Pharmacokinetics/pharmacodynamics cut-off determination for fosfomycin using Monte Carlo simulation in healthy horses.

Fosfomycin (FOM) is an approved veterinary medicinal product for large animals in Japan, but Clinical breakpoint (CBP) for antimicrobial susceptibility test (AST) is not defined for animals. This study aimed at conducting a pharmacokinetics/pharmacodynamics (PK/PD) analysis to determine the PK/PD cutoff for the CBP in horses. Drug concentrations following single intravenous administration (IV) of 20 mg/kg body weight (BW) FOM in nine horses were measured using liquid chromatography/mass spectrometry. The data were modelled using a nonlinear mixed-effects model, followed by Monte Carlo simulations. A 90% probability of target attainment for a PK/PD target of the ratio of Area Under the free plasma concentration-time curve divided by the minimal inhibitory concentration (MIC) >24 hr was set as PK/PD cut-off. The PK/PD cutoff for FOM 20 mg/kg BW q12 hr IV was estimated with the MIC value of ≤16.0 mg/L, and this regimen was considered effective against E. coli (MIC90; 16.0 mg/L) in healthy horses based on the MIC90 values of the wild population. Owing to the relevance of FOM to human health, veterinarians should use q 12 hr FOM 20 mg /kg against E. coli infections with an MIC <16 µg/mL, as suggested by our PK/PD cutoff after AST.

Ultrasonographic Assessment of Small Intestinal Motility Following Hyoscine Butylbromide Administration in Horses: A Pilot Study.

Horses commonly receive hyoscine butylbromide (HB) prior to hospital admission for colic. This could alter the appearance of the small intestine (SI) on ultrasound scan and affect clinical decision making. The aim of this study was to assess the impact of HB on ultrasonographically assessed SI motility and heart rate. Six horses hospitalised for medical colic with no significant abnormalities on baseline abdominal ultrasound examination were included. Ultrasound was performed in three locations (right inguinal, left inguinal and hepatoduodenal window) before and at 1, 5, 15, 30, 45, 60, 90, and 120 minutes after intravenous injection of 0.3 mg/kg HB. Three blinded reviewers assessed SI motility using a subjective grading scale from 1 to 4, one being normal motility and four being no motility. Moderate interindividual and interobserver variability was observed, but none of the included horses developed dilated turgid loops of SI. Hyoscine butylbromide did not significantly reduce SI motility grade in any location (P = .60 left inguinal, P = .16 right inguinal, P = .09 duodenum). Heart rate (mean ± SD) was 33 ± 3 prior to HB injection and peaked at 71.3 ± 9 one-minute postinjection. Heart rate was significantly increased until 45 minutes (48 ± 9) after HB administration (P = .04). The appearance of dilated turgid SI loops common with strangulating intestinal lesions did not appear to develop following HB administration. Hyoscine butylbromide administered shortly before abdominal ultrasound examination would not be expected to affect clinical decision making in horses without small intestinal disease.

Mechanical nociceptive assessment of the equine hoof after navicular bursa anesthetic infiltration validated by bursography.

The analgesic specificity of navicular bursa (NB) anesthetic infiltration is still questionable. The study aimed to determine the mechanical nociceptive threshold of non-specific analgesia in the dorsal lamellar stratum, as well as in the sole, coronary band, and heel bulbs of the hoof, after navicular bursa anesthetic infiltration. Six healthy horses with no clinical or radiographic changes of the digits and no communication between the NB and the distal interphalangeal joint, were used. After random selection, the NB of one of the forelimbs was infiltrated with 2% lidocaine and the contralateral one with lactated ringer's solution. Contrast was added to confirm radiographic infiltration. The mechanical nociceptive threshold was determined using a portable pressure dynamometer, before and at various times after the infiltration, in 10 points of the hoof. The effects of time and treatment were verified by ANOVA (P<0.05). There was no statistical difference in the values of the mechanical nociceptive threshold (P>0.05) in all regions evaluated. However, in one of the six hooves that receives lidocaine, complete absence of response to the painful stimulus (maximum force of 6 Kg over an area of 38.46 mm2, for a maximum of 4 seconds) was observed in the dorsal lamellae between 30 and 60 min after infiltration. In conclusion, lidocaine infiltration of NB did not promote significant increases in the nociceptive threshold of the sole, coronary band, bulbs of the heel and dorsal lamellae clinically healthy horses. However, the occurrence of analgesia in one of the six hooves subjected to NB anesthesia indicates that the technique may not be fully specific in few horses.

