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Topic:Veterinary Medicine
Veterinary medicine for horses encompasses the study and application of medical practices to diagnose, treat, and prevent diseases in equine species. This field involves a comprehensive understanding of equine anatomy, physiology, pathology, and pharmacology. Veterinary practitioners employ a range of diagnostic tools and therapeutic interventions to address health issues in horses, including lameness, gastrointestinal disorders, respiratory conditions, and infectious diseases. Preventative care, such as vaccination and deworming programs, is also a significant aspect of equine veterinary medicine. This page gathers peer-reviewed research studies and scholarly articles that explore various aspects of veterinary medicine as it pertains to horses, including advancements in diagnostic techniques, treatment protocols, and preventive health strategies.
Follicular and gonadotrophic changes during transition from ovulatory to anovulatory seasons. Observations of follicular and gonadotrophic changes were conducted on 14 Pony mares for 31-day periods beginning at the penultimate (second last) ovulation and at the last ovulation of the season. There were no main effects or interaction of day or period on the numbers of small follicles (less than 20 mm). Concentrations of FSH, numbers of large follicles (greater than 20 mm), and oestrous behaviour each showed an effect of day (P less than 0.01), but no effect of period. Concentrations of LH and diameter of the largest follicle each showed an interaction (P less than 0.01) between day and p...
The control of oestrous behaviour in the mare. Using a range of positive and negative sexual behaviour components, proceptivity of cycling, non-lactating mares and postpartum, lactating Pony mares was quantified around ovulation. Behavioural observations were compared to plasms concentrations of progesterone, total oestrogens and androstenedione. In addition, in cycling mares, comparison with plasma testosterone concentrations was carried out. Overall rejection behaviour by the mare was apparent both during dioestrus and during periods of basal plasma progesterone concentrations. Within cycling, non-lactating mares, and between postpartum ...
The use of fibre-optic techniques in clinical diagnosis and visual assessment of experimental intrauterine therapy in mares. Intrauterine fibroscopy was used in the clinical evaluation of 40 mares with established histories of subfertility. The average age of the mares was 12.2 years with a 2.8-year interval from last foaling in multiparous mares. Transluminal adhesions, endometrial cysts, diffuse fibrosis, fluid accumulation or myometrial tumours were found in 26 mares. When compared to other techniques, fibroscopy did not seem to be superior to uterine biopsy but had some advantage over rectal palpation as a single diagnostic technique. Only 3 mares failed to exhibit pathological findings when all 3 techniques wer...
Serum levels of progesterone, 5 alpha-dihydroprogesterone and hydroxy-5 alpha-pregnanones in the prepartum and postpartum equine. Blood samples were collected from eight mares for ten days before and two days following parturition. Progesterone, 5 alpha-dihydroprogesterone and hydroxy-5 alpha-pregnanones were extracted from serum, separated by Sephadex LH-20 column chromatography and quantitated by radioimmunoassay. Progesterone levels ranged from 8.5 to 4.1 ng/ml among mares with normal parturition and decreased to 1.2 ng/ml after parturition. One mare with a retained placenta maintained the prepartal levels of progesterone into the postpartum period. 5 alpha-dihydroprogesterone increased to a level of 133 ng/ml at 80 h...
A comparative study of bovine herpesvirus 1247 and equine herpesvirus 1 in ponies. The clinical and immunological response of ponies exposed to a bovine herpesvirus isolate and equine herpesvirus 1 were compared. Each virus was inoculated into two ponies by the intranasal route. One uninoculated pony was used with each group as a contact control. The four inoculated ponies developed a mild rhinitis with an increase in rectal temperature. Virus was recovered from nasal secretions collected from the four inoculated and one contact pony. All ponies developed a serum neutralizing antibody to each virus. The data show that the two viruses are similar.
Immunity to equine herpesvirus 1 infection in foals during the first year of life. A band of 23 pregnant mares on a Thoroughbred breeding farm all had serum virus-neutralizing antibody titres to equine herpesvirus 1 (EHV-1). Antibody was not transferred to their foals in utero. All foals received antibody from colostrum and developed antibody titres similar to their dams. The serum virus-neutralizing antibody titres were observed in 10 of these foals for 1 year. Decay of passive immunity occurred at the rate of 3.25 two-fold dilutions in 100 days and reached zero at the mean time of 180 days. The foals were exposed to EHV-1 twice. Foals with a geometric mean titre of 1 : 25 ...
The effect of intrauterine and cervical manipulation on the equine oestrous cycle and hormone profiles. Endometrial biopsy or endometrial biopsy and uterine culture taken on Day 4 after oestrus induced lysis of the corpus luteum (CL), resulting in a sharp decline in serum progesterone concentration and shortened the interoestrous interval in 8/12 and 32/33 oestrous cycles, respectively, during 2 experiments. Cervical dilatation 4 days after oestrus shortened the interoestrus interval in 5/10 and 0/5 oestrous cycles. Endometrial biopsy and culture on Days 1 and 3 after oestrus also induced CL lysis during 4 of 7 cycles. Total oestrogen (oestrone plus oestradiol) concentrations increased at the on...
