Topic:Shetland Ponies
Shetland Ponies are a distinct category within the equine species with unique characteristics and uses. Shetland Ponies are a small, hardy breed originating from the Shetland Islands in Scotland, known for their strength, intelligence, and adaptability to harsh climates. This topic explores the comparative anatomy, physiology, and behavioral traits of Shetland Ponies, as well as their respective roles in equestrian activities and agriculture. Included are peer-reviewed research studies and scholarly articles that investigate genetic, nutritional, and health aspects specific to each group, providing insights into their care and management.
Iron toxicity in neonatal foals. Newborn Shetland foals died of acute hepatic failure following oral administration of approximately 16 mg/kg body weight ferrous fumarate. Lesions in these foals were indistinguishable from lesions in foals given an oral digestive inoculant containing ferrous fumarate and were also similar to the syndrome characterised as 'toxic hepatopathy' in foals in the United States in 1983. We conclude that foals are susceptible to toxicity from low doses of iron compounds in the first few days of life. Vitamin E and selenium deficiency may contribute to this susceptibility.
Epidemiology of strongyles in ponies in Ontario. The transmission of strongyles among 54 Shetland-cross mature ponies was examined from May 30 to November 22, 1983 when the ponies were on pasture and over the ensuing winter when they were in loose housing. Fecal and pasture herbage samples were taken fortnightly through the pasture season and periodically thereafter. Three foals born and reared on pasture were weaned and removed from pasture, two in early August and one in mid-September, and housed for a period before necropsy. Daily maximum and minimum air temperature and total precipitation were recorded. The mean fecal strongyle egg count...
Course and extent of variation of equine infectious anemia virus during parallel persistent infections. Comparisons of peptide and oligonucleotide maps of glycoproteins and RNA from nine isolates of equine infectious anemia virus (EIAV) that were generated during parallel infections of two Shetland ponies revealed that each isolate was structurally unique. Each EIAV isolate contained a unique subset of variant peptides, oligonucleotides, or both, indicating that structural variation in EIAV is a random and noncumulative process and that a large spectrum of possible EIAV variants can be generated in infected animals.
Investigation into the heredity of congenital lateral patellar (sub)luxation in the Shetland pony. A breeding experiment was carried out in a group of Shetland ponies in order to investigate the heredity of congenital lateral patellar (sub)luxation. A breeding herd was established and consisted of stallions and mares acquired at different times. Some were free from, and others were affected by lateral patellar (sub)luxation in either one or both femoropatellar joints. Over a period of 20 years, 49 foals were born from different mating combinations. Some offspring were free from the defect and others showed the abnormality. Though the number of foals bred during the experiment is rather smal...
Comparison of two control systems for cyathostome infections in the horse and further aspects of the epidemiology of these infections. The small strongylid infections of two groups of three yearling female Shetland ponies and one yearling Shetland tracer pony were studied. One group was set stocked from April to November and was treated monthly with 5 mg kg-1 albendazole from two days before turnout until July. The other group grazed similar pasture until July, was treated with 5 mg kg-1 albendazole and subsequently removed to pasture grazed by sheep from April to July. The tracer ponies were added to both groups in September. The efficacy of both methods was not completely satisfactory probably because of low efficacy of ant...
Histochemical staining characteristics of normal horse skeletal muscle. The histologic and histochemical staining characteristics of the triceps brachii (long head), extensor carpi radialis, gluteus medius, vastus lateralis, biceps femoris, semimembranosus, semitendinosus, and extensor digitorum longus muscles of 8 Thoroughbreds, 2 Quarter Horses, 1 Arabian, 1 Paso Fino, and 1 Shetland Pony are described. Muscle fiber morphology, staining distribution and intensity, amount of IM connective tissue, number of IM blood vessels and IM nerves, calcium-activated adenosine triphosphatase activity (CaATPase), percentage of fibertype population, percentage of relative fibe...
