Animal nutrition for veterinarians--recent cases of clinical disorders in horses after intake of ionophore-containing feed

Anamnesis and clinical signs of horses form five different stables after ingestion of ionophores are reported and techniques of feed examination are described. Within a few hours or days after feeding of new types or batches of concentrates horses fell ill. They showed colic-like symptoms with intense sweating and ataxia. Most of the sick animals died within a short time span. Samples of the concentrates were analysed and different types and amounts of ionophores were detected. In four cases contamination by monensin in concentrations of less than 5 mg to 679 mg/kg feed were found. One feed sample contained monensin (8.8 mg/kg feed) as well as salinomycin (67.3 mg/kg feed). In one case lasalocid (7.9 mg/kg feed) was present. One horse from the stable where animals had obtained concentrates containing monensin (679 mg/kg feed) was necropsied. Typical signs of monensin intoxication with severe myocardial degeneration were found. Veterinarians should be alert to this rare but severe intoxication of horses.     

An Intensive Approach in the Treatment of Clinical Equine Protozoal Myeloencephalitis

Equine protozoal myeloencephalitis (EPM) is a serious parasitic disease of horses producing neurologic clinical signs. Sarcocystis neurona is an incriminated pathogen. If approximately 50% of US horses are seropositive but only 0.5 to 1% become clinically affected, there is a suspected immunologic influence whether a horse is S. neurona-exposed or has clinical EPM syndrome. This report presents a treatment of 28 performance horses that were serum immunoblot positive for exposure to S. neurona. This patient population was in full athletic competition, travel, or training with associated stress. We attempted to (1) improve the immunologic status of the horse, (2) protect it against inflammatory reactions, and (3) provide medication to kill the protozoa. The cell-mediated immunity was stimulated by transfer factor in the feed for 37 days. The inflammatory reactions of treatment crises from antiprotozoal activity were prevented by MicroLactin (a neutrophil-activation inhibitor) in feed for 28 days concurrently. The antiprotozoal drug ponazuril was given concurrently for 28 days. Gait abnormalities, stumbling, and behavior change were the most frequent and combined clinical signs before treatment. There were 82% (23/28) treatable horses that were back at work, including five horses that were in physical rehabilitation under saddle. Five severely affected horses were not helped by therapy.     

Endemic status of <Emphasis Type="Italic">Trypanosoma evansi</Emphasis> infection in a horse stable of eastern region of India – a field investigation

Diagnosis of Trypanosoma evansi infection in a horse stable of Eastern Region of India on the basis of examination of Giemsa stained blood smears have been done. A high percentage (12.74%) of horses of this stable was found suffering from T. evansi infection. This high prevalence of T. evansi in horses, in this area could be considered as an alarming situation which has never been explored previously in horses of Eastern Region of India. After a period of 2 months and 18 days of treatment with quinapyramine sulphate and quinapyramine chloride, reinfection with T. evansi in treated horses of this stable were noticed. Clinical signs of affected horses and possible causes of reinfection have been discussed.     

Comparative study of three feeding methods for draught horses of the Swiss army

Three feeding methods were compared in 36 4- to 6-year-old Franche-Montagne horses during the military school of St-Luzisteig (GR) of Spring 1992. The horses were separated into 3 groups: a group with the traditional oats-hay ration (OH), a group with a pelleted feed and hay ration (PFH), and a group with the complete diet (CD). Feed analyses were performed and food consumption, eating behavior and digestibility were studied. The horses received their daily amount of feed in 3 portions covering the requirements for a medium work: OH = 8 kg hay and 3 kg oats, PFH = 8 kg hay and 3 kg pelleted feed and CD = 10 kg of the complete diet. For the 3 rations, the amount of digestible crude protein for horses was higher than the reference value for the requirement of a 600 kg horse with a medium work. In the 3 diets, the calcium content was higher than the required 32 g per day (g/d). Not enough sodium (OH: 1.2 g/d; PFH: 7.3 g/d; CD: 9.6 g/d) and too much potassium (OH: 140.3 g/d; PFH 153.0 g/d; CD: 167.5 g/d) were present in the diets, both without consequences for the blood parameters. In 3 meals of 60 minutes, the horses of the group OH, PFH and CD ingested 82%, 89% and 92%, respectively, of the daily ration. The complete diet was ingested more quickly than the hay. The number of mastications per minute was smaller for the complete diet than for the hay. Ingestion times were similar for oats and pelleted feed. However, the number of mastications per minute was smaller for the pelleted feed. The digestibility of nutrients was not influenced by the method of feeding. In conclusion, these results demonstrate that the 3 types of ration studied here are adequate for the swiss army horses if sodium is added to the diet. However, despite the fact that both PFH and CD correct excessive supply or deficiencies of nutrients and despite the fact that these two feeding methods offer nutrients in amounts that are closer to the requirements of the horse, the method PFH was introduced in 1994.     

