Equine protozoal encephalomyelitis

BackgroundThe back plays a vital role in horse locomotion, where the spine functions as a spring during the stride cycle. A complex interaction between the spine and the muscles of the back contribute to locomotion soundness, gait ability, and performance of riding and racehorses. Conformation is commonly used to select horses for breeding and performance in multiple horse breeds, where the back and croup conformation plays a significant role. The conformation of back and croup plays an important role on riding ability in Icelandic horses. However, the genes behind this trait are still unknown. Therefore, the aim of this study was to identify genomic regions associated with conformation of back and croup in Icelandic horses and to investigate their effects on riding ability. One hundred seventy-seven assessed Icelandic horses were included in the study. A genome-wide association analysis was performed using the 670 K+ Axiom Equine Genotyping Array, and the effects of different haplotypes in the top associated region were estimated for riding ability and additional conformation traits assessed during breeding field tests.ResultsA suggestive quantitative trait loci (QTL) for the score of back and croup was detected on Equus caballus (ECA) 22 (p-value = 2.67 × 10− 7). Haplotype analysis revealed two opposite haplotypes, which resulted in higher and lower scores of the back and croup, respectively (p-value < 0.001). Horses with the favorable haplotype were more inclined to have a well-balanced backline with an uphill conformation and had, on average, higher scores for the lateral gaits tölt (p-value = 0.02) and pace (p-value = 0.004). This genomic region harbors three genes: C20orf85, ANKRD60 and LOC100056167. ANKRD60 is associated with body height in humans. C20orf85 and ANKRD60 are potentially linked to adolescent idiopathic scoliosis in humans.ConclusionsOur results show that the detected QTL for conformation of back and croup is of importance for quality of lateral gaits in Icelandic horses. These findings could result in a genetic test to aid in the selection of breeding horses, thus they are of major interest for horse breeders. The results may also offer a gateway to comparative functional genomics by potentially linking both motor laterality and back inclination in horses with scoliosis in humans.

Equine recurrent uveitis (ERU) is an autoimmune disease defined by inflammation of the uveal tract of the eye. The cause of ERU is thought to be complex, involving both genetic and environmental factors. The purpose of this study was to investigate potential genetic risk factors for ERU in the Icelandic horse. Fifty-six Icelandic horses (11 affected with ERU and 45 controls) living in Denmark and the USA, eight years or older, were included in the study. A case-control GWAS was performed using the GGP Equine 80K array on the Illumina Infinium HD Beadchip using 40 horses. A mixed linear model analysis identified a single SNP on ECA 11 (BIEC2_141650; NC_009154.3:g.3817009A>G) that reached genome-wide significance (p=1.79×10-7 ). This variant was within an intron of tissue inhibitor of metalloproteinase 2 (TIMP2), a gene previously implicated in ERU. Sanger sequencing identified a single coding variant in this gene; however it was a synonymous mutation (NC_009154.3:g.3858193C>T) and was not perfectly concordant with ERU phenotype (p=0.68). Further investigation of TIMP2 is warranted. Additional horses and markers are needed to identify other potential loci worthy of further investigation as contributors to ERU risk in Icelandic horses.

BackgroundAn oral sugar test (OST) using Karo® Light Corn Syrup has been developed in the USA as a field test for the assessment of insulin dysregulation in horses but the syrup is not available in Scandinavian grocery stores. The aim of the study was to compare the results of a modified OST between horses with equine metabolic syndrome (EMS) and healthy horses using a Scandinavian commercially available glucose syrup (Dansukker glykossirap). In addition, the effect of breed and the repeatability of the test were evaluated. In the present study, clinically healthy horses (7 Shetland ponies, 8 Icelandic horses, 8 Standardbred horses) and 20 horses of various breeds with EMS underwent the modified OST test. The Icelandic horses and Shetland ponies underwent the OST twice. Insulin and glucose data from the OST were used to calculate peak insulin concentration (PeakINS), time to peak insulin concentration (T-peakINS), area under the curve for insulin (AUCINS) and glucose (AUCGLU) as well as whole body insulin sensitivity index (ISICOMP).ResultsCompared to the healthy group, the EMS group had 6–7 times higher geometric mean for PeakINS and AUCINS and 8 times lower geometric mean for ISICOMP. The EMS group had a delayed T-peakINS compared to the healthy group. There was no effect of breed in the group of healthy horses on PeakINS, T-peakINS, AUCINS, AUCGLU and ISICOMP. Coefficient of variation for repeated tests was 19.8, 19.0 and 17.6 % for PeakINS, AUCINS and ISICOMP respectively.ConclusionsThe results of the present study demonstrate that the modified OST appears to be a practical and useful diagnostic tool for assessment of insulin dysregulation in the horse. However, to make it possible to establish the most appropriate sampling interval and to evaluate the accuracy of the modified OST, further studies in horses with a variable degree of insulin resistance are needed, where results from the modified OST are compared with quantitative measurements for IS.

