Caudal vena cava point-of-care ultrasound in dogs with degenerative mitral valve disease without clinically important right heart disease.

OBJECTIVES: Caudal vena cava (CVC) diameter and collapsibility index (CVCD and CVCCI) have been used to assess intravascular volume status (IVS). Maladaptations with progressive degenerative mitral valve disease (DMVD) lead to hypervolemia. We hypothesised that stages of DMVD will affect ultrasonographic CVC variables in dogs without clinically important right heart disease. ANIMALS, MATERIALS AND METHODS: This retrospective study included 79 dogs with DMVD presented to the cardiology department between January 2017 and 2019. Subxiphoid views were used to obtain CVC cineloops. By visual inspection, CVC was subjectively scored as flat, normal or fat. Maximal and minimal CVCD were measured and indexed to aortic diameter (CVCD-max/Ao and CVCD-min/Ao); CVCCI was calculated as (CVCD-max-CVCD-min)/CVCD-max. Fisher's exact and Kruskal-Wallis tests were used to compare CVC variables. RESULTS: Subjective assessment was associated with American College of Veterinary Internal Medicine (ACVIM) stages (P < 0.001). The proportion of fat CVC was greater in stages C and D. In stage D, CVCD-max/Ao was larger compared with stages B1, B2 and C (P = 0.002, P = 0.002 and P = 0.035, respectively). In stages C and D, CVCD-min/Ao was larger compared with B1 (P = 0.016 and P = 0.001) and B2 (P = 0.002 and P < 0.001. In stages C and D, CVCCI was less than stage B1 (P = 0.016 and P = 0.044) and B2 (P = 0.001 and P = 0.010). CONCLUSIONS: In dogs with DMVD without clinically important right heart disease, CVC variables differ across ACVIM stage. Subjective and objective CVC variables may be used to predict hypervolemia.

CSF omeprazole concentration and albumin quotient following high dose intravenous omeprazole in dogs.

Clinical signs of syringomyelia and hydrocephalus occur secondary to cerebrospinal fluid (CSF) accumulation within the central nervous system. Omeprazole is recommended to treat these conditions despite little evidence of its capacity to decrease CSF production in the dog. Studies into new treatments are hampered by difficulties in measuring CSF production. The albumin quotient (QAlb), the ratio between CSF and serum albumin concentrations, may reflect CSF production and any decrease in CSF production should be associated with an increase in QAlb. The primary objective of this study was to determine CSF omeprazole concentration after administration of a high intravenous dose of omeprazole and to evaluate its impact on QAlb in the dog. The second aim was to validate QAlb as a surrogate marker of CSF production. Eighteen dogs were included in this prospective crossover placebo-controlled study. Each dog received omeprazole (10 mg/kg), acetazolamide (50 mg/kg) combined with furosemide (1 mg/kg) and saline. Blood and CSF samples were obtained on day 0 and then every 7 days, one hour after drug administration. Omeprazole concentrations (2.0 ±â€¯0.4 µmol/L) reached in CSF after high dose omeprazole were lower than the concentrations previously described as decreasing CSF production in dogs. There was no significant increase in QAlb following administration of acetazolamide/furosemide, prohibiting validation of QAlb as a surrogate marker for CSF production. Several dogs presented transient mild side effects after injection of acetazolamide/furosemide. High dose omeprazole was well tolerated in all dogs.

Effects of a P-class CpG-ODN administered by intramuscular injection on plasma cytokines and on white blood cells of healthy horses.

