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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.
Expression of major histocompatibility complex (MHC) antigens on horse trophoblast. Antibodies to fetal major histocompatibility complex (MHC) antigens are routinely detected in the serum of pregnant mares some 2-4 weeks after formation of the endometrial cups at Day 36-38 after ovulation. Several experimental approaches were taken to determine whether paternal MHC antigens are expressed on horse placental tissues. First, absorption of anti-paternal MHC antisera with a large volume of endometrial cup cells removed antibody activity in only 2 of 4 experiments. Second, repeated immunization of horses with endometrial cup tissue recovered from a mare on Day 47 of pregnancy faile...
Apneic oxygenation in anesthetized ponies and horses. Apneic oxygenation was studied in six ponies for 30 minutes, and six horses for 10 minutes. Arterial blood was sampled at regular intervals for measurement of oxygen and carbon dioxide tensions (PaO2 and PaCO2) and calculation of alveolar-arterial oxygen tension difference (PAO2-PaO2). In both groups of animals, PaO2 decreased rapidly during the first 3 minutes of apnea, then more slowly. Although the mean value was above 100 mmHg at 10 minutes, there was considerable inter-animal variability. Before apnea, PAO2-PaO2 was slightly, but not significantly, larger in horses than in ponies and incr...
A modified parainguinal approach for cryptorchidectomy in horses. An evaluation in 107 horses. A modified parainguinal approach was used to castrate 119 abdominal cryptorchid horses. The operative time ranged from 10 to 30 minutes. Follow-up information was obtained for 107 horses. Swelling, more severe than that expected in routine castrations, was reported in six horses. An incisional abscess had to be drained in one horse and one horse died of unexplained causes 3 days after the surgery.
The postnatal development of serum zinc, copper and ceruloplasmin in the horse. 1. Serum samples were collected from ten foals at predetermined times during the first 12 months following birth and zinc and copper concentrations and ceruloplasmin activity were evaluated. 2. Serum zinc concentrations were found to be quite variable with respect to age (range = 67-95 micrograms/dl). 3. Serum copper concentrations increased in a linear fashion from day 0 to day 28 before levelling off at 190-247 micrograms/dl. 4. Ceruloplasmin activity was found to correlate with the concentration of serum copper (r = 0.92) and reached a plateau at an activity of 30-38 IU by day 28.
Alternative solutions to hCG induction of ovulation in the mare. Injection of hCG (2000-2500 i.u., i.v.) to mares when a follicle reaches 35 mm induces ovulation between 24 and 48 h. However, repeated injections induce antibodies against hCG. We report attempts to induce ovulation without this inconvenience. We called 'response' an ovulation between 24 and 48 h after treatment. The typical response to hCG was obtained in 73% (N = 145) of treated mares. After immunization against hCG, the response (0%, N = 10) was less than in nonimmunized controls (100%, N = 9). Simultaneous injection of dexamethasone and hCG resulted in induction of ovulation (71%, N = 14)...
Carnitine concentrations in the milk of different species and infant formulas. Carnitine concentrations were measured in the milk of sheep, cows, goats, and horses, in human milk of term and preterm infants and in European infant formulas. There were significant species' differences in carnitine milk content. Acylcarnitine concentrations ranged from 13 to 47% of total carnitine. This may be related to differences in maternal and/or mammary gland metabolism. The concentration of long-chain acylcarnitine in milk was under 1% in all investigated species. In cow's milk, there was a decrease in acylcarnitine concentration during the first 2 months of lactation. In human milk,...
Ventilation imaging in the horse with 99mtechnetium-DTPA radioaerosol. This study describes the development of a radioaerosol technique for horses using 99mtechnetium-DTPA (diethylenetriaminepentacetate). In 24 normal, adult horses, very satisfactory ventilation images were obtained with the technique. Four-minute administrations of the aerosol resulted in a mean uptake of radioactivity in the lung fields of 3.02 mCi, with mean maximum counts (+/- sd) of 159,800 +/- 75,000 per camera field. The mean clearance half-time for the 99mtechnetium-DTPA from the lung fields was 55.6 +/- 14.2 mins which is very similar to figures obtained for normal human and dog lungs. T...
Plasma concentrations of progestagens, oestrone sulphate and prolactin in pregnant mares subjected to natural challenge with equid herpesvirus-1. Multiparous pregnant mares, on two studfarms, were studied following natural challenge with equid herpesvirus-1 (EHV-1). They were divided into three groups according to serum complement fixation titres: Group A (N = 11) were not challenged and delivered normal foals; Group B (N = 13) were challenged but delivered normal foals; Group C (N = 23) were challenged and delivered infected foals which were stillborn or lived for less than 31 h. In Groups A and B mean (+/- s.d.) gestational age at delivery was 343 (+/- 8) and 339 (+/- 8) days respectively, whereas in Group C it was significantly (P le...