Normal motility of the cecum and right ventral colon in ponies. To study the normal motility of the cecum and right ventral colon (RVC) in 3 mature Shetland ponies, a 6-part, indwelling, intraluminal catheter system was used to measure intraluminal pressure changes. Three catheters were placed in the cecum at 10, 25, and 40 cm from the cecocolic orifice, and 3 catheters were placed in the RVC at 10, 20, and 30 cm from the cecocolic orifice. Recordings were made during the interdigestive period beginning 2 weeks after surgical operation was done. Frequent, low-amplitude peaks (0.35 +/- 0.13 coordinated peaks/min) were seen involving the cecal body and cauda...
Exogenous corticosteroids increase serum iron concentrations in mature horses and ponies. Corticosteroid preparation was administered to 7 Shetland Ponies and 10 Quarter Horses. Serum iron concentration increased dramatically for 48 to 72 hours after the steroid treatment, whereas serum iron-binding capacity and serum ferritin concentration did not. An increase in available iron may allow bacteria to proliferate when ponies or horses are stressed or treated inappropriately with corticosteroids.
Control of strongylosis in horses by alternate grazing of horses and sheep and some other aspects of the epidemiology of Strongylidae infections. Alternate grazing of horses and sheep as a control measure for gastrointestinal helminthiasis was studied in three grazing experiments in 1981, 1982 and 1983. Each year a group of three mare yearling Shetland ponies, which were kept on a small pasture from spring to autumn, were compared with a similar group which grazed a similar or the same pasture until July and were subsequently removed to a similar pasture which had been grazed by sheep from April to July. In addition both groups were treated with an anthelmintic when the latter group was removed to the sheep pasture. Pasture larval count...
Rapid emergence of novel antigenic and genetic variants of equine infectious anemia virus during persistent infection. Previous results from our laboratory have demonstrated that equine infectious anemia virus displays structural variations in its surface glycoproteins and RNA genome during passage and chronic infections in experimentally infected Shetland ponies (Montelaro et al., J. Biol. Chem. 259:10539-10544, 1984; Payne et al., J. Gen. Virol. 65:1395-1399, 1984). The present study was undertaken to obtain an antigenic and biochemical characterization of equine infectious anemia virus isolates recovered from an experimentally infected pony during sequential disease episodes, each separated by intervals of ...
The distribution of inhibited early third stage Cyathostominae larvae in the large intestine of the horse. The distribution of inhibited early third stage Cyathostominae larvae in different parts of the large intestine of the horse was studied in 20 Shetland ponies necropsied in autumn 1982, 1983 and 1984. The location of the larvae in the large intestinal wall was studied by histological examination of the intestines of the eight ponies from 1984. Inhibited larvae were located predominantly and more or less equally in the caecum and the ventral colon. Generally fewer early L3 were in the dorsal colon. In 1984 a considerable proportion (mean 17%, range 9.7-36.9%) of the inhibited larvae was found i...
Use of oxibendazole for control of cambendazole-resistant small strongyles in a band of ponies: a six-year study. Oxibendazole (OBZ; 10 mg/kg of body weight) was administered to ponies at 8-week intervals to control strongylosis in a breeding band of Shetland-type ponies (n = 29 to 50) from October 1978 through September 1984. A similar use of cambendazole (CBZ; 20 mg/kg of body weight) in this band of ponies during the preceding 4-year period resulted in the survival of a CBZ-resistant population (S) of small strongyles. Effectiveness of OBZ treatments was monitored by pre- and posttreatment counts of the number of strongyle eggs per gram of feces (epg) and of the number of strongyle larvae per gram of f...
In vivo bone strain in the equine tibia before and after transection of the peroneus tertius muscle. The present study was undertaken to determine the influence of the peroneus tertius muscle on the loading regime of the tibia in the horse. Strain gauge rosettes were bonded to the cranial and caudal cortices of the left and right tibiae in six Shetland ponies. In vivo bone strain recordings were made before and after unilateral transection of the peroneus tertius muscle. Relatively large individual variations in response to transection were observed in both the experimental and the contralateral control limbs. The principal strain values on the cranial and caudal cortices increased during the...