Preliminary Observations on Experimental Ruta graveolens Toxicosis in Nubian Goats

We present the first reported study of Ruta graveolens toxicity in 7–8-month-old Nubian goats. Oral administration of 5 g/kg bw per day of R. graveolens leaves caused tremor, dyspnoea, frequent urination, incoordination of movement, ataxia and recumbency, with death after 1–7 days. In goats receiving oral doses of 1 g/kg bw per day of the leaves, the course of toxicity was prolonged and the animals had pallor of the visible mucous membranes and loss in condition; one died on day 17, the others being slaughtered on days 41 and 46. The clinical effects were correlated with pathological changes in various organs, alterations in serum aspartate transaminase, creatine kinase, total protein, cholesterol, urea and other serum constituents, haematological values and the concentrations in the tissues of copper, iron, zinc, manganese, calcium and phosphorus.     

The use of force plate measurements to titrate the dosage of a new COX‐2 inhibitor in lame horses

Reasons for performing study: Lameness is a highly prevalent condition in horses and the principal cause of removal from athletic activity. In clinical studies to evaluate nonsteroidal anti‐inflammatory drug therapies, force plates are commonly used to assess improvement of lameness objectively. Hypothesis: To use a force plate to determine the optimal dose of a new COX‐2 inhibitor (firocoxib) that will reduce lameness, when administered orally to horses once daily. Methods: Sixty‐four horses that exhibited chronic lameness presumed due to osteoarthritis, including navicular disease, in at least one of the frontlimbs and at a stable level of severity, were included. Horses were treated per os s.i.d. for 7 days as follows: vehicle control, firocoxib at 0.05, 0.1 or 0.25 mg/kg bwt. Force plate analysis of each horse was done for the selected (most) lame frontlimb at trot. Once between Days ?19 and ?4 (initial examination), and again on Day ?2 or ?1 (baseline), pretreatment force plate assessments were performed, and thereafter horses were assessed on Days 0, 2 and 6, approximately 10 h post treatment each time. Peak vertical force (PVF) and lameness grades at initial examination and at baseline, and their change from baseline in the 4 different treatment groups were analysed statistically at a significance level of P<0.05. Results: The PVF results were found to be superior to vehicle control already at Day 0 for 0.25 mg/kg bwt and at Days 2 and 6 for 0.1 and 0.25 mg/kg bwt (P<0.05). Mean clinical lameness for both concentrations decreased >1 grade at Day 6. Conclusions and clinical relevance: With the dosage of 0.25 mg/kg bwt lameness did not improve more than with 0.1 mg/kg bwt. Thus, 0.1 mg/kg bwt s.i.d. was considered to be the effective dose at reducing chronic lameness in horses presumed due to osteoarthritis, including navicular disease.     

64,XX, SRY-, and ZFY-Negative Icelandic Horse Likely to Be True Hermaphrodite

A 4-year-old Icelandic horse, considered to be a mare, showed stallion-like behavior in a group of mares. On clinical examination, the horse turned out to have an enlarged erectable phallic clitoris. Ultrasound examination showed a normal-sized left ovary covered with numerous small follicular cysts and a compact testis-like tissue in place of the right ovary. The karyotype was normal for a mare (64,XX), and the horse was found to be negative for the Y chromosome–specific markers SRY, ZFY, and EIF1AY. This case indicates that the intersexual phenotype may be caused by autosomal recessive mutation, resulting in defects in cortisol biosynthesis rather than transferal of Y chromosome male–specific genes. This is the first report of an intersexual phenotype in an Icelandic horse that is likely to be a true hermaphrodite because of female sex chromosomes and a mixture of female and male gonads and external genitals.     

