganisms.
Microorganism: Small, one-celled or multicellular organisms that can only be viewed with a microscope.
Milking unit: An assembly consisting of shells, inflation, claw, air and milk tubes, and pulsator.
Milking vacuum: The vacuum to which the teat of the cow is exposed when the inflation is open.
Milk tube or milk hose: The tube that conveys milk from the claw or reservoir to a pipeline or bucket.
Milk-producing tissue: The glandular part of the udder that produces milk.
Mycobacteria: Slender, acid-fast microorganisms resembling the bacilli that cause tuberculosis.
Mycoplasma: Microorganisms those are intermediate in size between bacteria and viruses.
Nonbacterial mastitis: A form of mammary inflammation in which no microorganisms can be isolated from milk samples.
Neutrophil: A type of white blood cell that engulfs and destroys microorganisms in milk.
Opsonins: Antibodies that function by preparing microorganisms for engulfment by white blood cells.
Oxytocin: The hormone that causes milk let-down.
Pathogen: Any microorganism that causes disease.
Peracute mastitis: A form of udder inflammation with systemic involvement that includes depression, rapid pulse, dehydration, and diarrhea.
Phagocytosis: The process by which white blood cells engulf microorganisms.
Plasmin: An enzyme that breaks down fibrin clots as well as milk casein.
Polymorphonuclear neutrophilic leukocyte: A type of white blood cell that engulfs and kills bacteria.
Prevalence (of mastitis): The percent of cows or mammary gland quarters that are infected at any one time.
Pseudomonas: Gram-negative, catalase-positive, motile, rod-shaped microorganisms.
Pseudopodia: Finger-like projections of leukocytes, which aid in the engulfment of bacteria.
Pulsation ratio: The amount of time a pulsator creates vacuum to open the liner compared with the amount of time it admits air to collapse the liner.
Pulsation rate: Number of pulsation cycles per minute.
Pulsator: A device that varies the vacuum (pressure) between the liner and shell, thus opening and closing the liner to provide milk and massage to the teat.
Serum albumin: A blood protein that leaks into the mammary gland when inflamed.
Scar tissue: Fibrous tissue accumulating in the udder after infection that permanently replaces milk-producing tissue and prevents drugs from reaching sites of infection.
Somatic cells: Includes mainly white blood cells that move into the udder during inflammation and a small percentage of epithelial cells from milk producing tissues.
Spontaneous recovery: The ability of a cow to cure herself of an udder infection without the aid of antibiotics or other drugs.
Staphylococci: Spherical bacteria that grown in grape-like clusters.
Stray voltage: Small electrical currents on milking equipment originating on or off the farm, which may elicit a response from cows.
Streptococci: Spherical bacteria that grow in chains.
Strippings: That portion of milk left in the udder after machine detachment.
Subacute clinical mastitis: A form of udder inflammation that is mildly clinical where symptoms include clots or flakes in milk.
Subclinical mastitis: The most prevalent form of udder inflammation. It cannot be detected visually but causes the greatest economic loss.
Summer mastitis: A form of mastitis characterized by thick, foul-smelling secretion (pus) usually caused by Actinomyces pyogenes and Peptococcus indolicus.
Teat canal: Passageway through which milk flows from the udder. It is surrounded by a muscle sphincter that maintains tight closure between milkings.
Toxemia: A condition caused by toxins or poisons that enter the bloodstream and cause illness.
Toxin: A poison produced by microorganisms that kills cells.
Transferrin: A blood protein that transports iron into the mammary gland.
Vacuum pulsator line: The pipe or line that supplies vacuum to the pulsator(s).
Vacuum pump: A pump that removes air from the milking system to develop partial vacuum.
Walling-off: A condition in which microorganisms in the udder become enclosed (walled off) by scar tissue and are inaccessible to drugs.
Wet milking: The milking of teats that have not been thoroughly dried.
From: "Current Concepts of Bovine Mastitis", NMC, 1996. www.nmconline.org

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