Patterns of injury following equine trauma: a non-trauma centre experience

INTRODUCTION

Horse riding carries risk of injury which can result in fatality. The majority of published literature describes major trauma centre experience. We aimed to characterise injury patterns following equine trauma at a Scottish district general hospital.

METHODS

A retrospective review of admissions following equine trauma was undertaken from 2014 to 2019. Mechanism and nature of injuries were noted. Patient management and outcomes were recorded and analysed to determine correlation.

RESULTS

Of the 162 patients identified, 121 (74.7 per cent) were female. The commonest mechanism and injury sustained were falling from a horse (86.4 per cent) and head injury (17.9 per cent) respectively. Forty-four (27.2 per cent) had multiple injuries identified. Being crushed or kicked resulted in more abdominal visceral injuries (22.7 vs 0.7 per cent, p = <0.05) and ITU admissions (18.2 vs 6.4 per cent, p = 0.06) when compared with falling from alone. Eight (4.9 per cent) required transfer to a major trauma centre and 30-day mortality was 0.6 per cent.

CONCLUSION

Although variable, injuries following equine trauma can be life threatening. Increased awareness and development of safety legislation is needed. In addition, research could be directed at assessing functional outcomes given the large number of orthopaedic injuries.

Biomechanical Effects of Unidirectional Expansion Using Anisotropic Expanders in Horse Skin Tissue

The use of a self-inflating tissue expander is a technique to stretch cutaneous tissues for potential use in reconstructive skin surgeries. This study investigates the mechanical properties of horse skin stretched by the subcutaneous implantation of anisotropic tissue expanders at the forehead, right shoulder, and dorsomedial part of the cannon region of the right forelimb in six (n = 6) horses. After 14 days of skin expansion, expanded and normal (control) skin samples were harvested and their mechanical properties of elastic modulus (EM), maximum force (MF), maximum stress (MSs) and maximum strain (MSr) were evaluated using uniaxial tension test. The expanded skin from shoulder area has higher EM, MSs, MSr and MF than the normal skin when compared to the forehead and lower forelimb. Statistically, there was a significant (P= .02) mean difference for MSs between the expanded shoulder and lower forelimb skin, but the pairwise comparison of EM, MSr and MF showed no significant difference between the locations. The overall effect of locations on EM and MSs was statistically significant (P < .05), however, there was no overall effect of horse factor, treatment factor (normal and expanded skin) and location interaction on the EM, MSS, MF and MSr. In conclusion, the expanded skin from the frontal head and the distal limb are less elastic (stiffer) compared to that of the expanded skin of the shoulder, thus anatomical location of the skin has some degree of effect on EM and MSs.

Pilot Videodermoscopic Examination of Hair and Skin in Arabian Mare Horses During the Winter Season

Videodermoscopy is a novel, noninvasive technique used to examine the appearance of skin and its adnexa. The aim of this study was to assess specific dermoscopic parameters in Arabian purebred mares in particular areas of the body during the winter season. The study was performed in the winter season. Videodermoscopic evaluations of the hair and skin were performed over seven areas of the body: the forehead, mane, neck, chest, flank, croup, and tail. Twenty-one healthy, non-breeding Arabian mares aged 3 to 21 years were selected for the study. The Video-Dermatoscope Vidix 7 (Medici Medical SRL) equipped with a 5-Mpx camera, and the VX1 cover (contact type cap 3.5 cm) was used. The CellSens Dimension was used to perform the above-mentioned measurements. Videodermoscopy revealed marked pigmentary differences in the hair of gray Arabian mares with blood vessels visible on unpigmented skin. The density of the hair in one dermoscopy field of view ranged from 1,458 (croup) to 3,680 (head) hairs and the thickness of hair ranged from 52.70 (chest) to 87.45 µm (tail). Uniform group of horses consisting of one sex, one breed, and one season. When compared to previous studies, our findings demonstrated that the density and thickness of hair are contingent upon a horse's breed and body region.

Chronic Collateral Sesamoidean Desmopathy in Draft Horses: Magnetic Resonance Imaging and Histopathological Findings

Desmopathy of the collateral sesamoidean ligament (CSL) is an unusual disorder in draft horses. This study records the magnetic resonance imaging (MRI) features of chronic CSL desmopathy in eight draft horses and confirms these features by histopathology. The recorded chronic CSL desmopathy has usually affected the forelimbs (100%) and commonly bilateral (62.5%). All horses showed positive proximal digital nerve block, positive front digital flexion test, and negative interphalangeal extension test. Radiography revealed no osseous abnormalities in all feet. MRI features of chronic CSL desmopathy included thickening of the ligament with increased moderate intensity in fast low-angle shot, T1 turbo spin echo, and proton density images in the affected part of the ligament. Chronic CSL desmopathy was concomitant with deep digital flexor tendon injury and distal sesamoidean impar desmitis. In most chronic cases of CSL desmopathy, heterogeneous signal intensities were seen with multiple foci of low signal intensities interlaced with increased moderate signal intensities of thickened CSL. Histopathology confirmed the MRI findings and revealed separated bundles and fascicles by septa of less organized and loose connective tissues containing fibroblasts and loose collagen fibers. Multifocal islands of cartilaginous metaplasia, mineralized areas, and dystrophic calcification were observed in the injured ligament. In conclusion, chronic CSL desmopathy may progress to cartilaginous metaplasia and dystrophic calcification. MRI is a beneficial diagnostic and prognostic tool for chronic CSL desmopathy, and histopathology is a gold standard to document the MRI findings associated with CSL dysmopathy in draft horses.

The expression of androstenone receptor (OR7D4) in vomeronasal organ and olfactory epithelium of horses

Androstenone is the first mammalian steroidal pheromone to be identified. Pheromones are chemicals that animals use to communicate within a species. Pheromone detections are related to vomeronasal organ (VNO) and olfactory epithelium (OE) in mammals. Olfactory Receptor Family 7 Subfamily D Member 4 (OR7D4) is an odorant receptor that responds to androstenone. Several studies indicated that spray with androstenone changes behaviors of the boar and dogs. However, the expression of OR7D4 in VNO and OE was not reported in mammals except human. Thus, the main objectives of this study were to investigate the expression of OR7D4 in VNO and OE of horses. Tissue samples were collected from the VNO and nasal cavity of 6 thoroughbred horses. The presence of OR7D4 gene was investigated with reverse transcription-polymerase chain reaction. The expression of OR7D4 was determined using Western blot and immunofluorescence. As a result, the bands for OR7D4 were observed at approximately 462 bp. The protein band of OR7D4 of VNO and OE was detected at 38 kDa. Immunofluorescence result showed that the cilia and cytoplasm of olfactory receptor cells of VNO and nasal cavity tissues were immunolabeled with OR7D4 antibody. The intensity of OR7D4 protein bands in the ventral region of the ethmoidal concha tissues was not significantly different between mares and geldings. In conclusion, thoroughbred horses are capable of androstenone perception through OR7D4 expressed in the VNO and OE.

Association of plasma concentrations of oxytocin, vasopressin, and serotonin with docility and friendliness of horses

Oxytocin (OXT) and vasopressin (AVP) have been associated with social interaction and affiliative behavior in animals. Additionally, AVP is known to affect socially aggressive behavior. In addition, serotonin has an association with aggressive behaviors. The objectives of this study were (1) to evaluate OXT, AVP, and serotonin concentrations in the plasma of horses of different breeds, sexes, and ages and (2) to determine if the neurotransmitters are associated with horse docility and friendliness. This study was performed at Sangju International Equestrian Center. Blood samples were collected from 23 horses, including 6 Thoroughbreds (11 to 18 yr), 6 Warmbloods (15 to 26 yr), 6 ponies (8 to 17 yr), and 5 Quarter Horses (4 to 12 yr). The group of horses consisted of 13 mares and 10 geldings. The plasma concentrations of OXT and AVP were measured by enzyme-linked immunosorbent assay, and the serum concentration of serotonin was measured by high-performance liquid chromatography. The characteristics of each horse were surveyed by 3 horse trainers. The effects of breed, sex, and age on the concentration of each neurotransmitter were assessed by a 3-way ANOVA with LSD post-hoc analysis. Linear regression analysis was performed to determine if the concentration of neurotransmitters is related to the docility and friendliness of horses. As a result, the concentrations of OXT and AVP did not vary with the breed, sex, or age of horses. However, the serotonin concentration varied depending on the breed and age of horses. Interestingly, there was a trend toward the existence of a correlation between docility and OXT in Thoroughbred horses. However, AVP and serotonin concentrations had no correlation with the docility and friendliness of horses. In conclusion, the docility and friendliness of Thoroughbred might be related with the blood OXT concentration.

