NAHMS Reports Baseline Data on Antimicrobial Stewardship

New data from the National Animal Health Monitoring System (NAHMS) provides a baseline for antibiotic trends in food animal during 2016, prior to implementation of key rule changes. The NAHMS “Antimicrobial Use and Stewardship on U.S. Feedlots, 2017” study focused on how antimicrobials were used on U.S. cattle feedlots with 50 or more head in 2016. Beginning on January 1, 2017, the FDA implemented new rules that eliminate the use of medically important antibiotics for performance purposes in food animals and require veterinary oversight for purchase or use of most antimicrobials in feed.

NAHMS, under the authority of the Veterinary Services (VS) division of the USDA’s Animal and Plant Health Inspection Service (APHIS) conducts periodic national surveys of livestock sectors to track trends in animal health. The new report provides detailed information on antimicrobial use in feed and water in feedlots with a capacity of 50 to 999 head. NAHMS researchers collected data as a benchmark for comparison with antimicrobial use on feedlots in future studies, after the implementation of the FDA policy changes. In total, 378 feedlots provided data for this report.

Some key findings include:

• Overall, 87.5 percent of feedlots gave antimicrobials in feed, water, or by injection in 2016. Almost all feedlots (99.5%) with capacity for 1,000 or more head used one or more antimicrobials in feed, water, or by injection. For smaller feedlots with 50 to 999 head, the number dropped to 86.6%.
• Antimicrobials were administered in feed on 70.8 percent of all feedlots, 87.1 percent of large feedlots, and 69.5 percent of small feedlots.
• Almost 86% of feedlots placed cattle weighing less than 700 pounds and of those, 71.6% used antimicrobials to those cattle. Of the 28.2 percent of feedlots that placed cattle weighing 700 lbs. or more, 68% gave antimicrobials to those cattle.
• Reasons for feeding antimicrobials included prevention, control, or treatment of respiratory disease; prevention and control of coccidiosis; and growth promotion.
• Ionophores and chlortetracycline were the antimicrobials fed on the highest percentages of feedlots.
• Almost half of feedlots (44.4%) did not use any medically important antimicrobials in feed.
• Among feedlots that placed cattle weighing less than 700 lbs., 42.6% did not use any medically important antimicrobials in feed for these cattle. Of the 28.2% of feedlots that placed cattle weighing 700 lbs. or more, 60.9% did not use any medically important antimicrobials in feed for those cattle.
• Only 8.5 percent of all feedlots administer one or more antimicrobials in water, with most of that use among small feedlots (9.1%) compared with just 1.1% for large feedlots. Among those using antimicrobials in water, most cited control or treatment of respiratory disease as the reason.
• Overall, just under 15% of feedlots treated high-risk cattle as a group upon arrival with injectable antimicrobials. Large feedlots (39.3%) were more likely to use that practice than smaller feedlots (12.8%).
• Overall, 80.0 percent of feedlots treated at least one sick steer or heifer with injectable antimicrobials in 2016, with 97.9% of large feedlots and 78.5% of small feedlots doing so.
• Nearly 80% of feedlots used the services of a veterinarian in 2016, and about 85% indicated they had a veterinarian-client-patient relationship (VCPR). Of those feedlots, 13.7% described their VCPR as a written document signed by the veterinarian and the producer, 42.4% had a verbal agreement, and 43.8% had an implied VCPR based on the relationship between the veterinarian and the producer.
• Among all feedlots that used a veterinarian in 2016, the veterinarian visited more than once on 80.5% percent of all feedlots. A veterinarian visited more than once during the year on a 95.6% of large feedlots compared with 78.8% on small feedlots.

Due to the FDA rules, future surveys likely will show a significant decline in use of some antimicrobials during 2017 and subsequent years, particularly those used in feed and those used for performance purposes.

Study results and data for Beef Feedlots and Swine Operations are available on the APHIS website.

For more on antibiotic stewardship, see these articles on BovineVetOnline:

Make Antibiotic Stewardship work

Antibiotic Stewardship: FDA Cites Progress

AABP Releases Antimicrobial Stewardship Guidelines for Bovine Practice