Practices and Strategies for the Prevention and Control of Mastitis in Livestock
1Jinu Manoj and 2Manoj Kumar Singh
1Disease Investigation Officer, College Central Laboratory, COVS, LUVAS, Hisar, Haryana
2Assistant Professor, COVAS, SVPUAT, Meerut, Uttar Pradesh
Introduction
Mastitis, the potentially fatal udder tissue infection is the most common disease in dairy animals. It usually occurs due to the inflammatory response to bacterial invasion of the teat canal. It can also occur as a result of chemical, mechanical or thermal injury to the udder. Mastitis occurs when white blood cells (leukocytes) are released into the mammary gland as a result of inflammatory process. Milk secreting tissue and various ducts throughout the mammary gland are damaged due to toxins released by the bacteria resulting in reduced milk yield and quality. Mastitis is a worldwide problem responsible for heavy economic loss to dairy industry due to its high morbidity, loss of milk production, high cost of treatment and major adverse effects on quality of byproducts made from contaminated milk. It affects the public health due to the transmission of pathogenic bacteria and their toxins through the food chain. In addition to that, the worries about antimicrobial residues, antimicrobial resistance, milk quality and animal welfare, mastitis has also become a concern to consumers and society.
Mastitis may be classified according to the clinical symptoms as clinical mastitis, sub-clinical mastitis, per acute mastitis, acute mastitis, sub acute mastitis and chronic mastitis. Depending on the mode of transmission, it is classified as contagious mastitis or environmental mastitis. A large number of microorganisms are responsible for causing mastitis in animals. The most common bacteria accountable for mastitis are Staphylococcus aureus, S. epidermidis, Streptococcus agalactiae, S. dysgalactiae, S. uberis, Escherichia coli, Klebsiella pneumoniae, K. oxytoca, Enterobacter aerogenes, Pseudomonas aeruginosa, Trueperella pyogenes, Corynebacterium bovis, Brucella melitensis and Mycoplasma spp.
Diagnosis of Mastitis
The diagnosis of mastitis can be performed at field level by the following routine diagnostic tests.
- Physical examination of udder
- Strip cup test
- California mastitis test
- Modified white side test
- pH Determination test
- Chloride test
- Electrical conductivity test.
- Somatic cell count of milk.
- Methylene blue reduction test (MBRT)
Culture Methods
The gold-standard method for the identification of mastitis pathogens are culture-based techniques. Results rely on incubating a known volume of milk in culture plates, for at least 18 h at defined temperatures to promote growth. The analysis of colony morphology is performed to identify the organism. Culturing is also used to evaluate treatment efficacy and to establish susceptibility patterns to aid in the development of rational treatment strategies.
Molecular Methods
The use of polymerase chain reaction (PCR) is known to be highly sensitive and specific, providing accurate pathogen identification. It also allows detection of mastitis pathogens that do not grow by conventional culturing techniques within few hours. Genotypic tests are specific include specific culture, PCR and its various versions (qRT-PCR), loop-mediated isothermal amplification, lateral flow assays, nucleotide sequencing, matrix-assisted laser desorption ionization, mass spectrometry and other molecular diagnostic methods. Nowadays research on development of biosensors for detection of mastitis which measures the variation of milk yield and milk temperature is undergoing.
Biosensor based diagnosis of bovine mastitis
Biosensor based diagnostic assays are emerging in veterinary applications and lab-on-chip devices impregnated with biomarkers are the latest trend for the diagnosis of mastitis. The need to provide the milk supply chain with rapid, portable and cost-effective biosensors for pathogen detection is a latent concern. Recent advances in biosensors and miniaturization techniques can provide microbiological and molecular data on a faster manner at a lower cost. They can detect the presence of specific cells and cell markers with high sensitivity benefitting from high signal to noise ratios and fast response times.
Practices and strategies for prevention and control of mastitis
Understanding the many aspects of mastitis can lead to more effective prevention and treatment strategies. Preventing mastitis is mainly based on approaches like minimizing the presence of bacteria at the teat end and optimizing resistance of the cow against those bacteria. Improvement in mastitis management at the herd level can be obtained by treatment of all cows at drying off, optimal treatment of cows with clinical mastitis based on its antibiotic sensitivity, proper milking procedures and post milking teat disinfection of all cows, proper maintenance and use of milking equipment, maintenance of a clean dry comfortable environment, regular monitoring of udder health status and good record keeping.
Management practices
Prevention and control program should emphasize factors that are responsible for reducing the rate of new infections and eliminating the existing ones. A combination of preventive measures and therapeutic use of antibiotics will markedly reduce the incidence of mastitis. Proper milking hygiene should be followed. The milker’s hands should be washed thoroughly with disinfected soaps before milking while the clinically infected cows should be milked last. The udder should be washed thoroughly in a sanitizing solution. Teats should be cleaned and dried before milking. Machines for milking should function and operate properly.
The infected animal should be kept separately from other animals. The calf should not be allowed to suck the infected teats. The milk from infected teat should be milked out daily three times and disposed hygienically without contaminating the environment. Mastitis milk should be properly disposed. 5% phenol may be added to the infected milk at the time of disposal. The healthy animals should be milked first and known infected cows should be milked at last. The non responsive quarter should be permanently dried up and culling of chronically infected animals are advised. Immediately after detecting clinical signs, it should be consulted with qualified veterinarian for further antibiotic treatment.
Teat Dipping
Dipping teats in a solution of suitable disinfectant after completion of the milking process has been found to be the most effective single hygienic practice for preventing mastitis. Effective teat dips include the preparations of 0.1-1% iodophores, 4% sodium hypochlorite, 0.6% sodium dicholro-s-triazenetrione, 0.2-0.5% quaternary ammonium compounds and 0.5% chlorhexidine. Post-milking teat dipping controls the bacteria residing on teat skin and prevents new intramammary infections occurring between two milking. It also helps in repairing minor damages to teat skin. The practice is known to be quite effective against staphylococci, S. agalactiae and S. dysgalactiae. The teat cup assembly, milk pipes and other utensils should be cleaned and sanitized between each milking.
Dry cow therapy
Dry animal therapy has become an important component of mastitis control programme in livestock. Dry cow therapy is the use of intramammary antibiotic therapy immediately after the last milking of lactation. Approved products applied by intramammary infusion at drying off can decrease the number of existing intramammary infections and prevent new infections during the early weeks of the dry period. This therapy is administered either as a blanket treatment of all quarters of all cows or as a selective treatment of only infected cows or quarters. Dry cow therapy is the one of the best way to cure chronic and subclinical mastitis that is difficult to treat successfully during lactation. Continued use of dry cow treatment will help to maintain a good herd udder health status. The herd veterinarian should be consulted to determine which dry cow product should be used.
Conclusions
Analysis of mastitis with epidemiological tools and the corrective action to be followed can enhance the production of high quality milk in dairy farms. Strategies involving prudent use of antibiotics for treatment encompass identification of the pathogen causing the infection, determining the susceptibility/resistance pattern of the pathogen to assess the most appropriate antibiotic to use for treatment and a long enough treatment duration to ensure effective concentrations of the antibiotic to eliminate the pathogen are recommended. Alternatives to use of antibiotics for maintaining animal health and productivity based on preventative measures such as vaccination, improved nutrition, environmental sanitation, use of teat sealants and selection for disease resistance genetic traits together with advances in more rapid pathogen detection and characterization systems will undoubtedly play an integral role in strategies aimed at improving dairy productivity with improved safety of dairy products for human consumption. This in turn, will increase income through increased milk production, increase premium benefits and decreased cost of treatment.
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