Horse-related events have been popular in Iceland for many decades, as well as in other countries. Such events attract many people that are both enthusiastic about and involved in horse-related activities. The biggest horse event in Iceland since 1950 has been the National Championships of the Icelandic Horse - Landsmót - which enables the owners of the best horses in Iceland to come together and compete in various categories. Landsmót is organized by the Icelandic Equestrian Association (Landssamband hestamannafélaga [National Association of Equestrian Associations], referred to as LH) and the Farmers Association of Iceland in cooperation with local horse clubs that act as hosts for Landsmót. In this chapter, the Landsmót events held in the years 1998-2008 are studied from a strategic management point of view. The chapter looks into the lessons learnt from the events, based on a four-dimensional approach to strategic management. The main goal of the research, which was completed in 2010, was to bring forward important knowledge and information on the Landsmót events that could be used in the strategy and the development work for upcoming events over the following years. The study of Landsmót 1998-2008 was based on a case study method. Six cases were studied from an illustrative and explorative point of view. The study also made use of focus groups, interviews, questionnaires and document analysis. The study concluded that Landsmót as a biennial event is a celebration of success in breeding and training of the Icelandic horse. Landsmót is also a social gathering, uniting people who are dedicated to the Icelandic horse, both within Iceland and from abroad. The study also concluded that Landsmót is about competition and ranking of the best horses, while at the same time it is an event true to tradition and family activity. Finally, the main conclusions reveal that Landsmót is very important for marketing and communication of the qualities of the Icelandic horse.

The relationship between the welfare quality and stress index in working and breeding horses

The spectrum of modern horse populations encompasses populations with a long history of development in isolation and relatively recently formed types. To increase our understanding of the evolutionary history and provide information on how to optimally conserve or improve these populations with varying development and background for the future, we analyzed genotype data of 184 horses from 9 Dutch or common horse populations in the Netherlands: The Belgian draft horse, Friesian horse, Shetland pony, Icelandic horse, Gelder horse, Groninger horse, harness horse, KWPN sport horse and the Lipizzaner horse population. Various parameters were estimated (e.g., runs of homozygosity and FST values) to gain insight into genetic diversity and relationships within and among these populations. The identified genomic makeup and quantified relationships did mostly conform to the development of these populations as well as past and current breeding practices. In general, populations that allow gene-flow showed less inbreeding and homozygosity. Also, recent bottlenecks (e.g., related to high selective pressure) caused a larger contribution of long ROHs to inbreeding. Maintaining genetic diversity through tailor-made breeding practices is crucial for a healthy continuation of the investigated, mostly inbred and (effectively) small sized horse populations, of which several already experience inbreeding related issues.

Selection for performance in horse breeding benefits from precise genetic insights at a molecular level, but knowledge remains limited. This study used whole-genome sequences of 39 elite and non-elite Icelandic horses to identify candidate causal variants linked to previously identified haplotypes in the STAU2 and RELN genes affecting pace and other gaits. A frameshift variant in linkage disequilibrium with the previously identified haplotypes in the STAU2 gene (r2 = 0.85) was identified within a predicted STAU2 transcript. This variant alters the amino acid sequence and introduces a premature stop codon but does not appear harmful or disease-causing and is potentially unique to equine biology. A large portion of the RELN haplotype overlapped with an H3K27me3 modification mark, suggesting a regulatory role of this region. Despite the small sample size, the RELN haplotype’s effects were validated for tölt, trot, and canter/gallop. Additionally, the RELN haplotype significantly influenced the age at which horses were presented for breeding field tests, indicating a potential role of the region in precocity and trainability. Functional experiments are needed to further investigate the regions’ influences on biological processes and their potential impact on horse performance.