Distribution of enzymes of purine metabolism in lymphocytes of horse, Equus caballus. A microassay requiring as few as 2 X 10(5) cells per assay was developed for systematic analysis of 9 purine enzymes in lymphocytes from equine peripheral blood, spleen, lymph node, thymus and bone marrow. The activities of adenosine deaminase (ADA), purine nucleoside phosphorylase (PNP), adenosine kinase (AK), deoxyadenosine kinase (dAK), deoxycytidine kinase (dCK), 5'-nucleotidase (5'-N), AMP deaminase, hypoxanthine-guanine phosphoribosyl transferase (HGPRT or HPRT), and adenine phosphoribosyl transferase (APRT) were measured by this microassay in lymphocytes from peripheral blood from four ...
Equine lymphocyte antigens in four major Belgian horse populations. Contribution to serology and antigen distribution. 158 Belgian Saddlebreds, 130 Belgian Trotters, 108 Belgian Draft horses and 92 Shetland ponies have been typed for serologically defined antigens at the ELA and ELY systems. Gene frequencies were estimated in each breed for the internationally established ELA, ELY-1 and ELY-2 alleles as well as for locally assigned additional ELA markers and for subtypes of ELA-W3, W9 and W11. The distribution of ELA alleles was in agreement with the expected Hardy-Weinberg equilibrium for the 4 horse breeds described here. Differences in gene frequencies between these main Belgian horse populations were obser...
Three-year study on trace mineral concentration in the blood plasma of Shetland pony mares. Changes in some trace minerals concentrations (calcium, inorganic phosphorus, magnesium, zinc, iron, copper, sodium and potassium) in blood plasma were investigated during a three-year period in Shetland pony mares. Blood plasma mineral concentrations were determined by the atomic absorption method and colorimetric method. The three-year averages were in micrograms/ml; Na 4630 +/- 168; K 277 +/- 3.8; Ca 171 +/- 3.8; P 31.5 +/- 0.74; Fe 1.92 +/- 0.14; Zn 1.07 +/- 0.04 and Cu 1.06 +/- 0.02. Two trace minerals (magnesium in inorganic phosphorus) showed only long-term tendency changes--upward or d...
Gluconeogenesis from caecal propionate in the horse. The production of propionate in the caecum of the horse has been measured in two Shetland-type ponies fitted with caecal and colonic cannulas and fed on hay or on hay and wheat bran. A continuous intracaecal infusion of 14C-labelled sodium propionate was used and samples were obtained from a cannula at the origin of the right ventral colon. A simultaneous intravenous infusion of [2-3H]glucose was used to measure total glucose entry. On a hay diet which provided 177 kJ/kg body-weight per d, mean caecal propionate production was 19.6 (range 17.2-21.2) mg/h per kg body-weight and on a hay and whe...
Inhibited development of cyathostominae in the horse in the early third stage. Inhibited early third stage larvae of Cyathostominae were found in the digested mucosa of the large intestine of 12 yearling, female Shetland ponies, which were used in two grazing experiments. The ponies were killed in late autumn. In some ponies the inhibited larvae were very abundant and in most animals the majority of the Cyathostominae populations consisted of these early third stage larvae, suggesting that the phenomenon has an epidemiological significance.
Alternate grazing of horses and sheep as control for gastro-intestinal helminthiasis in horses. Gastro-intestinal helminth infections of a group of three yearling mare Shetland ponies, which were set-stocked on a small pasture from February until September, were compared with those of a similar group of ponies, which grazed a similar pasture from February to July and subsequently was removed to a pasture which had been grazed by sheep from April to July. In addition both groups were treated with cambendazole when the latter group was removed to the sheep pasture. Pasture larval counts and worm counts demonstrated that the group grazed after the sheep acquired considerably smaller burdens...
