Inducing Natural Defense Mechanisms to Promote Mastitis Control

Abstract

Strategies to control mastitis now rely heavily upon antibiotics and topical germicides; but are coming under increasing scrutiny and regulation because of the potential for adulteration of the food product. The considerable therapeutic efficacy of antibiotics especially when administered during the dry period, has led to too great reliance on curing the disease rather than preventing it on the farm, and has discouraged efforts in research laboratories to develop alternative means of protection, such as enhancement of natural mammary defense mechanisms. Among the components which comprise the intramammary defense mechanisms, the streak canal, lactoferrin, and phagocytic activity of PMNL seem the most accessible to enhancement. The methods used to enhance these defense mechanisms will be discussed in this paper. The discovery that significant variation exists among cows in the ease in which substances can penetrate the streak canal, offers the possibility of selecting cows with heightened genetic resistance to mastitis. The successful manipulation of the lactoferrin to citrate ratio in mammary secretions offers the possibility of enhancing the control of coliforms. The phagocytic and bactericidal properties of leukocytes appear to be regulated by a number of control mechanims that are accessible to man.