Two Novel Cases of Autosomal Translocations in the Horse: Warmblood Family Segregating t(4;30) and a Cloned Arabian with a de novo t(12;25)

We report 2 novel autosomal translocations in the horse. In Case 1, a breeding stallion with a balanced t(4p;30) had produced normal foals and those with congenital abnormalities. Of his 9 phenotypically normal offspring, 4 had normal karyotypes, 4 had balanced t(4p;30), and 1 carried an unbalanced translocation with tertiary trisomy of 4p. We argue that unbalanced forms of t(4p;30) are more tolerated and result in viable congenital abnormalities, without causing embryonic death like all other known equine autosomal translocations. In Case 2, two stallions produced by somatic cell nuclear transfer from the same donor were karyotyped because of fertility issues. A balanced translocation t(12q;25) was found in one, but not in the other clone. The findings underscore the importance of routine cytogenetic screening of breeding animals and animals produced by assisted reproductive technologies. These cases will contribute to molecular studies of translocation breakpoints and their genetic consequences in the horse.

Dynamic Change of Free Serum L-carnitine Concentration in Relation to Age, Sex, and Exercise in Anglo-Arabian Thoroughbred Horses

The physiological role of L-carnitine in equine species is worthy of investigation; however, the systemic content of free L-carnitine and its dynamic change in growing foals as well as in exercising horses are still poorly investigated. In this study, the influence of age and exercise on free serum L-carnitine levels was evaluated in equine species. Ten foals were monitored from 6 up to 18 months of age (group 1), whereas 60 horses were divided in six groups in accordance with their age: group 2, 2-year-old; group 3, 3-year-old; group 4, 4-year-old; group 5, 5-year-old; group 6, 6-year-old; group 7, 7-year-old. To assess the age and sex effect on free serum L-carnitine values, blood samples were collected from foals and horses. Adult horses (groups 2-7) were subjected to a simulate 1,660-m race, and blood samples were collected before the simulate race (T_PRE), within 10 minutes (T_POST10) from the end of race, and after 30 minutes (T_POST30) from the end of race. The amino acid levels were influenced by age (P < .0001) in foals and horses. Decreased levels of amino acid were observed at T_POST10 with respect to T_PRE and T_POST30. (P < .001). The findings suggest that the biosynthetic pathway of L-carnitine is organizing and adapting to the metabolic needs of skeletal and cardiac muscle tissue in the course of growth. L-carnitine could play a role for the provision of energy to the exercising muscles. Further studies are needed to evaluate possible beneficial effects of L-carnitine during growing phase and on parameters of equine physical performance.

Adverse Effect of Antibiotics Administration on Horse Health: An Overview

Antibiotics-based therapy plays a paramount role in equine medicine because of their potential pharmacokinetics and pharmacodynamics properties. Conventional antibiotics show bacteriostatic and bactericidal properties by interfering bacterial cell wall and protein synthesis as well as inhibiting RNA polymerase, DNase 1, and DNA gyrase. Antibiotics are extensively used not only for the treatment of varied bacterial infections but also the prevention of postoperative and secondary infections. Surprisingly, antibiotics such as sulfonamides or trimethoprim/sulfonamide combinations, benzylpenicillin, cefquinome, fluphenazine, enrofloxacin, and sodium ceftriaxone cause detrimental effects on horses' health, namely, diarrhea, colitis, nephrotoxicity, ototoxicity, dysrhythmia, arthropathy, ataxia, anorexia, seizures, peripheral neuropathy, and certain neurologic abnormalities. Therefore, in equine practice, it is essential to optimize and analyze the combinations, formulations, route of administration, and dosages of certain antibiotics before administration. This review overviews the mode of actions and pharmacologic attributes of certain antibiotics, commonly used toward the treatment of disparate horse diseases. Most importantly, special emphasis was given to spotlight the potential adverse effects encountered during the administration of antibiotics as therapeutics in horses.

Application of Raman Spectroscopy for the Evaluation of Metabolomic Dynamic Analysis in Athletic Horses

Raman spectroscopy is a rapid qualitative and quantitative technique that allows the simultaneous determination of several components, both biomolecules both chemical compounds, in the biological fluids to assess the metabolic status. In this study, the serum composition was evaluated in regularly trained athletic horses using Raman spectroscopy to identify biomarkers of sports performance. Five clinically healthy and regularly trained Italian Saddle horses were subjected to a standardized obstacle course (350 m/minute; eleven 1.25 high jumps) preceded by a warm-up. On the collected sera, at rest, immediately after exercise, 30 minutes, and 1 hour after the end of the exercise Raman measurements were performed using a diode laser with the excitation wavelength of 785 nm. The analysis of the obtained spectra allowed the identification of peaks and bands different in position and intensity among the experimental conditions. The acquired spectra, obtained from horse sera collected during the experimental protocol, were visually similar, except for the large band detected in the 1,250-1,800 cm^-1 range. The spectral intensity of the Raman spectrum decreased after training and 30 minutes after the end of exercise respect to the before exercise value, to come to the basal value after 60 minutes the end of the exercise. In conclusion, we can claim the ability of Raman spectroscopy to reveal the metabolic status of horses after physical exercise.

Retrospective serological survey for influenza in horses from Brazil

Equine influenza (EI) virus is one of the most economically important pathogens of respiratory diseases of horses worldwide. Despite availability of vaccines for control of EI, the highly contagious nature and variability properties of the virus mean global outbreaks occur. Thus, continuous surveillance programs, including seroprevalence studies of disease in different countries, may contribute to better control of the disease. In this study, the seroprevalence of equine influenza in 850 horses from Brazil was investigated. The serodiagnosis was based on the single radial hemolysis (SRH) assay using influenza A/equine/Richmond/1/2007 (H3N8) antigen. Antibodies against A/equine/Richmond/1/07 (H3N8) were detected in 44.7% (380/850, 95% CI: 41.4-48.1%) of horses. Seroprevalence was significantly lower (p = 0.001) in younger animals (< 5 years, 38.6%) than in "adult" animals (5-14 years, 52.1%). There was also a significant relationship between the year of sampling and seroprevalence (p < 0.0005). The mean SRH antibody value was 42.0 mm² (range 4-238.9 mm²), with the majority of horses (95.3%) having an SRH value ≤ 150 mm², which is considered an insufficient level for protection of equine hosts against influenza infections and potential virus shedding. These findings indicate the need to reinforce preventive/control measures against equine influenza in Brazil.

Analysis of Genetic Variability in the Argentine Polo Horse With a Panel of Microsatellite Markers

Argentine Polo (AP) is a young horse breed with a fast expansion because of an open registry policy and the application of assisted reproduction technologies. In the last years, AP showed a remarkable progress associated with the use of embryo transfer technology and intensive selection based on sport performance. However, these practices could have affected the genetic variability of the breed. To monitor these potential changes, a parentage panel of 11-15 microsatellites was investigated for changes in allele frequencies, heterozygosity, and exclusion probability over a 16 year period. Frequency of 36 alleles in 13 markers showed significant departures from expected changes because of random genetic drift. Six markers showed both allelic frequency increase and expected heterozygosity (He) reduction, suggesting the influence of selective breeding or hitchhiking effects. The average He decreased significantly although was lower than the observed heterozygosity, indicating a still low inbreeding level. Although the exclusion probability of the panel showed a trend to decrease, it is over 0.9995, the recommended value for equine parentage exclusion.

Detecting antibodies to Leishmania infantum in horses from areas with different epizooticity levels of canine leishmaniosis and a retrospective revision of Italian data

Background

Leishmania infantum is a vector-borne pathogen endemic in countries in the Mediterranean basin, including Italy. Dogs act as the primary reservoir for this parasite, but other animal species may also be infected. Low-to-moderate seroprevalence levels of infection have been reported in apparent healthy equine populations in southern Europe, reinforcing the importance of exploring those species, including horses, that act as a food source for vectors and may thus participate in the epizoological scenario of canine leishmaniosis (CanL) and zoonotic visceral leishmaniosis (ZVL). Since little is known regarding the exposure to L. infantum in horses in Italy, we assessed the seroprevalence in healthy equine populations from different CanL endemic areas.

Methods

The survey was conducted on 660 apparently healthy horses distributed throughout central and northern regions of Italy between 2016 and 2019. Blood samples were collected and the presence of anti-Leishmania antibodies (IgG) was investigated by the immunofluorescence antibody test. Information on the location and altitude of the stables, along with the horses’ breed, age, sex, and reproductive status was obtained by filling in a questionnaire. This was then used for statistical analysis by generalized linear models to explore risk factors associated with seroreactivity to L. infantum.

Results

An average seroprevalence of 13.9% was detected for L. infantum in the equine populations investigated, with statistically significant associations between seroprevalence, geographical variables (northern vs central Italy, origin and altitude) and individual factors (i.e. age and breed morphotype).

Conclusions

Our results highlight that horses are frequently exposed to L. infantum. Further prevalence surveys in horses, also using direct methods (e.g. PCR), are warranted to clarify the role of these hosts in the epidemiology of Leishmania in Italy.