Disseminated alimentary mycobacteriosis in the horse: a retrospective study of nine cases

This paper summarises the clinical findings of 9 cases of disseminated alimentary mycobacteriosis in horses presented at a Finnish referral equine hospital 2009–2014. Four of 9 horses were Standardbreds and 8/9 horses were male. The median age was 2 years, ranging from 6 months to 15 years. The duration of clinical signs before admission ranged from 2 weeks to 6 months. All horses demonstrated deterioration of the clinical signs after a protracted period of the disease and were finally subjected to euthanasia after poor response to multiple medical therapies. The most common complaints on admission were weight loss and diarrhoea (9/9), pyrexia (7/9), ventral oedema (7/9), lethargy (7/9) and inappetance (6/9). The most common clinicopathological abnormalities were hypoalbuminaemia and hyperfibrinogenaemia, which were present in all horses. Rectal biopsy specimens were examined from 5/9 horses and specimens were stained with Ziehl‐Nielsen (ZN). At rectal biopsy, mild multifocal neutrophilic or mild granulomatous proctitis was recognised in all 5 horses, but the ZN stain for mycobacteria was positive in only one biopsy. A liver biopsy was taken from one horse in which hepatomegaly was observed clinically and revealed marked granulomatous hepatitis with the presence of mycobacteria. The rectal biopsy from this horse was ZN negative. At post mortem examination, chronic, multifocal to coalescing granulomatous typhlocolitis and lymphadenitis were found in all horses with the small intestine less frequently involved. At histopathological examination of post mortem samples, a ZN stain was performed and intracellular acid‐fast bacilli were identified in macrophages and multinucleated giant cells in the large intestine, liver and lymph nodes in 9/9 horses and in the small intestine in 5/9 horses. Mycobacterium avium ssp. hominissuis was isolated in 5/9 horses from post mortem samples.     

Growth and carcass characteristics of male Sahelian goats fed leaves or pods of Pterocarpus lucens or Acacia senegal

The effect of feeding browse on growth and carcass characteristics was studied using thirty-two 10–12 months old growing Sahelian goats weighing an average of 15.6 kg. The treatments were four diets: Acacia senegal pods, Pterocarpus lucens leaves and pods and a positive control. The browses were offered ad libitum and supplemented with 200 g of hay of Schoenefeldia gracilis and 200 g of millet bran, while the control group received 200 g of millet bran, 200 g of cottonseed cake and hay ad libitum. The highest DM intake was observed for goats fed A. senegal pods, resulting in higher CP intake from this diet. The diet with P. lucens leaves gave a higher feed consumption than the control diet, but CP intakes were similar. The goats fed P. lucens pods diet had the lowest CP intake. The higher intake of the A. senegal pods diet resulted in higher growth rate (56 g/day), comparable to the P. lucens leaves and the control diets (55 and 51 g/day respectively). However, the feed conversion ratio was the lowest for the control diet. The carcass weight, dressing percentage and weight of the primal cuts were higher for goats fed A. senegal pods, P. lucens leaves and the control diet. In conclusion A. senegal pods and P. lucens leaves showed good intake characteristics for goats under stall-feeding conditions. Pods from P. lucens, resulting in lower performance, can be fed with small amounts of millet bran for maintenance of goats during the dry season.     

The effects of dose and diet on the pharmacokinetics of omeprazole in the horse

This study aimed to investigate the effect of diet and dose on the pharmacokinetics of omeprazole in the horse. Six horses received two doses (1 and 4 mg/kg) of omeprazole orally once daily for 5 days. Each dose was evaluated during feeding either a high‐grain/low‐fibre (HG/LF) diet or an ad libitum hay (HAY) diet in a four‐way crossover design. Plasma samples were collected for pharmacokinetic analysis on days 1 and 5. Plasma omeprazole concentrations were determined by ultra‐high pressure liquid chromatography–mass spectrometry. In horses being fed the HG/LF diet, on day 1, the area under the curve (AUC) and maximal plasma concentration (C_max) were higher on the 4 mg/kg dose than on the 1 mg/kg dose. The AUC was higher on day 5 compared to day 1 with the 4 mg/kg dose on the HG/LF diet. On days 1 and 5, the AUC and C_max were higher in horses being fed the HG/LF diet and receiving the 4 mg/kg dose than in horses being fed the HAY diet and receiving the 1 mg/kg dose. These findings suggest that both dose and diet may affect pharmacokinetic variables of omeprazole in the horse.     

