Mastitis in Cows

Mastitis is an inflammatory reaction of mammary glands caused by various infectious or non-infectious etiological agents. It is characterized by a series   of physical, chemical and microbiological changes and some pathological changes in the mammary tissue and udder.  Consequently it causes increase in the number of somatic cells in the milk, changes in milk composition and reductions in milk yield. Adult lactating cows are most at risk for infections.

The infection occurs when the micro organisms gain access to the udder through the teat canal. The infections in the udder affect the quantity and quality of the secreted milk. The disease is known to cause economic losses of up to 40 % of the herd productivity.

However, mastitis is a global problem as it adversely affects animal health, quality of milk and economics of milk production and every country including developed ones suffer huge financial losses.

Mastitis can be described as;

• Clinical mastitis
• Subclinical mastitis

Clinical Mastitis

The inflammatory response to the infections of clinical mastitis is visible and the abnormal milk is readily detected.

Subclinical Mastitis

• No changes in the milk is apparent.
• No obvious clinical signs such as abnormal milk, udder swelling or tenderness, or systemic signs.
• It can only be detected by the laboratory examination of milk drawn from the udder of affected cow.

Pathogens involved

• Streptococcus agalactiae
• Streptococcus dysgalactiae
• Streptococcus uberis
• Staphylococcus epidermidis
• Staphylococcus aureus
• Enterococci
• Corynebacterium sp
• Klebsiella sp.
• Pseudomonas aeriginosa
• Brucella meletensis
• Mycoplasma sp
• Pasturella sp
• Proteus

Common causes and transmission

• Mastitis is usually caused by poor sanitation in the sheds like unclean floorings, bedding, animals and the milking surroundings. Unhygienic conditions favor multiplication of bacteria and infect the animals.
• Poor milking practice, not washing the animal’s udders before milking, not practicing the dipping of teats in antiseptic solution and incomplete milking of animals are also responsible for mastitis.
• Infection also spreads through milking machines if they are not cleaned well before use.
• Infection also spreads through milking persons if their hands are contaminated and not cleaned well with a disinfectant before milking.
• Improper milking methods like milking using thumb and pressing or pulling the teat causes a mechanical injury to the teat.
• Injuries to the udder or teats also cause mastitis.

Symptoms

• Redness and pain of udder
• Swelling of udder and teats
• Milk gets curdled becomes watery with blood streaks in some cases
• Fever, listlessness and anorexia
• Reduced milk production
• In chronic and sub clinical cases the teat canal gets thickened, when the teat is palpated it appears like a thread inserted in the teat canal.
• In subclinical cases, the milk is not affected and appears normal but the somatic cell count increases and the milk yield are decreased. If the subclinical cases are more in the farm it becomes a problem to control the disease.

Diagnosis

Based on clinical signs;

• Strip cup test to detect the curdled milk pieces
• California Mastitis Test
• Milk culture to identify the causative organism

Treatment

Intramammary infusions of antibiotic: Prior to intramammary 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. The antibiotic comes in a plastic tube with a plastic infusion cannula on the end.

• Penicillin at a dose rate of 50 - 200,000 units
• Tetracycline at a dose rate of 100 - 400 mg
• Streptomycin at a dose rate of 0.25 - 1 g
• Neomycin at a dose rate of 0.5 - 1 g
• Polymixin at a dose rate of 50 mg
• Erythromycin at a dose rate of 300 - 600 mg

How to apply antibiotic directly into the teat:

Step 1: Milk the udder until it's empty                

Step 2: Clean the end of the teat

Step 3: Put the tip of the tube into the

              teat and squeeze the antibiotic

              up into the udder  

Step 4: Massage the teat and the udder

Oxytocin treatment: 

A key contributing factor to effective milk let down. Clearly removal of the primary growth medium of the bacteria, the milk, more often should enhance rate of recovery from infection.