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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.
Effect of exogenous progesterone on its endogenous levels: biological half-life of progesterone and lack of progesterone binding in mares. The disappearance rate of progesterone from blood plasma of an ovariectomized mare was rapid and occurred in three phases. The half-life of the first component was 2-5 min and that of the second was 20 min; the half-life of the much slower third component was not measured. Progesterone, administered to ovariectomized and deeply anoestrous mares at the rate of 150 or 300 mg/day, maintained maximal peripheral levels of 6 to 8 ng/ml. Physiological levels were reached in 21 days using a dose of 150 mg and in 11 days with 300 mg daily. After withdrawal, circulating levels dropped rapidly. Blood pla...
Selected pathological changes of the mare uterus and ovary. Focal enlargements of the uterus are palpable through the rectal wall and have various aetiology. Aspects of their diagnosis, possible pathogenesis, significance and treatment are presented. Lymphatic lacunae appear to be quite common in older mares and may occasionally give rise to large endometrial cyst, but more frequently cause widespread change throughout the uterine horns. Three unusual ovarian abnormalities are presented, a large, oestrogen-producing granulosa cell tumour, an oestrogen-producing large follicle in a 4-month-old filly, and an ectopic progesterone-producing adrenal structu...
Synchronization of oestrus in mares with a prostaglandin analogue and HCG. Following an initial observation period of 13 days when plasma progesterone levels were determined, synchronization of oestrus and ovulation was investigated in thirty-three mares treated with a prostaglandin analogue ('Equimate') and HCG. Two courses of treatment were given 8 days apart and each consisted of a single intramuscular injection of Equimate (250 mug) followed 6 days later by an intramuscular injection of HCG (2500 i.u.). The first course was designed to remove all luteal tissue and to induce ovulation of any follicles that developed in response to the withdrawal of progesterone. T...
The frequency of infertility in thoroughbred mares. In a group of 852 Thoroughbred mares, 69-7% had foals which survived beyond 6 weeks, 7-1% had dead, premature or full-term foals and 1-1% had foals which died within 6 weeks after birth. Possible factors which may have influenced these data are mentioned.
Studies on pressure-volume relationships in excised equine lungs. Forty-eight lungs from fetal and neonatal horses were examined for pressure-volume relationships between pressures of 0 and 40 cmH2O. The inflation-deflation curves obtained were analysed by four different methods and the stability of the lung assessed in terms of hysteresis, stability indices and volume of air retained at maximal pressure (Vmax). Differences in the shape of the deflation curve between ventilated and non-ventilated lungs were similar to findings in other species. It is postulated that breathing alters lung-tissue elasticity during the neonatal period, as demonstrated by a sign...
Retention of tubal eggs in mares. Genital tracts from 227 mares slaughtered in various reproductive states were investigated to study egg retention in the oviducts. Eggs were found in 88-2% of 212 non-pregnant mares; the number/mare ranged from 0 to 21, and averaged 4-34. Retained eggs were twice as common in heavy as in light breeds and were found more frequently in early than in late pregnancy. Eggs were not found in the oviducts of two anovulatory post-partum mares. A few globular masses, probably consisting of desquamated tubal mucosa, were frequently lodged in the distal region of the ampulla and appeared, to some extent ...
Coital exanthema in stallions. Equine coital exanthema can be produced experimentally in stallions by inoculation with an equine herpesvirus (strain 65/61) and be transmitted during coitus with an infected mare. Serological responses to this infection include the production of complement-fixing and serum-neutralizing antibodies which reach maximum levels 14 to 21 days after infection. Complement-fixing antibodies decline rapidly and are usually not detectable by 60 days after infection, whereas serum-neutralizing antibody activity is maintained for at least 1 year. This disparity provides a useful method for the diagnosis o...
Induction of parturition in mares. Thirty-seven induced parturitions involving thirty-one mares were studied over a 2-year period using various doses of oestrogen and oxytocin. The time of appearance and degree of expression of the major clinical signs of parturition, and the time for completion of delivery and the passage of the placenta were significantly influenced by increasing doses of oxytocin. Oestrogen was useful in softening and relaxing the cervix when it was tight, but was not essential to induction when the cervix was already soft and dilating. Fertility was not adversely affected by induced parturition.
Endocrine patterns of the mare at term. The levels of progesterone and total progestins increased during late pregnancy and then fell dramatically during the last few days before parturition, although birth occurred in the presence of significant amounts of plasma progesterone. Oestrogen levels decreased slowly but insignificantly until birth occurred, and then remained at a low level until the post-partum oestrus 10 to 12 days later. Total 11beta-hydroxycorticosteroids were unchanged from Day 45 before to Day 15 after birth. The endocrine pattern of one ovariectomized pregnant mare during the last month of gestation was similar to ...
The relationship between dialy sperm production as determined by quantitative testicular histology and daily sperm output in the stallion. The relationship between daily sperm productions (DSP) and daily sperm output (DSO) was determined in eleven stallions. The DSO was determined by collecting single ejaculates, with an artificial vagina, at 24-hr intervals. The stallions were killed 24 hr after the last collection and the DSP was determined by quantitative testicular histology. The mean DSP was 8-0 X 10(9) (S.E. +/- 0-4 X 10(9), and the mean DSO was 7-0 X 10(9) (S.E. +/- 0-4 X 10(9)). It was estimated that 87% of the spermatozoa produced by the testes were harvested. The correlation between DSP and DSO was 0-80 (P less than 0-0...