FSH and LH concentrations in periparturient mares. The influence of the ovaries and presence of a foal on periparturient concentrations of FSH and LH were studied in 19 Pony mares. In intact and ovariectomized mares, mean concentrations of FSH fluctuated between 1.1and 9.9 ng/ml on Days -14 to-1 before parturition (Day 0). A surge of FSH occurred in all mares in association with parturition. From Days 1 to 10, the high levels of FSH gradually decreased in the intact group to the minimal concentrations that occur during oestrus, but remained elevated in the ovariectomized mares. There were no significant pre-partum changes in LH in either type ...
Case report: An outbreak of herpesvirus myeloencephalitis in vaccinated horses. In the foaling season of 1977, five vaccinated horses in a Standardbred breeding stable were affected with herpesvirus myeloencephalitis. Respiratory and abortigenic forms also occurred in other individuals on the premises. Equine herpesvirus type 1 was isolated from the brain of one case of myeloencephalitis and from lungs of two aborted fetuses. Twelve of 16 horses demonstrated fourfold or greater increases in titres to equine herpesvirus type 1.
Specific PGF-2 alpha binding by the corpus luteum of the pregnant and non-pregnant mare. The binding of prostaglandin (PG) F-2 alpha to corpora lutea (CL) from pregnant and non-pregnant Pony mares was examined. Studies of the rates of association and dissociation indicated that [3H]PGF was bound specifically and reversibly to a luteal cell membrane preparation (MP) that was isolated by high speed (100,000 g) ultracentrifugation. Various PGs and PG metabolites displaced [3H]PGF from the receptors in the following decreasing order: PGF-2 alpha greater than 13, 14-dihydro-PGF-2 alpha = 13,14-dihydro-15-keto PGF-2 alpha greater than PGD-2 greater than PGF-1 alpha = PGE-2 greater than ...
Testicular measurements and reproductive characteristics in stallions. Factors affecting testicular measurements in situ and the relationships among the measurements and various reproductive characteristics were studied using data from 48 stallions. Mean values during the breeding season are provided for scrotal width, widths and lengths of individual testes, combined weight of testicular parenchyma, daily sperm production and daily sperm output. Testicular measurements were highly repeatable from day to day and for repeated measurements on a given day; technician provided the largest source of variation in the measurements of a given stallion. Age significantly ...
Effect of ovariectomy on pregnancy in mares. Pony mares were bilaterally ovariectomized at different stages of pregnancy between Days 25 and 210. Abortion or fetal resorption occurred within 2 to 6 days after operations in all 14 mares ovariectomized between Days 25 and 45 and after an interval of 10 to 15 days in 9 of 20 other ovariectomized between 50 and 70 days. All 12 mares ovariectomized on either 140 or 210 days carried their foals to normal term. The termination of early pregnancy was preceded by a loss of uterine tone and of a palpable uterine bulge. The mean length of gestation in all mares in which pregnancy was not interrupte...
Fertility of donor mares following nonsurgical collection of embryos. Embryos were collected nonsurgically on Day 7 or 8 after ovulation from 7 Quarter horse mares using a modified 30-ml Foley catheter to flush the uterine horn ipsilateral to the recent ovulation with 500 ml TCM-199 containing Hepes buffer. After collection, the uteri were infused with nitrofurazone to reduce the chances of infection due to the procedure. Eleven collections from 7 mares resulted in recovery of 9 embryos and nonsurgical transfer of 4 of these resulted in the birth of one foal. After collections, 8 oestrous cycles averages 22.75 days and 2 extended oestrous cycles were 43 and 59 d...
Arthropod-borne encephalitides in the Americas. The arthropod-borne encephalitides are an important cause of equine and human morbidity in the Americas. Between 1975 and 1978, 6970 human cases of arboviral encephalitis were reported in the United States of America; however, this represents only a fraction of the true incidence. St Louis encephalitis (4824 cases), California encephalitis (1035 cases), and western equine encephalitis (WEE, 947 cases) accounted for 98.5% of all reported infections. Approximately 1000-4000 cases of equine encephalitis occur annually in the United States, the majority due to WEE. In tropical America, important o...
Ultrastructural studies of the equine uterus and placenta following parturition. Post-partum placentae and uterine biopsy samples from mares after normal and abnormal foalings are described. After normal delivery there is little damage to fetal or maternal tissues. The villous epitheliochorial palcenta separates cleanly at the maternal-fetal interface and the afterbirth consists almost exclusively of fetal tissue. Uterine involution is well advanced by the 3rd and 4th days post partum and the changes are usually complete by the oestrus 7--10 days after parturition. Placental separation and involution of the uterus appear to proceed normally in malpresented foals and in oth...