An assessment of the effectiveness of hyaluronic acid and polyacrylamide hydrogel in horses with osteoarthritis: Systematic review and network meta-analysis.

For several years, hyaluronic acid (HyA) and, more recently, polyacrylamide hydrogel (PHyd) have been used to reduce lameness and pain caused by osteoarthritis. However, there is still a lack of scientific evidence of the efficacy of these substances to allow veterinary experts to make decisions about their use in horses. The objective of this study was to evaluate, through a systematic review and network meta-analysis (NMA), the efficacy of HyA, associated or not with other drugs, and PHyd in relieving lameness in horses with osteoarthritis. The searches for primary studies were conducted on four search platforms. The efficacy of HyA and PHyd was estimated through the relative risk difference method. Heterogeneity was observed in the efficacy of HyA, indicating long-term ineffectiveness of this drug when associated or not with anti-inflammatory drugs. In contrast, the results indicate that PHyd is an effective alternative therapy, with a long period of action in reducing lameness in horses with osteoarthritis. This study provides evidence that the application of PHyd and HyA is effective in reducing lameness caused by osteoarthritis in horses at different time periods, where PHyd has a longer time of action.

Monitoring equine ascarid and cyathostomin parasites: Evaluating health parameters under different treatment regimens.

BACKGROUND: Strongylid and ascarid parasites are omnipresent in equine stud farms, and ever-increasing levels of anthelmintic resistance are challenging the industry with finding more sustainable and yet effective parasite control programs. OBJECTIVES: To evaluate egg count levels, bodyweight and equine health under defined parasite control protocols in foals and mares at two Standardbred and two Thoroughbred stud farms. STUDY DESIGN: Longitudinal randomised field trial. METHODS: A total of 93 foals were enrolled and split into two treatment groups, and 99 mares were enrolled and assigned to three treatment groups. All horses underwent a health examination, and episodes of colic or diarrhoea were recorded at each faecal collection date. Bodyweights were assessed using a weight tape, and mares were body condition scored. Group A foals (FA) were dewormed at 2 and 5 months of age with a fenbendazole/ivermectin/praziquantel product, while group B foals (FB) were dewormed on a monthly basis, alternating between the above-mentioned product and an oxfendazole/pyrantel embonate product. Group A mares (MA) were dewormed twice with fenbendazole/ivermectin/praziquantel, group B mares (MB) were dewormed with the same product, when egg counts exceeded 300 strongylid eggs per gram, and group C mares (MC) were dewormed every 2 months, alternating between the two products. Health data were collected monthly for 6 months (foals) and bimonthly for 13 months (mares). Data were analysed with mixed linear models and interpreted at the α = 0.05 significance level. RESULTS: There were no significant bodyweight differences between foal groups, but MA mares were significantly lighter than the other two groups. Very few health incidents were recorded. Foals in group FA had significantly higher ascarid and strongylid egg counts, whereas no significant differences were observed between mare groups. MAIN LIMITATIONS: Study duration limited to one season. CONCLUSIONS: Anthelmintic treatment intensity was lowered from the traditional intensive regimes without measurable negative health consequences for mares and foals.

In vitro assessment of triterpenoids NVX-207 and betulinyl-bis-sulfamate as a topical treatment for equine skin cancer.

