Cytokines are useful for the ability to improve the natural defense system of the involuting mammary gland. In addition to the immunopotentiating activity, cytokines accelerate the normal physiology of involution of the mammary gland and thereby afford further protection against new infections of mammals. The involuting mammary gland is very susceptible to infection during the early stages of involution and therefore decreasing the period of highest susceptibility while also improving the natural defense mechanisms is of great advantage over most therapies. Used alone, in various cytokine combinations, or in combination with other therapeutics, cytokines protect the mammary gland and cure existing infections and are particularly useful during cessation of lactation and early reinitiating of lactation.