DESIGN AND IMPLEMENTATION OF THE UNITED-STATES NATIONAL ANIMAL HEALTHMONITORING-SYSTEM 1995 NATIONAL SWINE STUDY

The United States Department of Agriculture's National Animal Health M onitoring System 1995 National Swine Study was designed to estimate ma nagement, health and productivity parameters on pig operations in the United States. Sixteen major swine-producing states that accounted for nearly 91% of June 1, 1995 swine inventory and nearly three-fourths o f United States swine producers were included in the study. In the ini tial phase of the study, National Agricultural Statistics Service enum erators collected information from 1477 producers involved in all phas es of swine production (farrowing, nursery, and grower/finisher). Of t hese, 405 operations with greater than or equal to 300 finisher pigs ( with at least one finisher pip greater than or equal to 54 kg) partici pated in the subsequent component of the study, which involved on-farm visits by state and federal veterinary medical officers and animal he alth technicians, and which concentrated on the grower/finisher phase of production. Of those eligible to take part in the second phase of t he study, participation was higher among independent producers (48.3%) than among contract producers (15.3%). Participation was also higher among operations that used advanced record-keeping systems (such as re cord cards for individual breeding hogs or a computer-based record-kee ping system). Thus, study results could have been influenced by respon se biases. As a biosecurity measure, 40.5 +/- 2.1% of operations restr icted entry to employees only. For operations that permitted non-emplo yees to enter the premises, relatively few enforced other biosecurity measures on visitors (0.4 +/- 0.1% required feed-delivery personnel an d livestock handlers to shower before entering the premises; 3.3 +/- 0 .9% required a footbath and 7.0 +/- 1.5% required feed-delivery person nel and livestock handlers not to have visited another operation with pigs on that day). The most common method of waste storage (used by 49 .9 +/- 3.8% of operations with greater than or equal to 300 finisher p igs) was below-floor slurry or deep pit. (C) 1998 Elsevier Science B.V .