Equine sarcoid (ES) is the most prevalent skin tumor in equids worldwide. Additionally, aging grey horses frequently suffer from equine malignant melanoma (EMM). Current local therapies targeting these skin tumors remain challenging. Therefore, more feasible topical treatment options should be considered. In order to develop a topical therapy against ES and EMM, betulinyl-bis-sulfamate and NVX-207, derivatives of the naturally occurring betulin and betulinic acid, respectively, were evaluated for their antiproliferative (crystal violet staining assay), cytotoxic (MTS assay) and apoptotic (AnnexinV staining, cell cycle investigations) effects on primary ES cells, EMM cells and equine dermal fibroblasts in vitro. The more potent derivative was assessed for its in vitro penetration and permeation on isolated equine skin within 30 min and 24 h using Franz-type diffusion cells and HPLC analysis. Betulinyl-bis-sulfamate and NVX-207 inhibited the proliferation and metabolism in ES cells, EMM cells and fibroblasts significantly (p < 0.001) in a time- and dose-dependent manner. NVX-207 had superior anticancer effects compared to betulinyl-bis-sulfamate. Both compounds led to the externalization of phosphatidylserines on the cell membrane and DNA fragmentation, demonstrating that the effective mode of action was apoptosis. After 48 h of treatment with NVX-207, the number of necrotic cells was less than 2% in all cell types. Detected amounts of NVX-207 in the different skin layers exceeded the half-maximal inhibitory concentrations calculated by far. Even though data obtained in vitro are auspicious, the results are not unconditionally applicable to the clinical situation. Consequently, in vivo studies are required to address the antitumoral effects of topically applied NVX-207 in ES and EMM patients.

Assessment of Antimicrobial Susceptibility of Virulent Strains of Rhodococcus equi Isolated From Foals and Soil of Horse Breeding Farms With and Without Endemic Infections.

Rhodococcus equi is an opportunistic, intracellular saprophyte that causes severe pyogranulomatous pneumonia in foals. The bacterium displays in vitro susceptibility to many antibiotics. The highest efficacy against R. equi in vitro and in vivo is achieved by using a combination of rifampicin and macrolide antibiotics. Recent years have seen an upward trend in the minimum inhibitory concentration (MIC) of rifampicin and erythromycin, suggesting increasing resistance of R. equi to these antibiotics. The aim of the study was to determine the antimicrobial activity of 24 selected antibiotics against R. equi strains isolated from dead foals and from the environment of horse breeding farms with and without endemic R. equi infections. Minimum inhibitory concentration gradient strips were used to determine the lowest concentration of the antibiotic that inhibited the growth of R. equi. Based on normal MIC distribution, an epidemiologic cutoff values (ECOFF) were assessed for particular antibiotics and R. equi strains. The results were compared with ECOFFs for S. aureus, according to the European Committee on Antimicrobial Susceptibility Testing data. The data indicate that the lowest MIC values were obtained for clarithromycin, rifampicin, imipenem, and vancomycin. The majority of R. equi strains can be classified as wild type in relation to the majority of antibiotics. A small percentage of strains presented non-WT (NWT) with the exception of SXT, for which 35% of strains were classified as NWT. The lack of interpretative criteria for R. equi creates a real problem in the assessment of antibiotic sensitivity both for clinical and scientific purposes.

Assessment of the anti-inflammatory and engraftment potential of horse endometrial and adipose mesenchymal stem cells in an in vivo model of post breeding induced endometritis.