Cytosine-phosphate-guanosine (CpG-ODN) has been described as a potent immunostimulatory agent in different species. No study reported the effect of a P-class CpG when administered systemically in healthy horses. The aim of this study was to evaluate the tolerance and the effect of an intramuscularly administered P-class CpG-ODN on hematology and on plasma cytokines (IFN-α, IL-10, TNF-α, IFN-γ) in 8 healthy horses. Intra-muscular CpG-ODN or placebo (PBS) was administered twice at a 7 days-interval. Groups were inversed after 2 months of washout period. A physical examination, complete blood count (CBC) and plasma cytokine measurements were performed from 2 days before injection up to 21 days after injection. P-class CpG-ODN injection was well tolerated with minor side effects. After the first injection a significant transient drop in circulating total leukocytes, lymphocytes and an increase in monocytes were observed. A transient drop in eosinophils was also noted after each CpG injection. P-class CpG-ODN at a dose of 5 mg did not create major side effects in 7 horses, one horse showed transient pyrexia. A redistribution of white blood cells was observed in horses receiving CpG, but no change in plasma cytokines was observed at the indicated dose, route of administration and sampling times.

Reference values of two-dimensional and M-mode echocardiographic measurements as a function of body size in various equine breeds and in ponies.

INTRODUCTION: The aim of this study was to establish echocardiographic reference values for the equine species using allometric regression equations based on body weight (BW) and thoracic circumference (TC). ANIMALS: A total of 239 horses or ponies were studied, including 65 warmbloods, 33 Standardbreds, 41 Thoroughbreds, 32 Arabian horses, 28 draft horses, and 40 ponies aged from 1 day to 30 years, weighing from 18 to 890 kg, with no evidence of cardiac disease. METHODS: For each horse or pony, a two-dimensional and M-mode echocardiography was performed. Within each breed, the relationships between BW or TC and echocardiographic dimensions were examined using power regression equations. Predictions and their 95% prediction intervals were calculated for the echocardiographic measurements. RESULTS: Within each breed, all echocardiographic measurements showed a significant and positive relationship with a high coefficient of determination for the estimation of the regression equations using BW and TC as the main explanatory variables. Breed-specific power regression equations as well as the 95% prediction intervals were calculated for each echocardiographic measurement as a function of BW and TC. CONCLUSIONS: In the future, the body size-corrected and breed-specific echocardiographic reference values calculated in the present study could be used to discriminate between normal and abnormal values in a given animal.

[Brain abcesses associated with a systemic infection by Nocardia Farcinica]. / Abcès cérébraux a Nocardia Farcinica dans le cadre d'une infection systémique.

The prevalence of nocardia infections is increasing because of both improved detection laboratory techniques and a higher number of immunosuppressed patients. We report the case of a patient with brain abcesses resulting from nocardia farcinica cerebral dissemination associated with lung infection, endocarditis and ocular lesions for which we suspected a similar origin. This case gives the opportunity to discuss the main issues of these infections and the current therapeutic guidelines.

La prévalence des infections à nocardia est en augmentation depuis plusieurs années en raison, d'une part, de l'amélioration des techniques de détection de ces germes en laboratoire et, d'autre part, d'un nombre accru de patients immunodéprimés. Nous rapportons ici l'histoire d'un patient porteur d'une infection multifocale à Nocardia Farcinica associant des abcès cérébraux, une infection pulmonaire, une endocardite et une atteinte ophtalmique. Ce cas permet de discuter les principales caractéristiques de ces infections, ainsi que les recommandations thérapeutiques actuelles.

Axillary temperature measurement: a less stressful alternative for hospitalised cats?

Rectal temperature measurement (RTM) can promote stress and defensive behaviour in hospitalised cats. The aim of this study was to assess if axillary temperature measurement (ATM) could be a reliable and less stressful alternative for these animals. In this prospective study, paired rectal and axillary temperatures were measured in 42 cats, either by a veterinarian or a student. To assess the impact of these procedures on the cat's stress state, their heart rate was checked and a cat stress score (CSS) was defined and graded from 1 (relaxed) to 5 (terrified). A moderate correlation was found between RTM and ATM (r=0.52; P<0.0001). RTM was on average 0.9 °C (1.6 °F) higher than ATM (P<0.0001), although a wide variation was found in the difference between these two measurements (-2.1 °C to 3.6 °C (-3.8 °F to 6.5 °F)). ATM failed to identify hypothermia in 25 per cent of the cases and hyperthermia in 19 per cent of the cases but may be considered less stressful than RTM. Indeed, RTM induced a mildly greater increase in heart rate (+6 bpm; P=0.01) and in CSS (+0.2; P=0.001) than ATM. The results were not affected by operator type. In conclusion, RTM should remain the standard method to obtain accurate temperatures in cats.