Results of artificial insemination of horses in Poland in the post-war period. Artificial insemination (A.I.) of mares in Poland has not yet been widely applied. Initial attempts were made by research groups between 1945 and 1955 but A.I. of mares was only introduced into the normal practice of A.I. Centres during 1964-67. Intensive research into methods for preserving stallion semen in liquid nitrogen has been undertaken since 1968. Of the total of 3734 mares artificially inseminated in Poland since 1945, 350 were inseminated with frozen semen. The slow progress of A.I. in horses is imputed to the small numbers of people involved in the work, to the conservation of the ...
Plasma progestagens in the pregnant mare in the first and last 90 days of gestation. Plasma progestagens were measured in eighteen pregnant mares to establish normal levels in the first and last 90 days of gestation. Progestagens increased from 25 ng/ml at 90 days before birth to 60 ng/ml at 10 days before birth, decreased to 58 ng/ml at 5 days before, and were 3 ng/ml or less by 5 days after perturition. During the first 90 days of pregnancy, progestagens reflected luteal activity with an increase in plasma levels from Day 30 to Day 60.
Results of long-term storage of stallion semen frozen by the pellet method. Stallion semen frozen by the pellet method showed no significant loss of sperm motility and fertility over long periods of storage in liquid nitrogen. Eighteen of thirty mares conceived after insemination with semen recovered in nine ejaculates from seven stallions and stored for 18 months to 7 years.
Babesiosis in the newborn foal. A short account is given of babesiosis (equine biliary fever) caused by the tick-borne protozoan Babesia equi and B. caballi, endemic in the Cape Province of South Africa. The clinical picture, diagnosis and treatment are described. In the absence of any prophylactic measures, prognosis is poor; control of the parasites in the tick-infested areas is essential.
A review of the influence of nutrition upon the oestrous cycle and early pregnancy in the mare. Attention is drawn to the beneficial effect of improved nutrition during winter and early spring on the ovarian activity of mares. Furthermore, the necessity of an adequate plane of nutrition during early pregnancy to prevent embryonic resorption is stressed.
Results of insemination of mares with fresh and frozen stallion semen. Artificial insemination using deep-frozen semen was performed on 116 mares in 1973 using twelve ejaculates from eight stallions of the Hanoverian breed. Despite the fact that the quality of the semen used was poor, the majority of the mares inseminated were subfertile and some mares were inseminated during one oestrus only, 44% nevertheless conceived and gave birth to live foals. Of a small group of ten mares inseminated in the same year with fresh semen, seven conceived.
Pelviscopy in the mare. A method of endoscopic examination of the internal genital (pelvic) organs of the mare is described. Special emphasis is placed on the induction of artificial pneumoperitoneum and the installation of an endoscopic peritoneal fistula device for prolonged observation. The potential of pelviscopy in the mare as a diagnostic aid, a new device for research in equine reproduction and as an auxillary aid to teaching is discussed.
The effect of HCG on duration of oestrus, ovulation time and fertility in mares. Two experiments were conducted to determine the effects of HCG on duration of oestrus, dioestrus, the length of the oestrous cycle, the time of ovulation and fertility in non-lactating mares. In the first experiment, the injection of HCG was repeated for three successive cycles. Mares injected with 2000 i.u. HCG on Day 2 of oestrus during their first cycle had a shorter oestrus and ovulated sooner than untreated control mares, but in the third cycle, treated mares had a longer oestrus and ovulated longer after the onset of oestrus than controls. In the second experiment, one intramuscular inje...
The effect of rectal palpation on the fertility of cyclic mares. The effect of rectal palpation of fertility of non-lactating, normal cyclic mares was studied over 3 years. During the first year (1971), the conception rates in mares after daily paplaption during oestrus only, and during oestrus and the first 50 days of pregnancy, were not significantly lower (P greater than 0-05) than the conception rates recorded in mares not palpated. No abortions could be attributed to palpation. Oestrus lasted longer (P less than 0-05) in non-palpated than palpated mares. During the second year (1972), first-cycle pregnancy rates in two groups of mares palpated daily du...
Plasma progestagens in pregnant mares. Peripheral plasma progestagens were quantified by a competitive protein-binding assay throughout pregnancy. The level of progesterone increased significantly between Days 0 and 8 (P less than 0-05) and again between Days 28 and 44 and reached a maximum on Day 64. Subsequently, it fell slowly until about Day 300 and then rose again during the last 30 days before reaching a minimum on the day after foaling. Very low concentrations of 17alpha-hydroxyprogesterone were found except between Days 40 and 120 and during the last 30 days before birth. Two unidentified compounds, one eluting slightly bef...
Plasma LH levels in the mare during the oestrous cycle. Plasma levels of LH were determined by heterologous radioimmunoassay utilizing highly purified equine LH as standard. Samples were taken regularly from eleven mares for twenty-six oestrous cycles over a period of 10 weeks. The mean cycle length was 20-5 +/- 3-1 (S.D.) days, and ovulation occurred on average 4-3 +/- 1-6 (S.D.) days from the time heat was first detected. Levels of LH were persistently low from Days 5 to 16 of the cycle (ovulation = Day 0). They then increased slowly over a number of days and continued to rise beyond the levels observed at any time during the immediate preovulato...
Anatomy of the placental barrier in the mare. The study of the equine placenta, which began in Venice in 1598, has a long but discontinuous history. Early observations were purely morphological, but new techniques have stimulated a broader and more functional approach. Histological and ultrastructural observations at various stages of pregnancy have shown that the fetal side of the placenta comes to acquire certain features in common with the air-blood barrier of the mammalian lung. These changes may reflect the increasing O2 requirements of the fetus as gestation proceeds.