Horse mesenchymal stem cells (MSC) are potential anti-inflammatory tools for post-breeding induced endometritis (PBIE). In this research MSCs isolated from the endometrium or subcutaneous fat of the same donors were infused iu into mares with PBIE for assessment of their anti-inflammatory action and engraftment. PBIE was induced in nine gynecologically healthy mares by iu infusion of 500 million dead sperm in saline. Inflammatory markers were analyzed in uterine lavages and biopsies immediately before (phase I) and 3 h after infusion of sperm (phase II). Measurements: polymorph nuclear cells (PMN), proteins IL-6 and TNFα (ELISA in the lavages) and immunostaining in biopsies, transcripts of IL-1α, 6, 8, 10, TNFα and COX2 (qPCR of pelleted lavages). At 24 h after sperm deposition (phase III), mares were instilled iu with 20 ml of saline containing 2 × 107 adipose MSCs (n = 3, group 1) or endometrial MSCs (n = 3, group 2). Cells were labeled previously with carboxyfluorescein diacetate succinimidyl ester (CFDA SE). A third group (n = 3) received 20 mL of sterile saline alone. After 48 h another biopsy/lavage were done and the same parameters analyzed. For engraftment, additional biopsies were taken at days 10 and 30 of sperm infusion and analyzed by confocal microscopy. Dead sperm in saline markedly increased PMNs counts, IL-6 and TNFα expression in the ELISA (p < 0.05) and immunostaining. In phase III a significant reduction (p < 0.0001) of PMN was found in all samples, including control mares. A decrease (p < 0.05) of IL-6 and TNF-α was detected by ELISA, in the groups that received MSC, but not in control group. In the aMSC-treated group, a significant decrease was found in the expression of (IL1α, p = 0.0003; IL-6 p 0.04; IL-8, p = 0.006, TNFα p = 0.004). Expression of IL-10 and COX2 remained unchanged (p = 0.08). In the mares that received eMSC, IL-6 and 8 decreased significantly (p = 0.01), IL-10 increased (p = 0.009), while TNFα, COX2 and IL1α did not significantly change their expression. In the engraftment experiment CFDA label was found sparingly in all the samples analyzed until day 30, mainly at the stromal compartment of the endometrium. No differences in the engraftment pattern was found among cell origins. We conclude that inoculation of MSCs significantly reduced inflammation independently of the origin of the cells and that cells perform limited engraftment detectable after one month of infusion. These findings can be of help for the design of new anti-inflammatory therapies of uterine diseases in mares.

Quantitative assessment of intravenous regional limb perfusion of tiludronate as an adjunctive treatment for lameness caused by navicular syndrome in horses.

OBJECTIVE To determine effects for 2 IV regional limb perfusion (IVRLP) protocols involving tiludronate on lameness of horses with navicular syndrome. ANIMALS 15 horses with bilateral forelimb navicular syndrome. PROCEDURES Shoeing and anti-inflammatory injection into the distal interphalangeal joint (DIPJ) of both forelimbs (day 0) were performed on all horses. On day 14, horses received 1 of 3 IVRLPs consisting of 0.1 mg of tiludronate/kg (low-dose tiludronate [LDT]; n = 5), 0.2 mg of tiludronate/kg (high-dose tiludronate [HDT]; 5), or saline (0.9% NaCl) solution (placebo; 5); treatments were repeated at days 24 and 34. Lameness severity of both forelimbs was evaluated via subjective evaluation and force plate analysis before and after shoeing on day 0 and at days 14, 34, 60, and 120. Mean subjective lameness score and peak vertical ground reaction force (PVGRF) for the more severely lame forelimb (LFL) and both (combined) forelimbs (CFL) were compared over time. RESULTS For all horses, mean PVGRF for the LFL and CFL was increased at 14 days. No difference in mean subjective lameness score or mean PVGRF was detected within groups at any time. Mean PVGRF of the CFL was higher for the HDT group than the LDT and placebo groups only at 120 days. CONCLUSIONS AND CLINICAL RELEVANCE Use of the tiludronate IVRLP protocols described here provided no further improvement in lameness over therapeutic shoeing and anti-inflammatory injection of the DIPJ in horses with navicular syndrome. However, HDT-treated horses were objectively less lame than LDT- or placebo-treated horses at 120 days.

Assessment of Draxxin® (tulathromycin) as an inhibitor of in vitro growth of Babesia bovis, Babesia bigemina and Theileria equi.