Treatment of periocular tumours of horses using radioactive gold198 grains. The literature is briefly reviewed concerning the clinical features of equine cutaneous tumours. The data from 19 horses with periocular skin tumours are reported together with the results of their treatment by implantation with radioactive gold198. The principles governing the implantation of radioactive sources are explained and a method for computing the initial activity of the sources is outlined. Five histologically different tumour types were treated in this series of 19 horses, 2 horses were bilaterally affected. The techniques of implantation using a simple needle/stillette combination...
The mature mid-cycle follicle in the mare. Oestrogen and progesterone concentrations in blood and follicular fluid and blood levels of LH were determined in 426 mares at different stages of the oestrous cycle. Mature follicles occur at all stages of the cycle; they ovulate readily in early metoestrus, occasionally in late metoestrus and very rarely in dioestrus. Maturation of a mid-cycle follicle is associated with intermediate levels of LH, which are less than those found during oestrus. This lower level of LH together with a high level of progesterone are probably responsible for the failure of ovulation and regression of most of the...
Haematological correlates of phytohaemagglutinin-induced lymphocyte transformation in horses. The purpose of these investigations was to assemble and compare data which might illustrate a functional relationship between phytohaemagglutinin-induced transformation of equine lymphocytes in vitro and the haematological profiles of the lymphocyte donors. Statistically significant correlation between transformation and a haematological parameter was taken as evidence that both may be part of a common regulatory system. There was no evidence that transformation in vitro was affected by artefactual variation in the cellular composition of the cultures. Transformational behaviour of lymphocytes...
Purification of horse renal kallikrein and chemical relations with horse urinary kallikrein. Kallikrein was purified from horse kidney by several steps of chromatographic procedure and by affinity chromatography on Sepharose-Concanavaline. Horse urinary kallikrein was previously purified by DE-32 hydroxylapatite and by Sephadex G-100 gel filtration. On the purified final sample of renal and urinary kallikrein the aminoacid composition and the gel electrophoretic molecular weight were determined. The ratio in micronMoles between each aminoacid residue of both hydrolyzed renal and urinary kallikrein of horse is about 1,00 +/- 0,30. Except for Pro, 1/2 Cys and basic aminoacid residues a ...
The binding of FSH, LH and PMSG to equine gonadal tissues. Gonadotrophin-receptor binding studies involving the use of 125I-labelled highly purified FSH and LH have shown that equine gonadal tissues possess similar numbers of specific FSH and LH receptors per cell as the gonadal tissues of other mammals. However, while rat, cow and pig gonadal tissues were shown to bind as much 125I-labelled PMSG as 125I-labelled LH on a molar basis, the equivalent equine tissues bound only less than or equal to 4% as much of the labelled PMSG as LH. Competitive binding studies involving the use of radioreceptor assay techniques have further demonstrated that the smal...
Reproductive management of mares without detection of oestrus. The use of photoperiod, progestagen, prostaglandin and hCG treatments was investigated to obtain mating of mares at predetermined times. The objectives were: (1) synchronization of oestrus at an early time of the year, (2) simplification of treatment schedules by use of vaginal sponges, and (3) use of several controlled cycles by successive synchronization. The following conclusions were reached. First, after a 16 h photoperiod was applied beginning on 25 November, hormonal synchronization of oestrus and ovulation followed by cyclicity were obtained on 1 February; i.e. 2 months of light are es...
Corticosteroid-potentiated vascular responses of the equine digit: a possible pharmacologic basis for laminitis. Spirally cut digital arteries and veins were mounted isotonically in organ baths containing oxygenated Krebs' Q-Henseleit solution. Twelve arterial and 12 venous preparations all contracted dose dependently when epinephrine, norepinephrine, serotonin, or histamine were added to the bathing fluid. Addition of hydrocortisone or betamethasone alone did not cause contractions in any of the tissues tested. However, when hydrocortisone or betamethasone was added to vessel strips that were partially contracted (40% to 60% maximal) by epinephrine, norepinephrine, or serotonin, each vessel strip invari...
Effects of age and frequency of ejaculation on sperm production and extragonadal sperm reserves in stallions. Extragonadal reserves totalled 89 X 10(9) spermatozoa for 5--16-year-old sexually rested stallions and 60 X 10(9) for 2--4-year-olds. Regardless of age, the cauda epididymidis contained 62% of the total reserves and the vas deferens, including the ampulla, contained 7% of the total reserves of spermatozoa. The caput plus corpus epididymidis from 5--16-year-old stallions (N = 41) contained 14.9 X 10(9) spermatozoa per side as compared (P less than 0.01) to 8.5 X 10(9) for 2--4-year olds (N = 30). Frequency of ejaculation did not influence the number of spermatozoa found in caput plus corpus epi...