Evaluation of chemokines CXCL8 and CCL2, serotonin, and vascular endothelial growth factor serum concentrations in healthy dogs from seven breeds with variable predisposition for canine idiopathic pulmonary fibrosis.

The West Highland white terrier (WHWT) is particularly prone to canine idiopathic pulmonary fibrosis (CIPF). We hypothesized that higher circulating concentrations of chemokines CXCL8, CCL2, serotonin (5-HT), or vascular endothelial growth factor (VEGF) could serve as predisposing factors for CIPF development in the WHWT breed. Serum samples from 103 healthy dogs of seven different breeds variably predisposed to CIPF were collected. Serum CXCL8 concentrations were higher in healthy WHWT compared with each of the other groups of healthy dogs. Serum CCL2 concentrations were higher in healthy WHWT and Maltese compared with King Charles spaniels and Malinois Belgian shepherds. No relevant inter-breed differences were observed for serum 5-HT concentrations regarding CIPF predisposition. VEGF values from 89.3% of samples tested were below the kit detection limit. In conclusion, high CXCL8 blood concentrations and possibly CCL2 concentrations might be related to the breed predisposition of the WHWT for CIPF and warrants further investigations.

Complications and outcome of a new modified Maquet technique for treatment of cranial cruciate ligament rupture in 82 dogs.

OBJECTIVES: To describe the complications, short and long-term outcome and owner satisfaction of dogs with cranial cruciate ligament rupture treated with a recently described new osteotomy for the modified Maquet technique (N-MMT). MATERIALS AND METHODS: Medical records and radiographs of 82 dogs (84 stifles) were reviewed. Details regarding short-term outcome and complications were recorded from the medical records. Long-term follow-up information was obtained by telephone interview. Historical data and complications were statistically analysed. RESULTS: Major complications occurred in 34/84 stifles. Intra-operative complications occurred in 26/84 stifles, all of which were fissures or fractures of the cortical hinge. Twenty-one of these fractures or fissures were repaired with a figure-of-eight wire. The second most common major complication was late meniscal tears in 3/84 stifles. One dog sustained a complete tibial fracture. Non-displaced fracture of the cortical hinge was the most common postoperative minor complication, which occurred in 5/84 stifles. The median preoperative lameness score was 3 out of 6. Final in-hospital re-evaluation of limb function was available in 58 dogs. The median lameness score at that time was 0 out of 6. Development of osteotomy related complications was not associated with a significant change in the postoperative lameness score. CLINICAL SIGNIFICANCE: Subjectively assessed clinical outcome with the N-MMT was good to excellent in this cohort of dogs. However, a high rate of intra- and postoperative complications of the N-MMT procedure was also present in these dogs.

Health screening to identify opportunities to improve preventive medicine in cats and dogs.

OBJECTIVES: To describe the results of a prevention campaign in terms of participation and pet health status and to identify opportunities to improve preventive medicine in cats and dogs. METHODS: An awareness campaign was designed to highlight the role of veterinarians and emphasise the benefits of a veterinary visit. Owners were invited to make an appointment for a free pet health check in a voluntarily participating veterinary clinic. Observations recorded by the veterinarians were entered in a database and subsequently analysed using simple descriptive statistics. RESULTS: A total of 5305 completed health check forms were analysed. The percentages of overweight and obese dogs and cats were 34 and 36%, respectively; this was the most common finding, followed by dental calculus (31% in dogs, 21% in cats). In total 67% of cats did not undergo flea control and 59% were not vaccinated. CLINICAL SIGNIFICANCE: Opportunities for increased quality of care are numerous given the high percentage of intact, unvaccinated or non-permanently identified pets and the low level of worm and flea control. Animal health should benefit from preventive measures, and improved management can be undertaken after early detection of diseases.

