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Topic:Equine Health
Equine health encompasses the study and management of diseases, disorders, and overall well-being of horses. It involves understanding various physiological systems, preventive care, and treatment strategies to maintain optimal health in equine populations. Common areas of focus include nutrition, infectious diseases, orthopedic conditions, and reproductive health. Research in equine health aims to advance knowledge on diagnostic methods, therapeutic interventions, and management practices that improve horse welfare and performance. This page collects peer-reviewed research studies and scholarly articles that explore the diverse aspects of equine health, offering insights into current findings and advancements in the field.
Identification of multiple equine infectious anemia antigens by immunodiffusion reactions. Equine infectious anemia (EIA) cell antigens prepared from infected equine spleen, equine leukocyte cultures or a persistently infected equine dermis cell line contained at least two serologically reacting components. For convenience one component was designated as soluble antigen (SA) and the other as cell-associated antigen (CAA). The SA appeared as a single component when it was prepared from EIA virus precipitated from infectious tissue culture fluid with polyethylene glycol and ether treated but it was mixed with CAA when the source was infected cells. Cytolytic or mechanical disruption o...
The site of ovulation in the mare. Serial photography of the ovary of a mare by periodic surgical exteriorization of the ovary and peritonescopy in situ revealed that the ovulatory fossa is the site of ovulation in this species.
The ultrastructure of endometrial cups in pregnant mares. Electron microscopy and immunofluorescence techniques were used to study the various epithelial cells in the endometrial cups of ten pregnant mares, and in the uterine epithelium of one non-pregnant mare. Evidence was obtained which suggested that epithelial gland cells within the endometrial cups, as distinct from the hypertrophied decidual-like cells in the cup, may synthesize PMSG. The suggestion does not agree with the findings of other workers in the fetal origin (chorionic girdle cells) of this gonadotrophin.
Levels of LH, prolactin and oestrogens in the serum of post-partum mares. The levels of LH, prolactin and oestrogen were measured by radioimmunoassay in serum obtained from six mares during the post-partum period, and LH was also assayed in blood samples collected at 6-hr intervals from four normal cyclic mares during oestrus and at daily intervals during dioestrus. The concentrations of oestrogen and LH suggested that the mares were having ovulatory cycles during the post-partum period irrespective of behavioural oestrus, and the levels of prolactin seemed to rise in association with probable ovulatory LH peaks. In these mares levels of LH had increased significant...
An ultrastructural and histochemical study of the interstitial cells in the gonads of the fetal horse. Gonadal tissue obtained at about 50-day intervals from Days 60 to 300 of gestation was examined histologically, histochemically and in the electron microscope. The marked enlargement of the gonads (ovaries or testes) reached a peak around Day 250 and was caused by hypertrophy and hypoplasia of interstitial cells. These cells had all the ultrastructural characteristics of a steroid-secreting cell but delta5-3beta-hydroxysteroid dehydrogenase (3beta-HSD) was not detected at any stage of their development. There was no significant change in the ultrastructure of the interstitial cells between Day...
Morphology and pathology of the equine umbilical cord. A brief description is given of the morphology of the umbilical cord and some variations encountered. In 95% of normal Thoroughbred foals the cord measures less than 84 cm. Factors which govern cord length are not known. Seven pathological conditions involving the umbilical cord are described. Increased length is the most common abnormality and predisposes to three potentially lethal conditions, strangulation of the cord around the fetus, excessive torsion, and allantochorionic necrosis at the cervical pole.
Neuropathology of the convulsive foal syndrome. Brains from eighteen Thoroughbred foals suffering from the convulsive foal syndrome were examined neuropathologically and compared with brains from nine foals dying from different causes. In the brains of nine convulsive foals there was necrosis of the cerebral cortex, accompanied in three by severe necrosis of the diencephalon and brain stem; haemorrhage into the cerebral cortex was also present in most of this group. In the other nine brains from convulsive foals there was haemorrhage, often severe, especially in the white and grey matter of the cerebral cortex and in the cerebellum. Minimal...
