HPAI dairy herd infection case report

What happens in a dairy herd with HPAI? What should I expect if my herd became infected? This case report describes what one farmer has faced since herd infection began.

May 1, 2024 marked day one of the onset of an outbreak of Highly Pathogenic Avian Influenza (HPAI) on one dairy farm in Michigan. The farmer, recognizing the potential benefit to other farmers, willingly shared this information and agreed to have official testing of his herd. This report is what was known and reported on day 15 of the HPAI infection in a herd of approximately 500 lactating cows. Prior to infection, the average cow production on this farm ranged from 95 to 100 lbs. per day.  

Initial symptoms were detected with the SmaXtec monitoring boluses that they currently have in about 90% of lactating cows. The onset was manifested by a spike in body temperature of 4 to 5 degrees above normal, followed by a decrease in rumination 6 hours later. The decrease of rumination in infected cows was severe with almost no activity occurring.