Do Metal Shoes Contract Heels?-A Retrospective Study on 114 Horses

Heel contraction is an undesired but common condition in domestic horses. Some authors indicate shoeing as a risk factor. There is a correlation between shoeing and a restriction of heel expansion, but the clinical significance is unknown. This study aimed to evaluate the influence of shoeing and other risk factors, such as age, access to paddock, and breed, on heel contraction. This study included 114 horses, 55 of which were barefoot their whole life and 59 had been shod consistently for at least the previous year. The width and length of the frog were measured. Linear mixed-effects models were performed for the width:length ratio, where the fixed effects were age, sex, breed, pasture or paddock time, shoeing and its duration, and limb. The random effects included the horse and the yard. Although heel contraction occurs more often in shod horses compared with barefoot horses, the difference between the two conditions was not statistically significant, when other factors were considered. The most important factors that impacted contraction were individual horse features and breed (P < .001). The effect of age and a yard was noticed (P < 0,5). The sex, paddock time, and the shoeing and its duration were found not to have statistical significance. The study concluded that heel contraction is multifactorial problem, mainly caused by breed and unknown features correlated with individual. It was not confirmed that horseshoeing causes heel contraction. Because of significant difference in incidence of contraction between yards, there is a need to further investigation of environmental factors causing this hoof distortion.

Bugs and drugs: a systems biology approach to characterising the effect of moxidectin on the horse's faecal microbiome

Background

Anthelmintic treatment is a risk factor for intestinal disease in the horse, known as colic. However the mechanisms involved in the onset of disease post anthelmintic treatment are unknown. The interaction between anthelmintic drugs and the gut microbiota may be associated with this observed increase in risk of colic. Little is known about the interaction between gut microbiota and anthelmintics and how treatment may alter microbiome function. The objectives of this study were: To characterise (1) faecal microbiota, (2) feed fermentation kinetics in vitro and (3) metabolic profiles following moxidectin administration to horses with very low (0 epg) adult strongyle burdens. Hypothesis: Moxidectin will not alter (1) faecal microbiota, (2) feed fermentation in vitro, or, (3) host metabolome.

Results

Moxidectin increased the relative abundance of Deferribacter spp. and Spirochaetes spp. observed after 160 h in moxidectin treated horses. Reduced in vitro fibre fermentation was observed 16 h following moxidectin administration in vivo (P = 0.001), along with lower pH in the in vitro fermentations from the moxidectin treated group. Metabolic profiles from urine samples did not differ between the treatment groups. However metabolic profiles from in vitro fermentations differed between moxidectin and control groups 16 h after treatment (R² = 0.69, Q²Y = 0.48), and within the moxidectin group between 16 h and 160 h post moxidectin treatment (R² = 0.79, Q²Y = 0.77). Metabolic profiles from in vitro fermentations and fermentation kinetics both indicated altered carbohydrate metabolism following in vivo treatment with moxidectin.

Conclusions

These data suggest that in horses with low parasite burdens moxidectin had a small but measurable effect on both the community structure and the function of the gut microbiome.

and piroplasm infections of horses at Obollo-Afor southeastern Nigeria and resistance profiles of trypanosomes to isometamidium and diminazene salts

Epidemiological data on trypanosomosis and piroplasmosis of horses are lacking in southeastern Nigeria. The prevalence of trypanosome and piroplasm infections in horses and resistance profile of isolated trypanosomes to diminazene and isometamidium salts were investigated. For the cross-sectional study of horses billed for slaughter, 304 horses were randomly sampled. Approximately 2 ml of blood was collected into anticoagulant-treated bottles for haematocrit (HCT) determination, direct microscopic examinations, and rat inoculation. Gender, body condition scores (BCS), age groups, and body weights of sampled horses were noted. Two isolates of Trypanosoma brucei recovered from the cross-sectional study were profiled for resistance to isometamidium hydrochloride and diminazene diaceturate in 36 BALB/c mice. Standardized protocols were used (Eisler et al., Veterinary Parasitology 97:171-182, 2001). 19.1% of horses (95% confidence interval 14.7-23.5%) were positive for haemoparasite infections including Theileria equi (16.1%) and Babesia caballi (3.9%). Only two (0.66%) Trypanosoma brucei infections were seen, being from active cases. Associations between age or gender, and presence of haemoparasites were only random. Haemoparasite-infected horses had significantly (p < 0.05) lower mean HCT and body weights and poorer BCS. From resistance profiling, for each isolate, all mice in control groups were parasitaemic by day 6 post-inoculation, while mice in test groups remained aparasitaemic over 60-day observation period. The study showed the endemicity and weights of Trypanososma spp. and piroplasm infections and among horses within the area. Furthermore, circulating strains of Trypanosoma brucei in the area are still susceptible to isometamidium and diminazene salts in mice. The pharmacoepidemiological significances of these findings were discussed.

Metabolomics analysis of bronchoalveolar lavage fluid samples in horses with naturally-occurring asthma and experimentally-induced airway inflammation

The present work characterized the metabolomic profile of bronchoalveolar lavage fluid (BALF) in healthy horses, experimentally-induced airway inflammation by lipopolysaccharide (LPS) nebulization, and naturally-occurring asthma (n = 3 in each group). All animals underwent clinical and upper airway endoscopic examinations, and bronchoalveolar lavage. BALF supernatant samples were subjected to metabolic analysis based on gas chromatography-mass spectrometry (GC-MS). Overall, 67 peaks were obtained from BALF GC-MS analysis, corresponding to 53 metabolites which were categorized according to chemical class, such as organic acids, fatty acids, nucleosides or their derivatives, amino acids, peptides or their derivatives, carbohydrates, and other compounds. Our results showed that the airway inflammation induction model with LPS produced the same pattern of metabolite changes as in horses with naturally occurring asthma. Metabolic pathway analysis was done by means of Fisher's exact test, for detection of metabolites over-represented in asthma affected-horses and LPS-induced airway inflammation as compared with healthy horses. The most significant altered metabolic pathways were fatty acid biosynthesis, galactose metabolism and citrate cycle. These results suggest that the airway inflammation induction model with LPS is a good study model for asthma-affected horses, due to the similarity of the profile of inflammatory cells (specifically neutrophils) and similar metabolic alterations found in BALF that occur during the inflammatory process of the airways. Further research may increase understanding of metabolomics disturbances and their significance in the pathogenesis of equine asthma.

Seroprevalence and risk factors associated with Equine piroplasmosis in North Egypt

Equine piroplasmosis (EP) is caused by Theileria equi and/or Babesia caballi and has economic importance particularly in equines reared in poor management systems. This study is based on cELISA test to study the seroprevalence of EP among 370 horses and 150 donkeys in four Governorates north Egypt. Additionally, its risk factors were studied for the first time. The seroprevalence rates 36.5 %, 20 %, and 5.6 % for T. equi, B. caballi, and mixed infections, respectively. The highest antibody levels against T. equi were detected in Kafr ElSheikh (40 %) and Giza (40.1 %) Governorates, whereas those of B. caballi were detected in Qalyubia (25 %) and Kafr ElSheikh (24.1 %) Governorates. Concerning T. equi, animals >10 years (OR = 2.06) were more likely to be infected with EP than those <5 years old. In addition, the seropositivity increased among grazing (OR = 5.7, 95 % CI: 1.73-19.27) males (OR = 1.8, 95 % CI: 1.23-2.61) infested with ticks (OR = 2.3, 95 % CI: 1.60-3.48) during summer (OR = 4.3, 95 %CI: 2.53-7.46); whereas the seropositivity of animals for B. caballi increased among grazing equines (OR = 7.8, 95 % CI: 1.05-58.25) over 10 years old (OR = 2.08, 95 % CI: 1.10-3.94) and infested with ticks (OR = 2.4, 95 % CI: 1.54-3.76) during summer (OR = 7.12, 95 % CI: 3.15-16.06). Therefore, EP is an important prevalent disease in Egypt and deserves further attention regarding the management system, treatment, and vector control.

Tramadol Effects on Lameness Score After Inhibition of P-GP by Ivermectin Administration in Horses: Preliminary Results

This study aimed to evaluate the effects and lameness degree in horses administered tramadol after the P-glycoprotein (P-gp) enteric inhibitor ivermectin. Six horses were randomly distributed into three groups, which received two different doses of tramadol by a nasogastric tube: 1 mg/kg (tramadol group 1(GT1)), 4 mg/kg (tramadol group 4 (GT4)), and tramadol 1 mg/kg combined with ivermectin 0.2 mg/kg PO (ivermectin tramadol group (GT1 + Ive)), with one-week washout interval. Heart rate (HR), respiratory rate (RR), intestinal motility, body temperature, and the degree of lameness were evaluated for 360 minutes. The blood gas parameters were evaluated at 0, 60 minutes, and 120 minutes. There were no differences in HR and the degree of lameness. Hypomotility occurred in GT1 and GT4 only at the end of the evaluation period, and RR increased in all groups. We conclude that inhibition of enteric P-gp by ivermectin did not alter the effects of tramadol, suggesting that tramadol is not a substrate for P-gp. However, future studies should be conducted to assess the interaction between P-gp inhibitors on the pharmacokinetics of tramadol.

