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Anthelmintic resistance among cyathostomin parasites is a wide-spread problem. The parasite control guidelines written by the American Association of Equine Practitioners (AAEP) encourages the preservation of anthelmintic efficacy by reducing treatment frequency, using targeted deworming, and implementing environmental management practices. While there is knowledge regarding parasite management practices of affluent horse farms in the United States, surveys rarely explore the rural and underserved regions. The purpose of this study was to observe the management practices of horse farms in rural regions Kentucky, including working Amish farms, and determine factors associated with strongyle prevalence. A total of 160 horses among 38 owners from 28 different farms were enrolled in this study. A questionnaire survey regarding equine information, farm management, and deworming history was performed with each owner. Fecal samples were collected to determine fecal egg counts, perform coprocultures for subsequent strongyle larvae identification, and Strongylus vulgaris specific PCR. Serum samples were collected for the S. vulgaris antibody specific ELISA. The mean number of deworming treatments given in the last year was 2.1 with a 95% confidence interval of 1.9-2.3 with ivermectin being the most common active used. Statistical analysis showed horses treated within the last three months with a macrocylic lactone (ML) drug had significantly lower egg counts than horses treated with a ML 7-9 months ago (p = .0005). Despite the AAEP recommendations to reduce the overall number of treatments by using a surveillance-based approach and to no longer rotate treatments, only 17 horses reportedly had a fecal sample submitted for a fecal egg count and 65 horses were dewormed in a rotational manner. Horses whose owners utilized an informative deworming source (i.e., veterinarian, internet, magazine, local feed store) also had significantly lower counts (p = .0026). All coprocultures were negative for S. vulgaris while five horses were PCR positive. Interestingly, 95 horses tested ELISA positive for S. vulgaris. The strongyle egg counts of the working Amish horses were not significantly different from the other horses in this study and deworming practices including the use of efficacious drugs and low treatment frequencies were in accordance with the AAEP guidelines. This study was the first to summarize deworming management practices of rural regions in Kentucky, including a working Amish community. Overall, horse owners employed deworming practices recommended by the AAEP, however rotational deworming is still commonly implemented and fecal egg counts are rarely used., (Copyright © 2018 Elsevier B.V. All rights reserved.)

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., (© 2014 EVJ Ltd.)

Strongyle parasites are ubiquitous in grazing horses, and the large strongyle Strongylus vulgaris is considered the most pathogenic helminth parasite of horses. Recent investigations have suggested an association between occurrence of this parasite and usage of selective therapy based on regular fecal egg counts. The established diagnostic method for S. vulgaris involves larval culture and subsequent morphological identification of third stage larvae under the microscope. Recently, a real-time PCR assay was developed and validated for the detection and semi-quantification of S. vulgaris eggs in equine fecal samples. The purposes of the present study were (a) to determine the presence of S. vulgaris by real-time PCR in Danish and American horses on farms using vastly different anthelmintic treatment regimens and (b) to evaluate the association between larval culture results and the PCR. A total of 991 horses representing 53 different horse farms in Denmark and Central Kentucky were studied. Fresh fecal samples were collected from all horses, and strongyle eggs retrieved for DNA extraction and subsequent real-time PCR analysis. Individual larval cultures were performed on the Danish part of the data set (663 horses on 42 farms). On the Danish farms, the S. vulgaris PCR prevalence was found to be 9.2% on farms not basing parasite control on fecal egg counts, and 14.1% on farms using selective therapy. No horses were PCR positive in the American part of the study (328 horses on 11 farms). Kappa-values indicated a moderate agreement between PCR and larval culture results, while McNemar tests revealed no statistical difference between the paired proportions. Significant associations were found between PCR cycle of threshold (Ct) value groups and larval culture counts. Results indicate that both diagnostic methods can be useful for determining the occurrence of S. vulgaris on horse farms, but that they both are affected by potential sources of error. The PCR results confirmed previous findings suggesting that S. vulgaris can reemerge under selective therapy regimens., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Increasing levels of anthelmintic resistance in equine nematodes have led to recommendations of more sustainable anthelmintic treatment protocols with emphasis on parasite surveillance and diagnosis, rather than prophylactic calendar-based treatments. This requires knowledge of the diagnostic test performance of techniques for counts of eggs per gram of feces (EPG) as well as methods for culturing, counting and identifying third stage (L(3)) strongyle larvae per gram of feces (LPG). For horses, such information does not exist in the published literature. The aim of this study was to examine the relationship between worm count and fecal egg count (FEC) data for strongyle and Parascaris equorum infections as well as larval culture counts for diagnosing Strongylus spp. infections. Necropsy data from 693 horses used for critical or controlled tests, including information on total worm counts, fecal egg counts (FEC) and larval culture results collected at the University of Kentucky over a period of 50 years were analyzed. Sensitivity, specificity, positive and negative predictive values, and receiver operator characteristic (ROC) curves were generated for the larval cultures and ascarid egg counts. For the strongyle egg counts, potential FEC cutoff values for treatment were evaluated statistically by comparing the total strongyle worm counts below and above chosen cutoff values. All tests had high positive predictive values (>0.95), but moderate negative predictive values (<0.70). The negative predictive values of the larval counts were negatively affected by increasing egg count levels. Strongyle FEC cutoff values up to the level of 500 EPG yielded significantly higher strongyle worm counts in the treatment group, whereas no differences were found at higher cutoffs. This supports usage of cutoffs for treatment in the 0-500 EPG range. Altogether, the present study yields unique and useful information of widely used methods for parasite surveillance and diagnosis in equine establishments., (Copyright © 2010 Elsevier B.V. All rights reserved.)