How to perfectly Diagnose, treat, and control mastitis in dairy cows?
Dr.provet has addressed the causes and the clinical signs of mastitis in dairy cows through the previous article and decided to continue to address the diagnosis, treatment, and control of the same disease through this article which includes:
- Diagnosis of mastitis in dairy cows.
- Case history and clinical signs.
- Field examination.
- Laboratory diagnosis.
- Differential diagnosis.
- Treatment of mastitis in dairy cows
- Causes of Failure of mastitis treatment, how to overcome them?
- Prevention and Control of mastitis in dairy cows.
Diagnosis of mastitis in dairy cows
The perfect diagnosis of mastitis in dairy cows involves many important steps, including:
Case history and Clinical signs
The clinical signs of mastitis in dairy cows are obvious, and the cow should be examined for:
Inspection of the udder by visual examination.
Digital palpation of the udder for detection of udder abnormalities such as swelling, induration, pain, abnormal size, atrophy, abscessation, and enlargement of the supramammary lymph nodes.
Clinical examination of the animal to determine if mastitis is associated with systemic reaction or not.
Field examination:
Field tests are carried out for detection of milk changes:
Strip cup test:
It is done by stripping a few streams of milk from each quarter into a cup for visual detection of flakes, clots, pus, blood, and watery milk.
Electrical conductivity test:
It is based on the detection of the increased Sodium and Chloride ions of mastitic milk, which consequently increases the electrical conductivity.
PH indicator paper or PH meter:
Normal milk has a PH 6.4-6.8 while mastitic milk has a 6.7 up to 7.4 by pH meter
Determination of the cell count
It can be applied through:
1. Direct method:
Direct counting of leukocytes of milk smear or Electronic cell counter, is used for estimation of the number of cells.
A count of more than 400,000 cells per ml milk indicate mastitis
2. Indirect method:
Gel test
California mastitis test (CMT):
This test is carried out by mixing equal quantities of milk samples and California reagent in a white plastic paddle.
These tests determine the number of leukocytes.
They can't be used in cows 7-10 days after calving due to the increased leukocytic count.
There is a high degree of correlation between CMT and leukocyte content.
Strong gel formation indicates the milk contains leukocytes of more than 5 million/ml.
NAGase test:
The test measures the cell-associated enzyme N. acetyl B.D glucosaminidase in milk. The high level of this enzyme indicates a high cell count
Chlorine test:
Mastitic milk contains more than 0.14% chloride
Laboratory diagnosis
Samples:
Milk samples are collected after washing the udder with warm water and soap and swabbing the teats with 70% alcohol.
The first two streams should be discarded and 25 ml from each quarter must be collected.
Milk of the last streams should be collected when tuberculosis is suspected.
Direct microscopic examination of milk:
Smears prepared from fresh milk or milk sediment or milk incubated at 37 C for 12 days. Milk smears are stained with methylene blue, Newman's stain, or Ziehl-Neelsen stain. A count of more than 4×105 cells/ml in bulk samples indicates mastitis.
Isolation and identification of the causative agents using:
blood agar for all microorganisms, Macc. for G-ve bacteria, Subarude agar for fungal isolation, and Dorset egg for T.B.
Differential diagnosis
Mastitis in dairy cows should be differentiated from:
physiological udder edema
The udder becomes swollen precalying: edema may extend along the abdomen, front of the odder The condition is due to:
Circulation interference by the gravid uterus.
Passage of beta and gamma globulins from blood to the mammary glands.
Hereditary factors.
Such condition usually disappears within 2.3 days It responds rapidly to injection of diuretics
Bloody milk:
It occurs in high-producing animals after calving, such a condition disappears spontaneously. It responds rapidly to calcium therapy and vitamin K.
In leptospiral infections, bloody milk with flaccid udder without udder inflammation.
It occurs in Staph. Aureus infection.
Actinomycosis:
Hard, painless masses in the udder are characteristic.
Agalactiae occur due to:
Absence of milk secretion due to toxemia or other infectious diseases.
Failure of milk letdown due to inverted teat nipples.
The condition was treated by removal of the cause and supplementing the animal with potassium iodide on ration at 0.2 mg/kg body weight daily.
Dripping of milk from the quarter.
The condition occurs due to a weak teat sphincter.
It can be treated by touching the teat apex with turpentining oil.
Treatment of mastitis in dairy cows
There are general considerations before treatment, including:
The udder should be washed and dried.
Complete evacuation of milk from the quarter.
It is advisable to carry out a sensitivity test.
Milk of treated cows should not be used for calves feeding or human consumption for at least 7 days from the last dose.
Line of treatment:
The treatment strategy for lactating cows is different from that for the dry cow.
Treatment of lactating cows:
The treatment plan includes:
Parenteral treatment:
It is indicated in cases of mastitis associated with systemic reaction to control or prevent septicemia or bacteremia, as well as to help in local treatment of the udder.
Antibiotics used for parenteral treatment should be diffusible from blood to the udder, these include Ampicillin 10 mg/kg b.w, Erythromycin, and tylosin 12.5 mg/kg b.w, Penicillin 16.000 I.U/KG b.w. Oxytetracycline 10 MG/KG b.w and Sulphadimidine 200 mg/kg b.w.
