Epidemiological and Economic Evaluation of Alternative On-Farm Management Scenarios for Ovine Footrot in Switzerland

Abstract

Footrot is a multifactorial infectious disease mostly affecting sheep, caused by the bacteria Dichelobacter nodosus. It causes painful feet lesions resulting in animal welfare issues, weight loss, and reduced wool production, which leads to a considerable economic burden in animal production. In Switzerland, the disease is endemic and mandatory coordinated control programs exist only in some parts of the country. This study aimed to compare two nationwide control strategies and a no intervention scenario with the current situation, and to quantify their net economic effect. This was done by sequential application of a maximum entropy model (MEM), epidemiological simulation, and calculation of net economic effect using the net present value method. Building upon data from a questionnaire, the MEM revealed a nationwide footrot prevalence of 40.2%. Regional prevalence values were used as inputs for the epidemiological model. Under the application of the nationwide coordinated control program without (scenario B) and with (scenario C) improved diagnostics [polymerase chain reaction (PCR) test], the Swiss-wide prevalence decreased within 10 years to 14 and 5%, respectively. Contrary, an increase to 48% prevalence was observed when terminating the current control strategies (scenario D). Management costs included labor and material costs. Management benefits included reduction of fattening time and improved animal welfare, which is valued by Swiss consumers and therefore reduces societal costs. The net economic effect of the alternative scenarios B and C was positive, the one of scenario D was negative and over a period of 17 years quantified at CHF 422.3, 538.3, and −172.3 million (1 CHF = 1.040 US$), respectively. This implies that a systematic Swiss-wide management program under the application of the PCR diagnostic test is the most recommendable strategy for a cost-effective control of footrot in Switzerland.

A genome‐wide significant association on chromosome 2 for footrot resistance/susceptibility in Swiss White Alpine sheep

“…Ovine footrot is a contagious disease caused by Dichelobacter nodosus , a gram negative and obligate anaerobic bacteria from the Cardiobacteriaceae family (Clifton & Green ; Zingg et al . ). It is one of the most important causes of lameness in sheep and is characterized by infection of the interdigital skin (Bennett et al .…”

“…The disease phenotype can vary greatly from mild lameness with no other clinical signs to extreme lameness or locomotion on the carpal joints accompanied by secondary signs such as reduced wool growth/quality, poor fertility and poor growth rates (Zingg et al . ). Affected sheep are often weak and, as a consequence, more susceptible to other diseases (Conington et al .…”

The prevalence of Dichelobacter nodosus in clinically footrot-free sheep flocks: a comparative field study on elimination strategies

“…Regional elimination programs are usually aimed at virulent D nodosus, as large-scale elimination of benign D nodosus is not economically justifiable [25]. In Switzerland, the use of the PCR test was found to be the most economic and sensitive way to eliminate footrot in the planned nationwide control program [18]. Moreover, the PCR test can be applied to other ruminants like goats and cattle or camelids, which is important for targeted disease control [26].…”

“…Footrot is the economically most relevant infectious hoof disease in sheep [16]. Cost-benefit-analyses support elimination programs to obliterate the disease [14,17,18]. Different treatment strategies have been assessed all over the world, ranging from total elimination of the causative agent by culling infected flocks to genetic selection of resistant animals and use of specific vaccines [19,20].…”

Identifying maintenance hosts for infection with Dichelobacter nodosus in free-ranging wild ruminants in Switzerland: A prevalence study

“…Among domestic ruminants, mainly sheep are affected. Footrot is endemic in sheep flocks worldwide, including Switzerland [3]. In free-ranging wildlife, footrot has been documented in several European countries, affecting Alpine ibex (Capra ibex ibex) and mufflon (Ovis orientalis orientalis) [1,[4][5][6] (Meneguz, Frey and Ryser, unpublished data).…”