Transforming growth factor beta 1 activation, storage, and signaling pathways in idiopathic pulmonary fibrosis in dogs.

BACKGROUND: The pathogenesis of idiopathic pulmonary fibrosis (IPF) in dogs is poorly understood. In human, transforming growth factor ß1 (TGF-ß1) is considered central in the pathogenesis. OBJECTIVES: To investigate TGF-ß1 pathway in IPF. ANIMALS: Lung tissues from 12 affected and 11 control dogs. Serum from 16 affected West Highland white Terriers (WHWTs) and healthy dogs from predisposed (13 WHWTs, 12 Scottish Terriers and 13 Bichons Frise) and nonpredisposed breeds (10 Whippets, 10 Belgian shepherds, 8 Labradors). METHODS: In this prospective study, immunohistochemistry was used to evaluate expression and localization of TGF-ß1 protein and proteins involved in TGF-ß1 signaling (TGF-ß receptor type I and phospho-Smad2/3). Pulmonary expression of TGF-ß1 and molecules involved in its storage (latent TGF-ß binding proteins [LTBP] 1, 2, and 4), activation (ανß6 and ανß8 integrins, thrombospondin-1) and signal inhibition (Smad 7) was analyzed by quantitative reverse transcriptase PCR. Circulating TGF-ß1 concentration was measured by ELISA. RESULTS: In IPF, high level of TGF-ß1 protein was found in areas of fibrosis, epithelial cells had strong expression of TGF-ß receptor type 1 and phospho-Smad2/3, gene expression was decreased for LTBP 4 (P = .009) and ß8 integrin (P < .001) and increased for thrombospondin-1 (P = .016); no difference was seen for Smad7, LTBP1 and 2. Serum TGF-ß1 concentration was higher in predisposed compared with nonpredisposed breeds (P < .0001). CONCLUSIONS AND CLINICAL IMPORTANCE: This study identified an enhanced TGF-ß1 signaling activity in IPF. TGF-ß1 storage and activation proteins with altered expression represent potential therapeutic targets. Higher circulating TGF-ß1 concentration in predisposed breeds might partly explain their susceptibility for IPF.

Effect of breed, sex, age and body weight on echocardiographic measurements in the equine species.

Little is known about the effect of various animal's signalment variables on echocardiographic reference values in the equine species. This study was performed to evaluate the effect of sex, breed, age and body weight (BW) on echocardiographic measurements in the equine species. Echocardiography was performed on 212 ponies or horses of various breeds, aged from 1 day to 37 years old (mean±SD: 7.8 ± 5.8 years), BW 38-890 kg (mean ± SD: 421 ± 133 kg), and free of cardiac disease. Fifty of those animals aged from 2 months to 35 years old (mean ± SD: 11.6 ± 6.4 years old); BW 77-662 kg (mean ± SD: 436 ± 135 kg) were also examined using the pulsed-wave Doppler mode. Standard two-dimensional and M-mode echocardiography were performed on all animals. Standard pulsed-wave Doppler examination of each cardiac valve was performed on the 50 first examined animals. Data were analysed using a general linear model including the effect of sex, age, breed and BW after logarithmic transformation of the data. Therefore, the same analysis was performed separately on animals aged ≤ 2 years-old and on older animals. All dimensional echocardiographic measurements were significantly affected by BW and most of them were significantly affected by breed, but not by sex. Only the aortic and the pulmonary artery internal diameter were significantly affected by age. None of the Doppler measurements were significantly affected by the tested variables. In conclusion, in the equine species, dimensional echocardiographic reference values should be established using regression equations as a function of BW, which could increase the diagnostic value of this leading technique in equine cardiology. Breed could also have an effect on those measurements.

Mechanical testing of a new osteotomy design for tibial tuberosity advancement using the Modified Maquet Technique.