Babesia bovis, Babesia bigemina and Theileria equi are worldwide tick-borne hemoprotozoan that cause diseases characterized by fever, anemia, weight loss and abortion. A common feature of these diseases are transition from acute to chronic phases, in which parasites may persist in the host for life, and becoming a reservoir for tick transmission. The live-attenuated vaccines for B. bovis and B. bigemina are not available for worldwide use due to legal restrictions and other concerns such as potential erythrocyte antigen and pathogen contamination, and a vaccine for T. equi is not available. The use of chemotherapeutics is essential to treat and control these diseases, but several studies have shown the development of drug-resistance by these parasites, and safe and effective alternative drugs are needed. Tulathromycin, a macrolide antibiotic, has proven to be effective against a vast range of bacteria and Plasmodium yoelli, a Babesia and Theileria related intra-erythrocytic apicomplexan. Draxxin® (tulathromycin) is currently licensed to treat infections that cause respiratory diseases in cattle in several countries. In this study, the activity of Draxxin® was tested in vitro on cultured B. bovis, B. bigemina and T. equi. Addition of the drug to in vitro cultures resulted in cessation of parasite replication of the three species tested, B. bovis, B. bigemina and T. equi, with estimated IC50 of 16.7 ±â€¯0.6 nM; 6.2 ±â€¯0.2 nM and 2.4 ±â€¯0.1 nM, respectively, at 72 h. Furthermore, neither parasites nor parasite DNA were detectable in cultures treated with IC100, suggesting Draxxin® is a highly effective anti-Babesia/Theileria drug. Importantly, the IC50 calculated for Draxxin® for the Babesia/Theileria parasites tested is lower that the IC50 calculated for some drugs currently in use to control these parasites. Collectively, the data strongly support in vivo testing of Draxxin® for the treatment of bovine babesiosis and equine piroplasmosis.

An estimation of US horse-owner/caregiver willingness-to-pay for daily use and infectious upper respiratory disease treatment options.

BACKGROUND: Equine injury and disease cause two types of costs for those financially responsible for treating and caring for the infected horse(s); direct costs of treating the horse and indirect cost of lost use of the horse for a period of time to the user of the horse (daily horse use). Indirect costs are more difficult to estimate but pose significant financial implications for equine-owners/caregivers. Additionally, there exists a gap in existing research regarding the valuation of infectious treatment options in horses. OBJECTIVE: To estimate the value a US horse-owner/caregiver places on daily horse use and describe respondents' willingness-to-pay for various attributes of equine treatment options. STUDY DESIGN: Online questionnaire survey. METHODS: An online questionnaire was provided to equine-owners and caretakers, and owner demographic, horse care and horse use information from respondents were requested. Additionally, respondents were presented with hypothetical disease treatment options with the following attributes: daily dosage, number of days of rest required, route of administration and out-of-pocket cost to the owner/caretaker through a choice experiment. Data were analysed using a rank-ordered logit analysis and willingness-to-pay estimates for daily use and treatment options were calculated. RESULTS: Results suggest that the average horse-owner with an uninsured and insured horse is willing to pay $12.07 (95% confidence interval: -$15.01, -$9.69) and $17.95 (95% confidence interval: -$25.30, -$11.20) per day to reduce lost use days required (due to need for rest) respectively. Respondents showed preferences for oral administration over treatments requiring i.m. injections. MAIN LIMITATIONS: As this study employed an online survey it was subjected to self-selection bias and a sample size calculation was not performed. CONCLUSIONS: Veterinarians and pharmaceutical companies may use these results when promoting various treatment options to horse-owners/caregivers and in product development. Additionally, promotion efforts may be targeted towards equine-owners with higher daily use values (owners with insured horses).

Management practices associated with strongylid parasite prevalence on horse farms in rural counties of Kentucky.

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.

A survey of UK prescribers' experience of, and opinions on, anthelmintic prescribing practices for livestock and equines.