Hypoglycemic seizures in a Shetland pony. A 12-year-old, 195 kg Shetland pony broodmare had eight seizures between May 29 and August 7, 1979. Plasma glucose levels during three of these seizures were markedly depressed (16, 18 and 19 mg/100 ml). Serum insulin levels were elevated during two of the seizures (86.0 and 97.7 microU/ml). Although a fasting hypoglycemia was not demonstrated, plasma glucose values during a normal day were abnormal; a plasma glucose level of 42 mg/100 ml was noted eight hours post-feeding. Serum insulin values obtained during an oral glucose tolerance test and intravenous glucagon tolerance test were consiste...
Equine marker genes: polymorphism for plasminogen. Polymorphism for two autosomal alleles of equine plasminogen, PLG1 and PLG2, was demonstrated in plasma by isoelectric focusing and immunofixation, with a goat anti-human plasminogen antibody. The frequency of PLG2 was 0.16 in 150 Standardbreds, 0.20 in 96 Thoroughbreds, and 0.39 in 32 Shetland ponies. No evidence for linkage of PLG with any of 13 marker loci was found.
Virulence and in vitro growth of a cell-adapted strain of equine infectious anemia virus after serial passage in ponies. Five serial passages of a cell-adapted strain of equine infectious anemia (EIA) virus were conducted in Shetland ponies. The 13 recipient ponies became agar-gel immunodiffusion test-positive by 25 days after they were inoculated. The virulence of the cell-adapted strain of EIA virus markedly increased through 3 serial passages, although individual variation within passages was high. The 1st serial-passage recipient remained afebrile through 200 days, whereas a febrile episode occurred about every 185, 44, 35, and 33 days in the 2nd, 3rd, 4th, and 5th serial-passage recipients, respectively. Se...
Glucose utilization in the horse. 1. Total entry, irreversible loss and recycling rates of glucose were measured in four non-pregnant female Shetland ponies before and after a 24 h fast by the continuous intravenous infusion of a mixture of [U-14C]glucose and [2-3H]glucose. 2. The post-fasting fall in the concentration of glucose and the rise in the concentration of ketones in plasma were not significant. 3. After fasting the total entry rate fell from 1.44 +/- 0.11 (n4) to 1.19 +/- 0.12 mg/min per kg body-weight (P less than 0.01) and irreversible loss fell from 1.36 +/- 0.10 (n4) to 1.05 +/- 0.10 mg/min per kg body-weight (P...
Effect of diethylcarbamazine on Strongylus vulgaris infection in ponies. Shetland ponies (n = 4) were given diethylcarbamazine orally at a dose level of 22 mg/kg/day for 1 week before they were inoculated with 800 third-stage larvae of Strongylus vulgaris. Treatment was continued for 86 (1 pony) or 200 days (3 ponies) after the inoculation. As compared with the changes seen in a similarly inoculated group of ponies (group 2) which were not treated, diethylcarbamazine did not prevent the clinical or pathologic changes due to the migrating larvae. Fewer adult parasites were recovered at necropsy from treated ponies than from nontreated (group 2) ponies, even when tre...
Chlamydia psittaci induced pneumonia in a horse. An agent lethal to embryonated chicken eggs was isolated from lung tissues of a quarter horse mare with a fatal respiratory disease. The lesions induced in embryonated chicken eggs, the tinctoral properties, the ultrastructural morphology, the resistance of the organism to sodium sulfadiazine, and the presence of a chlamydial complement fixing antigen, identify this isolate as a member of the family Chlamydiaceae and suggest the agent to be Chlamydia psittaci. Two Shetland ponies experimentally infected with the isolated agent developed subclinical infection as demonstrated by an increase in c...
Toxicity of Cassia occidentalis in the horse. Three Shetland ponies were given a single oral dose of ground Cassia occidentalis seeds in aqueous suspension. The clinical signs observed resembled those seen in naturally occurring and experimental cases in cattle. The syndrome was characterized by an afebrile course, incoordination, recumbency and death. Elevations of blood alkaline phosphatase, CPK, LDH, and SGOT were observed. Although muscle lesions were not seen grossly, microscopic lesions included segmental necrosis of skeletal muscle fibers. The findings were regarded as sufficiently characteristic of C. occidentalis poisoning to be ...