OBJECTIVES: To evaluate the mechanical properties of the distal cortical hinge associated with a new osteotomy design for the Modified Maquet Technique (MMT). STUDY DESIGN: Ex vivo mechanical study. METHODS: The osteotomy was started 10 mm caudal to the tibial tuberosity and extended over 150% of the length of the tibial crest; it was slightly curved distally to stay at a distance of 2 to 4 mm from the cranial cortex, according to the body weight. Ninety-six tibiae were tested in advancement, and 60 tibiae were axially loaded perpendicular to the tibial plateau, until failure of the crest. Desired advancement was measured using the common tangent method in 60 tibiae. Angle of opening, thickness, and area of the cortical hinge were recorded. RESULTS: Desired advancement of 6 mm, 9 mm, 12 mm and 15 mm was recorded in 16, 12, 18 and 14 tibiae respectively. Mean maximal advancement in these bones was 15.6 ± 6.4 mm, 20.8 ± 5.2 mm, 21.3 ± 5.2 mm and 22.7 ± 5.2 mm respectively. The desired advancement was reached in all but one tibia. Advancement was mainly influenced by the angle of opening and the stiffness of the cortical hinge. Mean ultimate load to failure was 6.12 ± 2.4 times the body weight. It was significantly associated with the body weight, thickness, and area of the cortical hinge. CLINICAL RELEVANCE: Mean maximal advancement was higher than clinically required without occurrence of fissure or fracture. Ultimate load to failure and maximal advancement could be predicted using calculated formulae.

Perilimbal pocket technique for surgical repositioning of prolapsed nictitans gland in dogs.

The objective of this prospective study was to investigate the success rate, practicality and complications of a new perilimbal pocket technique for the replacement of prolapsed nictitans gland in 30 dogs (44 eyes). A first incision was made in the bulbar conjunctiva, 2-3 mm from and parallel to the infero-nasal limbus, a second incision on the bulbar aspect of the nictitating membrane (NM), 2-3 mm parallel to the free edge. The gland was returned to its normal position by suturing the subconjunctival tissues of the NM to the episcleral tissues, using four to six interrupted horizontal mattress sutures. The English bulldog, Neapolitan mastiff, great dane and American cocker spaniel were commonly presented. Nictitans gland prolapse occurred prior to one year of age in 83.3 per cent of dogs, and unilaterally in 15 patients. The procedure was easy to perform, and had a 90.9 per cent success rate, with minimal complications. The median duration of follow-up, conducted by ophthalmic examination or telephone contact with the owners, was 21.5 months. Tear production and ocular health were not affected in 17 eyes with at least six months follow-up. There was a statistically significant increase between preoperative and postoperative Schirmer tear test-1 measurements.

Ancestral haplotype-based association mapping with generalized linear mixed models accounting for stratification.

MOTIVATION: In many situations, genome-wide association studies are performed in populations presenting stratification. Mixed models including a kinship matrix accounting for genetic relatedness among individuals have been shown to correct for population and/or family structure. Here we extend this methodology to generalized linear mixed models which properly model data under various distributions. In addition we perform association with ancestral haplotypes inferred using a hidden Markov model. RESULTS: The method was shown to properly account for stratification under various simulated scenari presenting population and/or family structure. Use of ancestral haplotypes resulted in higher power than SNPs on simulated datasets. Application to real data demonstrates the usefulness of the developed model. Full analysis of a dataset with 4600 individuals and 500 000 SNPs was performed in 2 h 36 min and required 2.28 Gb of RAM. AVAILABILITY: The software GLASCOW can be freely downloaded from www.giga.ulg.ac.be/jcms/prod_381171/software. CONTACT: francois.guillaume@jouy.inra.fr SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Two-dimensional and M-mode echocardiographic reference values in healthy adult Saanen goats.