The aim of this study was to determine practices, attitudes and experiences of UK prescribers of anthelmintics for horses and livestock. A questionnaire was sent by direct email to groups licenced to prescribe these medicines. These were veterinarians, Suitably Qualified Persons (SQPs, registered with the Animal Medicines Training Regulatory Authority) and veterinary pharmacists. The survey was also advertised through social media. It comprised questions relating to demographics, training experiences, current prescribing practices, as well as personal opinions on anthelmintic selection, diagnostics and anthelmintic resistance. A total of 193 veterinarians and 326 SQPs were included in final analysis. Pharmacists were excluded from detailed analysis due to the low numbers that responded (n=3). The results indicated that SQP participants were more likely to receive post-certification parasitology training than the veterinarians, and that both channels consulted similar sources for information about helminths and their control (paper articles in journals, online sources). The SQP participants stated a higher frequency of face-to-face interactions with clients/customers (96.1%) than the veterinarians (76.4%), who stated a higher frequency of telephone interactions (55.1% and 73.5%, respectively). Veterinarians were more likely to state that there were specific factors that limited interactions with their clients (54.1%) than SQPs (19.6%), such as competition from other suppliers. SQP participants considered a wider range of factors as important when deciding on which anthelmintic to recommend (i.e. knowledge of specific parasites, knowledge of specific anthelmintics, discussion of measures to avoid anthelmintic resistance and time to talk with clients/customers); however, the veterinarian participants were more likely to consider the results of diagnostic tests. While discussions about anthelmintic resistance were stated with similar frequency in both groups, less frequent were specific discussions about anthelmintic sensitivity testing. In-house faecal egg count analysis was more likely to be available from those that prescribed anthelmintics for equines alone, compared to prescribers who dispensed anthelmintics for livestock alone or livestock and equines. The SQP participants indicated that they felt a large number of organisations were responsible for ensuring that anthelmintics are used responsibly, whilst veterinarian participants were more likely to place responsibility on the prescribers alone. Taken together, these findings provide an insight into how prescribers of anthelmintics in the UK interact with their clients/customers before and at the point of sale and act as a unique source of information on how best practice advice pertaining to sustainable helminth control is disseminated by the various prescribing channels.

Quantitative assessment of two methods of tiludronate administration for the treatment of lameness caused by navicular syndrome in horses.

OBJECTIVE: To determine effects of 2 tiludronate administration protocols on measures of lameness in horses with navicular syndrome (NS). ANIMALS: 12 horses with bilateral forelimb NS. PROCEDURES: Horses were randomly assigned to receive tiludronate (1 mg/kg), diluted in 5 L of isotonic electrolyte solution and delivered through a jugular vein catheter (systemic treatment group; n = 6), or tiludronate (0.1 mg/kg), diluted with saline (0.9% NaCl) solution to a total volume of 35 mL and delivered into the lateral digital vein of each forelimb with an IV regional limb perfusion (IVRLP) technique (IVRLP group; 6). Mean peak vertical ground reaction force (pVGRF) measured with a stationary force plate and subjective lameness scores (SLSs) were recorded before (day -1) and at predetermined time points after tiludronate administration on day 0. Mean pVGRFs (standardized as percentage body weight of force) and mean SLSs for the most lame forelimb and for both forelimbs of horses in each group were compared with day -1 values to determine treatment effect. RESULTS: Mean pVGRF for both forelimbs and for the most lame forelimbs of systemically treated horses were significantly increased on days 120 and 200, compared with day -1 results. No significant difference in mean pVGRF was observed for IVRLP-treated horses. The SLSs were not improved at any time point following systemic treatment and were improved only on day 120 following IVRLP. CONCLUSIONS AND CLINICAL RELEVANCE: Tiludronate (1 mg/kg, IV) as a single systemic treatment appeared to be beneficial for horses with NS, but no horses were judged as sound during the study period. Additional research on IVRLP with tiludronate is needed before this method can be recommended.

Economic assessment of FEC-based targeted selective drenching in horses.

In the face of an increased prevalence of drug-resistant cyathostomin populations, a targeted selective treatment (TST) strategy based on Faecal Egg Counts (FECs) has been proposed as an alternative management strategy. However, associated costs may be a barrier to the uptake of this strategy. Our study aims to provide an economic assessment of FEC-based TST. FECs were determined in a Welsh pony herd thrice a year from 2010 to 2014. This database was used to explore the impact of FEC price, sampling strategy (individual or pooled) and labour-associated costs. Drug price was set at the cheapest level, hence providing a conservative framework to determine the maximum viable FEC price in the context of a cost-driven horse industry. The maximum viable FEC price for a cost-efficient individual based strategy was determined by an in silico bootstrap approach consisting of randomly sampling 1000 virtual pony herds of various sizes (1 to 100 ponies) from the available database and estimating the associated costs (FEC price ranging from € 1 to € 10, anthelmintic costs and labour-associated costs). The costs and benefits of the pooling strategy that consists of basing the decision to treat on group FEC values were also investigated. This is thought to reduce FEC-based costs but may result in highly infected individuals being left undrenched, i.e. in false-negatives, as a result of FEC overdispersion. For various pool-sizes (1-20 ponies) and various cut-off thresholds (50-200 eggs/g), we sampled 1000 pony herds in silico to estimate the associated costs and determine the number of positive ponies within a negative pool. Following these simulations, pool-based FECs of various sizes were performed on 40 ponies to compare predictions with real data. Within 4 years, anthelmintic costs were cut by 80%, albeit with free FECs. In silico estimations suggested that an individual FEC-based TST would not be cost-efficient in this context for an FEC price above € 5. With a pooled FEC strategy, the proportion of false-negatives never exceeded 15% of the pool size. The combination of a 14-pony pool and a cut-off value of 150 eggs/g minimized total costs while keeping the number of false negatives to a reasonable level. Real data obtained from infected ponies however, suggested that pool size should not exceed 10 individuals, since the inhomogeneous mixing of faeces of larger pools probably reduced the correlation between average pooled FECs and the mean of individual FECs. Our study provides an economic framework that could be valuable for emphasizing the use of FEC-based approaches in the field.

