Not far from a triumphant victory over mastitis in dairy cows

Mastitis in dairy cows causes huge economic loss in the global dairy industry. Despite various measures has been adopted to tackle mastitis, its occurrence has not been declined significantly. A recent research developed a possible solution by creating transgenic cows with the enzyme lysostaphin secreted in their milk. Transgenic cows carrying lysostaphin in the study has shown to be more resistant to S.aureus, a major contagious mastitis pathogen which accounts for 30% of all intramammary infections. While lysostaphin effectively eliminates the pathogen S.aureus, it is relatively harmless to both the cows and the milk consumers compared with commonly used antibiotics. Furthermore, it has minimal effect on milk composition.

To maximize the efficiency in tackling mastitis in dairy cows, major pathogens other than S.aureus need to be dealt with also. Antimicrobials which satisfy a series of criteria, including harmlessness to cows and milk consumers, no biological activity when taken orally and high sensitivity to pathogens, are hard to find. Nevertheless, the development of transgenic cows that secrete antimicrobials in milk is a breakthrough in the field of dairy science and surely of great benefit to the global dairy industry.

Aiming at an increase in milk yield and improvement in milk quality, more dairy science research in creating mastitis-resistant cows are expected to be done in the near future.

Primary source:
Donovan, D.M., Kerr, D.E., Wall, R.J., 2005. ‘Engineering disease resistant cattle’, Department of Animal Science, University of Vermont, Burlington
http://www.springerlink.com/content/u1m28j7732815g68/fulltext.pdf

Secondary source:
Kerr, D.E., Wellnitz, O., 2003. ‘Mammary expression of new genes to combat mastitis’, Department of Animal Science, University of Vermont, Burlington
http://jas.fass.org/cgi/reprint/81/suppl_3/38.pdf

Written by: Kin Fai, Lau
Student number: 41281941