Control through vaccines
|Mastitis is a disease in dairy cattle that causes huge economic losses for the dairy industry. Vaccination against mastitis has been recommended to prevent new infections, thus eliminating the use of antibiotics in animals intended for human consumption. The purpose of vaccinating against the bacteria that cause mastitis is to stimulate the cow’s immune system to protect against further infection or disease. Vaccination can increase circulating antibodies in the bloodstream against certain mastitis pathogens to prevent or limit bacterial growth after the invasion of a mammary quarter. The resulting enhanced immunity may also minimize pathogen damage to milk-producing tissues, modify the inflammatory response, promote tissue repair, and reduce the clinical expression of disease.|
Several commercial vaccines are currently available for E. coli and S. aureus in developed countries to prevent environmental and contagious mastitis respectively, but none are available in Pakistan. Researchers at the Animal Health Research Laboratory, Department of Veterinary Medicine, University of Veterinary and Animal Sciences, Lahore have developed a monovalent E. coli mastitis vaccine.
The purified and molecular characterized isolate of E. coli (aggR) was used for the preparation of E. coli vaccines using different adjuvants. In the first step, the antigenic response of the selected isolate of E. coli was tested in laboratory animals. Once the immunogenicity was confirmed in rabbits, the isolate was used to prepare a vaccine as per standard procedures. Then, the prepared vaccines were tested in laboratory animals (mice and rabbits) and lactating cows for safety, side effects and efficacy.
Results demonstrated that the isolate of E. coli (aggR) from the mastitic milk of cows was immunogenic in rabbits. Different types of monovalent E. coli mastitis vaccines were developed successfully and were found safe, and had no side effects when used in laboratory animals and dairy cattle. Montanide oil adjuvanted monovalent E. coli (aggR) mastitis vaccine was the most effective for the control of mastitis in dairy cattle, while aluminium hydroxide adjuvanted monovalent E. coli (aggR) vaccine was the second most effective vaccine.
The monovalent E. coli mastitis vaccine had positive effects on milk quality in terms of somatic cell count, milk fat and milk protein. Vaccines also provoked a cell-mediated immune response. The commercialization of this vaccine is expected to mark a milestone in the control of E. coli mastitis and help reduce the use of antibiotics in dairy cattle.
- SAIRA JABEEN AND
DR. MUHAMMAD AVAIS,