Nephrotoxicity in lambs apparently caused by experimental feeding withNarthecium ossifragum

Seven lambs were fed a mixture of bog plants containing 15 g (wet matter)Narthecium ossifragum per kg live weight for 10 consecutive days. Their serum creatinine concentration increased from day 1 to 4 but then fell to normal by day 6 after feeding started. In the same animals, the serum magnesium concentration was increased on days 3, 4 and 5. Histopathological examination of the kidneys of 2 lambs killed after being fed 25 gN. ossifragum per kg live weight for one day revealed tubular epithelial cell degeneration and necrosis. There were no signs of disease or distress in the experimental animals and their appetite remained normal throughout the experimental period. It was concluded thatN. ossifragum is probably nephrotoxic to lambs.Abbreviations ALP alkaline phosphatase - ASAT aspartate aminotransferase - -HBA -hydroxybutyric acid - CK creatine kinase - d.m. dry matter - -GT -glutamyltransferase - GLDH glutamate dehydrogenase - MCV mean cell volume - RBC red blood cells - SEM standard error of the mean - WBC white blood cells - w.m. wet matter     

Clinical and Laboratory Findings in Equine Piroplasmosis

The objective of this study was to evaluate equine piroplasmosis (EP) as a cause of morbidity in horses in Sardinia (Italy), describe the clinical signs and altered hematologic and biochemical parameters, and illustrate response to different treatments. Among 44 horses suspected of tick-borne disease, 38 were polymerase chain reaction (PCR) positive for Theileria equi (n = 27) or Babesia caballi (n = 6), whereas five were positive for both protozoans. Typical clinical features of piroplasmosis were seen in some of the horses, whereas others had nonspecific mild symptoms. Hematologic findings revealed involvement of the three blood cell lineages (anemia, leukopenia or leukocytosis, thrombocytopenia), and biochemical variations were related to increased bilirubin, alteration of serum phosphorus, and hypoalbuminemia. We suggest that the two protozoans are the most important causative agents of equine tick-borne disease in this geographic area, and we observe that different clinical features are associated with the disease; in addition to the typical aspects of piroplasmosis, characterized by fever, pale mucous membranes, and icterus, we can signal other nonspecific mild signs such as weight loss, weight loss associated with an insignificant leukopenia, or weight loss associated with depression, anorexia, and mild hyperbilirubin. The study is intended as a practical contribution for veterinary practitioners because it describes different clinical presentations and laboratory findings of EP, suggests diagnostic and therapeutic approaches to the disease, and shows diffusion of the disease in a Mediterranean region.     

Pyrrolizidine alkaloid-induced liver disease in horses: an early diagnosis

Nine adult horses were fed alfalfa hay cubes containing approximately 10% Senecio vulgaris until all horses had consumed approximately the same amount of toxic components of S vulgaris, pyrrolizidine alkaloids (PA). The amount of PA consumed was determined by the amount that induced clinical signs of PA toxicosis in 3 horses. The 6 other horses were given similar amounts per kilogram of body weight. An initial decrease of feed intake was observed when horses' diets were changed from alfalfa cubes to alfalfa/Senecio cubes, and feed intake was decreased further over 89 to 98 days. From 50 to 159 days, body weight decreased in all horses. Liver disease was induced in all 9 horses after they ate an average of 233 +/- 9.2 mg of PA/kg of body weight. Eight horses died or were euthanatized. Treatment with branched chain amino acids had no effect on mortality, but appeared to reduce neurologic problems. Clinical signs of PA-induced liver disease included ataxia, head pressing, and decreased feed intake. Other clinical signs of toxicosis were observed individual horses, but did not develop in most horses. Megalocytic hepatopathy developed. Liver abnormalities proceeded as PA was consumed and were severe in 8 of 9 horses before clinical signs of toxicosis appeared. Sulfobromophthalein sodium clearance did not decrease until PA-induced liver disease was advanced. Bile acid (BA) concentrations increased to greater than or equal to 50 mumol/L, in the 8 horses that died. One horse had hepatopathy and increased BA concentration, but survived. In this horse, BA concentration peaked at 33 mumol/L and then decreased.(ABSTRACT TRUNCATED AT 250 WORDS)     

Protein, energy and dry matter consumption by racing standardbreds: A field survey

A field survey involving 112 Standardbred race horses in 14 stables at a Detroit racetrack was conducted to determine feeding practices of the Standardbred trainers, to estimate crude protein (CP), digestible energy (DE), and dry matter (DM) consumption by racing Standardbreds, and to compare those intakes with 1989 recommendations of the National Research Council (NRC), “Nutrient Requirements of Horses.” Trainers were interviewed regarding: 1) the age and sex of the horses; 2) their feeding practices, and 3) the horse's training and racing schedule. Only adult horses which were actively racing and continuously stabled at the track were included.