Contagious equine metritis (CEM) is caused by Taylorella equigenitalis. It is a venereal disease that is detected in some breeds more than others and can cause temporary infertility with substantial costs for regular testing, sanitation and retesting. There was a perceived increase in T. equigenitalis-positive cases in Icelandic intact males where natural cover is common. We aimed to investigate the prevalence of T. equigenitalis in Icelandic intact males and compare to draught horse and Haflinger intact males. We hypothesised that prevalence of T. equigenitalis is higher in Icelandic compared with draught and Haflinger intact males. Cross sectional. Swabs from 76 Icelandic, 35 Haflinger, and 51 draught horse intact males were collected on 38 different farms and analysed by qPCR. Animals were further stratified into active breeding and non-breeding animals and age groups (1.5-7.0 and 8.0-26.0 years). Fisher's exact tests and mixed effect logistic regression with 'farm' as random effect were used to estimate differences in odds for T. equigenitalis-positive test results. The overall prevalence of T. equigenitalis in included intact males was 16.7% (27/162). The odds for T. equigenitalis-positive intact males were significantly higher in Icelandic compared with draught and Haflinger intact males (Odds ratio [OR] = 6.42, 95% confidence interval (CI) = 1.43-28.8, p = 0.02). Odds for T. equigenitalis-positive intact males were significantly lower in active breeding compared with non-breeding animals (OR = 0.09, 95% CI = 0.01-0.54, p = 0.009). Age had no significant influence on test results. Convenience sampling with regional restrictions to Southern Germany and Austria, small sample size. Significantly higher odds for T. equigenitalis-positive intact males were found within Icelandic over draught and Haflinger and within non-breeding animals compared with active breeding animals. Findings suggest that non-breeding animals could be a reservoir for T. equigenitalis. Testing for CEM should therefore be routinely performed in Icelandic horses prior to breeding and investigations into epidemiology and reservoirs on affected farms should be initiated.

Chronic progressive lymphedema in Clydesdale and Shire draft horses causes severe disability of the limbs which leads to premature death of these horses. Since appropriate function of lymph vessels is dependent on the presence of viable elastin fibers, the goal of this study was to document differences in skin elastin fibers in affected horse breeds, compared to a nonaffected draft horse breed. Biochemical analysis of cutaneous desmosine, a cross-linking amino acid found only in elastin, was used to measure elastin in the skin from 110 draft horses. This included 7 normal, 38 mildly affected, 30 moderately, and 15 severely affected horses, and 20 horses of a nonaffected draft breed. Desmosine concentrations in neck, considered a nonaffected skin region, and left forelimb, an affected skin region, were compared between the groups. A significantly lower desmosine concentration was found in the skin of the neck and limb of clinically normal animals of affected draft breeds compared to a nonaffected draft horse breed. During the progression of the disease in the affected breeds, cutaneous desmosine concentrations most prominently increased in the skin of the distal limbs. Chronic progressive lymphedema in draft horses was associated with an initially systemic lower cutaneous elastin level and a deposition of elastin during the progression of the disease. A failure of elastic fibers to appropriately support the skin and its lymphatics is proposed as a possible contributing factor for chronic progressive lymphedema in Shires and Clydesdales.

The solute carrier family 26, member 2 (SLC26A2) gene belongs to a family of multifunctional anion exchangers. Mutations in the human SLC26A2 gene are associated with autosomal recessively inherited chondrodysplasias. Hence, we postulate that the equine SLC26A2 could be a candidate gene for conformational traits in horses. An equine BAC clone harboring the SLC26A2 gene was isolated. The complete 142,625 bp insert sequence of this clone was determined by transposon sequencing. Together with the SLC26A2 gene the BAC clone contains four genes, i.e. the macrophage colony stimulating factor 1 receptor precursor (CSF1R), KIAA0194 protein gene similar to the SMF protein (KIAA0194), a tigger transposable element derived 14 (TIGD14), the 3′-5′-cyclic GMP phosphodiesterase alpha-chain (EC 3.1.4.35) and one unidentified open reading frame. The equine SLC26A2 gene encompassing 6,152 bp consists of two exons. The complete open reading frame of 2,211 bp encodes a protein of 736 amino acids. A comparison of the amino acid sequence with other mammalian orthologs revealed homologies with identity in a range between 80% and 88%. By contrast, the equine SLC26A2 protein lacks five C-terminal amino acids. Four single nucleotide polymorphisms (SNP) were identified (three synonymous and one non-synonymous variant Ser210Leu) in the coding region by comparative sequencing of 50 DNA samples representing the German Riding horse. Allele frequencies and distribution were further evaluated in a variety of different breeds: Arabians (for all four SNPs), Old Kladrub Horses, Draught Horses (including Westphalian Draught Horses, Rheinish Westphalian Draught Horses, Saxon-Thuringia Coldbloods, Altmärker Coldbloods), American Saddlebreds, Miniature Horses, Australian Riding Ponies, Appaloosa, Morgan Horses, and Lipizzaner for C629T (Ser210Leu) alone. No animal carrying the homozygous genotype TT has been detected. The overall frequency of the newly described variant T is low (between 2% and 6%). Simulation studies on the protein conformation predict structural protein changes mediated by the SNP.

