Mastitis

Autonomus University Of state Of Mexico

Faculty of Veterinary Medicine and Zootechny

Subject: English C1

.

Made by: Anhelo Bernabé Castillo Osorio

Teacher: Raziel

Toluca, Mexico on July 8, 2010

Introduction: Mastitis is the most common and most costly disease of dairy cattle. In
herds with out an effective mastitis control program, about 40% of the cows are infected
in anaverage of two quarters. It has been estimated that mastitis costs about $200 per
cow per year. Reduced milk production accounts for about 70% of the total loss
associated with mastitis.
Definition
Mastitis (Mast: breast, itis: inflammation) is defined as an inflammatory reaction of udder
tissue to bacterial, chemical, thermal or mechanical injury. Mastitis may be infectious
caused bymicrobial organisms or noninfectious resulting from physical injury to the
gland. The inflammatory response consists of an increase in blood proteins and white
blood cells in the mammary tissue and the milk. The purpose of the response is to destroy
the irritant, repair the damaged-tissue and return the udder to normal function.
Symptoms
Inflammation is characterized by
- Gross abnormalities inthe udder (swelling, heat, redness, pain). Persisting inflammation
leads to tissue damage and replacement of secretory tissues with of the udder with
nonproductive connective tissues.
- Change in composition (Table 1) and appearance of milk. Abnormalities in milk may
include flakes, clots or a watery appearance. The flakes in the milk are congealed
leukocytes, secretory cells and protein.
- Alower milk yield.
Table 1. Changes in milk composition associated with mastitis.
Normal milk Mastitic milk % of normal
Solid-not-fat 8.98 8.8 99
Fat 35.0 3.20 91
Lactose 4.90 4.40 90
Total protein 3.61 3.56 99
Total casein 2.8 2.30 82
Whey protein 0.8 1.30 162
Serum albumin 0.02 0.07 350
Lactoferrin 0.02 0.10 500
Immunoglobulins 0.10 0.60 600
Sodium 0.06 0.105 184
Chloride 0.09 0.147161
Potassium 0.17 0.157 91
Calcium 0.12 0.04 33
Development of the disease
Mastitis begins after bacteria pass through the teat duct and enter the cisternal area.
Invasion of the teat
usually occurs
during milking.
Organisms present in
the milk or at the teat
end enter the teat
canal and cistern
when there is
admission of
undesired air in the
milking unit. After
milking, the teatcanal remains dilated
for 1-2 hours while
the canal of a
damaged teat may
remain partially open
permanently. This
makes it easier for
organisms from the environment or those found on injured skin to enter the teat canal.
Adherence of bacteria to tissues lining cisterns and ducts may prevent flushing-out during
milking and help establish infections. Bacteria eventually enter the glandulartissues
where they affect alveolar cells. Toxins produced by bacteria cause death of or damage
to milk-secreting epithelial cells, and these cells produce substances to the blood stream
that increase blood vessel permeability. This allows leukocytes to move from the blood
into the alveolus where they function by engulfing bacteria.
Types of Mastitis
There are several ways of classifyingmastitis. A simple classification recognize mastitis
as two major groups:
A- Contagious Mastitis: Caused by bacteria live on the skin of the teat and inside the
udder. Contagious mastitis can be transmitted from one cow to another during
milking.
B- Environmental mastitis: Describes mastitis caused by organisms such as Escherichia
coli which do not normally live on the skin or in the udder butwhich enter the teat canal
when the cow comes in contact with a contaminated environment. The pathogens
normally found in feces bedding materials, and feed. Cases of environmental mastitis
rarely exceed 10% of the total mastitis cases in the herd.
Contagious mastitis can be divided into three groups:
1- Clinical mastitis
2- Sub-clinical mastitis
3- Chronic mastitis
1- Clinical mastitis...