Endangered domestic animal breeds in German-speaking countries. V. Horses

Due to motorization the heavy horses, in particular draught horses and carriage horses, were deprived of their "raison d'être". At present therefore, they mostly are found in small livestocks. The past few years they regained some significance through their work in the forests, as an attraction in tourism or somewhere else. In German speaking countries approximately 15 horse breeds must be considered to be threatened in their existence. Breeding history, appearance, use and geographical distribution of 12 of them are discussed in this article.     

Trichomonad infections of the oral cavity in horses in southern Germany]

Trichomonads of the oral cavity were found in 9 of 60 investigated horses. Apart from dental tartar, the oral cavity showed no clinical signs in all positive horses. The clinical investigation of these horses additionally revealed colic in 4 and coughing in 4 horses as well as lumbago in 1 animal. By means of scanning electron microscopy the trichomonads were shown to be round or piriform with an average length of 7.6 microns and greatest width of 6.3 microns. They had 4 anterior flagella with an average length of 8.3 microns, an undulating membrane measuring 8.7 microns with no trailing flagellum as well as an axostyle extending on average 7.8 microns beyond the body, and therefore have to be placed into the genus Trichomonas.     

Stomach ulcers in the horse--clinical and gastroscopic findings in 12 horses (1989-1990)

Twelve horses with clinical symptoms of a gastric disorder were studied by gastroscopy. Symptoms of gastric disorders were periprandial colic, bruxism, ructus and reflux. Preliminary to gastroscopy the horses were fasted for 24 h. Access to water was not restricted. The gastroscopy could be conducted easily using a fiberscope 2.5 m in length and 11 mm in outer diameter. While ulcers were present in the squamous fundus of all horses only one horse showed ulceration of the glandular fundus. Solitary ulcers near the margo plicatus were found in horses with mild clinical symptoms. In contrast, diffuse gastroesophageal ulceration was accompanied by severe clinical symptoms. Four horses were affected by an acute gastroesophageal ulceration with gastric reflux and subsequent aspiration pneumonia. Two of those horses suffered from acute gastric ulceration 3-4 days following laparatomy. All horses were treated with cimetidine (5 mg/kg bwt/q.i.d.) until clinical symptoms ceased.     

Pilot study of the relationship of free amino acids in serum and in the cerebrospinal fluid of horses

In a blind study serum and cerebrospinal fluid (CSF) of control horses and of horses in hepatic coma after chronic food intoxication with Senecio alpinus were collected simultaneously and the composition of free amino acids was determined. The hepatic encephalopathy index in serum (less than 1.65) and in CSF (less than 1.11) of liver patients was distinctly less than to the control values in serum (greater than 2.42) and in CSF (greater than 1.49). The serum concentrations of glutamic acid in hepatic coma were elevated five-fold in comparison to the controls. An indication of ammonia decontamination was that nearly ten-fold higher values of glutamine were found in the cerebrospinal fluids of patients than in serum. In comparison to controls the serum levels of glutamine in horses with hepatic encephalopathy were decreased by the factor 0.7.     

Antithrombin III determination in horses. Reference values and acquired antithrombin III deficiency

Antithrombin III (AT III) determinations were done in healthy and sick horses using the chromogenic substrate Chromozym TH. Reference values for adult horses at 25 degrees C were 18-25 IU AT III per ml plasma and 84-118% AT III activity of normal horse plasma, respectively. Precision and accuracy were good (intra assay coefficient of variation less than 2%, accuracy 10%). Surgical operations on healthy horses led to a biphasic decrease in AT III activity touching the lower border of the reference values on the second postoperative day. Other reasons for acquired AT III deficiencies included disseminated intravascular coagulation (DIC), liver disease and glomerulonephritis. Using follow-up studies, differences in the dynamics of acquired AT III deficiency and coagulation promoting factors were demonstrated. 12 of 35 horses with decreased AT III values suffered from phlebothrombosis of the jugular veins. It was presumed that acquired AT III deficiencies promote development and progression of phlebothrombosis/thrombophlebitis in horses.     

