A review of equine sepsis

Sepsis is defined as an exaggerated, systemic inflammatory response to infection and is a common condition in horses. Systemic inflammatory response syndrome (SIRS) associated with bacterial infection is a hallmark of sepsis. Sepsis in neonatal foals is a common sequela of failure of passive transfer and, in addition to development of SIRS, may be characterised by bacteraemia, pneumonia, enterocolitis, omphalophlebitis, meningoencephalitis or arthritis. Sepsis in mature horses is most commonly observed secondary to gastrointestinal lesions that result in disrupted mucosa and bacterial translocation into circulation (endotoxaemia). Pleuropneumonia and metritis may also cause sepsis in mature horses. Diagnosis of sepsis is based on SIRS criteria as well as suspected or confirmed infection. Due to the relatively low sensitivity of microbial culture and the subjectivity of sepsis scoring, many sepsis biomarkers are being studied for their usefulness in diagnosis and prognostication of sepsis in horses. Treatment of sepsis requires an intensive care approach that includes antimicrobial drug administration, fluid resuscitation and pressure support, and treatment for inflammation, endotoxaemia and coagulopathy. Early recognition of sepsis and prompt antimicrobial drug treatment are critical for a successful outcome. Multiple organ dysfunction syndrome may occur in severe cases of sepsis, with common manifestations including laminitis and coagulopathies. Although prognosis for septic mature horses depends highly on the primary disease process, the overall survival rate in septic neonatal foals ranges from 26 to 86%, with most studies indicating a survival rate of 45–60%.     

A review of equine sarcoid

Equine sarcoid is the most common tumour of horses and accounts for over half of all equine skin tumours. Six types of sarcoid based on gross appearance and clinical behaviour have been described including occult, verrucous, nodular, fibroblastic, mixed and malevolent. Common locations for sarcoid development include the periocular region, ear pinnae, lips, neck, extremities and ventrum (including groin region). Bovine papillomavirus (BPV) is causally associated with equine sarcoid with genetic haplotype, fly vectors and skin trauma identified as potential risk factors for development of the disease. Histopathology is required for definitive diagnosis of equine sarcoid but incomplete excision is thought to activate latent BPV and stimulate growth. Although there are no uniformly effective treatment options, several modalities have been successful in eliminating or managing equine sarcoid. Surgical excision, intratumoural chemotherapy, cryotherapy, hyperthermia, radiotherapy, immunotherapy and immune modulators are used with degrees of success relative to the accessibility and invasiveness of the tumour. Prevention of equine sarcoid may be facilitated by future development of vaccines against bovine papillomavirus.     

A review of equine laryngoplasty complications

Prosthetic laryngoplasty is a common treatment for equine recurrent laryngeal neuropathy (RLN). Complications of this surgery include immediate post operative problems, such as dysphagia, seroma formation, wound infection and sudden loss of arytenoid abduction. Longer term complications include gradual loss of arytenoid abduction, chronic coughing, arytenoid granulomas and dynamic upper airway collapse unrelated to RLN such as palatal dysfunction, and aryepiglottic fold or vocal fold collapse. However, the benefit of this procedure greatly outweighs these potential post operative complications, especially if appropriate surgical and post operative management practices are employed.     

A review of equine dental disorders

Equine dentistry is a very important but until recently rather neglected area of equine practice, with many horses suffering from undiagnosed, painful dental disorders. A thorough clinical examination using a full mouth speculum is a pre-requisite to performing any equine dental procedure. Common incisor disorders include: prolonged retention of deciduous incisors, supernumerary incisors and overjet--the latter usually accompanied by cheek teeth (CT) overgrowths. Overjet can be surgically corrected, but perhaps should not be in breeding animals. In younger horses, traumatically fractured incisors with pulpar exposure may survive by laying down tertiary dentine. Loss or maleruption of incisors can cause uneven occlusal wear that can affect mastication. Idiopathic fractures and apical infection of incisors are rare. The main disorder of canine teeth is the development of calculus of the lower canines, and occasionally, developmental displacements and traumatic fractures. The main indications for extraction of "wolf teeth" (Triadan 05s) are the presence of displaced or enlarged wolf teeth, or their presence in the mandible. Developmental abnormalities of the CT include; rostral positioning of the upper CT rows in relation to the lower CT rows--with resultant development of focal overgrowths on the upper 06s and the lower 11s. Displaced CT develop overgrowths on unopposed aspects of the teeth and also develop periodontal disease in the inevitable abnormal spaces (diastemata) that are present between displaced and normal teeth. Diastemata of the CT due to excessive developmental spacing between the CT or to inadequate compression of the CT rows is a common but under diagnosed problem in many horses and causes very painful periodontal disease and quidding. Supernumerary CT mainly occur at the caudal aspect of the CT rows and periodontal disease commonly occurs around these teeth. Eruption disorders of CT include prolonged retention of remnants of deciduous CT ("caps") and vertical impaction of erupting CT that may lead to large eruption cysts and possibly then to apical infections. Disorders of wear, especially enamel overgrowths ("enamel points"), are the main equine dental disorder and are believed to be largely due to the dietary alterations associated with domestication. If untreated, such disorders will eventually lead to more severe CT disorders such as shearmouth and also to widespread periodontal disease. More focal dental overgrowths will develop opposite any CT not in full opposition to their counterpart, e.g., following maleruption of or loss of a CT. Because of the great length of reserve crown in young (hypsodont) CT, apical infections usually cause infection of the supporting bones and depending on the CT involved, cause facial swellings and fistulae and possibly sinusitis. Diagnosis of apical infection requires radiography, and possibly scintigraphy and other advanced imaging techniques in some early cases. When possible, oral extraction of affected CT is advocated, because it reduces the costs and risks of general anaesthesia and has much less post-extraction sequelae than CT repulsion or buccotomy.     