5050 Background: The enzyme encoded by the HSD3B1(1245C) variant allele has been shown to promote castration-resistant prostate cancer by increasing intratumoral dihydrotestosterone synthesis. In the setting of biochemical recurrence (BCR) following prostatectomy, inheritance of the variant allele has been associated with inferior clinical outcomes for men treated with androgen deprivation therapy (ADT). Whether the same is true in the context of BCR after radiotherapy (RT) is unknown. Methods: We determined HSD3B1 genotype retrospectively in men treated with ADT for post-RT BCR using an established biorepository at a large academic center. We analyzed time-to-progression (TTP), time-to-metastasis (TTM), and overall survival (OS) according to HSD3B1genotype using an additive genetic model with the log-rank trend test. Multivariable analyses (MVA) were performed to adjust for known prognostic factors with Cox regression. Results: We identified 218 men treated with ADT for BCR after RT, of whom 213 (98%) were successfully genotyped (46%, 45% and 9% carrying 0, 1, and 2 variant alleles, respectively). Median follow-up was 7.9 years (yrs). Demographic and treatment factors were similar across genotypes. Median TTP was 2.3 (95% CI: 1.6, 3.1) yrs in men who inherited 0 variant alleles, 2.3 (1.5, 3.3) yrs with 1 variant allele, and 1.4 (0.7, 3.3) yrs with 2 variant alleles (P = 0.683). Median TTM diminished with the number of variant alleles inherited (7.4 [6.7, 9.7], 5.8 [4.9, 6.5] and 4.4 [3.0, 5.7] yrs, respectively (P = 0.030). No difference in OS was detected (P = 0.305). On MVA with 0 variant alleles as the reference, the adjusted hazard ratio (HR) for metastasis was (1.19 [0.74, 1.92]; P = 0.480) for 1 allele and (2.01 [1.02, 3.97]; P = 0.045) for 2 alleles. MVA did not demonstrate significant differences in TTP or OS. Conclusions: The HSD3B1(1245C) allele that enhances dihydrotestosterone synthesis is associated with time-to-metastasis in men treated with ADT for BCR after RT for prostate cancer. Notably, 49% of men had received prior ADT as part of local therapy and 56% received an anti-androgen during ADT for BCR, which may blunt the effect of the variant allele.

No Association between <i>hOGG1</i> Ser326Cys Polymorphism and Risk of Squamous Cell Carcinoma of the Head and Neck

Simple SummaryThere is currently limited information on the types, or risk, of injuries occurring for horses racing in flat races in New Zealand. Race reports and records from six racing seasons were used to determine the reasons why horses failed to finish a race. In total, 544 horses failed to complete a race, of which 177 were due to veterinary events. Most of the veterinary events that occurred during a race were classed as musculoskeletal injuries (136/177; 77%). The rate of musculoskeletal injuries during a race, 0.72 per 1000 starts, was lower than the rates reported for other racing jurisdictions. The condition of the track and the distance of the race were associated with the rate of musculoskeletal injury during a race. There may be differences in the training programmes and racing schedules for horses in the southern hemisphere, which may have contributed to the low rates reported in this study.The objective of the study was to determine the incidence of veterinary events that resulted in a horse failing to finish a race and identify risk factors for musculoskeletal injury (MSI) during a race. Data were obtained on Thoroughbred flat race starts in New Zealand between 1 August 2005 and 31 July 2011 (six racing seasons). Stipendiary Steward’s reports were key-word searched to identify veterinary events that prevented a horse from finishing a race. Race data were used calculate the incidence of veterinary events per 1000 horse starts and Poisson regression was used to investigate risk factors for MSI. There were 188,616 race starts and 177 reported veterinary events. The incidence of MSI on race day was 0.72 per 1000 starts, whilst the incidence of respiratory events was 0.21 per 1000 starts. The rate of MSI was significantly lower on ‘dead’ and ‘slow’ tracks compared with ‘good’ tracks and significantly greater in longer races (≥1671 m) compared with races of ≤1200 m. The rate of MSI during flat races in New Zealand appears lower than that reported worldwide, which may be due to the management and training of horses in New Zealand or differences in case definitions used in comparable studies.