Plasma gastrin levels in horses with colic]

The plasma gastrin levels in fasted horses (21.1 +/- 15.6 pg/ml), in horses with spasmodic colic (7.3 +/- 5.4 pg/ml) and in horses with impaction of the left ventral large colon and/or pelvic flexure (11.4 +/- 3.1 pg/ml) were not significantly different. The plasma gastrin concentrations of horses with strangulation obstruction of the small intestine, large colon displacement or adynamic ileus, and which had no gastric reflux, were 12.9 +/- 8.7 pg/ml and did not differ from fasted gastrin levels. Horses which had 5-10 litres of stomach content reflux had a higher mean gastrin level (32.2 +/- 22.6 pg/ml) (range 8.7-83.0) than the fasted horses. The mean plasma gastrin level (69.0 +/- 32.2 pg/ml) (range 27.0-122.0 pg/ml) in horses which had gastric reflux and 11-20 litres of stomach content outflow through the nasogastric tube were significantly higher (P less than 0.0004) than in fasted horses or in horses with spasmodic colic, impaction of the left ventral large colon or in horses from which no gastric reflux could be obtained.     

Nomenclature of the clitoris and preputium of the mare in relation to the surgical removal of the clitoral sinus according to CEM regulations

The cavity, that belongs to the glans clitoridis and that has to be removed in accord with the regulations and rules for the import of horses of CEM carrier states, has not been taken up in the NAV (1983). Conform to the statements of the clinical physicians and to the declarations of the American literature the nomenclature "Sinus clitoridis" is proposed for the international use.     

Etiology and occurrence of periodic eye inflammation of horses in the area of Berlin

Over 130 cases of equine periodic ophthalmia (p.o.), which were treated as in-patients at the Equine Clinic of the Free University of Berlin in the last 35 years, were examined statistically in relation to the age and gender of the animals involved as well as to the development of the illness and the season in which it arose. As regards aetiology, the extraction of 71 affected Trotters was investigated. Antibodies to toxoplasmosis, leptospirosis and intestinal parasites were found only in some of the patients. Younger animals, aged between one and four years, and male animals (63.6%) were predominantly affected. The results of the examinations of faeces showed no correlation between cases of p.o. and a vermination of the horses. The examinations for antibodies to toxoplasmosis gave no indication of a participation of the toxoplasmas in the aetiology of recurrent uveitis. In contrast, the results of the examinations for antibodies to leptospirosis, of which 58.8% were positive, showed a seven to ten times higher infection than in healthy horses in Berlin. Breed analysis showed that in certain breeds of Trotters and warm-blooded horses, p.o. illnesses were frequent, supporting the hypothesis that the occurrence of p.o. is due to a hereditary, allergic reaction, triggered by various factors, in particular an infection without clinical signs.     

Suture technics for the abdominal wall after midline laparotomy

During the last 10 years 268 laparotomies by a midline incision were performed. A high incidence of seromas, fistulas caused by suturing material and wound ruptures were observed. After finding only a small number of publications in the veterinary medicine about wound healing disturbances an analysis of the human medical literature was done. This induced the change of our surgical procedure and suturing technique: The midline incision and surgical management during the laparotomies in 14 horses suffering from colic were performed by a minimized trauma. The abdominal wall was closed layer by layer in the following manner: peritoneum by a running suture of catgut metric 5, linea alba by Sultan single sutures of polyglycolic acid material metric 5 (12 cases) or of polydioxanone metric 4 (2 cases), subcutaneous layer by a running suture of polyglycolic acid material metric 4, skin by single sutures of monofilamentous synthetic material metric 2. Thus, no complications in wound healing were observed in these 14 horses. Therefore, we recommend to prove the described surgical and suturing procedure by a larger number of horses undergoing a laparotomy by a midline incision.     

Anesthesia of horses with xylazine and ketamine. 2. Anesthesia in adult horses

Xylazine and Ketamine were used for anaesthesia in 250 adult horses. This combination is useful both for induction and maintenance of anaesthesia. The induction with Xylazine and Ketamine has been successful not only with foals but also with high risk patients such as horses with colic. During the maintenance of anaesthesia Xylazine/Ketamine can be used with injectable anaesthetics as well as with volatile anaesthetics at the same time. A form of injection anaesthesia for short-time surgical procedures like castration and wound repair is presented. The maintenance of a Thiobarbiturate/Guaifenesin anaesthesia with Xylazine/Ketamine seems to be suitable for field conditions.     

