Observational studies in horses involve systematically assessing and recording behaviors, conditions, or other characteristics without manipulating the study environment. These studies provide insights into natural equine behaviors, health conditions, and interactions with their environment. Researchers often focus on aspects such as herd dynamics, feeding patterns, or responses to environmental changes. The data collected can help identify trends, correlations, and potential risk factors for certain conditions. This page compiles peer-reviewed research studies and scholarly articles that explore various observational methodologies and their applications in understanding equine behavior and health.
Oijala M, Katila T.Detomidine was administered twice to six foals (14 to 94 days old) using three different doses (10, 20 and 40 micrograms/kg bodyweight intravenously) in a double blind trial. Sedation, analgesia, heart rate and clinically observed side-effects were recorded. Detomidine showed strong sedative effects at all doses tested. Sedation deepened very little by increasing the dose from 10 to 40 micrograms/kg bodyweight, but the duration of the effect was longer. Analgesia was considered good with the largest dose (40 micrograms/kg), and moderate or non-existent with the lower doses. Detomidine caused a...
Dyson S.The carpus and metacarpus of 40 horses which were free from lameness and 40 horses with lameness associated with the metacarpophalangeal joint or more distal limb were examined radiographically (Group A). The opacity of the proximal third of the third metacarpal bone was regular, with a uniform trabecular pattern. Osseous cyst-like lesions (OCLLs) were identified in the radial carpal bone (1), the ulnar carpal bone (2), the second carpal bone (15) and the fourth carpal bone (1). Thirty-one of 638 horses (4.8 percent) with forelimb lameness had pain localised to the proximal metacarpal region u...
Tulleners EP, Harrison IW, Mann P, Raker CW.Left-sided partial arytenoidectomy was performed in eight horses to evaluate healing. Four horses underwent conventional partial arytenoidectomy with suture apposition of the mucosa. In four horses, most of the arytenoid cartilage, including overlying mucosa, vocal fold, and laryngeal saccule, were excised en bloc without mucosal closure. The horses were monitored clinically by endoscopic examination. One horse from each group was euthanatized at weeks 2, 4, 8, and 16. Complete necropsies with gross and histologic examination of the arytenoidectomy sites were performed. Postoperative complicat...
Shaw EB, Houpt KA, Holmes DF.Average daily core body temperature and behavioural patterns of pregnant mares were studied, in search of definitive signs of parturition within 24 h of the event. Nineteen pony mares were sampled twice daily for core body temperature. A significant temperature drop, averaging 0.1 degrees C (0.2 degrees F) was observed during the day prior to parturition. Between 18.00 h and 06.00 h, during the two weeks before parturition, Thoroughbred and Standardbred mares (n = 52) spent an average 66.8 per cent of their time standing, 27.0 per cent eating, 4.9 per cent lying in sternal recumbency, 1.0 per ...
Barker BB, Stannard AA, Maibach HI.Epidermal cell labeling index and cell renewal time were estimated in 8 adult horses, using autoradiography after [3H]thymidine was given intradermally. The mean labeling index was 1.45 +/- 0.47%, and the mean cell renewal time of the viable epidermis was approximately 17 days.
Zweers AD, Dik KJ.The radiographic diagnostic value of Rose's palmaroproximal-dorsodistal ('skyline') projection and Oxspring's dorsopalmar projection of the equine navicular bone were compared, by examining radiographs of 102 navicular bones originating from 66 randomly selected horses with clinical evidence of lameness located in the navicular area. In 27 navicular bones essential information was obtained from the skyline view, 15 independently of Oxspring's projection and 12 in addition to this view. For 11 navicular studies the D.P. projection was the most important diagnostic view. In the other 64 navicula...
Gleed RD, Dobson A.Observations were made on horses spontaneously breathing oxygen, with halothane at a constant end tidal concentration. The horses were positioned in dorsal recumbency for the first 45 minutes of each anaesthetic episode during which the arterial oxygen tension (PaO2) was found to peak and then decline. The remaining 60 minutes of each anaesthesia was used to test the effect of various manoeuvres on PaO2. The PaO2 of horses decreased further both when remaining in dorsal recumbency and when repositioned in right or left recumbency. In contrast, placing the horses in sternal recumbency for these...