Body weights (BW) estimated using a chest girth measurement resulted in an overall mean BW of 449 kg. Body condition scores were established for each horse with an overall mean score of 5.7 which indicated average body condition for a racing Standardbred at this track. Typical rations from each stable were weighed, and feed samples of hays and concentrates were analyzed at a commercial laboratory to determine CP, DM, acid detergent fiber (ADF), and estimated energy density. A computer program calculated CP, DE, and DM values for each horse's ration based on amounts fed. The software program included with the 1989 NRC publication was used to compare estimated nutrient intakes with current NRC recommendations for a horse of a given BW.

All trainers fed a variety of hays and commercial grain mixes, and five trainers fed oats separately. The mean total intake of feed for all horses on an “as fed” basis was 16.1 kg. The estimated mean DM intake for all horses was 14.4 kg vs. NRC recommended 10.6 kg. The mean percentage of rough-age in the ration for all stables was 64% vs. a NRC recommendation of 35%. The mean CP% on a DM basis for all stables' rations was 14.5% vs. the NRC recommendation of 11.4%. The mean daily CP and estimated DE intakes for all horses were 2113 g and 37.6 Meal, respectively, in contrast to current NRC recommendations of 1189 g CP and 29.7 Meal DE. These data indicate that estimated CP, DE, and DM consumption are above the recommendations of NRC in 1989.     

Cross-sectional study of the seroprevalence to Borrelia burgdorferi sensu lato and granulocytic Ehrlichia spp. and demographic, clinical and tick-exposure factors in Swedish horses

A cross-sectional study of the seroprevalence to Borrelia burgdorferi sensu lato and granulocytic Ehrlichia spp. in Swedish horses was conducted to evaluate associations with demographic, clinical and tick-exposure factors. From September 1997–1998, blood samples from 2018 horses were collected from the animals presented to veterinary clinics affiliated with the Swedish Horserace Totalizator Board (regardless of the primary cause for consultation). Standardized questionnaires with information both from owners and attending veterinarians accompanied each blood sample. The apparent seroprevalences to B. burgdorferi s. l. and granulocytic Ehrlichia spp. were 16.8 and 16.7%, respectively. The northern region had the lowest seroprevalences. Four logistic models were developed (controlling for demographic variables). In the disease model of seropositivity to B. burgdorferi s. l., age, breed, geographic region, the serologic titer to granulocytic Ehrlichia spp., season and the diagnosis coffin-joint arthritis were significant. In the tick-exposure model of B. burgdorferi s. l., pasture access the previous year and gender were significant. Age, racing activity, geographic region, season and the serologic titer to B. burgdorferi s. l. were associated with positivity to granulocytic Ehrlichia spp. In the tick-exposure model of granulocytic Ehrlichia spp., pasture access was a risk factor. An interaction between racing activity and geographic region showed that the risk of positive serologic reactions to Ehrlichia spp. was increased in the horse population in the south and middle of Sweden, but only among horses not used for racing. Except for the positive association between coffin-joint arthritis and serologic reactions to B. burgdorferi s. l., there were no significant associations in the multivariable models between non-specific or specific clinical sign or disease with seropositivity to either of these agents.     

Hepatotoxicity to dogs of horse meat contaminated with indospicine

SUMMARY: An outbreak of liver disease which killed more than 30 dogs at Alice Springs was associated with feeding meat from horses, some of which had developed Indigofera linnaei poisoning (Birdsville horse disease). Affected livers were small, nodular and yellow. There was associated jaundice, ascites, elevation of alanine aminotransferase levels in serum, a tendency to bleed, and signs of hepatic encephalopathy. Histologically, livers showed periacinar necrosis, collapse and haemorrhage, with severe swelling, vacuolation and cholestasis in remaining hepatocytes. Indospicine, a toxic amino acid found in the genus Indigofera, was detected in samples of suspect horsemeat. Experimental feeding of horsemeat containing 16 mg indospicine/kg for 32 days produced periacinar necrosis and hepatocellular swelling in 2 dogs, although neither died nor showed clinical illness. In another experiment, intakes of as little as 0.13 mg indospicine/kg bodyweightlday for 70 days produced periacinar liver lesions, and indospicine concentrations in serum, muscle and liver rose during this period to 3.9, 7.9 and 17.5 mg/kg, respectively. It was concluded that meat from horses grazing l. linnael can be hepatotoxic for dogs, and that this toxicity may be related to its indospicine content.     

The apparent digestibility of fibre in trotters when dietary soybean oil is substituted for an iso-energetic amount of glucose.

