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National Animal Health Monitoring System (NAHMS) Swine 2000 Report Highlights

Livestock Update, October 2001

Allen Harper, Extension Animal Scientist - Swine, Tidewater AREC

The National Animal Health Monitoring System (NAHMS) is a program operated by veterinary and animal science professionals at USDA's Center for Animal Health Monitoring. A primary function of this branch of USDA is to make periodic surveys and assessments of animal health management practices on commercial livestock farms across the United States. The information is made available to producers, livestock service industries, animal health professionals and animal industry educators to assist in improving animal health and productivity.

During the year 2000 NAHMS conducted a broad study of swine operations in 17 leading production states representing 94% of swine production in the country. In August of this year, Part I of this study report was released. This section of the report focused on breeding herd management practices, preventive health practices for weanling pigs to market weight, and certain biosecurity practices. Some brief highlights of the report are as follows.

Breeding Methods. For sites with more than 500 breeding females, slightly more than 85% of sows were bred artificially. For sites with less than 250 breeding females only 15% of sows were bred artificially. Three-fourths (76%) of sows were mated two or more times during estrus. On sites with less than 250 breeding females, 65% of sows and 57% of gilts were pen mated.

Management of Replacement Stock. Forty percent of operations isolated or quarantined new breeding females before introducing them to the resident herd. For replacement boars this figure was 65%. Among those practicing isolation of new stock, 60% had new females and 52% had new boars tested as potential carriers of at least one disease. Primary acclimatization practices for new stock included vaccination for diseases of concern at the site (84%) and exposure to cull females (49%).

Antibiotic Use in Weaned Growing Pigs. Antibiotic use as a "preventive" health practice was quite extensive. In weaned, growing pigs, 80% received feed additive antibiotics during some phase of the production cycle. Antibiotics were also provided via injections (44%), in the drinking water (27%) and by oral dosing (7%). This is interesting data considering the fact that the Food and Drug Administration and other health agencies are calling for a review of routine use of antibiotics in swine and poultry production.

Death and Culling Losses in Breeding Herds. The average annual gilt and sow death loss ranged from 5% to 7.4%, and tended to be greater on larger than on smaller operations. The average culling rate for sows was 18%. Principle reasons for culling included age (42%), reproductive failure (21%) and lameness (16%).

Biosecurity Practices. About two-thirds of sites restricted entry to the operation to employees only. Of the sites that did not restrict entry, only 23% required a 24-hour "no-swine-contact" policy. The most frequent means of rodent control was the use of baits and poisons (88% of sites). The keeping of cats has been associated with transfer of toxoplasmosis and other diseases but they were used on 68% of smaller herd sites (less than 2000 head) for assistance in rodent control. Presence of cats was much less at large herd sites.

Just over 56% of sites allowed trucks to enter the perimeter of the farm. Smaller sights were less restrictive to truck entry than larger sites. For dead pig disposal, composting was used extensively for pre-weaning pigs (23%). For larger hogs, burial (38%) and rendering (45%) were used more extensively.

Other components of the NAHMS Swine 2000 report will be released as the results become finalized. Full-length NAHMS reports are available on the Internet at

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