The surgical therapy of equine recurrent uveitis]

Equine recurrent uveitis (ERU) is the most frequently encountered cause of eye problems and blindness in horses. Classic treatment of ERU includes mydriatics, corticosteroids and nonsteroidal anti-inflammatory drugs. Despite vigorous topical and systemic treatment, however, in many cases, the prognosis for preserving vision remains poor. Experiences with surgical treatment of chronic endogenous uveitis in human patients have shown that vision-impairing axial opacities in the vitreous body can be removed by pars plana vitrectomy, and that a considerable decrease in the frequency and severity of uveitic relapses results. So far, 11 eyes of 10 horses were subjected to vitrectomy. All horses had suffered from 3 or more uveitic attacks and had a hazy vitreous. In all cases, at discharge from the clinic, the vitreous chamber was less hazy compared to preoperative findings. At follow-up examinations, 8 eyes (8/10) had normal i.o. pressure, and 2 (2/10) had subnormal i.o. pressure and the vitreous chambers were clear or contained only small floaters. Uveitic attacks had not been observed in the operated eyes. Postoperative complications included fibrinous, or fibrinous-haemorrhagic exudate in the anterior chamber of all eyes, and in one eye, a minor haemorrhage in the vitreous chamber. Our preliminary results indicate that pars plana vitrectomy assuring proper case selection and accurate surgical technique, may contribute to improvement of vision and may delay the progression of uveitic complications in horses.     

The effect of vitamin H substitution on the growth and condition of hooves

A long-term treatment with biotin (vitamin H) in 5 warm-blooded horses and 10 trotter horses is reported. The dose of 0.031-0.037 mg/kg body weight was well tolerated, and with a therapy period up to 10 months an improvement of the horn quality of the growing hoof could be attained as it had not been possible before with other measures. Biotin (Gabiotan) is recommendable as a therapeutic in all cases of hoof problems which are based on disturbed horn elasticity.     

Indirect blood pressure determination in the horse with the Dinamap 1255 research monitor

In 26 horses measurings of blood pressure, using the Dinamap 1255 research monitor, were performed and compared for accuracy with blood pressure values obtained by direct measurement in the arteria carotis. It was found that oscillometrically ascertained initial blood values in standing horses have a sufficient correlation to initial blood pressure values obtained by direct measurement. But every blood pressure change is registered too late, when using the oscillometric blood pressure apparatus. This temporal delay becomes unacceptable, when a considerable increase in blood pressure occurs. A reliable oscillometric blood pressure measurement with uneven and irregular pulse waves is not possible at all.     

Studies in riding arenas and on different riding path surfaces with respect to respiratory tract contamination in horses. Air hygiene studies in riding arenas

Using the direct sedimentation method, the air pollution with fungal spores was measured in indoor riding arenas and compared to horse stables, outside riding arenas and covered sport courts. Depending on the location of indoor arenas and stables, the presence of "dust-nests", the number of horses ridden, and the moisture of the tread layer, an air pollution was measured which was equivalent to that in stables except at times of feeding and straw-giving. Outside and in sport arenas a low air pollution was found. Recommendations are given, regarding optimum air hygiene especially for horses with chronic and subclinical respiratory conditions.     

The treatment basis for anticoagulants in horses

The pharmacokinetics of racemic phenprocoumon were studied in 8 adult horses after the single intravenous and oral administration of 0.75 mg/kg. After i.v. administration the plasma concentration of phenprocoumon showed a biphasic decline in time. The pharmacokinetics were calculated on the two-compartment open model. The average plasma half-life (beta-phase) was 22 hours, the apparent volume of distribution was 0.61 l/kg, Cltot was 25.2 ml/kg/h (13.9-40.9 ml/kg/h). The systemic bioavailability of oral phenprocoumon was 97.6%, Tmax was found to be 4-12 hours. The effect of phenprocoumon on the coagulation system was determined by the activity of Factor X, the Quick's one stage prothrombin time and the PTT. Factor X showed the most marked effect. A reduction of the content of Factor X was seen over 7-9 days, it decreased to 11-33%. Quick's one stage prothrombin time was reduced over 4-8 days, the lowest values were 22-55%. The PTT showed only a small reaction on the single administration of 0.75 mg/kg phenprocoumon. Differences in the effect on the coagulation between the i.v. and the oral administration could not be observed. In comparison to warfarin, phenprocoumon showed a longer t0.5 (beta) and produced a markedly longer hypothrombogenic reaction. Therefore phenprocoumon appeared to be more suitable for a long term anticoagulation therapy in horses than the structurally related warfarin.     