Echocardiography has become a routine non-invasive cardiac diagnostic tool in most species. Accurate measurement of cardiac dimensions requires reference values, which are poorly documented in goats. The aim of the present study was to test the inter-day repeatability and to establish the reference values of two-dimensional (2D-) and time-motion (M-) mode echocardiographic variables in healthy adult Saanen goats. Six goats were investigated three times by the same observer at one-day interval using a standardised 2D- and M-mode echocardiographic protocol. The intra-observer inter-day repeatability was tested using analysis of variance, calculation of the coefficient of variation and confidence intervals. A single echocardiographic examination was performed in six other goats, and values obtained in the 12 goats were used to establish the 2D- and M-mode echocardiographic reference values in healthy adult female Saanen goats. Statistical analysis revealed a good inter-day repeatability of the echocardiographic cardiac measurements. Echocardiographic reference values obtained in healthy adult Saanen goats seemed slightly higher than those reported in healthy Swedish domestic goats and were similar to those reported in healthy adult sheep.

Biochemical markers of bone turnover during pregnancy in horses: a longitudinal study.

The effect of pregnancy on bone metabolism was investigated in healthy mares. Venous blood samples were collected 7 times from 19 multiparous mares starting at 20-weeks pre-parturition, continuing 6 times in 4-week intervals, including the week of parturition and one week after parturition. Serum concentrations of osteocalcin (OC) and carboxy-terminal cross-linking telopeptide of type I collagen (CTX-I) were determined. Measurement cycles and age had a significant (p < 0.01) influence on OC and CTX-I values. Pregnancy influenced bone metabolism with peak bone formation and resorption values around the time of parturition.

Duration of corneal anaesthesia following multiple doses and two concentrations of tetracaine hydrochloride eyedrops on the normal equine cornea.

REASONS FOR PERFORMING STUDY: There is a clinical impression that tetracaine hydrochloride (THCl) eyedrops is a suitable topical anaesthetic in horses. OBJECTIVE: To determine the duration of corneal anaesthesia following instillation of multiple doses and 2 concentrations of THCl in 10 healthy horses. METHODS: The corneal touch threshold (CTT) was determined, in both eyes, before (basal CTT) and after application of one drop of 0.5% THCl, 2 drops at a 1 min interval of 0.5% THCl or one drop of 1% THCl. CTT was measured in mm every 5 min until complete recovery of the basal CTT. Treatments were separated by an interval of at least one week. RESULTS: Corneal sensitivity was significantly reduced from baseline values for 30, 60 and 50 min after application of one drop of 0.5% THCl, 2 drops of 0.5% THCl and one drop of 1% THCl, respectively. Mean maximal anaesthetic effects, corresponding to a CTT of 0 mm, lasted 5.5, 16 and 15.25 min and maximal anaesthetic effect was present in 55, 90 and 80% of eyes, 5 min after application of one drop of 0.5% THCl, 2 drops of 0.5% THCl and one drop of 1% THCl, respectively. CONCLUSIONS: The application of a second drop or the use of more concentrated eyedrops significantly increases duration of both anaesthesia and maximal anaesthetic effect. POTENTIAL RELEVANCE: Duration of corneal anaesthesia following tetracaine instillation was established enabling a better use when performing diagnostic and therapeutic procedures. Comparison of tetracaine with other ocular anaesthetics needs to be published in the future.

Determination of tear break-up time reference values and ocular tolerance of tetracaine hydrochloride eyedops in healthy horses.