McCarthy RN, Hutchins DR.A retrospective analysis of 74 cases that underwent surgery for colic was undertaken to determine short and long term survival rates and the incidence of post-operative complications. In 28 cases colic was related to small intestinal lesions and in 46 cases to large intestinal lesions. Pre-operative packed cell volume and heart rate were found to be inversely related to short-term survival. Twenty-five horses (34%) recovered from surgery and were discharged. Of 18 of these cases with available histories, 6 subsequently had one or more episodes of colic since surgery of which 5 eventually died ...
Platt H.A retrospective study was carried out on post-mortem and biopsy tissue samples from 26 horses with non-alimentary lymphoma. On the basis of their histopathology and cytology, the cases were grouped into several categories: (1) Lymphoblastic lymphomas (6 cases) and primary lymphoblastic leukaemia (2 cases). (2) Histiolymphocytic lymphomas involving the skin (6 cases) or lymph nodes (3 cases). (3) Lymphomas showing follicular development (4 cases). (4) Plasmacytic lymphomas (4 cases). (5) Lymphocytic lymphoma (1 case). Most affected horses were middle-aged or old but lymphoblastic neoplasms tend...
Hurtig MB, Fretz PB, Doige CE, Schnurr DL.The mechanisms and completeness of equine articular cartilage repair were studied in ten horses over a nine month period. Large (15 mm square) and small (5 mm square) full-thickness lesions were made in weight bearing and nonweight bearing areas of the radiocarpal, middle carpal and femoropatellar joints. The horses were euthanized in groups of two 1, 2.5, 4, 5 and 9 months later. Gross pathology, microradiography, and histopathology were used to evaluate qualitative aspects of articular repair. Computer assisted microdensitometry of safranin-O stained cartilage sections was used to quantitate...
Houpt KA, Perry PJ, Hintz HF, Houpt TR.Twelve ponies were fed their total daily ration either as one large meal or divided into six small meals. Pre- and post-feeding behavior was recorded six times a day. Blood samples were taken for 30 min before and two hr after the meal. Plasma protein increased from 7.0 to a peak of 7.3 g/dl with small meals and from 7.3 to 8.1 g/dl with large meals, and returned to pre-feeding levels by 90 min post-feeding. Hematocrit rose from 33.3 to 34.1% with small meals and from 33.0 to 36.0% with large meals. These rapid and short-lived increases indicate a decrease in plasma volume. Plasma osmolality r...
Sillerud CL, Bey RF, Ball M, Bistner SI.After the observation of 2 horses with uveitis on a horse farm in the Minnesota River valley, 100 horses from this geographic area were given ophthalmologic examinations and were evaluated serologically for leptospirosis. A statistically significant (P less than 0.001) association was observed between the finding of antibodies against Leptospira interrogans serovar pomona and uveitis.
Bixby-Hammett DM.In a five-year study, 160 accidents occurred among 46,351 six-through 21-year-olds engaged in horse activities. Of these, 130 were riding accidents, 20 were horse-related and 10 did not involve horses. Bruises and abrasions were the most frequent injuries, and the area of the body most commonly injured was the head and face. The low accident rate may result from the requirement that riders wear approved protective headgear.
Jones RD, McGreevy PD, Robertson A, Clarke AF, Wathes CM.The design of 96 racehorse stables in the south west of England were surveyed. The 'typical' racehorse is kept in a loose box, bedded on straw and remains indoors while the stable is cleaned. It is given a floor area of 12 m2 and shares its airspace of 39 m3 with seven other horses. Overall, the predicted minimum rate of air change by natural convection in calm winds is 6.6 air changes/h but this is reduced to 2.2 if the top door of the stable is closed. On balance, racehorse stables in use today are based on designs which are worse overall than the best available in the 19th century.
O'Callaghan MW, Pascoe JR, Tyler WS, Mason DK.Detailed physical and clinical examinations were performed on 26 Thoroughbred racehorses which were used subsequently in a series of studies to investigate the contribution of the pulmonary and bronchial arterial circulations to the pathophysiology of exercise-induced pulmonary haemorrhage (EIPH). Twenty-five of the horses had been retired from race training in Hong Kong during the 1984-85 season, all but four raced that season; one horse had been retired the previous season. The average number of races for the group that season was 4.1 +/- 2 with an average distance of 1502 +/- 216 metres, me...
