Project Number: 3625-32000-093-05
Project Type: Reimbursable

Start Date: Mar 01, 2007
End Date: Feb 28, 2010

Objective:
The objective of this study is to evaluate the effectiveness of feeding heat-treated colostrum to calves in herds infected with Mycobacterium avium subsp. paratuberculosis (MAP). Since MAP is shed into the milk of infected dams, feeding colostrum from naturally infected dams can be a potential source for transmission of infection to neonatal calves. Pasteurization has proven effective in the destruction of viable MAP in colostrum and waste milk on-farm. However, little is known about the long-term effects of feeding pasteurized colostrum on the general health of the calf. Even less data are available documenting effects of feeding pasteurized colostrum on MAP infection in calves. We will receive colostrum samples from naturally infected dams from each of the selected herds within the study and determine the presence of MAP within the samples in order to evaluate the potential exposure of the neonates to the bacterium.

Approach:
Colostrum samples will be collected on the day of calving from cows on the study. Up to 600 colostrum samples will be frozen and shipped on ice to the NADC for processing. DNA will be extracted from the colostrum samples by a standard protocol used in the laboratory and then RT-PCR will be performed for the identification of a unique target gene for MAP (ISMap02). The RT-PCR method will include the use of a probe and a standard curve generated by a plasmid control that will allow for semi-quantitation of the MAP bacterium in the colostrum. The goal of the study is to identify colostrum samples that are positive for the MAP bacterium and utilize this information to determine if heat-treatment of colostrum will reduce the risk of transmission of MAP infection to neonatal calves.