BackgroundRecent studies have reported associations between a variant allele in a let-7 microRNA complementary site (LCS6) within the 3′untranslated region (3′UTR) of KRAS (rs61764370) and clinical outcome in metastatic colorectal cancer (mCRC) patients receiving cetuximab. The variant allele has also been associated with increased cancer risk. We aimed to reveal the incidence of the variant allele in a colorectal cancer screening population and to investigate the clinical relevance of the variant allele in mCRC patients treated with 1st line Nordic FLOX (bolus 5-fluorouracil/folinic acid and oxaliplatin) +/− cetuximab.MethodsThe feasibility of the variant allele as a risk factor for CRC was investigated by comparing the LCS6 gene frequencies in 197 CRC patients, 1060 individuals with colorectal polyps, and 358 healthy controls. The relationship between clinical outcome and LCS6 genotype was analyzed in 180 mCRC patients receiving Nordic FLOX and 355 patients receiving Nordic FLOX + cetuximab in the NORDIC-VII trial (NCT00145314).ResultsLCS6 frequencies did not vary between CRC patients (23%), individuals with polyps (20%), and healthy controls (20%) (P = 0.50). No statistically significant differences were demonstrated in the NORDIC-VII cohort even if numerically increased progression-free survival (PFS) and overall survival (OS) were found in patients with the LCS6 variant allele (8.5 (95% CI: 7.3-9.7 months) versus 7.8 months (95% CI: 7.4-8.3 months), P = 0.16 and 23.5 (95% CI: 21.6-25.4 months) versus 19.5 months (95% CI: 17.8-21.2 months), P = 0.31, respectively). Addition of cetuximab seemed to improve response rate more in variant carriers than in wild-type carriers (from 35% to 57% versus 44% to 47%), however the difference was not statistically significant (interaction P = 0.16).ConclusionsThe LCS6 variant allele does not seem to be a risk factor for development of colorectal polyps or CRC. No statistically significant effect of the LCS6 variant allele on response rate, PFS or OS was found in mCRC patients treated with 1st line Nordic FLOX +/− cetuximab.

We have examined melanocortin-1 receptor (MC1R) variant allele frequencies in the general population and in a collection of adolescent dizygotic and monozygotic twins to determine statistical associations of pigmentation phenotypes with increased skin cancer risk. This included hair and skin color, freckling, mole count and sun exposed skin reflectance. Nine variants were studied and designated as either strong R (OR = 63; 95% CI 32-140) or weak r (OR = 5; 95% CI 3-11) red hair alleles. Penetrance of each MC1R variant allele was consistent with an allelic model where effects were multiplicative for red hair but additive for skin reflectance. To assess the interaction of the brown eye color gene BEY2/OCA2 on the phenotypic effects of variant MC1R alleles we imputed OCA2 genotype in the twin collection. A modifying effect of OCA2 on MC1R variant alleles was seen on constitutive skin color, freckling and mole count. In order to study the individual effects of these variants on pigmentation phenotype we have established a series of human primary melanocyte strains genotyped for the MC1R receptor. These include strains which are MC1R wild-type consensus, variant heterozygotes, and homozygotes for strong R alleles Arg151Cys and Arg160Trp. Ultrastructural analysis demonstrated that only consensus strains contained stage III and IV melanosomes in their terminal dendrites whereas Arg151Cys and Arg160Trp homozygous strains contained only immature stage I and II melanosomes. Such genetic association studies combined with the functional analysis of MC1R variant alleles in melanocytic cells should provide a link in understanding the association between pigmentary phototypes and skin cancer risk.