Treatment should continue for at least 5 days.
Udder infusion:
It is the principal method for the treatment of mastitis using disposable tubes containing antibiotics and used for 3-5 successive days.
Parenteral injection of oxytocin is advisable in acute mastitis empty of the quarter before infusion.
The commonly used antibiotics are ampicillin, cephalosporins, penicillin G sodium, cloxacillin, tetracycline, erythromycin, and tylosin.
Mycotic mastitis respond to Nystatin and Clotrimazole udder infusion therapy
Intraparenchymal injection:
Injection of drugs into the mammary gland by needle through the skin.
It is used only when the gland is so swollen or that no diffusion is likely to occur from milk cisternae.
It is used in case of teat obstruction with highly inflamed udder (udder become mass)
Drying off chronically affected quarters.
If a quarter does not respond to treatment, the incurable quarter dried off by producing chemical mastitis via infusion one of the following:
30 ml of 3% silver nitrate solution I/M.
20 ml, 5% copper sulfate through 2 injections with 10 days interval.
100,300 ml of solution. 1/500 acriflavine solution (Two infusions may be necessary).
The use of enzymes:
It breaks down necrotic tissue and liquefies pus.
A mixture of Streptokinase and Streptodornase (25,000 IU. or stabilized trypsin (50 mg. in combination with local antibiotics appears to be safe & beneficial in the treatment of acute mastitis with no systemic reaction and to chronic cases which discharge pus or clots.
Detoxification
This treatment method. Is effective to some extent, including:
Steroidal anti-inflammatory drugs
Cortisone i/v or i/m: in high dose, 0.1 mg/lb is indicated to:
Conserve the cell wall of the mammary gland to promote sugar production through glycogenesis.
Cortisone locally: to facilitate the reduction of inflammation in acute mastitis, combined with adequate doses of antibiotics.
Non-steroidal anti-inflammatory drugs
The use of flunixin (Finadyne) 1m1/45 kg b.wt. i/v or i/m.
Fluid therapy:
As glucose or saline to control dehydration, dilute the toxin, and counteract acidosis.
Antihistamines to overcome the histamine released by the action of toxins.
Cold fomentation of the udder to reduce toxin absorption.
Diuretics to increase the toxin excretion.
Treatment of gangrenous mastitis: by amputation and massive doses of antibiotics and corticosteroids.
Treatment of dry cows:
It is used for chronic cases and to prevent new infections due to the same pathogens in the early lactation period. It is applied in herds with a high prevalence of contagious mastitis.
It is applied after the last milking of lactation by udder infusion of long-acting antibiotics. 10,000 I.U of long-acting cloxacillin 10,000 I.U and Cephalosporins.
Teats are dipped in 0.5% chlorhexidine or 0.5% iodine for 20 seconds, then the teat orifice is closed by wax.
Causes of Failure of treatment of mastitis in dairy cows, how to overcome them?
Treatment of mastitis can be failed due to:
The presence of inflammatory debris prevents antibiotics from reaching the infected foci.
It can be overcome by using normal saline Intramammary as a wash to evacuate it, to remove fibrin debris before using antibiotics.
Antibiotics in vivo differ from antibiotics in Vitro as some microorganisms can secrete enzymes to inhibit the antibiotic action, such as staph. which secrete the penicillinase enzyme.
It can be overcome by using clavulanic acid with Amoxicillin to protect Amoxycillin.
Prevention and Control of mastitis in dairy cows
7 principles should be perfectly considered for optimum control of the disease, including:
Detection of infected quarters:
Visual examination and digital palpation to full and milked out gland to detect clinical cases.
Periodical application of screening tests as CMT for detection of subclinical infection.
Milk should be examined bacteriologically two times at weekly intervals.
Treatment of infected quarters
Infected quarters should be treated and followed by three examinations at two weeks intervals for detection of relapsing quarters and to evaluate the efficacy of treatment.
Drying off incurable cases.
Dry cow treatment
All quarters should be treated after the last milking of lactation using long-acting antibiotics (cloxacillin by udder infusion).
Prevention of spread of infection through:
Muzzling of calves in infected farms to avoid suckling of the immature udder, as some pathogens may become established in the immature udder.
Infected cows should be milked separately by a special attendant and in a separate container.
Regular disinfection of animal house, milking equipment, and milking machine.
Disinfection of milker's hands between milking of each cow.
Udder sanitation: The udder and teats should be washed and dried before each milking, in iodophor solution containing-1% iodine or chlorhexidine 0.2%.
significance of iodine
enters the teat canal by osmosis to disinfect it completely.
act as stringently close the teat Canal.
remove inflammatory depress away from nerves.
Adding pot. iodide in ration daily helps in raising parathormone and so increases milk production.
Immunization: e.g E. coli.
The use of bovine cytokines
to enhance the specific immunity in the mammary gland of cows.
Nutritional management of dry cows:
Adequate levels of vitamin E and selenium support immunity.
Finally, the dairy cow is a treasure that needs special care to get its high economic profits, so the control strategy of mastitis in the dairy cow is very important to avoid any loss.
Written by: Dr. Mai Foda