Factors influencing foaling percentages in Australian mares. Foaling figures for Thoroughbred mares in Australia show a puzzling disparity between conception and foaling rates in the second half of the 22 years of official data collection between 1950 and 1972. In the first 9 years of the survey, the live foal percentages rose in parallel with conception rates, but then a divergence of the figures occurred with the conception rate continuing to improve by 6-25% while the foaling rate improved by only 0-01% over the same period. An hypothesis supported by data from two studs is considered that stress factors additional to those experienced by mares in th...
Reproduction in feral horses. A behavioural study of feral horses was conducted on the Pryor Mountain Wild Horse Range in the western United States. All 270 horses on the Range were identified individually. The sex ratio was nearly balanced. Foal to adult female ratio was 43-2:100. Morality was concentrated among foals and old horses. Horses were organized as forty-four harem groups each with a dominant stallion, one to two immature stallions, one to three immature mares, one to three adult mares and their yearling and foal offspring, and 23 bachelor groups of one to eight stallions. Harem groups were quite stable year-rou...
Morphology and histochemistry of the endometrial cup. The luminal and cut surface of endometrial cups were examined by scanning electron microscopy. The distribution of PAS-positive and lipid materials in cup tissue was studied and most of the lipid material was localized in the large polyhedral cup cells. The lipid droplets gave positive reactions for DNPH in the cholesterol test of Schultz. They also exhibited autofluorescence and were therefore considered to be steroidal in nature. The significance of this possibility, particularly with regard to maintenance of early pregnancy in the mare, is discussed.
An intersex (male pseudohermaphrodite) horse with 64XX/XXY mosaicism. The clinical, pathological and chromosomal findings in a male pseudohermaphrodite horse are reported. This animal appeared to be a female but showed strong male sexual behaviour. A small penis emerged from a rudimentary vagina. Two small testes were present in the abdomen and undifferentiated seminiferous tubules contained only supporting cells. No uterus was found. Culture of peripheral blood leucocytes revealed a 64XX/65XXY mosaicism.
Semen characteristics in thyroidectomized stallions. Three Quarter-horse stallions were surgically thyroidectomized at 18 months of age. Weekly semen collections were made from these and three control stallions from 25 to 39 months of age. Although the induced state of hypothyroidism in young stallions has a depressing effect on libido and general animation and can be corrected by thyroprotein supplementation, semen characteristics, testicular histology and fertility are not affected by the operation.
Evaluation of xylazine as a sedative and preanesthetic agent in horses. Xylazine administered intramuscularly (IM) to horses at the dose level of 2 mg/kg was an effective sedative and preanesthetic for thiamylal sodium narcosis or thiamylal sodium and halothane anesthesia. Evaluation of response of cardiovascular, respiratory, and hepatic function did not indicate serious untoward effects, although cardiac and respiratory rate decreased, calculated vigor of left ventricular contraction decreased, calculated peripheral vascular resistance increased, and transient innocuous cardiac arrhythmias occurred. Effects of the anesthetics used on respiratory function (blood ...
Immunoglobulin metabolism in the neonatal foal. The proteins IgG and IgG(T) are the predominant immunoglobulins in equine colostrum. Their distribution and catabolism were studied in the newborn foal using an isotopic tracer technique. More precise quantitation of the absorption of these immunoglobulins from colostrum is now possible.
The cycle of oestrus, ovulation and plasma levels of hormones in the mare. The duration of the oestrous cycle and day of ovulation were recorded in six mares which were used for concurrent assay of plasma levels of sex steroids and pituitary LH concentration. Peak of progesterone were reached during dioestrus and those of oestradiol and androstenedione occurred 2 days before ovulation and were in decline on the day of ovulation. Plasma oestrone remained constant (between 9 and 12 pg/ml) throughout the cycle. Plasma LH rose to a maximum near to the time of ovulation, and thereafter decreased gradually until mid-dioestrus. The pattern of secretion is compared with that...
Using body size to understand the structural design of animals: quadrupedal locomotion. Many parameters of gait and performance, including stride frequency, stride length, maximum speed, and rate of O2 uptake are experimentally found to be power-law functions of body weight in running quadrupeds. All of these parameters are reasonably easy to measure except maximum speed, where the question arises whether one means top sprinting speed or top speed for sustained running. Moreover, differences in training and motivation make comparisons of top speed difficult. The problem is circumvented by comparing animals running at the transition between trotting and galloping, a physiologicall...