Allen D, White NA.Twenty-five cases of fractures of the second and fourth metacarpal and metatarsal (splint) bones were reviewed. Fourteen fractures involved a thoracic limb and 11 involved a pelvic limb. Fractures of the proximal one-third of splint bones are reported in one of two forms: fractures that are closed, or fractures with a permanent or intermittent draining sinus. Thirteen of the fractures presented were closed fractures and the remaining 12 were open. All of the closed fractures were managed by surgical excision of the distal fragment and the exostosis at the fracture site, followed by primary sur...
Lane JG, Mair TS.The clinical records of 100 cases of headshaking in horses were reviewed. Possible causes of the abnormal behaviour were identified in 11 animals; these included ear mite infestation, otitis interna, cranial nerve dysfunction, cervical injury, ocular disease, guttural pouch mycosis, dental periapical osteitis and suspected vasomotor rhinitis. However, in only two of these could it be shown that correction of the abnormality led to elimination of the headshaking. The additional clinical signs exhibited by the other idiopathic cases of headshaking included evidence of nasal irritation, sneezing ...
Owen RA, Jagger DW.Clinical observations on the use of BCG cell wall fraction in oil for treating seven horses with periocular sarcoids and five horses with sarcoids in other regions are described. Therapy was successful when used for periocular or solitary and smaller sarcoids. For sarcoids previously treated with cryosurgery, therapy appeared to be less efficient. A horse with a sarcoid on the stifle developed a septic gonitis due to necrosis of the sarcoid tissue adjacent to the joint. Sarcoids of the axilla appeared to be more aggressive than sarcoids at other locations and did not respond favourably to this...
Little C, Hilbert B.The clinical features of 19 horses with pelvic fractures were reviewed. The most common problem was a grade III or IV unilateral hind limb lameness. The prevalence of fractures was greater in females and horses less than 4 years old. All horses were treated with a combination of analgesic administration and stall rest for 2 to 6 months. Seven of 11 horses (64%) available for long-term follow-up evaluation recovered and 4 of 11 (36%) had no lameness when being ridden. Five of seven (71%) horses with fractures that involved the acetabulum recovered, and 4 (57%) had complete resolution of lamenes...
Lloyd RG.All horse-related injuries presenting to an Accident Service over a two-year period were investigated. 237 patients presented. The injuries were not considerable in absolute number but were in severity. There was a high morbidity with 22% of all patients requiring admission to hospital, 50% of all admissions because of head injuries. At least seven life-threatening injuries were identified and there were other severe pelvic and spinal injuries. The wearing of protective head gear remains the most important safety measure.
Wood-Gush DG, Galbraith F.The social behaviour of a small herd of 10 Exmoor geldings, two Exmoor mares and one Highland pony gelding was studied in order to see whether any specific associations existed between ponies and, if so, whether these applied to all or only some of the ponies' main activities of grazing, eating hay and sleeping. Such relationships were found but only in a small number of cases did they apply to all activities. The results are discussed in relation to the individual histories of these ponies and in relation to the welfare of horses.
Whitlock MR, Whitlock J, Johnston B.A retrospective study of horse riding injuries in Berkshire was undertaken over a one year period from November 1983. The information was obtained from the Ambulance Service, the Jockey Club and the St. John Ambulance Brigade. There was a total of 103 injured persons with no deaths. Information from the Jockey Club was compared with the other two groups, the former sustaining more limb injuries and the latter more head injuries. A questionnaire was sent to all 42 ambulance patients. Thirty-eight had radiographs taken, 16 of which showed a fracture. Forty-one were wearing some form of hard hat,...
Still J.This case series describes clinical findings in 100 horses displaying pain patterns resembling the anatomical course of the gall bladder meridian. The palpatory pain (tenderness) was detected in individual points, as well as along entire sections of the meridian. A few tender points and areas were also diagnosed outside of the meridian. These data are clinically relevant in terms of the diagnosis and classification of musculoskeletal pain in horses. Therapeutic trials will be reported in a subsequent study.
Kudrnáčová M, Langrová I, Maršálek M, Jankovská I, Scháňková S, Brožová A, Truněčková J.The occurrence of Hypoderma diana (Diptera: Hypodermatidae) in a herd of 15 horses was observed during a 4-year period (2010-2013) in northwest Bohemia. During this period, infestation by the warble fly H. diana increased from 12.5% in 2010 to 53.3% in 2013. Nodules were observed on the neck, back, stomach, legs, and head. The incidence of H. diana was probably influenced by the presence of a specific host mouflon (Ovis orientalis musimon).
