Estimating US dairy clinical disease costs with a stochastic simulation model.

A farm-level stochastic model was used to estimate costs of 7 common clinical diseases in the United States: mastitis, lameness, metritis, retained placenta, left-displaced abomasum, ketosis, and hypocalcemia. The total disease costs were divided into 7 categories: veterinary and treatment, producer labor, milk loss, discarded milk, culling cost, extended days open, and on-farm death. A Monte Carlo simulation with 5,000 iterations was applied to the model to account for inherent system variation. Four types of market prices (milk, feed, slaughter, and replacement cow) and 3 herd-performance factors (rolling herd average, product of heat detection rate and conception rate, and age at first calving) were modeled stochastically. Sensitivity analyses were conducted to study the relationship between total disease costs and selected stochastic factors. In general, the disease costs in multiparous cows were greater than in primiparous cows. Left-displaced abomasum had the greatest estimated total costs in all parities ($432.48 in primiparous cows and $639.51 in multiparous cows). Cost category contributions varied for different diseases and parities. Milk production loss and treatment cost were the 2 greatest cost categories. The effect of market prices were consistent in all diseases and parities; higher milk and replacement prices increased total costs, whereas greater feed and slaughter prices decreased disease costs.

An ultrasonographic scoring method for transabdominal monitoring of ascarid burdens in foals.

REASONS FOR PERFORMING STUDY: Parascaris spp. infections can lead to life-threatening small intestinal impactions in foals. Currently available diagnostic techniques cannot estimate the magnitude of an ascarid burden, and hence identify foals potentially at risk of developing impactions. OBJECTIVES: To describe and evaluate an ultrasonographic transabdominal scoring technique for monitoring of ascarid burdens in foals and to perform a cost-benefit analysis of the application of this technique. STUDY DESIGN: A transabdominal ultrasonographic technique was validated against ascarid worm counts from 10 foals aged 162-294 days. In a treatment trial, 15 foals were randomly allocated to 3 treatment groups: ivermectin, oxibendazole and no treatment. Blinded ultrasound examinations were performed daily for 5 consecutive days following treatment. Foals were examined ultrasonographically twice by the same investigator, and by different investigators for intra- and interobserver agreement evaluation. Cost-benefit analyses identified threshold values for the probability of ascarid impactions above which the screening method becomes cost-effective. METHODS: The ultrasound technique used 3 locations along the ventral midline. An ascarid scoring system was established that assessed the magnitude of ascarid burden ranging from 1-4. The method was validated against worm burdens of 10 worms and above with calculation of diagnostic specificity, sensitivity, and predictive values. Treatment trial data were evaluated statistically using mixed model analysis. Kappa values were generated for intra- and interobserver agreement. RESULTS: Two consecutive examinations were found to detect worm burdens >10 ascarids reliably. Ascarid scores declined in response to both anthelmintic treatments, although differences were not statistically significant. Kappa values indicated fair to moderate intra- and interobserver agreements. The majority of cost-benefit analyses indicated that ultrasound examinations are cost effective when the probability of ascarid impactions is above a range of 0.0001-0.0082 (i.e. 1 in 10,000 to 8 in 1000 foals). CONCLUSIONS: The ultrasonographic screening techniques can be a useful tool for monitoring ascarid burdens in foals.

Attitudes towards implementation of surveillance-based parasite control on Kentucky Thoroughbred farms - Current strategies, awareness and willingness-to-pay.

REASONS FOR PERFORMING STUDY: Traditionally, equine parasite control has relied heavily on frequent routine anthelmintic treatments applied at regular intervals all year round. However, current recommendations aim to employ a more surveillance-based approach and it remains unknown to what extent these recommendations are being implemented on US horse farms. OBJECTIVES: To describe equine parasite control on Kentucky Thoroughbred farms and evaluate respondents' willingness to pay for various attributes of surveillance-based parasite control strategies. STUDY DESIGN: Questionnaire survey performed among the membership of the Kentucky Thoroughbred Farm Managers' Club. METHODS: The survey collected demographic data and information about current parasite control strategies. Further, respondents were asked to choose between hypothetical parasite control strategies described with a combination of different attributes: costs, time and effort needed, hypothetical disease-risk levels and hypothetical risks of anthelmintic resistance. Data were analysed with multivariable logistic analysis. RESULTS: About 26% responded to the survey (n = 112). Most respondents were concerned about anthelmintic resistance and incorporated veterinary advice in defining their deworming programme. However, almost 70% were following a traditional rotational deworming programme with little or no faecal surveillance. Respondents were willing to pay a premium for a product for which there is no known anthelmintic resistance and provided the highest possible decrease in health risks. The number of young horses on the farm, utilisation of veterinarian advice in developing a deworming programme, expressed concern about drug resistance in parasites and having documented drug resistance on the farm all associated significantly with the type of parasite control programme used. CONCLUSIONS: Traditional approaches for equine parasite control are still widely used in the Kentucky Thoroughbred industry. The data suggest that respondents were only willing to make these changes if they could be given assurance that the surveillance-based approach would prevent anthelmintic resistance and decrease health risks significantly for the horses.