Recent advancements in our understanding of equid gammaherpesvirus infections

Equid gammaherpesviruses are ubiquitous and widespread in the equine population. Despite their frequent detection, their contribution to immune system modulation and the pathogenesis of several diseases remains unclear. Genetic variability and the combination of equid gammaherpesvirus strains a horse is infected with might be clinically significant. Initial gammaherpesvirus infection occurs in foals peripartum with latency then established in peripheral blood mononuclear cells. A novel EHV-5 study suggests that following inhalation equid gammaherpesviruses might obtain direct access to T and B lymphocytes via the tonsillar crypts to establish latency. EHV-5 is associated with equine multinodular pulmonary fibrosis, however, unlike with EHV-2 there is currently minimal evidence for its role in milder cases of respiratory disease and poor performance. Transmission is presumed to be via the upper respiratory tract with periodic reactivation of the latent virus in adult horses. Stress of transport has been identified as a risk factor for reactivation and shedding of equine gammaherpesviruses. There is currently a lack of evidence for the effectiveness of antiviral drugs in the treatment of equine gammaherpesvirus infections.     

Suspected vagal reflex and hyperkalaemia inducing asystole in an anaesthetised horse

A 10-year-old 466 kg mustang gelding presented to an equine referral hospital for surgical repair of nasal, frontal and lacrimal bone fractures from an unknown trauma. Surgical repair was performed under general anaesthesia, including a right-sided maxillary regional anaesthetic block with mepivacaine hydrochloride. Progressive hyperkalaemia was documented perianaesthetically (T-3 mins; 134 mins after induction; potassium 6.4 mmol/L (ref 3.5-5.1 mmol/L). Perianaesthetic bradycardia was attributed to alpha −2 agonist infusion administration, and other characteristic ECG changes (flattened P waves, narrow T waves of increased amplitude, prolonged QRS complex) were not documented. Asystole occurred 137 min after induction of anaesthesia; however, a review of the available literature suggests the degree of hyperkalaemia documented was unlikely to be the primary cause of asystole but may have been a contributing factor. It is hypothesised that a trigeminocardiac reflex was the primary contributory factor to asystole in the described case, and may represent a maxillomandibulocardiac reflex that has not been previously described in the horse.     

Intra-articular administration of antibiotics in horses: Justifications,risks, reconsideration of use and outcomes

Antibiotics have been injected intra-articularly by equine veterinarians for decades, either prophylactically when other drugs are administered for osteoarthritis or therapeutically to treat septic arthritis. This route of administration has also more recently gained attention in human orthopaedic clinical practice, particularly as an alternative to systemic antibiotic administration to treat infections following prosthetic arthroplasty. While the rationale for injecting antibiotics intra-articularly has been largely focused on achieving high local drug concentrations, there has been relatively little focus on pharmacokinetic parameters of antibiotics administered by this route, or on the potential for local toxicity. The increasing incidence of antibiotic resistance in veterinary and human medicine prompts reconsideration of off-label antibiotic usage and evaluation of evidence-based dosing strategies. The purpose of this review was to summarise the current literature describing intra-articular antibiotic usage, including specific studies where pharmacokinetics, potential safety and toxicity have been evaluated. This review will advance practitioners’ understanding of the use of intra-articularly administered antibiotics, including the overall pros and cons of the approach.     

马产业及其转型优势

随着社会经济的发展,马业已从传统马业转变成集赛马、休闲骑乘、马术等于一体的第三产业.发达国家已基本完成马产业的转型,我国还处于转型初期.马匹质量差、育种水平低、资金不足、关注度不够成为阻碍我国马业发展的主要因素.充分利用我国马业优势,积极借鉴发达国家经验,发展具有中国特色的马产业,是我国马业由传统马业转变成现代马业的重中之重.     