Breit S.Ten horses, younger than 1 year, were used to investigate the articulatio interphalangea distalis of the pelvic limb. The expansion of the dorsal recess was compared to those of adult horses. The recessus dorsalis always formed a shape like the letter 'm' or like a triangle with oblique angles. Consequently the great proximo-distal expansion on the medial side of the dorsal recess very probably has nothing to do with the age of horses.
Gill J.1. The use of an electronic recorder for the horse motor activity was described. 2. Examples of different types of motor activities are given in Figs 1-8. 3. The ultradian pattern of activity in all records was stressed. 4. The possibility of receiving of more physiological informations by this type of apparatus is discussed.
Colahan P, Lindsey E, Nunier C.The pressure exerted on a flat level surface by recently trimmed, unshod hoofs of the front limbs of 23 sound, adult horses was measured using pressure-sensitive film and a specially built cassette. The horses were tranquilized and stood with one foot on the 2.9-cm-thick cassette and the other on a block of equal height. The hoofs were observed for motion during the measurement, and the developed film was examined for improper alignment of the film or slipping of the hoof. The center of pressure was located using the method of weighted proportions of Barrey. This static measurement system with...
Hodges AA, Harrison AG, Wathes CM.The heights of 89 horses were measured at the withers before and after half a furlong of trotting exercise. The mean (+/- sd) height increase after exercise was 1.75 +/- 0.86 cm and the horses returned to their resting height within seven minutes. There was no linear relationship between gain in height and pre-exercise height.
Stolk PW, de Waal Malefijt MC, Buma P, Barneveld A.In this paper the successful replacement of an equine metatarsophalangeal joint by a human total condylar knee prosthesis is reported. In the period of observation following implantation of the endoprosthesis the experimental animal showed almost no lameness when exercised at walk, bearing weight on the operated limb. Flexion and extension of the joint were markedly reduced. The clinical and histological observations clearly support further investigation into the equine metatarsophalangeal joint replacement by an endoprosthesis.
Martens P.An ossicle associated with the palmar aspect of the carpus is described in five horses. The size of the ossicle varied from 3 x 4 mm to approximately 12 x 10 mm. The ossicles were located at the junction of the proximal and distal rows of carpal bones, between the palmaromedial aspect of the fourth carpal bone and the ulnar carpal bone. In 3 horses they were bilateral, in one horse unilateral, and only one limb was examined in the remaining horse. In all horses it was an incidental finding and not regarded to be a pathologic entity.
Huricha , Kawai M, Inose Y, Yamada F, Ninomiya S.In this study, we investigated maternal effects on the growth of Hokkaido native horses kept outdoors throughout the year. We used the data on body weight (BW), height at withers (HW), heart girth (HG), and cannon circumference (CC) of 517 foals during the first year of life to (1) examine the growth patterns by comparing six linear mixed models and (2) analyze the maternal effect on BW, HW, HG, and CC for each month by estimating variance components. The segmented polynomial third-order regression equation was selected as the best model for all the traits. The estimated proportion of variance...
Carmalt JL, Johanssen B, Waldner C.To compare the performance of horses with intermittent dorsal displacement of the soft palate (IDDSP) treated surgically with a control group and to determine whether there was a difference in postoperative performance between horses treated with a staphylectomy or a tie-forward procedure. Methods: A retrospective observational study. Methods: Swedish Warmblood trotting horses (Standardbreds) with endoscopically confirmed IDDSP (n=56) and control horses (n=48) with endoscopically normal upper airways tested using overground endoscopy identified from medical records. Methods: Generalized estima...
Paryani MR, Gilanpour H.The Caspian miniature horse is one of the rare small breeds in the north of Iran. In the present study, the position of the heart and its valves were determined topographically in 4 miniature horses. We found that Caspian miniature horses have general similarities, with certain topographical variability, with other horses.
Pikuła R, Zaborski D, Grzesiak W, Smugała M.The aim of the present study was to analyse the mobility of Polish Konik horses in their natural environment. The study was conducted on a herd of 15 Polish Konik horses in 2018. The Global Positioning System (GPS) transmitter was used to track the horses' movements. Two habitats (forest and meadows), four seasons (autumn, winter, spring, and summer), and four times of the day (morning, midday, evening, and night) were distinguished. Season, habitat, and time of the day as well as the interaction among them significantly ( p < 0.0001 ) affected the mobility of Polish Konik horses. The use of ...