Immunochromatographic test and ELISA for the detection of glutamate dehydrogenase (GDH) and A/B toxins as an alternative for the diagnosis of Clostridioides (Clostridium) difficile-associated diarrhea in foals and neonatal piglets

Considering the lack of studies evaluating the performance of commercially available methods for diagnosis of Clostridioides (Clostridium) difficile infection (CDI) in animals, the present study aimed to assess an immunochromatographic test for detection of glutamate dehydrogenase (GDH) and A/B toxins of C. difficile, also evaluated by an ELISA kit, in foals and neonatal piglets. Intestinal contents of 47 piglets and feces of 35 foals were tested to GDH antigen and A/B toxins in a lateral flow method (Ecodiagnostica, Brazil). Also, these samples were submitted to A/B toxin detection by an ELISA kit (C. difficile Tox A/B II, Techlab Inc., USA), using the toxigenic culture (TC) as the reference method. The GDH component of the lateral flow test showed sensitivity and negative predictive value (NPV) of 100% and a high specificity in samples of piglets (82.61%) and foals (100%). Detection of A/B toxins using the lateral flow test and the ELISA resulted in a specificity of 100% in samples of both species. On the other hand, the sensibility ranged from 54.2 to 90% for the ELISA and from 12.5 to 60% for the lateral flow test for piglets' and foals' samples, respectively. In conclusion, the present work suggests that the lateral flow test for GDH detection could be a useful method for diagnosing CDI in these species. On the other hand, the low sensitivity of the lateral flow test for A/B toxins might compromise its utility in piglets.

Genotype-specific neutralizing antibody titers against Japanese encephalitis virus genotypes 1 and 3 in horses immunized with a genotype 3 vaccine

Purpose

Japanese encephalitis is one of the most important mosquito-borne and zoonotic diseases in Asia and the Pacific region. Although the dominant Japanese encephalitis virus (JEV) genotype has shifted from G3 to G1 in Korea since 1990, a G3 strain (Anyang 300) has been used in vaccines for horses for almost 40 years. This study aimed to investigate the seroconversion rates and geometric mean titers (GMTs) of virus-neutralizing antibodies (VNAs) against JEV G1 and G3 in horses immunized with the G3 vaccine.

Materials and Methods

Serum samples of 1,231 horses immunized with the Anyang 300 vaccine were collected in 2018. VNA titers against JEV KV1899 (G1) and Anyang 300 (G3) were measured in all serum samples using the virus neutralization test. Titers were analyzed according to blood sampling time (prior to and following annual revaccination), age, and region.

Results

Rates of VNA titer >10 were 45.1% and 77.8% for G1, and 49.1% and 82.9% for G3 in samples taken before and after revaccination, respectively. GMTs of genotype-specific VNAs against JEV G1 and G3 were 8.3 and 11.6 before revaccination and rose to 27.2 and 65.4 following revaccination. Overall sero-positivity did not significantly differ between genotypes, but GMTs significantly differed among genotypes and sampling times. No significant difference was found in GMTs among age groups or regions.

Conclusion

Genotype-specific neutralizing antibody titers against JEV G1 and G3 differed significantly in horses immunized with the G3 vaccine. Antigenic differences between genotypes could reduce the vaccine's efficacy, requiring the development of a new vaccine.

Genetics of Equine Ocular Disease

Horses perform in a variety of disciplines that are visually demanding, and any disease impacting the eye has the potential to threaten vision and thus the utility of the horse. Advances in equine genetics have enabled the understanding of some inherited ocular disorders and ocular manifestations and are enabling cross-species comparisons. Genetic testing for multiple congenital ocular anomalies, congenital stationary night blindness, equine recurrent uveitis, and squamous cell carcinoma can identify horses with or at risk for disease and thus can assist in clinical management and breeding decisions. This article describes the current knowledge of inherited ocular disorders.

Phylogenetic analysis and geographical distribution of Theileria equi and Babesia caballi sequences from horses residing in Spain

The intraerythrocytic protozoans Theileria equi and Babesia caballi are the causative agents of equine piroplasmosis (EP), one of the most important equine tick-borne diseases due to its significant impact on global international horse trade. Although EP is known to be endemic in Spain, previous phylogenetic studies have only been conducted for limited geographical regions. Therefore, the objective of this study was to evaluate the genetic diversity and distribution of these parasite species nationwide. This was performed by amplification of the 18S small subunit (SSU) rRNA gene from 100 EP positive equine blood samples using a nested PCR protocol, and sequencing the obtained amplicons. Seventy-seven T. equi and six B. caballi isolates were successfully sequenced and phylogenetic analysis revealed that the T. equi isolates grouped into the previously described clades A (n = 21/77), D (n = 1/77) and E (n = 55/77), while B. caballi isolates were placed into clades A (n = 5/6) and B (n = 1/6). Isolates from T. equi clade D and B. caballi clade B have not previously been reported in Spain. A greater intra-clade diversity (97.3-98.3 % identity) was observed between T. equi clade E isolates compared to those within clade A (99.7-100 % identity). Additionally, a multivariable logistic regression model was used to analyse associations between the clade of T. equi infection and available epidemiological data. Horses residing in Spanish northern regions were statistically more likely to be infected with T. equi clade E (p = 0.01). We conclude that while extensive sequence variation of equine piroplasms exists in Spanish infected horses, a requirement for increased equine movement controls between Spain and EP-endemic countries should be considered.

Infrared methodologies for the assessment of skin temperature daily rhythm in two domestic mammalian species

To assess the accuracy of infrared methodologies for daily rhythm monitoring of skin temperature, five clinically healthy Italian Saddle gelding horses, and five not pregnant and not lactating Camosciata goats, were monitored every 4 h over a 48 h period. The horses were housed in individual boxes, while the goats in two indoor pens, under natural photoperiod and natural environmental temperature. In each animal, skin temperature was recorded with the use of a digital infrared camera and a non-contact infrared thermometer, in five regions: neck, shoulder, ribs, flank and croup. Recorded values were compared with the well-established daily rhythm of rectal temperature. Rectal temperature was recorded at the same time by means of a digital thermometer. In horses, a lower value of skin temperature was recorded using the infrared thermometer for the croup region compared to shoulder and flank; a lower value of skin temperature was recorded using thermography for the croup region compared to the shoulder. In goats, a lower value of skin temperature was recorded using the infrared thermometer for the croup region compared to the flank. In both species, higher values of rectal temperature were observed, compared to the temperature recorded at the skin regions using the other two methodologies. Cosinor rhythmometry showed a daily rhythm of rectal and skin temperature recorded using both methodologies in all the examined regions. General linear model (GLM) showed statistically significant effect of breed on all rhythmic parameters; of day of monitoring on amplitude; of site of recording (rectal vs skin regions) on mesor, amplitude and acrophase; and no effect of methodologies used. The results of this study show the differences in rhythmicity of various body regions temperature and their differences in comparison with daily rhythm rectal temperature. The use of infrared methodologies was inaccurate in assessing body core temperature, but its use could be considered for the evaluation of inflammation in the different body sites.

Growth Rates of Thoroughbred Foals and In Vitro Gut Health Parameters When Fed a Cereal or an All-Fiber Creep Feed

Traditions and the economic advantage when producing big athletic Thoroughbred (TB) yearlings for sale encourage owners to feed high levels of cereals. Such diets can predispose gastric ulceration and developmental orthopedic diseases, impacting negatively on future careers. This study aimed to (1) determine if an all-fiber creep feed (total mixed fiber ration [TMFR] would sustain equal growth rates in TB foals versus a cereal-based stud cube (SC) and (2) compare pH and lactate produced by SC and TMFR in in vitro foregut and hindgut conditions. Eight TB foals in matched-pairs were fed SC or TMFR for 18 weeks. Weight gain (average daily gain [ADG]), height at wither and hip, heart girth, and body length were recorded weekly. Similar growth rates were recorded for all measurements. The ADG of TMFR and SC were 1 and 1.1 kg per head per day, respectively. In vitro foregut incubation of SC and TMFR at 37°C in pepsin HCl solution for 6 hours produced higher pH 5.84 (TMFR) compared with 5.33 (SC) (P < .05). Gas production measured fermentation rate, acidity, and lactate from TMFR and SC, incubated with fecal inoculum from the foals on the same diet. Fermentation rates and lag times were equal for both feeds; total gas produced at t50 and y50 were greater (P < .05) for SC. Lactate and pH levels were lower and higher, respectively, for the TMFR. This study showed that similar growth in TB foals was achieved on the TMFR feed and that potentially better gut health, denoted by higher pH and lower lactate levels, could be maintained by fiber compared with cereal feed.