Spontaneous bilateral ankylosis of the carpometacarpal joint in a Paint Horse

An 8‐year‐old Paint Horse gelding was evaluated for a persistent left forelimb lameness (grade 4/5), with a hard swelling at the dorsomedial aspect of the carpometacarpal joint, due to osteoarthritis. Previous systemic and local anti‐inflammatory therapy had only a temporary effect. Partial carpal arthrodesis was suggested, but the owner elected for conservative treatment. The horse was confined to a small paddock and received phytotherapeutic supplementation with Harpagophytum procumbens. The lameness gradually resolved but a similar hard swelling developed on the right carpus. Radiographic follow‐up 1.5 years later revealed a spontaneous bilateral ankylosis of the carpometacarpal joint.     

A survey on two years of medication regulation in horse races in Iran

Reasons for performing study: The present survey evaluated the use of prohibited substances cases in the first 2 years of medication regulation in horseracing in Iran so that the impact of these regulations on the level of positive cases over the period could be assessed. Objectives: To determine the prevalence of positive tests for prohibited substances in horse races during 2 years of a drugs testing programme in Iran. Methods: A total of 656 horses that were winners or second in races were tested during the 2 year study. In the first year 354 horses (209 males and 145 females) and in the second year 302 horses (155 males and 147 females) were tested. In the 2 years, 306 were found to be positive. Urine samples were taken from candidate horses and sent to the Central Doping Laboratory. Blood samples were taken from those horses where a urine sample could not be taken within one hour. Detection and measurement of prohibited substances were carried out by ELISA, GC and HPLC using standard methods. Results: Thirty‐two percent of males were positive for prohibited substances, which was not significantly different from the percentage of females (25.5%). In the second year, of the 302 horses tested for prohibited substances, 33.5% of males were positive, again similar to females (33.3%). Almost 83% of horses tested positive for prohibited substances once in the first year, 15% tested positive twice and 2% tested positive 3 times. In the second year 78% tested positive once, 15% tested positive twice and 7% tested positive 3 times. Morphine was the most used prohibited substance and was detected 42 times during the survey, followed by caffeine and phenylbutazone. Morphine was also the most used drug in combination with other drugs in both years. Conclusions: Morphine and caffeine were the most popular prohibited substances found in the measurements. As these substances were found in the environment and food stuffs, their presence in the samples may be due to unintentional feeding of contaminated materials (bread, hay and chocolate).     

Use of a jugular vein model for the instruction of equine intravenous catheter placement by third-and fourth-year veterinary students

Successful placement of an i.v. catheter in horses is a core competency required by the AVMA COE accreditation policy (section 7.11, #2,#3,#5). Therefore, we determined whether the use of a novel intravenous (i.v.) catheter placement training tool would improve confidence, time to successful placement and accuracy with which third- and fourth-year veterinary students acquire competence regarding this skill in adult horses. Students lacking earlier experience with i.v. catheter placement in horses were randomly assigned to either Group 1 (n = 15) or 2 (n = 10). Students with prior experience with the technique were assigned to Group 3 (n = 14). Group 1 students were instructed on i.v. catheter placement using the model and then assessed using a live horse. Group 2 students were instructed on i.v. catheter placement using a live horse and then assessed using a live horse. Group 3 students were assessed using a live horse. Assessments included number of placement attempts, number of redirects and time needed to achieve correct intraluminal placement. Student perceptions regarding the use of this model for the purpose of learning i.v. catheter placement in horses were evaluated using a questionnaire. Results of this study demonstrated that students receiving initial instruction with the model achieved better scores in terms of both time to accomplish the task and accuracy for catheter placement in a live horse when compared with students that received their first instruction on a live horse. The use of this i.v. catheter placement training tool therefore served to lessen the cost of training and to minimise animal discomfort during this component of veterinary student training.     

Antimicrobial regional limb perfusion: Does it really fight infection?

Over the last decades the use of antimicrobial regional limb perfusion (A-RLP) has increased and A-RLP is nowadays commonly used to treat orthopaedic infections by many equine practitioners. There have been a large number of studies published on the use of A-RLP, many of which describe regional drug pharmacokinetics and clinical safety of the administration of different antimicrobials by A-RLP. A limited number of studies describe the clinical use of A-RLP as prophylactic or therapeutic treatment. However, despite being in use for 30 years there is still limited evidence about the efficacy of A-RLP as a means to prevent and treat orthopaedic infections in horses.     

