Types, Major pathogens in Bovine Mastitis: A Mini-Review
Sehajpal Singh Dhillon1, Simarjeet Kaur1*
*Department of Animal Genetics and Breeding, College of Veterinary Science, Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana, India (141004)
*Corresponding Email: simarsharma08@gmail.com
Abstract
Bovine mastitis is characterized by a prolonged and inflammatory reaction of the udder tissue as a result of either physical trauma or microorganism-caused illnesses. It’s a potentially lethal mammary gland infection found mostly in dairy cows around the world. The pathogenic agents include a variety of gram-bacteria (gram-positive and gram-negative) can be either contagious pathogens named Staphylococcus aureus, Streptococcus agalactiae, Mycoplasma spp. or environmental (e.g., Escherichia coli, Streptococcus uberis). Although both pathogens and the host immune system can co-evolve to recognise, respond to, and adapt to each other, the interaction between mastitis pathogens and the host immune system is complex.
Keywords: Bovine, udder, clotting
Introduction
Mastitis is a major economic challenge in the dairy sector all over the world. Mastitis is one of the most financially destructive illnesses in dairy cattle around the world. It is also regarded as one of the most serious illnesses affecting the welfare of farm animals. It is an endemic infection of dairy cows that causes inflammation of the mammary organ and udder tissue. It is caused by bacteria (or bugs) entering the udder. A change in the milk, such as clotting, looking watery and/or bloody, is the most evident indicator of mastitis (Gomes and Henriques 2016). . Changes in milk composition are also caused by mastitis. Warm, swollen, and painful to the touch udders are also common, as are fever, sadness, and a lack of appetite. Bovine mastitis is normally treated with antibiotics. Genetic selection approaches currently used in the dairy industry to reduce the incidence of disease
Types of Mastitis
There are the two types of mastitis found in cattle.
- Clinical mastitis
- Subclinical mastitis
Clinical mastitis
Changes in the physical appearance of milk, swelling, redness, heat, and soreness in the udder are all signs of clinical mastitis. Phenotypic information is scarce, particularly in mastitis selection, where a low somatic cell count (SCC) is used as a proxy for clinical mastitis.
Subclinical mastitis
Subclinical mastitis affects animals who do not show any obvious changes in their milk or udder and can only be diagnosed through laboratory tests. Somatic cell count (SCC) level of >200,000 cells/ml indicates subclinical mastitis.
Table: 1 On the basis of severity, differet types of mastitis.
| Type of Mastitis | Features |
| Mild Mastitis
|
Abnormal milk production(eg, clots, flakes, watery) |
| Moderate Mastitis
|
udder inflammation and abnormal milk production |
| Severe Mastitis
|
Systemic illness (eg, dehydration, weakness) |
Major pathogens of bovine mastitis
- Contagious pathogen
- Environment pathogen
Contagious pathogens
Staphylococcus aureus
Staphylococcus aureus is a Gram-positive bacteria with a spherical shape. Staphylococcus aureus colonizes the nipple skin and penetrates the mammary gland canal. It’s more difficult to get rid of S. aureus. Infections with S. aureus reduce milk production by 45 percent per quarter or 15 percent per infected animal. S. aureus virulence factors and surface proteins have been studied for their ability to act as antigens, eliciting a protective immune response against recurrent S. aureus infection.
Streptococcus agalactiae
Streptococcus agalactiae is a gram-positive coccus (round bacteria) that tends to chain formation. Contagious mastitis is caused by Streptococcus agalactiae (S. agalactiae), an obligate infection of the mammary gland that is spread directly between cows during milking. S. agalactiae is a pathogen with a low global prevalence (Rosini and colleagues, 2015).
Mycoplasma spp
Mycoplasma spp. cause gland fibrosis, abscesses, and lymphatic nodule fibrosis by damaging secretory tissue. M californicum, M canadense, and M bovigenitalium are three other important species. Mycoplasmosis is usually linked to the beginning of mastitis outbreaks, the introduction of new animals into a herd, past bronchial or arthritic disease, and herds with antibiotic-resistant mastitis.
Environmental pathogens
Escherichia coli
Escherichia coli can infect the mammary gland by entering the udder through the teat canal. It is the most common gram-negative pathogen discovered. It’s present in the environment around dairy cows, such as the herd’s bedding, especially when it’s moist. Because its pathogenicity is not mediated by a single and particular virulence factor, E. coli was categorized as an opportunistic pathogen with many virulence factors.
Streptococcus uberis
Strep. uberis is a bacterial pathogen that causes persistent mastitis and is linked to both clinical and subclinical infections. Proteins play a major role in the production of Streptococcus uberis biofilms. Several S. uberis strains isolated from mastitis were able to form biofilms, indicating that milk components are potent biofilm inducers.
Conclusion
in conclusion, Bovine mastitis is a disease that affects millions of cows worldwide, making it one of the most serious bovine diseases and one of the most costly for the dairy sector. Different pathogens are responsible for causing the disease. Antibiotic therapy is still an important part of mastitis control regimens today.
References
Gomes, F., and Henriques, M. 2016. Control of bovine mastitis: old and recent therapeutic approaches. Curr. Microbiol. 72(4): 377–382
https://www.pashudhanpraharee.com/examination-of-milk-a-new-approach-of-handling-bovine-mastitis/
Rosini R, Margarit I. Biofilm formation by Streptococcus agalactiae: influence of environmental conditions and implicated virulence factors. Front Cell Infect Microbiol. 2015;5:6.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8752063/