Myopathies in a riding horse stable

In this case report on myopathies in 6 saddle-horses, a combined dietary vitamin E and selenium deficiency is presumed. Other disorders, such as exertional myopathy ("Monday morning disease") due to excessive energy intake or ionophore intoxication could be excluded by calculating the energy supply or by a simple colour test. The selenium requirement of horses is estimated to 0.1-0.2 mg/kg dry matter (Meyer 1986). If natural feed compounds are low in selenium, adequate amounts of this trace element can be supplied by means of supplemental feeds, sodium selenite (20 mg/500 kg BW/week) or bruised linseed (cooked, 200-500 g/d). In horses tolerance of increased selenium intake is low. After oral administration of sodium selenite lethal dose was 3.3 mg/kg bodyweight. In feedstuffs selenium concentration must be below 5 mg/kg dry matter (Traub-Dargatz et al, 1986). The intake of vitamin E should be 0.25-1 mg/kg bodyweight. The requirements are influenced by feed compounds, especially the concentration of dietary unsaturated fatty acids, and the performance of the horses (Meyer 1986). Foals, pregnant or lactating mares, and racing horses have higher requirements. In acute disease vitamin E and selenium are given parenterally (5 mg Se/horse) or by oral application of sodium selenite (46% selenium, 20 mg/horse), in addition to symptomatical treatment.     

Detection of dexamethasone in horses

Due to their marked antiinflammatory effect, synthetic corticosteroids are used to mask illness, especially lameness in horses. The detection of these drugs in equine body fluids requires accurate methods, particularly where misuse of corticosteroids is suspected. Gas chromatography/mass spectrometry (GC/MS) is well established as a reliable technique for the identification of drugs in biological fluids. Using GC/MS, we determined dexamethasone levels in horse urine and serum after intravenous application of a therapeutic dose. Dexamethasone was detectable, in serum for up to six hours, and in urine for up to 32 hours, after its administration. These findings indicate that serum measurements are unreliable for the detection of corticosteroid abuse, and demonstrate urine to be a more suitable body fluid for investigation. Nevertheless, it should be emphasized that, regardless of the technique employed, the clinical effects of dexamethasone last longer than 32 hours; thus, failure to detect dexamethasone does not disprove corticosteroid abuse.     

Changes in several blood and urine parameters during combined hyperfluid therapy for the treatment of chronic obstructive bronchitis (COB) in the horse

During the combination of oral and intravenous application of saline solution for treatment of the COPD of horses the level of hydraemia basing on the total protein concentration in the serum, the urine production and the specific weight of urine was determined. Additionally the development of serum concentration and of renal excretion rates of potassium, calcium and magnesium were ascertained. The level of hydraemia resulting from the combined method is almost identical with the solely intravenous performed hyperinfusion therapy. Due to the excessive application of fluid an extremely high level of urine production is reached which causes a reduced specific weight as well as an increased renal excretion of potassium, calcium and magnesium. The result is a real loss of electrolytes which is - apart from hydraemia - the reason for the lower level of the corresponding serum concentrations. This seems to be important, especially for potassium and magnesium, because the organism is unable to compensate the loss of these electrolytes in the same way as the loss of calcium. In connection with the renal loss of electrolytes during the high level of urine production glucosuria is observed.     

The immobilization of wild equines with STH 2130 and tiletamine/zolazepam

Successful immobilisation of Przewalski's horses and zebras was obtained by using a combination of STH 2130 (Boehringer) and Tiletamin/Zolazepam.     

Doping control in race horses

Doping in performance horses is defined as the "illegal application of any substance, except normal diet, that might modify the natural and present capacities of the horse at the time of the race." The prohibition of doping is mainly based on the protection of animals. Doping can be performed with various aims: "doping to win" can be regarded as the classical method by mobilization of overphysiological capacities. Such positive doping may be classified as an acute form using psychomotoric stimulants, as a chronic form using anabolic hormones, and as a paradoxical form using small doses of neuroleptics or tranquilizers in excitable horses. In larger doses these sedatives are acting for "doping to loose" in a more subtle manner as compared to hypnotics. According to the doping regulations there is no difference between therapy and doping at the time of the race. Thus at the race all medications to restore normal performance have to be regarded as doping. This fact especially concerns the therapy of lamenesses with non-steroidal antiinflammatory drugs or local anesthetics. A particular problem is "inadvertent" doping due to unknown side effects, combinations of drugs, galenic supplements or food additives. Accidental doping may further be caused by the unawareness of elimination times. At the moment no exact withdrawing times can be defined due to the manifold interindividual variations at different levels of the pharmacokinetics. As a border-line case of doping the application of endogenous substances, like electrolytes or glucose, may be regarded. Though their parenteral application is prohibited prior to the race, only bicarbonate or "blood doping" may be considered to be effective as positive doping. Special doping methods are the use of "masking" substances or diuretics in order to make more difficult the detection of illegal drugs as well as physical doping procedures which are often hardly to define and which thus are only in part included in the doping regulations.