Metabogenomics reveals four candidate regions involved in the pathophysiology of Equine Metabolic Syndrome

An analogous condition to human metabolic syndrome, Equine Metabolic Syndrome (EMS) is defined by several clinical signs including obesity, hyperinsulinemia, and peripheral insulin dysregulation (ID). Affected horses may also exhibit hypertension, hyperlipemia and systemic inflammation. Measures of ID typically comprise the gold-standard for diagnosis in veterinary care. Yet, the dynamic nature of insulin homeostasis and complex procedures of typical assays make accurate quantification of ID and EMS challenging. This work aimed to investigate new strategies for identification of biochemical markers and correlated genes in EMS. To quantify EMS risk within this population, we utilized a composite score derived from nine common diagnostic variables. We applied a global liquid chromatography/mass spectroscopy approach (HPLC/MS) to whole plasma collected from 49 Arabian horses, resulting in 3392 high-confidence features and identification of putative metabolites in public databases. We performed a genome wide association analysis with genotypes from the 670k Affymetrix Equine SNP array utilizing EMS-correlated metabolites as phenotypes. We discovered four metabolite features significantly correlated with EMS score (P < 1.474 × 10^-5). GWAs for these features results (P = 6.787 × 10^-7, Bonferroni) identified four unique candidate regions (r² > 0.4) containing 63 genes. Significant genomic markers capture 43.52% of the variation in the original EMS score phenotype. The identified genomic loci provide insight into the pathways controlling variation in EMS and the origin of genetic predisposition to the condition. Rapid, feasible and accurate diagnostic tools derived from metabogenomics can be translated into measurable benefits in the timeline and quality of preventative management practices to preserve health in horses.

Molecular detection of Theileria species and Babesia caballi from horses in Nigeria

Equine piroplasmosis (EP) is an infectious, tick-borne disease caused by the hemoprotozoan parasites, Theileria equi, Babesia caballi, and a recently reported new species, T. haneyi. Infections by these apicomplexan parasites limit performance and cause economic losses for the horse industry. Equine piroplasmosis is widespread in the northern regions of Nigeria, where an increasing portion of the animal population is composed of horses. This disease has remained epidemiologically challenging, especially as the movement of horses increases across Nigeria. In this study, blood samples from 300 horses were collected in three states of northwestern Nigeria. The presence of piroplasms was screened by nested PCR targeting 18S rDNA and positive samples were analyzed using species-specific-nested PCR-targeting genes including ema1 (T. equi), rap1 (B. caballi), and a gene coding a protein of unknown function (T. haneyi). Species-specific-nPCR results demonstrated that the prevalence of T. equi was 13.0% (39/300), B. caballi was 3.3% (10/300) and T. haneyi was 2.7% (8/300). Mixed infections with T. equi and B. caballi was 2.7% (8/300) while T. equi, B. caballi, and T. haneyi multiple infection prevalence was 0.6% (2/300). We used 18S rDNA sequences to determine close relationships between T. equi by phylogenetic analysis and demonstrated that among 57 sequences of Theileria parasites, 28 samples belonged to clade A (49%), 13 samples were found to be clade C (22%), and 16 were clade D (28%). These results demonstrate the genetic diversity of T. equi circulating in horses from Nigeria.

Assessment of the application for renewal of authorisation of Yea-Sacc® (Saccharomyces cerevisiae) for horses

Yea‐Sacc^® is an additive based on a live preparation of a strain of Saccharomyces cerevisiae intended for use as a zootechnical additive (digestibility enhancer). The current assessment is performed in the context of the renewal of the authorisation of the feed additive; however, the applicant proposed also to lower (6.5 × 10⁸ colony forming unit (CFU)/kg of complete feedingstuff) the minimum dose of the additive when used in feed for horses. The additive is produced in a powder (Yea‐Sacc^®) and in a prills (Yea‐Sacc^®_TS) forms. The Panel considered that the additive currently on the market complies with the existing conditions of authorisation. Saccharomyces cerevisiae is considered by EFSA to be suitable for the qualified presumption of safety approach to safety assessment. As the identity of the production strain has been confirmed, safety for the target species, consumer and the environment were presumed. Both formulations are non‐irritant to skin, Yea‐Sacc^®_TS is non‐irritant to the eye while Yea‐Sacc^® is a moderate irritant. Both formulations should be considered skin sensitisers and because of their high proteinaceous nature, they should be considered as potential respiratory sensitisers. The applicant submitted two efficacy studies: the FEEDAP Panel concluded that in the first study inconsistent results were observed for the two lower doses which are considered microbiologically equivalent. The second study demonstrated that Yea‐Sacc^® at the level of 7.5 × 10⁸ resulted in a better digestion of organic matter which may be explained by increases in digestibility of the fibre. Based on the data provided, the FEEDAP Panel cannot conclude on the efficacy of Yea‐sacc^® when used as a feed additive in horses at the proposed level (6.5 × 10⁸CFU/kg complete feed).

Trypanosome infections in naturally infected horses and donkeys of three active sleeping sickness foci in the south of Chad

Background

Equine trypanosomiases are complex infectious diseases with overlapping clinical signs defined by their mode of transmission. Despite their economic impacts, these diseases have been neglected by the scientific community, the veterinary authorities and regulatory organizations. To fill the observed knowledge gap, we undertook the identification of different trypanosome species and subspecies naturally infecting horses and donkeys within the Chadian sleeping sickness focus. The objective of the study was to investigate the potential role of these domestic animals as reservoirs of the human-infective Trypanosoma brucei gambiense.

Method

Blood samples were collected from 155 donkeys and 131 horses in three human African trypanosomiasis (HAT) foci in Chad. Rapid diagnostic test (RDT) and capillary tube centrifugation (CTC) test were used to search for trypanosome infections. DNA was extracted from each blood sample and different trypanosome species and subspecies were identified with molecular tools.

Results

From 286 blood samples collected, 54 (18.9%) and 36 (12.6%) were positive for RDT and CTC, respectively. PCR revealed 101 (35.3%) animals with trypanosome infections. The Cohen’s kappa coefficient used to evaluate the concordance between the diagnostic methods were low; ranging from 0.09 ± 0.05 to 0.48 ± 0.07. Trypanosomes of the subgenus Trypanozoon were the most prevalent (29.4%), followed by T. congolense forest (11.5%), Trypanosoma congolense savannah (4.9%) and Trypanosoma vivax (4.5%). Two donkeys and one horse from the Maro HAT focus were found with T. b. gambiense infections. No significant differences were observed in the infection rates of different trypanosomes between animal species and HAT foci.

Conclusions

This study revealed several trypanosome species and subspecies in donkeys and horses, highlighting the existence of AAT in HAT foci in Chad. The identification of T. b. gambiense in donkeys and horses suggests considering these animals as potential reservoir for HAT in Chad. The presence of both human-infective and human non-infective trypanosomes species highlights the need for developing joint control strategies for HAT and AAT.

First outbreak of autochthonous "surra" in horses in Santa Catarina State, Brazil: Parasitological, hematological and biochemical characteristics

This study reports the first autochthonous "surra" outbreak in horses in the State of Santa Catarina, southern Brazil. Six horses with clinical suspicion of trypanosomosis had the natural infection by T. evansi confirmed by PCR and rapid serum agglutination test. Clinical, parasitological, and hematology evaluations were performed at initial observation (T0) and 90 days after (T1). At T0, all animals that tested positive for T. evansi in PCR presented with severe clinical signs and out of normal range hematological hematological (hematocrit, leukocytes, platelets, hemoglobin) and serum biochemical parameters (alanine aminotransferase (ALT), creatinine phosphokinase (CPK), lactate dehydrogenase (LDH), creatinine, bilirubin, and glucose). At T1, the progressive clinical recovery of animals, normalization of hemato-biochemical parameters, and negative PCR results for T. evansi were observed. It was not possible to identify the vector/mechanism of transmission through which animals were infected; therefore, the implementation of surveillance and control measures is essential to prevent the spread of this disease in horse herds, as well as to other animal species.

Data set of the proteome of fresh and frozen thawed stallion spermatozoa

This paper provides the dataset of proteins of stallion ejaculates before and after cryopreservation. The data report the analysis and identification of stallion sperm proteins obtained from the same ejaculates and split in two subsamples. The first aliquot consisted on fresh spermatozoa and the second aliquot was frozen and thawed spermatozoa. Samples were analyzed using a UHPLC/MS/MS system consisting of an Agilent 1290 infinity series UHPLC coupled to an Agilent 6550 Q-TOF mass spectrometer (Agilent Technologies, Santa Clara, CA, USA). We provide a data set of 2226 different proteins, with 2180 aligned to the equine proteome database. The data can be used to identify potential targets to be explored to improve techniques for cryopreservation of spermatozoa. This data article refers to the article "Proteomic profiling of stallion spermatozoa suggests changes in sperm metabolism and compromised redox regulation after cryopreservation" (Martín Cano et al.; 2020) [1].

