There are more than 9 million dairy cows contributing to the 226-billion-pound milk supply in the United States. Each of these cows gives birth to a calf approximately once a year, resulting in roughly an equal number of newborn calves annually. Dairy calves rely on ingestion of a sufficient quantity and quality of the first milk after parturition, called colostrum, to establish transfer of passive immunity (TPI) by ingestion of colostral immunoglobulins (Ig) against important cattle pathogens. This is due to the type of placentation which allows no transfer of Ig in utero, instead calves ingest colostrum and absorb Ig through the intestine. In addition, newborn calves have reduced immunocompetence and inefficient production of antibodies early in life.

In a recent US nationwide survey including 2,360 calves, 38.7% of calves failed TPI as indicated by low levels of IgG1. Failure of TPI predictably results in increased morbidity and mortality1, and increases the on-farm use of therapeutics, including antimicrobials. This represents a serious concern for animal well-being and One Health implications of antimicrobial use in agriculture. Repeatable long-standing evidence shows that achieving pathogen-specific antibody transfer by adequate colostrum management is the single most important management factor in preventing early life disease and death in dairy calves.

Our proposed study will address the recently identified critical knowledge gap of the mammary gland´s contribution to colostral Ig and provide preliminary data to propose further research in this area directed at federal funding agencies (USDA, NIH). We will address the following objectives:
(1) Determine the effect of intramammary vaccination route alone or in combination with parenteral vaccination on blood and colostral Ig concentration and specificity of the dam.
(2) Measure the health effects of the different vaccination strategies on the dam, as well as the success of TPI, and pathogen-specific Ig in the newborn calf.