Meliani S, Benallou B, Halbouche M, Haddouche Z.To enhance effectiveness of reproduction management in Arabian mares, factors influencing the time of foaling were investigated in this study. Methods: Data were collected at the National Haras of Tiaret in Algeria from 2003 to 2010. The foaling time of 255 Arabian pure bred mares, aged from 3 to 20 years were used for this study. Results: A total of 78.07% of foaling happens between 7 pm and 6 am. Conclusions: The influence of the month of foaling and the sex of the foal, on the time of foaling was statically significant.
Little CB, Hilbert BJ, McGill CA.The clinical features of 21 horses which sustained head fractures are reviewed. There was a higher incidence of fractures in males and Standardbred horses. Surgical treatment was practical and successful in most cases when the fractures involved the bones of the jaws and the face. Fractures which involved the cranial cavity or the cranial nerves were difficult to treat and usually held a poor prognosis.
Lawson JS, Bolt DM, May S, Smith AJ, Felstead CW, Weller R.Joint effusion is one of the classic radiographic signs of osteoarthritis, but no information is available regarding clinicians' ability to detect joint effusion radiographically. This study determined the accuracy and precision of experienced and inexperienced observers in detecting joint effusion of the distal interphalangeal (DIP), metacarpophalangeal (MCP) and midcarpal joints on radiographs. Fresh cadaverous forelimbs were loaded in a material testing machine to mimic a standing horse. The joints were gradually distended and lateromedial and dorsopalmar radiographs were acquired. The imag...
Jabara AG, Hazard GH, O'Shea JD.This paper describes a case of a congenital vascular malformation in the skin of a colt. The lesion arose at the coronary border of the right hind leg. The microscopic structure of a biopsy suggested that the lesion, consisting of multiple foci of closely-packed convoluted small vessels in the dermis, represented a marked exaggeration of glomi which normally occur in considerable numbers in this region of the skin. On the basis of the clinical, macroscopic and histological findings, this lesion was considered to be an hamartoma, rather than a true tumour, and was therefore termed a congenital ...
Heinke ML, Sabo C.This article examines gender shifts in equine veterinary practice. A significant gender compensation gap continues across the spectrum of professions, including veterinary medicine. Many styles of practice serve the disparate and sometimes conflicting goals of financial well-being, patient care, and physical family presence.
Graves KT, Eberth JE, Bailey E.Homozygous and compound heterozygous Miniature horses for ACAN alleles D1, D2, D3* and D4 exhibit chondrodysplastic dwarfism (OMIA 001271-9796). In a previous study, the carrier rate for these four alleles, combined, was 26.2%. The purpose of this study was to investigate whether carriers of these dwarfism-causing alleles had a shorter withers height than non-carriers. A total of 245 Miniature horses were tested for these four ACAN alleles and also were measured for withers height. Of these horses, 98 were carriers and 147 were non-carriers. A statistically significant difference of 1.43 inche...
van Zadelhoff C, Ehrle A, Merle R, Jahn W, Lischer C.Scintigraphy is a standard diagnostic method for evaluating horses with back pain due to suspected thoracic processus spinosus pathology. Lesion detection is based on subjective or semi-quantitative assessments of increased uptake. This retrospective, analytical study is aimed to compare semi-quantitative and subjective methods in the evaluation of scintigraphic images of the processi spinosi in the equine thoracic spine. Scintigraphic images of 20 Warmblood horses, presented for assessment of orthopedic conditions between 2014 and 2016, were included in the study. Randomized, blinded image ev...
Andruskevich SM, Perry P, Houpt K, Houpt TR.The objectives were to measure changes in fluid balance of mares at parturition and relate those changes to the foals' acquisition of passive immunity. Twelve Thoroughbred mares and their foals were observed for suckling behavior for the first 12h post-partum. The mare's water intake, packed cell volume, plasma protein concentration, and plasma osmolality were measured pre- and post-partum. The foals' immunoglobulin concentrations were measured at birth and 24h later. The median increase from pre- to post-foaling in mares' packed cell volume was 4.0% (interquartile range=0.3-6.8). The median i...
