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Topic:Horses
"Horses" is a broad topic that encompasses various aspects of equine biology, behavior, and management. This category includes studies on the anatomy, physiology, and genetics of horses, as well as their behavior, nutrition, and care. Research in this area may also cover the historical and cultural significance of horses, their roles in agriculture, sport, and therapy, and the challenges associated with their conservation and welfare. The page aggregates peer-reviewed research articles and scholarly studies that explore the multifaceted relationships between humans and horses, examining both scientific and socio-economic perspectives.
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.
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...
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...
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.
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...
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.
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...
Oestrus, ovulation and plasma hormones after prostaglandin F2alpha in mares. The luteolytic effect of PGF2alpha, administered by intrauterine infusion or subcutaneous injection during early dioestrus, was observed in mares of mixed breeds. An infusion of 10 mg on Days 7 to 9 after ovulation caused a sharp fall in plasma progesterone levels and induced oestrus and ovulation. Oestrus was significantly longer than in the natural cycle but the time of ovulation in relation to the end of oestrus was normal. The time of return to oestrus following luteolysis was not dependent on the amount of PGF2alpha within the range of doses given. Luteolysis could be induced as early as ...
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.
Endometritis, a common cause of infertility in mares. Infertility, resulting from failure to conceive during the preceding breeding season, was caused by various forms of endometritis in forty-four mares of Highland and Arabian breeds in Yugoslavia. Chronic mucopurulent and latent catarrhal endometritis occurred most frequently. Douching of the uterus on alternate days for 9 days with warm and cold sterile salt solutions (ranging from 7% to 1% w/v) in the early autumn resulted in conception in 47-7% of mares at an average of 15-2 days after the onset of treatment, and another 36-7% becoming pregnant in the following spring. Mating at the wrong st...
Relationship between luteal function and metabolic clearance and production rates of progesterone in the mare. The functional activity of the equine CL was measured by its ability to convert [4-14C]3beta-hydroxy-5-en-20-one to [4-14C]pregn-4-en-3,20-dione. The capacity of homogenates of CL of different ages followed the temporal pattern of plasma progestagen concentrations. In ten mares which ovulated twice at intervals of 0 to 9 days in the same cycle, the conversion capacity of the CL from the second ovulation was similar to that from the first ovulation. After adjusting for age, the CL from the first of two ovulations had a similar conversion capacity as that resulting from a single ovulation. Plasm...
Studies on dioctyl sodium sulfosuccinate toxicity: clinical, gross and microscopic pathology in the horse and guinea pig. Concentrations of dioctyl sodium sulfosuccinate (DSS) ranging from three to five times the recommended dosage produced severe diarrhea, rapid dehydration and death in seven horses and 66 guinea pigs when administered experimentally per os. Clinicopathological findings indicated hemoconcentration in both horses and guinea pigs. There was a leucocytosis in the guinea pigs given the highest dosages. In all cases the principal finding at necropsy was extreme fluid distention of the intestinal tract. There was histopathological evidence of epithelial denudation and vascular stasis. The LD50 in the ...
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...
Leptospiral antibodies in serum from cattle, swine, horses, deer, sheep, and goats: 1973 and 1974. During 2 years (fiscal years 1973 and 1974), microscopic agglutination tests were performed on 12,565 serums from cattle, swine, horses, deer, sheep, and goats for the detection of leptospiral antibodies. The most frequent presumptive infecting serogroups were Hebdomadis, Pomona, Autumnalis, Ballum, Australis, and Canicola.
Laboratory studies of Venezuelan equine encephalitis virus in equines, Texas, 1971. During the summer and fall of 1971, epizootic and epidemic Venezuelan equine encephalitis was detected in Texas. Isolates of epizootic (IB) and vaccine (TC-83) strains were distinguished by virulence of the former for guinea pigs. Vaccine virus was isolated from 1 to 14 days after vaccination and neutralization tests demonstrated the appearance of antibody about a week after vaccination. Viremia titers of subtype IB in horses ranged from 2.2 to 8.3 log10 suckling mouse intracranial 50% lethal doses per ml. Of 101 equines from which Venezuelan equine encephalitis virus (IB or TC-83) strains wer...
Plasma immunoreactive calcitonin levels in pregnant mares and newborn foals. Plasma calcium and calcitonin levels were measured periodically during the two last months of pregnancy and at the time of parturition in 9 pregnant mares and their foals. In pregnant animals, there was an increase in plasma calcitonin levels in the days before parturition, which was not due to any change in plasma calcium. This result indicates that in the mare, as in the cow, in the days before parturition CT secretion escapes from its control by plasma calcium. In 0-day and 7-day-old foals plasma calcium levels were significantly higher than in their mothers, but plasma calcitonin levels we...
Bile acid kinetics and bile secretion in the pony. Bile acid pool size and synthesis rate were determined by both isotope-dilution and washout methods in ponies with chronic external biliary fistulas. Bile acid pool size (10.9 mumol/kg) and synthesis rate (11.2 mumol/day per kg) estimated by the isotope-dilution method did not differ significantly from pool size (9.4 mumol/kg) and synthesis rate (9.5 mumol/day per kg) estimated by washout method. Bile acid-dependent and -independent fractions of bile flow, determined by a method that circumvents any inevitable correlation of flow to bile acid secretion due to common factors in both parameters,...