Equine parasite control under prescription-only conditions in Denmark--awareness, knowledge, perception, and strategies applied.

Due to widespread development of anthelmintic resistance in equine parasites, recommendations for their control are currently undergoing marked changes with a shift of emphasis toward more coprological surveillance and reduced treatment intensity. Denmark was the first nation to introduce prescription-only restrictions of anthelmintic drugs in 1999, but other European countries have implemented similar legislations over recent years. A questionnaire survey was performed in 2008 among Danish horse owners to provide a current status of practices and perceptions with relation to parasite control. Questions aimed at describing the current use of coprological surveillance and resulting anthelmintic treatment intensities, evaluating knowledge and perceptions about the importance of various attributes of parasite control, and assessing respondents' willingness to pay for advice and parasite surveillance services from their veterinarians. A total of 1060 respondents completed the questionnaire. A large majority of respondents (71.9%) were familiar with the concept of selective therapy. Results illustrated that the respondents' self-evaluation of their knowledge about parasites and their control associated significantly with their level of interest in the topic and their type of education (P<0.0001). The large majority of respondents either dewormed their horses twice a year and/or performed two fecal egg counts per horse per year. This approach was almost equally pronounced in foals, horses aged 1-3 years old, and adult horses. The respondents rated prevention of parasitic disease and prevention of drug resistance as the most important attributes, while cost and frequent fecal testing were rated least important. Respondents' actual spending on parasite control per horse in the previous year correlated significantly with the amount they declared themselves willing to spend (P<0.0001). However, 44.4% declared themselves willing to pay more than what they were spending. Altogether, results indicate that respondents were generally familiar with equine parasites and the concept of selective therapy, although there was some confusion over the terms small and large strongyles. They used a large degree of fecal surveillance in all age groups, with a majority of respondents sampling and/or treating around twice a year. Finally, respondents appeared willing to spend money on parasite control for their horses. It is of concern that the survey suggested that foals and young horses are treated in a manner very similar to adult horses, which is against current recommendations. Thus, the survey illustrates the importance of clear communication of guidelines for equine parasite control.

Importance of the horse and financial impact of equine trypanosomiasis on cattle raising in Venezuela.

In Venezuela, horses are indispensable for extensive cattle raising, and extensive cattle raising prevails in all regions. This determines the numerical relationship between horses and cattle (r = 0.93) to be relatively constant nationwide. At regional level, the average extension of cattle ranches varies greatly. However, in relation to the area covered by pastures, the numbers of horses (r = 0.95) and cattle (r = 0.93) are relatively uniform nationwide. Water buffalo occupy small fractions of the territory; therefore, their numbers are related to the area of pastures less strongly (r = 0.56). There is no information on the numerical relationship between the numbers of horses and water buffalo. In the Llanos region of the country, equine trypanosomiasis is responsible for a high mortality in horses, causing considerable financial losses to cattle ranches. So far, such losses have not been assessed. For this region, in 2008, it can be calculated that: (1) with no treatment, losses owing to horse mortality caused by this hemoparasitosis would have amounted to US$7,486,000; (2) the diagnosis and treatment of affected horses would have required an investment of US$805,000; and (3) in terms of horses saved, this investment would have resulted in benefit of US$6,232,000. Therefore, for every monetary unit invested, there would be a benefit 7.75 times greater, this ratio being applicable to any year and all regions of the country. It follows that the profitability of investing in the diagnosis and treatment of equine trypanosomiasis is guaranteed.