Accuracy of differences in blood and peritoneal glucose to differentiate between septic and non-septic peritonitis in horses

Difference in blood and peritoneal glucose (DBPG) is used in clinical practice to support a diagnosis of septic peritonitis in horses. It is inexpensive, easy and rapid to perform. The aim of this study was to evaluate the accuracy of the DBPG to differentiate between septic and non-septic peritonitis in horses. Blood and peritoneal fluids were harvested from suspected animals. Plasma and peritoneal glucose levels, total nucleated cell count, direct microscopic and microbiological examinations of the peritoneal fluid were evaluated. Using DBPG levels, the animals were classified into two groups: difference ≥ 50 mg/dL (positive test) and difference < 50 mg/dL (negative test). Positive microbiological examination and/or presence of bacteria in direct microscopic examination was used as a gold standard to detect septic peritonitis. The accuracy parameters analysed were: sensitivity, specificity, and positive/negative predictive values, for which the results were respectively: 0.23, 0.91, 0.60 and 0.67. Due to poor accuracy, other cut-off margins and peritoneal glucose concentrations were evaluated. The test was considered most accurate when the DBPG was zero with sensitivity, specificity, and positive/negative predictive values of 0.85, 0.82, 0.73, 0.90 respectively. Peritoneal glucose concentrations alone were not a reliable feature to detect peritonitis. DBPG ≥50 mg/dL, widely used for the diagnosis of septic peritonitis, does not have a good accuracy and the DBPG = 0 has a better accuracy for detecting the disease.

Prevalence of Juvenile Osteochondral Conditions in Yearling Thoroughbred Racehorses in Southern Brazil

This study aimed to investigate the prevalence of juvenile osteochondral conditions (JOCCs) in yearling Thoroughbred (TB) racehorses in Southern Brazil, as well as to examine the same animals studied as weanlings by Bastos et al. (2017) and compare the radiographic findings for the two ages. Radiographs of 76 male and female TB yearlings from Paraná State, Southern Brazil, were investigated. The proximal interphalangeal, metacarpophalangeal/metatarsophalangeal (MC/MT), tarsal, and femorotibial (FT) joints were evaluated using 24 radiographic projections. The evaluation consisted of a severity index (rated as 0, 1, 2, 4, or 8), the sum of which resulted in an osteoarticular status (OAS) of good, intermediate, or poor for each animal. Radiographs of 92% of the investigated animals presented at least one finding consistent with JOCCs. The most affected region was the tarsal joint (72.9%), followed by the FT (50%), MT (25%), and MC (23%) joints. Thirty-three (43.4%) horses presented a decline in their OAS, whereas nine (11.8%) presented an improvement from the weanling to yearling age. The radiographic findings suggest that JOCCs are frequent in TB yearlings, but the meaning and relevance of these radiographic findings require further study.

Serum Amyloid A (SAA) Concentration after Vaccination in Horses and Mules

Serum amyloid A (SAA) is a sensitive acute-phase response (APR) marker in equids. Prominent APRs with elevations of SAA concentrations ([SAA]) have been reported after vaccination. The authors hypothesized that vaccination with an inactivated EHV-1/-4 vaccine would cause increase in [SAA] and antibody responses and that higher [SAA] would be positively correlated with the antibody titer in both equids. Twelve Haflinger horses and 12 mules were included in this longitudinal prospective study. All horses and mules were vaccinated with a commercially available EHV-1/-4 vaccine. Blood was sampled before and after vaccination to measure [SAA] and virus-neutralizing response (VN-T). In horses and mules, significantly higher [SAA] were measured on days 1, 3, and 5 after EHV-1/-4 vaccination; [SAA] on day 1 after vaccination were only measured in animals that developed fever, where mean [SAA] were significantly higher in horses than in mules (horses: 1,365.75 ± 87.64 mg/L, mules: 615.5 ± 153.444 mg/L) (P > .05). Four horses and 2 mules developed fever after vaccination, lasting for ≤24 hours. Increased antibody responses (VN-T) on days 7 and 14 after vaccination were observed in all animals, whereas mules showed higher overall antibody responses. Nevertheless, [SAA] did not correlate with the intensity of the antibody responses (VN-T) stimulated by the vaccine (P < .05). EHV-1/-4 vaccination caused a prominent APR, higher in horses than in mules, but [SAA] did not correlate with antibody responses. Measuring [SAA] after vaccination could help identify severe APRs that may require longer resting intervals before training or competition.

Genetics of Equine Respiratory Disease

Genetic factors influence the development of guttural pouch tympany, recurrent laryngeal neuropathy, severe equine asthma, exercise-induced pulmonary hemorrhage, and possibly also some malformations and infectious diseases of the respiratory tract. The current data suggest that most of these diseases are complex, resulting from the interaction between several genes and environmental factors. To date, no specific genes or causative mutations have been identified that would allow the development of practical genetic tests. In the future, genetic profiling panels, based on multiple genetic markers and environmental risk factors, may allow identification of individuals with an increased genetic risk.

Genetics of Skin Disease in Horses

Equine skin diseases are common, causing increased costs and reduced welfare of affected horses.Genetic testing, if available, can complement early detection, disease diagnosis, and clinical treatment and offers horse breeders the possibility to rule out carrier status. The mechanisms of complex disease can be investigated by using the latest state-of-the-art genomic technologies. Genome-based strategies may also serve as an efficient and cost-effective strategy for the management of the disease severity levels, with particular interest in complex traits such as insect bite hypersensitivity, chronic progressive lymphedema, and melanoma.

Genetic Testing in the Horse

Genetic testing in horses began in the 1960s, when parentage testing using blood group markers became the standard. In the 1990s, parentage testing shifted from evaluating blood groups to DNA testing. The development of genetics and genomics in both human and veterinarian medicine, along with continued technological advances in the last 2 decades, has helped unravel the causal variants for many horse traits. Genetic testing is also now possible for a variety of phenotypic and disease traits and is used to assist in breeding and clinical management decisions. This article describes the genetic tests that are currently available for horses.

Fibrinonecrotic Placentitis and Abortion Associated With Pantoea agglomerans Infection in a Mare

Pantoea agglomerans, family Enterobacteriaceae, is a Gram-negative bacterium that may be isolated from soil and from plants. This bacterium has been associated with disease in plants, humans, and rarely in domestic animal species. We describe here a case of fibrinonecrotic placentitis and equine abortion associated with P. agglomerans infection in southern Brazil. A fetus with 10 months of gestation and its placenta were evaluated. Gross lesions were observed in the cervical star extending to the body of the chorioallantois and consisted of a focally extensive, transmural, severely thickened yellow area. Histologically, this area in the chorioallantois was effaced by severe necrosis, associated with marked inflammatory infiltrate of neutrophils and abundant deposition of fibrin and cellular debris. Aggregates of bacterial rods were noted intermixed with inflammation areas. No significant lesions were observed in the remaining organs inspected. Tissue samples of the lung, placenta, and stomach contents were cultured, and microbiological tests revealed the growth of P. agglomerans in all evaluated samples. The present study reaffirms the participation of P. agglomerans as a cause of bacterial placentitis and abortion in horses.

Detection of antibodies against tick-borne encephalitis flaviviruses in breeding and sport horses from Spain

Tick-borne encephalitis virus (TBEV) and louping-ill virus (LIV) are two closely related zoonotic flaviviruses leading to neurological diseases and belonging to the tick-borne encephalitis (TBE) serocomplex. Both viruses are transmitted by the same ixodid tick vector, Ixodes ricinus. Due to global warming affecting vector biology and pathogen transmission, the viruses pose an emerging threat for public health in Europe and Asia. These flaviviruses share some hosts, like sheep, goats and humans, although the main hosts for LIV and TBEV are sheep and small rodents, respectively. Whereas LIV has been detected in Spanish sheep and goat herds, circulating antibodies against TBEV have only been reported in dogs and horses from particular regions in this country. The limited available information about the prevalence of these viruses in Spain led us to investigate the serological evidence of TBE flaviviruses in horses from Spain. Serum neutralization tests (SNT) were performed using sera from 495 breeding and sport horses collected during two periods (2011-2013 and 2015-2016). A seroprevalence of 3.1 % (95 % CI 1.5-4.6) was found and cross-reactivity with West Nile virus was excluded in the positive samples. Sport horses showed a significantly higher TBE serocomplex seropositivity compared to breeding horses. An increased seroprevalence was observed in the second sampling period (2015-2016). Our results demonstrate for the first time the presence of antibodies against TBE flaviviruses in horses residing in mainland Spain; further epidemiological surveys are necessary in order to understand and monitor the active transmission of TBE flaviviruses in this country and rule out the presence of other flaviviruses co-circulating in Spain.

