Characterization of livestock herds in extensive agricultural settings in southwest Texas

摘要

Because of an ever-increasing threat of foreign animal disease outbreaks in theUnited States, there is a desire to develop strategies to prevent the occurrence of aforeign animal disease and control an outbreak if it does occur. Infectious diseasemodels have been developed and are being used to determine reasonable mitigationstrategies. However, little information is available concerning premises characteristicsand movement of animals in extensively managed livestock areas. Hence adaptation ofthese models to areas where there is low livestock density is not easy. We collectedempirical data, via mail out surveys, from an extensively managed livestock area. Thiswill aid in improving the results of infectious disease models in these areas.In contrast to the intensively managed livestock that have previously beenmodeled, this study has shown that in areas of low livestock density, multiple livestocktypes often are managed on the same premises. Direct contacts, facilitated through theplanned movement of animals, appear to have a greater seasonality in extensivelymanaged areas as compared to intensively managed areas. Furthermore, wildlife contactsare likely and of potential importance. The results of this study add to the knowledge base used to model the spread ofinfectious disease in extensively managed livestock populations. Seasonal changes inanimal densities and contact rates may impact the results of the models. Additionally, theeffect of multiple livestock types on premises should be considered when the expectedspread of disease is modeled in extensive livestock areas.