Pathogen-specific production losses in bovine mastitis

Area of Science:

• Animal Science
• Veterinary Medicine
• Dairy Production

Background:

• Bovine mastitis leads to substantial economic losses in the dairy industry, primarily due to reduced long-term milk yields.
• Understanding the specific impact of different mastitis-causing pathogens is crucial for developing effective prevention and control strategies.

Purpose of the Study:

• To investigate and quantify the pathogen-specific effects of bovine mastitis on milk production in dairy cows.
• To compare the milk yield reductions associated with various common udder pathogens, considering mastitis type and timing within lactation.

Main Methods:

• Utilized milk and health recording data from 20,234 Finnish dairy cows (2010-2012).
• Employed a 2-level multilevel model to estimate lactation curves, comparing periods with and without mastitis within the same cow.
• Adjusted lactation curves to represent the third lactation for standardized comparison across different parities.

Main Results:

• All investigated pathogens caused milk production loss, with the extent varying by pathogen, timing, and mastitis type (clinical vs. subclinical).
• Escherichia coli clinical mastitis diagnosed before peak lactation resulted in the largest yield reduction (10.6%).
• Staphylococcus aureus mastitis caused significant losses (7.1% before peak, 4.3% later), with similar impacts in clinical and subclinical forms.

Conclusions:

• Minor pathogens like Corynebacterium bovis and non-aureus staphylococci (NAS) contribute significantly to milk yield reduction and should not be underestimated.
• Controlling E. coli mastitis offers potential for substantial milk production increases on dairy farms.
• Reducing Staphylococcus aureus mastitis presents the most significant challenge for the Finnish dairy sector's milk production.