Resistance to avermectin/milbemycin anthelmintics in equine cyathostomins - current situation

Avermectins and milbemycins (AM) are potent compounds against all major nematode parasites, but their continuous usage has led to the development of widespread resistance in many of the important species of ruminant and equine parasites. The exception to this has been the cyathostomins, where AM resistance was recently first reported only after decades of drug exposure. Data from a Brazilian study suggests that AM resistance has developed in cyathostomins and reports of shortened egg reappearance periods after ivermectin treatment have been published recently from USA and Germany. Thus, AM resistance in cyathostomins is an emerging worldwide concern, but there is only limited amount data on the extent of this problem. To limit the development and spread of AM-resistant cyathostomins the equine industry must implement new strategies for worm control, and the veterinary parasitology community must develop and validate improved protocols for detecting anthelmintic resistance in the field.     

Reducing equine hauling stress: A review

The transport problems of horses have been aired for many years. It was not until the 1960s, however, that two independent studies, by Wentworth Telllington of California and David J. Holmes of New Zealand, established that horses are more comfortable in transport in which they face away from the direction of travel. These studies, benefitting from the researchers' knowledge of physics and engineering as well as of equine anatomy and psychology, brought together information and ideas that had long been discussed by students of the horse but never before synthesized.

In 1975–79, the author endeavored to test and validate the Tellington and Holmes research, with special emphasis upon Holmes's rear-face safety trailer. The latter was found to integrate patterns of training, loading, and transport fully adapted to the horse's need for comfort and security. The author's research established that even extremely nervous horses, with histories of “transport stress,” may be safely loaded and hauled in the rear-face trailer—although such an animal is unlikely to feel completely confident even in this improved type of conveyance. Further research by the author demonstrated the effectiveness of rear-face transport with more tractable horses in a variety of transport situations.     

A review of approaches to assessing equine welfare

Veterinary surgeons are required to assess an animal's welfare in a range of different circumstances in the course of their daily work. These assessments may relate to the long‐term welfare of an individual animal under their care, or the current welfare of a population of animals that are unfamiliar to them as individuals. The welfare assessment made may subsequently have implications for the treatment that an animal receives or for the decision of whether or not an animal should remain in its current home. Yet welfare assessment is not straightforward. Here we review the challenges that welfare assessment presents and review the tools currently available to meet them. Lastly, we look towards the future of equine welfare assessment, with examples of current research to develop tools and optimise welfare assessment.     

A review of equine mucocutaneous squamous cell carcinoma

Squamous cell carcinoma (SCC) accounts for approximately 20% of all equine mucocutaneous (MC) tumours and continues to present a therapeutic challenge to practitioners. Most MC‐SCC are locally invasive and slow to metastasise, but metastasis to local lymph nodes is not uncommon. The most common location for MC‐SCC is the periorbital region, with the eyelid most commonly affected. Although only 13% of MC‐SCC involves the external genitalia, MC‐SCC is the most common neoplasm of male genitalia. Equine caballus papillomavirus‐2 has recently been linked to MC‐SCC and may prove to be necessary for tumour development. Risk factors may include chronic exposure to ultraviolet light and chronic skin irritation. Horses developing genital MC‐SCC tend to be older compared to those with periorbital MC‐SCC. Histopathology is required for definitive diagnosis of MC‐SCC, although horse phenotype and lesion location may suggest MC‐SCC. Several treatment modalities have been successful in eliminating or managing MC‐SCC, with surgical excision and intratumoural chemotherapy yielding the best results. Other treatment options including cryotherapy, hyperthermia, radiotherapy and photodynamic therapy are often used as adjunctive therapies. Early recognition of tumours and prompt intervention are associated with a positive outcome.     

A review of the Western language equine acupuncture literature

A thorough review of the existing Western language equine acupuncture literature was conducted and studies selected based on the existence of objective criteria for evaluation. When the most rigorously designed studies were evaluated, the results do not support the contention that acupuncture has clinically relevant effects. Randomized, controlled clinical trials are sorely needed to resolve issues of efficacy.     

Speed of actin of some anthelmintics against Dictyocaulus viviparus infection in cattle

In a study of the comparative speed of action of anthelmintics against Dictyocaulus viviparus infection in cattle levamisole reduced the lungworm burdens by 87 per cent within three hours of administration whereas fenbendazole and febantel required 36 hours to achieve 80 and 87 per cent reduction, respectively. The more rapid action of levamisole may be advantageous in the treatment of bovine parasitic bronchitis since it allows virtually immediate elimination of the majority of the lungworms and limits undesirable sequelae dependent on the continued presence of the parasite.     

The use of progestins in equine medicine: A review

Progesterone is in constant fluctuation throughout the lifespan of the horse. As a key regulator of the hypothalamic–pituitary–gonadal axis, progesterone is involved in numerous aspects of reproduction. Synthetic analogs of progesterone, deemed progestins, are widely available to industry to act as progestogenic within the reproductive tract, although few are bioactive in the horse. Utilised to suppress oestrous, delay ovulation, maintain pregnancy, and for behavioural modifications, progestins are a commonly administered class of pharmaceuticals in veterinary medicine. In this review, we discuss the progestins available to equine industry, in addition to assessing efficacy, pharmacokinetics, and potential side effects following administration of each.