REASONS FOR PERFORMING STUDY: Tetracaine hydrochloride (THCl) has been reported to cause irritation in dogs. In man, some topical anaesthetics have been shown to disrupt the tear film. Tear break-up time (TBUT) is a useful test allowing an assessment of the quality of the precorneal tear film. Only one TBUT value has been reported in horses with no information on the technique used. OBJECTIVES: To provide a method for performing the TBUT in horses and to report any side effects of a single application of THCl in clinically normal horses, particularly on the stability of the tear film. METHODS: In Study 1, one drop of 0.5 or 1% THCl was applied to one eye of 20 horses divided in 2 groups. Treated eyes were assessed for the development of side effects 2.5 and 5 min after treatment. In Study 2, the TBUT was measured in both eyes of 2 groups of 10 horses, before and 2.5 and 5 min after, instillation of one drop of either 0.5 or 1% THCl. RESULTS: No animals developed any ocular side effect after instillation. Basal TBUT was 8.3±1.3 s. TBUT decreased from baseline 5 and 2.5 min after application of one drop of 0.5% THCl and one drop of 1% THCl, respectively. CONCLUSIONS: A technique to measure the TBUT in healthy horses is described and normal range values that could be used as a reference were obtained. POTENTIAL RELEVANCE: THCl is well tolerated in horses but lowers the TBUT.

Altered systolic left ventricular function in horses completing a long distance endurance race.

REASONS FOR PERFORMING STUDY: It is unknown whether or not exercise-induced cardiac fatigue (EICF), as demonstrated in human athletes performing long duration exercise, occurs in endurance horses. OBJECTIVE: To examine the effects of a long distance endurance race on left ventricular systolic function in horses. METHODS: Echocardiography was performed before, and after, a 2 or 3 star international endurance race (106-132 km) in 11 horses. Systolic (s) and diastolic (d) interventricular and left ventricular free wall thickness (IVS and LVFW, respectively), left ventricular, left atrial and aortic internal diameter (LVID, LA and Ao, respectively), fractional shortening (FS) and ejection fraction (EF) were measured by echocardiography. Heart rate (HR), peak flow velocity (Vmax), flow velocity integral (FVI), ejection time (ET), pre-ejection period (PEP), velocity of circumferential fibre shortening (Vcf), stroke volume (SV) and cardiac output (CO) were measured from aortic Doppler wave recordings. RESULTS: After the race, LVIDd, Ao, LA, EF, FS, FVI, SV, ET and ET indexed for HR were significantly lower and IVSd, LVFWd, HR, PEP, PEP/ET and Vcf significantly higher as compared with prerace values. Pre- to post exercise changes in those parameters were not significantly correlated with changes in HR or in LVIDd. CONCLUSIONS: Results suggest that EICF, with a decrease in left ventricular systolic function, could occur post exercise in horses performing long duration endurance races. However, a multanecus effect of altered preload and heart rate on the studied variables cannot be discounted.

Bovine herpesvirus 4 ORF73 is dispensable for virus growth in vitro, but is essential for virus persistence in vivo.

ORF73 orthologues encoded by different rhadinoviruses have been studied extensively. These studies revealed that the ORF73 expression product (pORF73) is a multifunctional protein essential for latency that enables episome tethering to mitotic chromosomes and modulates cellular pathways implicated in growth and survival of latently infected cells. Comparison of pORF73 orthologues encoded by rhadinoviruses reveals important variations in amino acid sequence length and composition. Bovine herpesvirus 4 (BoHV-4) encodes by far the shortest ORF73 orthologue, with a size equivalent to only 22 % of that of the largest orthologues. The present study focused on determining whether BoHV-4 ORF73 is a bona fide gene and investigating whether it is essential for latency, as established for larger ORF73 orthologues. Our results demonstrate that BoHV-4 ORF73 is transcribed as immediate-early polycistronic mRNA together with ORF71. Using a BoHV-4 bacterial artificial chromosome clone, we produced a strain deleted for ORF73 and a revertant strain. Deletion of BoHV-4 ORF73 did not affect the capacity of the virus to replicate in vitro, but it prevented latent infection in vivo using a rabbit model. Interestingly, the strain deleted for ORF73 induced an anti-BoHV-4 humoral immune response comparable to that elicited by the wild type and revertant recombinants. Together, these results demonstrate that, despite its relatively small size, BoHV-4 ORF73 is a functional homologue of larger rhadinovirus ORF73 orthologues, and highlight the potential of ORF73 deletion for the development of BoHV-4 as a vector in vaccinology.