Hendra Virus Infection in Horses: A Review on Emerging Mystery Paramyxovirus

Hendra virus (HeV) is a zoonotic paramyxovirus which causes acute and deadly infection in horses (Equus caballus). It is a rare and unmanaged emerging viral infection in horses which is harbored by bats of the genus Pteropus (Australian flying foxes or fruit bats). The virus is pleomorphic in shape and its genome contains nonsegmented negative-stranded RNA with 18234 nucleotides in length. The virus is transmitted from flying foxes to horses, horse to horse, and horse to humans. Human-to-human transmission of HeV infection is not reported yet. The infection of HeV in horses is highly variable and shows broad range of signs and lesions including distinct respiratory and neurological disorders. Currently, there are no specific antiviral drugs available for the treatment of HeV infection in horses. Vaccination is considered as prime option to prevent HeV infection in horses. A subunit vaccine, called as "Equivac HeV vaccine" has been approved recently for preventing this viral infection in horses. In addition, a plethora of common preventive strategies could help restrict the inter- and intra-species transmission of HeV. Considering the scanty but severe fatality cases of this mystery virus as well as lack of proper attention by veterinary scientists, this review article spotlights not only on the clinical signs, transmission, epidemiology, biology, pathogenesis, and diagnosis of HeV but also the preventive managements of this uncommon infection in horses by vaccination and other precautious strategies.

Is the T-ligament a ligament? A histological study in equine cadaver forelimbs

Foot pain is a frequent cause of lameness in horses and can involve multiple structures within the hoof. The T-ligament (an anatomical structure connecting the synovium of the distal interphalangeal joint, the digital flexor tendon sheath and the navicular bursa) is poorly described. Five pairs of equine cadaver distal forelimbs were collected from a slaughterhouse. Sagittal sections (medial, middle and lateral) were obtained and processed with Haematoxylin Eosin Safran, Unna's Orcein, and Picrosirius red stains. Histological assessment revealed that the T-ligament was covered by the surrounding synovia of the distal interphalangeal joint, the digital flexor tendon sheath and the navicular bursa. Its collagen content was lower (30.01%±10.15) than that of the collateral sesamoidean ligament (89.48%±5.8; P = .0008) and the middle phalanx (85.72%±3.67; P = .0008). Under polarized light microscopy, it showed a slight heterogeneous pattern of birefringence, with angle-related changes. Elastic fibres were more numerous (21.76%±8.72) than in the collateral sesamoidean ligament (0.28%±0.45), or deep digital flexor tendon (0.04%±0.02); and were more densely packed. Mean cell count was higher for the T-ligament than for other tissues (P = .0007). Blood vessels were identified in the T-ligament and were penetrating the deep digital flexor tendon (8/10 limbs, 5/5 horses). In conclusion, the T-ligament looked like a vinculum for the deep digital flexor tendon, with a central elastic core, surrounding loose connective tissue and blood vessels. It is not a ligament. Its clinical relevance still needs to be determined.

Concussion knowledge, attitudes and behaviour in equestrian athletes

OBJECTIVE

To determine knowledge, attitudes and behaviour towards concussion in adult equestrian athletes.

DESIGN

Nationwide, cross-sectional, questionnaire.

METHODS

Participants were recruited via advertisements circulated through social media, community presentations and equestrian organisations. Participants were sent a web link to an online questionnaire previously designed for high school athletes and modified to ensure relevance to equestrian activities. The percentage of correct responses per item and a total knowledge score were calculated. Differences in concussion knowledge by age, sex, level of experience and previous history of concussion were explored using t-tests, 95% confidence intervals (CI) and effect sizes.

RESULTS

The questionnaire was completed by 1486 participants (Mean age=39.1±15.4). Knowledge of what concussion was, how to recognise it and key symptoms (except poor sleep) was high (>80%). In contrast, awareness of guidelines was moderate (56%) and inability of helmets to prevent concussion was low (12%). Significantly higher levels of knowledge of concussion were identified in females compared with males (t=-6.55 p<0.001, 95%CI=-3.26 to -1.75). The majority (87%) of participants reported that a helmet should be replaced after a fall, yet 46% reported re-using a helmet following a hit to the head.

CONCLUSIONS

Knowledge of and attitudes towards concussion were positive. However, there were knowledge gaps and discrepancies between some attitudes and behaviour on some aspects of concussion. Targeted campaigns to promote awareness of concussion and improve recognition and onward management are needed. Education related to equestrian activities such as helmet use and injury mechanisms is needed to change behaviour and minimise the risk of injury.

Stallion Semen Cooling Using Native Phosphocaseinate-based Extender and Sodium Caseinate Cholesterol-loaded Cyclodextrin-based Extender

The objective of this study was to compare semen parameters and embryo recovery rates of cooled stallion semen extended with INRA 96 or BotuSemen Gold. In experiment 1, 45 ejaculates from nine mature stallions were collected, assessed, and equally split between both extenders and then extended to 50 million sperm/mL. Then, the extended semen was stored in three passive cooling containers (Equitainer, Equine Express II, and BotuFlex) for 48 hours. In experiment 2, the same ejaculates extended in experiment 1 were cushion-centrifuged, the supernatant was discarded, and the pellets were resuspended at 100 million sperm/mL with their respective extender. Semen was then cooled and stored as in experiment 1. In both experiments, sperm motility parameters, plasma membrane integrity, and high mitochondrial membrane potential were assessed at 0, 24, and 48 hours post cooling. For experiment 3, 12 mares (n = 24 cycles) were bred with 48 hour-cooled semen from one stallion. Semen was processed as described in experiment 1. Mares had embryo flushing performed by 8-day post-ovulation. In experiment 1, BotuSemen Gold displayed superior total and progressive motility relative to INRA 96 (P < .05). There were no significant differences between the types of containers in any experiment. In experiment 2, INRA 96 and BotuSemen Gold extenders had similar total and progressive motility, but BotuSemen Gold had superior sperm velocity parameters at all timepoints. Embryo recovery was identical for both extenders (50%). Finally, the results obtained herein suggest that BotuSemen Gold is a suitable alternative to be included in semen cooling tests against INRA 96 in clinical practice.

Evidence of circulation of West Nile virus in Culex pipiens mosquitoes and horses in Morocco

West Nile virus (WNV) is one of the most widely distributed mosquito-borne viruses in the world. In North Africa, it causes human cases of meningoencephalitis with fatalities in Algeria and in Tunisia, whereas only horses were affected in Morocco. The aims of this study were to detect WNV in mosquitoes and to determine seroprevalence of WNV in Moroccan horses by the detection of IgG antibodies. A total of 1455 mosquitoes belonging to four different species were grouped by collection site, date, and sex with 10 specimens per pool and tested for 38 arboviruses using a high-throughput chip based on the BioMark Dynamic array system. Out of 146 mosquito pools tested, one pool was positive for WNV. This positive pool was confirmed by real time RT-PCR. The serosurvey showed that 33.7% (31/92) of horses were positive for competitive enzyme-linked immunosorbent assay (cELISA) test. The flavivirus-sphere microsphere immnoassay (MIA) test, targeting three flaviviruses (WNV, Usutu virus (USUV) and Tick borne encephalitic virus (TBEV)) showed that 23 sera out of 31 were positive for WNV, two for USUV, two for USUV or WNV, and four for an undetermined flavivirus. Virus neutralization tests with USUV and WNV showed that 28 of 31 sera were positive for WNV and all sera were negative for USUV. This study reports, for the first time, the detection of WNV from Culex pipiens mosquitoes in Morocco and its circulation among horses. This highlights that the detection of arboviruses in mosquitoes could serve as an early warning signal of a viral activity to prevent future outbreaks in animals and humans.

Impact of Dietary Cellobiose on the Fecal Microbiota of Horses

Cellobiose is a disaccharide with potential prebiotic effects, as demonstrated in different animal species, but not yet in horses. It was, therefore, the aim of the present study to evaluate the impact of dietary cellobiose on the fecal microbiota of horses. Eight healthy adult horses and two ponies were included in this study. The animals received a diet without or with 10 g and 20 g cellobiose per day for 14 days each. At the end of the feeding periods, fresh fecal samples were collected to measure bacterial metabolites and the microbial composition. For the microbiota analysis, 16S rRNA gene sequencing was used. Cellobiose was well accepted and tolerated by the animals. The lowest fecal concentrations of D-lactate, propionic acid, i-valeric acid, and total short-chain fatty acids were measured at the dose 10 g cellobiose per horse per day (quadratic effect: P < .05). A dose-dependent increase of the relative abundance of Firmicutes (P = .049), Coriobacteriales (P < .001), and Clostridium (P = .031) could be detected. In addition, a dose-dependent decrease of the relative abundance of Bacteroidetes (P = .035) was observed. In conclusion, the increase of Coriobacteriales and Clostridium indicates a bacterial fermentation of cellobiose in the equine intestine, as members of both groups exert saccharolytic activity. As clostridia have previously been assumed to be a key component of the intestinal microbiota in horses, the observed increase of Clostridium in the feces might indicate beneficial and potentially prebiotic effects of cellobiose in horses. However, this finding requires further investigation, particularly with regard to the Clostridium species that have been promoted by dietary cellobiose.