Ultrasonography of accessory sex glands in the stallion. The accessory sex glands of 10 stallions were examined by transrectal ultrasonography. Seminal vesicles were 26.4 +/- 5.2 (s.d.) mm in width and 9.2 +/- 3.1 mm in height. Ampullae were 16.3 +/- 3.6 mm in width and 12.9 +/- 3.9 mm in height. Bulbourethral glands were 19.7 +/- 4.6 mm in width and 32.4 +/- 6.7 mm in length. Prostate lobes exceeded 34 mm in width and were 23.5 +/- 5.7 mm in height. The prostatic isthmus was 6.0 +/- 1.4 mm in height. The seminal colliculus, masculine uterus, and deferent ducts were also identified and characterized. Five of these stallions were killed to compare tr...
Distribution of spermatozoa in the mare’s oviduct. The morphology of the uterotubal junction (UTJ) and caudal isthmus during the peri-ovulatory period, and the distribution of spermatozoa within the region, were studied in 10 Pony mares. The proximal tip of the uterine horn and caudal 1-2 cm of the isthmus were removed during oestrus or shortly after ovulation from animals mated or artificially inseminated within the previous 24 h. The tissues were incised longitudinally and fixed for scanning electron microscopy. Analysis of micrographs showed deep longitudinal and oedematous folds in the preovulatory samples. After ovulation, much of the fol...
Plasma endotoxin levels in horses subjected to carbohydrate induced laminitis. Thirteen (65 per cent) of 20 horses subjected to carbohydrate overload developed Obel Grade 3 lameness within 56 h. Increases in plasma endotoxin from control levels of less than 0.1 ng/litre to values ranging from 2.4 to 81.53 ng/litre were measured in 11 (85 per cent) of 13 horses during the onset of Obel Grade 3 lameness. Obel Grade 3 lameness was associated with rises in plasma Gram-negative endotoxin levels in 11 (92 per cent) of 12 horses. Two peak increases separated by 16 h were verified in five (45 per cent) of 11 horses that exhibited both endotoxaemia and Obel Grade 3 lameness. The ...
[The morphology and innervation of the levator muscles of the ribs in the dog, cat, horse, and pig]. In the anatomical literature there are inconsistencies in the description of the levatores costarum muscles in man and in the domestic animals, and their innervation either by the dorsal or the ventral branches of the thoracic nerves. Therefore we studied the form, structure and, with the aid of the dissecting microscope, the innervation of these muscles in 7 dogs, 8 cats, 5 horses and 12 pigs. In the dog, cat and horse, mm. levatores costarum are present from the second to the last rib. In the pig, these muscles are present from the second to the 15th rib, even in individuals with 16 pairs of...
Induction of ovulation in anoestrous mares with a slow-release implant of a GnRH analogue (ICI 118 630). A total of 18 experimental pony and 136 commercial maiden, barren and foaling Thoroughbred mares in seasonal or lactation-related anoestrus were injected subcutaneously with 1 or 2 slow-release D,L-lactide-glycolide co-polymer implants impregnated with 0.9 or 1.8 mg of the potent GnRH analogue, ICI 118 630, to give a daily release of, respectively, 30 or 60 micrograms analogue for 28 days; 32 of the Thoroughbred mares were also given a daily oral dose of 27.5 mg allyl trenbolone for 5 days after injection of the implant. Thirteen pony (76%) and 120 Thoroughbred (88%) mares ovulated 3-18 days a...
[Effect of ascorbic acid on the intestinal motor activity in domestic animals]. In this paper, the effect of ascorbic acid on motoric activity of the intestines of rabbits, pigs, cows, sheep and horses has been determined, and a possible participation of the adrenogenic system in this mechanism has been shown. In experiments in vitro the motility of the duodeum, jejunum, caecum and colon in the animals mentioned abowe was recorded by the method of Magnus after administration of ascorbic acid. Diastolic reactions were observed in all animals, which were much greater in small intestines than in large ones. To elucidate the diastolic mechanism under the influence of ascorbic...
Oxytocin stimulation of plasma 15-keto-13,14-dihydro prostaglandin F-2 alpha during the oestrous cycle and early pregnancy in the mare. In Exp. 1, 4 mares were given oxytocin intravenously (10 i.u./500 kg body wt) daily between Days 9 and 14 (Day 0 = day of ovulation) when pregnant and on Days 9-14, 16, 18, 20 when non-pregnant (not inseminated). In the non-pregnant mares the increase in plasma PGFM response to oxytocin was greater at Day 13 (235 +/- 54 pg/ml) than at Day 11 (113 +/- 38 pg/ml; P less than 0.05) and was maximum at Day 16. However, these animals did not return to oestrus and plasma progesterone did not fall below 4 ng/ml. There was no significant increase in response to oxytocin between Days 9 and 14 in the preg...