Sustainable equine parasite control: perspectives and research needs.

Clinically important equine parasites are ubiquitous in managed horse populations. The traditional approach to parasite control is frequent administration of anthelmintics to all horses on a farm. However, increasing levels of anthelmintic resistance is forcing horse owners and veterinarians to shift this control paradigm. Treatment regimens involving routine deworming of all horses throughout the year are now being replaced by more sustainable approaches, which take in to account the importance of maintaining adequate parasite refugia. The selective therapy principle has been recommended for more than 15 years, but there is limited experience with this approach. The relative magnitude of the faecal egg count for an individual horse is a consistent trait, and this provides a reliable basis for selective therapy. But no studies have evaluated the consequences of selective therapy in the long-term, and such studies are strongly needed to validate this approach. Importantly, it remains unclear how selective therapy may affect the prevalence and intensity of other parasites of significant pathogenic potential (e.g. Strongylus vulgaris), which have become uncommon due to years of intensive chemotherapy. Consequently, a selective approach requires vigilant surveillance of the parasite fauna and intensity. This places a demands for reliable diagnostic tools. Also noteworthy is the fact that the majority of equine nematode parasites are more pathogenic during their larval stages, when they cannot be detected by traditional egg counting techniques. Consequently, parasite-specific diagnostic tools capable of assessing prepatent parasite burdens, and able to differentiate between strongyle species of different pathogenic potentials, would be of great value to the equine clinician. Tools for detecting infections with the tapeworm Anoplocephala perfoliata are laborious, difficult to interpret, and at present there is no established method to evaluate treatment efficacy. Thus, better diagnostic tools are needed for tapeworms as well. Biological control, especially the predacious fungi have demonstrated good potential as an adjunct for strongyle control and such a product could easily have a market in equine establishments. In summary, there is general agreement that the traditional treat-all at frequent interval approach should be abandoned, and that optimal parasite control can be maintained with far fewer anthelmintic treatments. But better diagnostic techniques and more evidence documenting the long-term consequences of selective therapy programs are needed to develop and validate systems for sustainable equine parasite control.

Owner assessment in judging the efficacy of airway disease treatment.

REASONS FOR PERFORMING STUDY: Efficacy of medications for recurrent airway obstruction is typically tested using clinical, cytological and lung function examinations of severely affected animals. These trials are technically challenging and may not adequately reflect the spectrum of disease and owner complaints encountered in clinical practice. OBJECTIVE: To determine if owners of horses with chronic airway disease are better able to detect drug efficacy than a veterinarian who clinically examines horses infrequently. METHOD: In a double-blinded randomised controlled trial, owners and a veterinarian compared the efficacy of dexamethasone (0.1 mg/kg bwt per os, q. 24 h, for 3 weeks; n = 9) to placebo (n = 8) in horses with chronic airway disease. Before and after treatment, owners scored performance, breathing effort, coughing and nasal discharge using a visual analogue scale (VAS). The clinician recorded vital parameters, respiratory distress, auscultation findings, cough and nasal discharge, airway mucus score, bronchoalveolar lavage fluid (BALF) cytology and arterial blood gases. RESULTS: The VAS score improved significantly in dexamethasone- but not placebo-treated horses. In contrast, the clinician failed to differentiate between dexamethasone- and placebo-treated animals based on clinical observations, BALF cytology or endoscopic mucus score. Respiratory rate (RR) and arterial oxygen pressure (PaO(2)) improved with dexamethasone but not placebo. CONCLUSIONS AND CLINICAL RELEVANCE: In the design of clinical trials of airway disease treatments, more emphasis should be placed on owner-assessed VAS than on clinical, cytological and endoscopic observations made during brief examinations by a veterinarian. Quantifiable indicators reflecting lung function such as RR and PaO(2) provide a good assessment of drug efficacy.