Natural Resistance Mechanisms of the Udder - Physical Mechanisms

Question 1

How does streak canal work for this purpose?

Answer 1

Keration in the streak canal serves as physical barrier that trap bacteria and inhibits pathogens through a chemical defense system composed of antimicrobial lipids and proteins. Bacteria attached to keratin may be sealed in this location by tight closure of the sphincter muscle or extruded during milking as keratin desquamates

Question 2

How does bacteria may enter through the streak canal?

Answer 2

Teat canal opens for up to 2 hours during milking. Also, dry cow treatment may cause excessive dilatation of the streak canal that may contribute to new intramammary infections during dry period.

Question 3

When does an udder become the most susceptible to new intramammary infections?

Answer 3

During early dry period before teat canal forms a thick keratin plug