The fine structure of the glycocalyx of equine spermatozoa: a high-resolution cytochemical study. Equine spermatozoa were obtained from ejaculates of young stallions. The seminal plasma was removed and the sperm pellets washed three times with 0-15 M-NaCl solution before final centrifugation at 4500 g for 15 min. The pellets were fixed in a mixture of 2-5% glutaraldehyde in 0-1 M-cacodylate buffer, pH 7-4, with 0-5% Alcian blue and post-fixed in 1% osmium tetroxide with 1% lanthanum nitrate; other samples were treated with ruthenium red. All samples were dehydrated in ascending concentrations of ethanol, embedded in araldite and thin sections examined in an electron microscope. Electron de...
Effect of photoperiod on reproductive activity and hair in mares. The effects of photoperiod on reproductive activity and hair changes in pony mares were studied in 2 experiments. In experiment I, the effect of a fixed daily photoperiod on the onset of the breeding season was studied in 36 mares from Nov 13, 1973, to June 13, 1974. The 4 treatment groups were as follows: daily photoperiod equivalent to the normal day length (control group); constant light 24 hours a day with no dark (L24:D0 group); 16-hour daily photoperiod with 8 hours of dark (L16:D8 group); and 9-hour daily photoperiod with 15 hours of dark (L9:D15 group). The intervals from beginning of ...
[Production of antirickettsial sera by immunizing horses. II. Obtaining and testing an immune serum to D. sibericus]. The authors present the results of immunization of horses-producers with a commercial antigen and the yolk culture of the living R. sibericus (strain K1) for the purpose of obtaining specific immune sera for many purposes. It was shown that the original combined scheme of immunization and reimmunization of horses, successfully approved in the preparation of immune sera to Rickettsia prowazeki also proved to be highly effective for obtaining the antisera to R. sibericus. Sera obtained after the primary immunization of horses could be successfully used as diagnostic sera, but they were of no use...
Mammalian erythrocyte glutathione reductase: kinetic constants and saturation with cofactor. Glutathione reductase (GR) was studied in erythrocytes of horses, cats, dogs, and man. Glutathione reductase activity was measured in hemolysates with and without preincubation of hemolysates with flavinadenine dinucleotide. The percentage saturation of GR apoenzyme with cofactor (flavin-adenine dinucleotide) was lower in cats and dogs than in horses or man. The greatest amount of inactive apoenzyme was in feline erythrocytes. Total GR activity listed in order by species is cat greater than man greater than dog greater than horse. Kinetic constants for oxidized glutathione and reduced nicotina...
Postnatal lung growth and function in the foal. Respiratory function in newborn foals is discussed with particular reference to the important part played by functional residual capacity and chest wall compliance in maintaining blood gaseous exchange within normal limits.
Diarrhoea in horses associated with ulceration of the colon and caecum resulting from S vulgaris larval migration. The clinical manifestations of a diarrhoeic syndrome of horses with ulceration of the mucosae of the colon and caecum are described. Patients could be divided into three groups according to their presenting symptoms and the disease is probably caused by the thrombo-embolism associated with migrating larvae of Strongylus vulgaris. The differential diagnosis, prognosis and treatment are outlined with particular reference to the use of antithrombotic agents.
Antigenic relationship between the surface antigens of avian and equine influenze viruses. Influenza virus Equine 1 (A/equine/Prague/56) has a hemagglutinin which is antigenically related to the hemagglutinin of fowl plague virus strain Rostock (FPV) and a neuraminidase which cross-reacts with the enzyme of virus N (A/chick/Germany/49). After a single injection of chickens with Equine 1 virus no hemagglutination inhibiting (HI) and neutralizing antibodies against FPV can be demonstrated, although the birds are fully protected against a lethal dose of FPV. HI and neutralizing antibodies against FPV appear after a second injection of Equine 1 virus several weeks after the first one. L...
[The effect of pregnant mare’s serum on the level of K+ ions in the immature rat ovary]. Pregnant Mare Serum Gonadotrophin enhanced potassium level in immature rat ovaries in comparison with controls, three hours after intravenous injection. In vivo 42K uptake was also 36% higher (p less than or equal to 0,01) in PMSG primed rat ovaries. This response was specific to the ovary. Experiments are carried out to determine correlation between K+ level and macromolecule biosynthesis.