An attempt was made to quantify the effect of extra fat intake on fibre utilization in horses. In a 4 x 4 cross-over trial with feeding periods of 24 days each, eight mature trotting horses (age 4 to 12 years, 407 to 531 kg BW) were given four diets. The concentrates were formulated to contain either soybean oil or an iso-energetic amount of glucose or combinations of the two ingredients. The concentrates were fed in combination with the same amount of hay so that the whole diets contained 30, 50, 77 or 108 g EE/kg DM. Apart from the amounts of fat and glucose the four diets were identical. With an increase of 10 g/kg DM of soybean oil the apparent total tract digestibility of crude fibre was reduced with 0.9 percentage units. Extra fat intake also reduced apparent protein and NFE digestibility, but raised apparent fat digestibility. Although the present results may hold specifically for the conditions of this study, it is suggested that the observed interaction between fat content of the diet and macronutrient utilization might have consequences for practical horse feeding in that calculating the energy content of high-fat diets on the basis of feedstuff tables will lead to over- or underestimating the amount of energy provided by the various ingredients of the diets.     

Serum Vitamin E Concentration of Horses on Different Vitamin E Supplementation Levels

Abstract

The influence of vitamin E supplementation on blood serum vitamin E concentration as well as the seasonal variation of serum vitamin concentration was investigated. Forty horses were divided into a control and three vitamin E supplementation (experimental) groups. The levels of the vitamin E supplementation in the three experimental groups were 1, 3 or 5 mg/kg body weight (bwt) per day. The vitamin was dosed orally. The supplementation was started either at the beginning or in the middle of the indoor (winter) feeding period. There was seasonal variation in the serum vitamin E content; the serum vitamin concentration increased during the grazing and decreased during the indoor feeding period. The basal feeding and a daily supplement of 1 mg/kg bwt were not adequate to maintain or increase the serum vitamin E concentration during the indoor feeding period in an exercising horse. The minimum daily intake of vitamin E would seem to be greater than 1.5 mg/kg bwt. It is suggested that a daily supplement of 3 to 5 mg/kg bwt may be required by horses in training to increase the serum vitamin E levels. This amounts to 1500–2500 mg/day for a horse weighing 500 kg. Supplementation should be started at the beginning of the indoor feeding period.     

Effect of feeding increasing quantities of starch on glycaemic and insulinaemic responses in healthy horses

The aim of this study was to investigate the effect of increasing the intake of starch on the glycaemic and insulinaemic responses of horses. A cross-over study design was used in which four horses were fed increasing amounts of a compound feed (0.5–3.5 kg) to provide 0.3, 0.6, 0.8, 1.1, 1.4 and 2 g starch/kg bodyweight (BW)/meal. The glycaemic response increased with starch intake (P < 0.05), while feeding <1.1 g starch/kg BW resulted in a lowered response, compared to when 1.1–2 g starch/kg BW was fed (P < 0.01). The results suggested that insulin responses may be more appropriate to define the effect of feeding different starch levels than glycaemic responses. A starch intake of <1.1 g/kg BW/meal produced only moderate glucose and insulin responses, even though highly processed cereals were used. It is therefore recommended that a starch intake of <1.1 g/kg BW/meal or a meal size of 0.3 kg/100 kg BW (starch content of 30–40%) is used for horses.     

RADIOGRAPHIC APPEARANCE OF EQUINE LUMBOSACRAL AND PELVIC ABNORMALITIES BY LINEAR TOMOGRAPHY

Radiologic findings are described in 20 horses with clinical signs of a caudal lumbar or hindlimb problem; the horses were subjected to linear tomography of the lumbosacral and pelvic regions. The cases could be divided into four groups: sacroiliac arthrosis (6 horses), lumbosacral abnormalities (3 horses), pelvic or lumbar fracture (6 horses), and no radiographic abnormalities (5 horses). Five of the six horses with sacroiliac arthrosis had spur formation, with localized arthrosis at the caudal aspect of the sacral wing and its articulation with the auricular surface of the ilium. In one horse these lesions were confirmed at postmortem examination. The sixth horse, a Standardbred trotter, had more even and widespread arthrosis of the sacroiliac joint. The three lumbosacral abnormalities were present in two horses with fusion of the L₅-L₆ articulation and one horse with a wider than normal sacrolumbar articulation. Linear tomography also proved to be of diagnostic and prognostic value in the evaluation of lumbar and pelvic fractures. Finally, tomography could be used to eliminate the presence of sacroiliac or lumbosacral damage in some horses that presented with clinical signs suggestive of disease of the lumbosacral or sacroiliac region.