Surgical treatment of colic in the miniature horse: a retrospective study of 57 cases (1993-2006)

REASONS FOR PERFORMING STUDY: It has been suggested that the rate of post operative abdominal adhesions in miniature horses is higher than that for other breeds. However, few reports exist in the veterinary literature describing complications and long-term survival following surgical treatment of colic in these horses. OBJECTIVES: To determine the prevalence of surgical lesions in miniature horses with acute abdominal disease in terms of clinical signs, surgical management, post operative treatment and complications, as well as short- and long-term survival. METHODS: Medical records of 57 American Miniature Horses undergoing surgical treatment for acute abdominal pain at the Michigan State University Large Animal Veterinary Teaching Hospital 1993-2006 were evaluated for clinical information. Owners and trainers were contacted to gain information regarding long-term survival. RESULTS: The most common surgical lesion was a faecalith (38/57 cases) located primarily within the descending colon and most frequently diagnosed in horses age <6 months (19/38 cases). Short-term survival to hospital discharge for horses recovered from anaesthesia was 98% (55/56) with the most common post operative complications being diarrhoea and inappetance. Intra-abdominal adhesions were identified in 2/8 horses requiring a second celiotomy. Long-term follow-up was available for 45 horses and 87% (39/45) were alive at least 12 months after surgery. CONCLUSIONS: As previously reported, faecalith obstruction is a frequent surgical lesion in the miniature horse and is most common in miniature horses age <6 months. The incidence of adhesion formation may be lower than previously reported.     

Position of the head is not associated with changes in horse vision

It has become accepted that the horse cannot see directly in front when the nose is lowered and must therefore rely on the rider. We tested the hypothesis that this conclusion would be correct only if the horse did not adjust the eyeball horizontal axis to changes of the head position. The results of the present study suggest that it is unlikely that horses have limited vision in relation to their head position when driven by the rider, and that the horse maintains the optimal horizontal eyeball position regardless of head position relative to the ground.     

Dystocia in Friesian mares: Prevalence,causes and outcome following caesarean section

Friesian horses appear to suffer a relatively high incidence of dystocia but there are, to the authors' knowledge, no published reports on the incidence or types of dystocia in Friesian horses. A retrospective survey of clinical details and post treatment recovery was performed for 66 mares referred to Wolvega Equine Hospital for dystocia during 2001–2006. Friesian mares appear to be particularly prone to dystocia due to fetal ankylosis or transverse presentation. However, despite dystocia of relatively long duration prior to caesarean section, post operative survival and fertility of mares and, more surprisingly, survival of foals were similar to those reported in surveys for other breeds.     

The prevalence and anatomical distribution of equine gastric ulceration syndrome (EGUS) in 201 horses in Denmark

Reasons for performing study: The prevalence (up to 93% in Thoroughbred racehorses) and severity of equine gastric ulceration syndrome (EGUS) have been correlated with the type of training and associated management practices. However, there have been few reports to confirm these findings in nonracehorses in Europe. Objectives: To describe the prevalence, anatomical distribution, severity and number of gastric ulceration lesions in a population of Danish pleasure horses; and to investigate differences for groups based on age, breed type and workload. Methods: A total of 201 horses not in active race‐training, age 7 months‐27 years, were evaluated, representing 23 different stables from all 5 regions of Denmark. These horses were considered to be healthy by the owner and not on veterinary treatment for EGUS. Endoscopically observed ulcer lesion scores were based on the number present (0–4) and severity (0–5). The presence or absence of ulcers in the glandular and/or nonglandular regions of the stomach was recorded and which site the most severe ulcers were found. Results: The prevalence of EGUS severity score ≥2 was 53%. The most severe lesions were commonly observed at the margo plicatus. Although older horses were not more likely to be affected by clinically significant EGUS they were more likely to have lesions in both the glandular and nonglandular regions. Differences in location of EGUS lesions were identified in different age groups, breed types and in horses exposed to different levels of work. Conclusion and potential relevance: This study confirms that gastric ulceration can be prevalent in a group of apparently clinically normal horses, not in intensive work. Further investigation of reasons for differences in EGUS location between different populations may aid toward the development of novel preventive measures.