April 18, 2014
This information has been compiled and quoted from USDA Animal and Plant Inspection Service documents and personal communication with Keith Poulsen, DVM PhD, DACVIM, director of the Wisconsin Veterinary Diagnostic Laboratory.
Since late March 2024, the U.S. Department of Agriculture, Food and Drug Administration, Centers for Disease Control and Prevention, and state veterinary and public health officials have been investigating the emergence of highly pathogenic avian influenza in dairy cows, with one human infection. USDA’s Animal and Plant Health Inspection Service is maintaining resources, including a list of detections in cattle to date as well as biosecurity information for farmers, veterinarians and farmworkers at https://www.aphis.usda.gov/livestock-poultry-disease/avian/avian-influenza/hpai-detections/livestock.
How did these cattle contract H5N1? Wild migratory birds are believed to be the original source of the virus. However, the investigation to date also includes some cases where the virus spread was associated with cattle movements between herds. Additionally, we have similar evidence that the virus also spread from dairy cattle premises back into nearby poultry premises through an unknown route.
How is a case of H5N1 in cattle confirmed by USDA? USDA encourages producers to work with their veterinarians to report cases of sick cattle to State Animal Health Officials and their APHIS Veterinary Services Area Veterinarian in Charge.
What signs of illness should farmers look out for in their herds? Producers should report animals with the following clinical signs to their state veterinarian immediately: Decreased herd level milk production; acute sudden drop in production with some severely impacted cows experiencing thicker, concentrated, colostrum-like milk; decrease in feed consumption with a simultaneous drop in rumen motility; abnormal tacky or loose feces, lethargy, dehydration, and fever. Initial cases indicated older cows in mid-lactation may be more likely to be severely impacted than younger cows and fresh cows or heifers. Additional data indicates younger cattle have been affected; more data and reporting from impacted producers will help to clarify the range of animals affected.
Who are the cows affected, how long are they sick and how can they be treated? (From Dr. Poulsen) An outbreak affects about 10% of the multiparous cattle >150 DIM. Peak incidence is at 4-6 days from the initial case and that drops off by 12-14 days, but herds do not recover until approximately 45 days in general. Treatment options are really supportive. Some use NSAIDs and fluids, but we have to be careful with oral fluids because affected cows seem to have poor rumen motility.
Treatment Options – Palliative care, providing relief from symptoms is currently the best option. This includes rehydrating drench products such as Drench-Mate EDT or Drench-Mate Drench. These drench products administered with Drench-Mate’s specialized cattle drenching equipment will help rehydrate and stimulate rumen motility. Additional yeast products or probiotics may also be used to help improve rumen function.