Azzie MA.The clinical effects and therapeutic value of a 500 mg implant of oestradiol benzoate was observed in thirty-nine Thoroughbred brood mares showing various abnormalities of the ovary and/or the reproductive tract. Sixteen similarly affected, untreated mares acted as controls. The implant was inserted during the early part of the normal anoestrous period and was removed 6 to 10 weeks later. The conception rate among the treated group (59%) during the onset of the ensuing breeding season was significantly higher (P less than 0-02) than that in the control group. The value of this form of treatmen...
VOR DER DOMESTIKATION HING DAS ÜBERLEBEN DER EQUIDEN VON DER FäHIGKEIT AB, SICH IHRER UMGEBUNG UND MIT IHR VERBUNDENEN GEFAHREN ANZUPASSEN. DIES BETRAF V. A. RAUBTIERE, AUF DIE DIE PFERDE SCHNELL REAGIEREN MUSSTEN. MODERNE PFERDE UNTERSCHEIDEN SICH VON IHREN VORFAHREN U. A. IN IHRER REAKTION AUF STRESSOREN. SIE WURDEN üBER JAHRHUNDERTE HINWEG SO GEZüCHTET, DASS EIN FüR MENSCHEN SICHERER UMGANG MIT IHNEN MöGLICH IST. DIES REDUZIERTE AUCH IHRE REAKTIONEN AUF ANGSTERZEUGENDE FAKTOREN. DIE STUDIE UNTERSUCHTE, OB PFERDE NOCH IMMER DIE FäHIGKEIT BESITZEN, RECHTZEITIG AUF GEFAHREN DURCH RAUBTI...
Caudron I, Grülke S, Gabriel A, Serteyn D.This study is a part of a work to design a radiographical method to objectively define the conformation of an equine digit and to assess the individual appropriate trimming of a horse. Various angles were measured directly from the phalangeal bones. The authors observed that the bone relief of the sesamoid ligament insertions on the proximal phalanx was an essential landmark to determine the phalangeal alignment. The same angles were measured from specific radiographs and made it possible to quantify the rotation imposed to the proximal phalanx. The authors also noticed that the phalangeal rot...
Peters JW, de Boer B, Broeze-ten Voorde G, Broeze J, Wiemer P, Sterk T, Spoormakers T.Prevalence of dental disorders in 483 horses and ponies Five equine veterinarians working at three equine referral hospitals examined the oral cavity of 483 horses and ponies prior to surgery, to gain information about the prevalence of common dental disorders in the horse. A thorough examination, using hands/fingers, a full-mouth speculum, a dental mirror and a good light source, is essential to detect such disorders. Many horses examined needed dental attention even though there were no problems with mastication or riding. The most detected abnormalities were sharp enamel points on the bucca...
Weaver MP, Wilant L.A postal survey of the owners of Clydesdale horses in the UK and USA was conducted to obtain information on tarsocrural effusion ('bog spavin') as an indicator of osteochondrosis from 935 horses. Additional information requested included details of how this condition was investigated and treated. The reported tarsocrural effusion incidence was 10 per cent. The majority of respondents believed the condition to be of concern to Clydesdale owners, but only a minority were aware of the implications of tarsocrural effusion, suggesting that owner education would be of benefit.
Crowell-Davis SL, Houpt KA.A thorough behavioral history is essential for adequate assessment of a given case. In reviewing the chief complaint, a description of what actually happened, rather than the owner's interpretation of what happened, is required. Other behavior problems, environment, rearing history, and training need to be reviewed. Sample question sets for some common problems are given.
Fox AE, Bailey SR, Hall EG, St Peter CC.Biting and chewing by horses on crossties can result in injury to the handler and damage to equipment. Operant-conditioning techniques have been used to train horses and could be used to reduce or eliminate undesirable biting and chewing. Presently, a differential-reinforcement-of-other-behavior (DRO) schedule, in the context of a reversal design, was effective in reducing biting and chewing in two horses. In DRO schedules, a reinforcer is delivered contingent on the absence of a target behavior for a specified interval. Positive-reinforcement procedures offer an alternative to aversive-contro...
Deane NJ, Davies AS.A photographic study of the angles of 71 carpal joints of horses at the end of a race has shown that overextension of the joint is normal at this stage. Further study is needed to determine the factors which may influence hyperextension, and whether they are relevant to carpal injury.