Information delivery and the veterinarian-horse owner relationship in the context of Hendra virus in Australia

Hendra virus (HeV) is an emerging bat-borne virus endemic in Australia that can be transmitted from horses to humans and has a high fatality rate for horses and people. Controversy surrounding HeV risk mitigation measures have strained the veterinarian-horse owner relationship. This study aimed to characterise the veterinarian-horse owner relationship in general and also in the context of HeV by analysing data derived from the 'Horse Owners and Hendra Virus: A Longitudinal Study to Evaluate Risk' (HHALTER) study. Australian horse owners were recruited via emails, social media and word-of-mouth for a series of five surveys that were administered online at six-monthly intervals over a two-year period to capture baseline knowledge, attitudes and practices of horse owners regarding HeV and any changes over time. In the current study, descriptive analyses of information sources were performed to understand the use of veterinarians as a HeV information source (Surveys 1 and 5; n = 1195 and n = 617). Ordinal logistic regression analyses were conducted to determine factors associated with the frequency of horse owner contact with a veterinarian (Survey 3; n = 636). This study found a relative increase over the study period in the proportion of horse owners who had used veterinarians as HeV information source in the last 12 months (from 51.9% to 88.3%). Owning more horses, being older, having a 'duty of care' for other people working with horses and deriving the main income from horse related business were factors associated with more frequent veterinary contact. Results suggest that traditional information sources such as workshops, information packs and risk training are likely to be used by horse owners. Smart phone applications should be considered for use in the future and require further investigation for horse health communication. The findings of this study may be helpful in optimising strategies for horse health information delivery.

Myelopathy and Reactive Microgliosis and Astrogliosis in Equine Back Pain

Equine chronic back pain (CBP) has been linked to different pathologic processes, which directly or indirectly involve spinal structures. Thus, making diagnosis and management very challenging with most horses with the condition recommended for early retirement from athletic activity. This study described the spinal cord lesions and the development of reactive microgliosis and astrocytosis in the spinal cords of horse with CBP. Thoracolumbar spinal cord segments from three horses euthanized because of unresolved CBP were dissected and grossly and histopathologically examined. The expression of activated microglia and astrocytes were demonstrated immunohistochemically using polyclonal rabbit anti-Iba-1 and anti-glial fibrillary acidic protein antibodies, respectively. All horses had radiological evidence of varying degrees of kissing spine involving six to nine vertebrae with the majority of the lesions graded between 2 and 5. Grossly, there was myelomalacia with intramedullary hemorrhages. The gray matters of the spinal cords were characterized by hemorrhagic malacic lesions with medullary disintegration. Reactive microgliosis and astrocytosis were evident in the spinal dorsal horns. White matter lesions include axonal swollen and/or loss, satellitosis, and varying degrees of dilation of myelin sheaths with some containing macrophages. In conclusion, the presence of reactive microgliosis and astrogliosis in the spinal dorsal horn indicates that they are possible precipitating factors in the development of equine CBP.

Horses are susceptible to natural, but resistant to experimental, infection with the liver fluke, Fasciola hepatica

Fasciola hepatica is a common parasite of livestock in Ireland, causing significant economic losses and affecting animal welfare. A previous abattoir study of 200 horses led to an estimated 9.5 % prevalence of infection in horses slaughtered in Ireland. However, the epidemiology and pathogenic significance of this infection in this species is not well-described. The objectives of this study were to determine the susceptibility of horses to oral challenge infection with F. hepatica metacercariae, and to document the course of the infection along with serological and biochemical response. We attempted an experimental infection of horses (n = 10; 9 geldings and 1 mare) with F. hepatica. Four were given 1000 metacercariae, four 500 metacercariae and two were sham-infected. Blood and faecal samples were taken at intervals up to 18 weeks post-infection (wpi). ELISA assays were used to assess sero-conversion in the experimental horses and also in a panel of sera from horses of known fluke status. No flukes were recovered from any of the livers, and neither were any lesions that could be attributed to F. hepatica infection observed. Coproantigen ELISA was negative throughout for all horses. Three antibody detection ELISAs, useful in diagnosing fasciolosis in other species, had limitations as diagnostic aids as determined using a panel of sera from horses of known F. hepatica infection status. This study is limited by the relatively small number of animals included, and the relatively short duration of the study period. Failure to establish infection after oral challenge raises fundamental questions on the pathophysiology and epidemiology of equine fasciolosis.

Proteomic profiling of stallion spermatozoa suggests changes in sperm metabolism and compromised redox regulation after cryopreservation

Proteomic technologies allow the detection of thousands of proteins at the same time, being a powerful technique to reveal molecular regulatory mechanisms in spermatozoa and also sperm damage linked to low fertility or specific biotechnologies. Modifications induced by the cryopreservation in the stallion sperm proteome were studied using UHPLC/MS/MS. Ejaculates from fertile stallions were collected and split in two subsamples, one was investigated as fresh (control) samples, and the other aliquot frozen and thawed using standard procedures and investigated as frozen thawed subsamples. UHPLC/MS/MS was used to study the sperm proteome under these two distinct conditions and bioinformatic enrichment analysis conducted. Gene Ontology (GO) and pathway enrichment analysis were performed revealing dramatic changes as consequence of cryopreservation. The terms oxidative phosphorylation, mitochondrial ATP synthesis coupled electron transport and electron transport chain were significantly enriched in fresh samples (P = 5.50 × 10^-12, 4.26 × 10^-8 and 7.26 × 10^-8, respectively), while were not significantly enriched in frozen thawed samples (P = 1). The GO terms oxidation reduction process and oxidoreductase activity were enriched in fresh samples and the enrichment was reduced in frozen thawed samples (1.40 × 10^-8, 1.69 × 10^-6 versus 1.13 × 10^-2 and 2-86 × 10^-2 respectively). Reactome pathways (using human orthologs) significantly enriched in fresh sperm were TCA cycle and respiratory electron transport (P = 1.867 × 10^-8), Respiratory electron transport ATP synthesis by chemiosmosis coupling (P = 2.124 × 10^-5), Citric acid cycle (TCA cycle)(P = 8.395 × 10^-4) Pyruvate metabolism and TCA cycle (P = 3.380 × 10^-3), Respiratory electron transport (P = 2.764 × 10^-2) and Beta oxidation of laurolyl-CoA to decanoyl CoA-CoA (P = 1.854 × 10^-2) none of these pathways were enriched in thawed samples (P = 1). We have provided the first detailed study on how the cryopreservation process impacts the stallion sperm proteome. Our findings identify the metabolic proteome and redoxome as the two key groups of proteins affected by the procedure. SIGNIFICANCE: In the present manuscript we investigated how the cryopreservation of stallion spermatozoa impacts the proteome of these cells. This procedure is routinely used in horse breeding and has a major impact in the industry, facilitating the trade of genetic material. This is still a suboptimal biotechnology, with numerous unresolved problems. The limited knowledge of the molecular insults occurring during cryopreservation is behind these problems. The application and development of proteomics to the spermatozoa, allow to obtain valuable information of the specific mechanisms affected by the procedure. In this paper, we report that cryopreservation impacts numerous proteins involved in metabolism regulation (mainly mitochondrial proteins involved in the TCA cycle, and oxidative phosphorylation) and also affects proteins with oxidoreductase activity. Moreover, specific proteins involved in the sperm-oocyte interaction are also affected by the procedure. The information gathered in this study, opens interesting questions and offer new lines of research for the improvement of the technology focusing the targets here identified, and the specific steps in the procedure (cooling, toxicity of antioxidants etc.) to be modified to reduce the damage.

Dorsal Displacement of the Soft Palate Secondary to Persistent Frenulum of the Epiglottis in Neonatal Foal

Dorsal displacement of the soft palate (DDSP) usually occurs in athletic adult horses. Congenital DDSP in foals secondary to the persistent frenulum of the epiglottis is rarely observed. The aim of this report was to describe a case of a seven-day-old female neonate Quarter Horse presenting dysphagia, milk reflux through the nostrils and mouth, and expiratory dyspnea since 4 days. Thoracic auscultation was indicative of aspiration pneumonia. Diagnosis of DDSP associated with local inflammation was made after endoscopic examination of upper respiratory tract. Radiographic examination was performed to rule out hypoplasia of the epiglottis. No clinical improvement was observed after anti-inflammatory treatment with flunixin meglumine. Oral endoscopy under general anesthesia revealed that the displacement of the soft palate was caused by a persistent frenulum of the epiglottis. Using a 30° rigid endoscope and a curved laparoscopic scissors, the frenulum was transected. After surgery, no dysphagia or dyspnea at rest was observed. However, discreet respiratory noise persisted during exercise for 5 days postoperatively. After discharge, the owner reported that the animal was completely normal during exercise. The animal is currently 3 years old and is developing a normal athletic performance. Persistent frenulum of the epiglottis should be considered while examining neonates with nasal milk reflux associated with expiratory dyspnea. This case report emphasizes the importance of the differential diagnosis for DDSP and for DDSP secondary to the persistent frenulum of the epiglottis in neonatal foals. It also underlines the importance of oral endoscopic examination for diagnosis.