Extensive large colon resection in the pony. I. Surgical procedures and clinical results. The effect of resection of 75% (length measurement) of the large colon in ponies was studied. Ten ponies in good physical condition were divided into two groups: group I consisted of the six experimental ponies and group II of four control ponies. Preoperatively and postoperatively for five months, ten clinicopathological parameters were determined: body weight, venous blood pH, plasma bicarbonate, total plasma protein concentration, serum electrolyte values (sodium, potassium, chloride), and fecal osmolarity. Subjective assessment of attitude and appetite revealed no difference between the gr...
Ultrastructure of cryopreserved horse embryos. Embryos were recovered non-surgically at about Day 6 after ovulation from 15 Quarter horse-type mares and were evaluated for morphological changes which may occur because of exposure to the cryoprotectant and/or cryopreservation. Electron microscopy was used to elucidate the fine structure of intracellular organelles which, if damaged, could cause cellular death. The horse embryo does not totally re-expand in the 10% glycerol freezing medium, nor will it completely re-expand in the isotonic holding medium following glycerol removal whether or not the embryo has been frozen. Embryos in this stu...
Patterns of oxytocin secretion during the oestrous cycle of the mare. From a group of 11 cyclic mares, blood samples were collected at 3-min intervals for 2 h and at 15-min intervals for an additional 6 h during four stages of the oestrous cycle. Mean plasma oxytocin concentrations (pg/ml, LSM +/- se) were greater on Day 15 after ovulation (169.9 +/- 17.6) than on Day 0 (82.6 +/- 17.6; P less than 0.01), Day 3 (97.2 +/- 20.4, P less than 0.01) and Day 7 after ovulation (104.0 +/- 25.0, P less than 0.05). Oxytocin was secreted in a pulsatile manner throughout the oestrous cycle, with short (0-29 min), medium (30-89 min) and long (greater than 90 min) duration rhy...
Idiopathic effusive pericarditis with tamponade in the horse. Pericarditis and pericardial effusion are considered to occur rarely in the horse. The clinical and laboratory features of idiopathic pericarditis with effusion diagnosed in 10 horses over a seven-year period were reviewed. Consistent physical findings included tachycardia, ventral oedema, jugular venous distention and diminished heart sounds. Electrocardiographic features included diminished voltages and electrical alternans, and the effusion was identified by echocardiography in the six horses in which it was performed. Pericardiocentesis relieved clinical signs in nine horses. Laboratory an...
Equine degenerative myeloencephalopathy: a vitamin E deficiency that may be familial. Two horse farms, on which there was a high incidence of proven and suspected equine degenerative myeloencephalopathy (EDM), were studied. Symmetric ataxia and paresis, along with laryngeal adductor, cervicofacial, local cervical, and cutaneous trunci hyporeflexia, characterized the syndrome. Serum vitamin E concentration reflected a deficient state in affected and unaffected horses on both farms when compared with selected reference groups and with published values. A high incidence of the disease was evident in offspring of two particular sires on one farm. Vitamin E supplementation resulted ...
Electromyographic properties of the myometrium correlated with the endocrinology of the pre-partum and post-partum periods and parturition in pony mares. A complete set of electromyographic recordings, plasma samples and behavioural observations were collected from 2 mares beginning 7 days pre partum, through parturition and into the early post-partum period. During the week pre partum, EMG activity was elevated, occurring 26-73% of the time. Activity was least during the day and greatest at night with no significant difference for the hours of the day or between days pre partum. During the 24 h before delivery, EMG activity was increased for 7-13 h (55-80%) during the daylight hours. EMG activity decreased 2-4 h immediately preceding delivery ...
Electrophysiological studies on atrial fibrillation. We tested the multiple-wavelet hypothesis by studying the initiation and maintenance of atrial fibrillation in normal mules, horses, cows, calves, and goats. Persistence of atrial fibrillation in animals with a large atrial mass was compared with results in adult goats and calves having a smaller atrial mass. Atrial stimulation in clinically normal cows, mules, calves, and goats was accomplished using an intra-atrial stimulating catheter with rapid atrial pacing (30/s). Once initiated, atrial fibrillation persisted for 95,120,125 min, 3 days, and 8 weeks in five adult cows, respectively. In co...
Use of push-pull perfusion techniques in studies of gonadotrophin-releasing hormone secretion in mares. Push-pull perfusion was used to study GnRH secretory ability of the hypothalamus in anoestrous, transitional, dioestrous and oestrous Pony mares. The technique involved placement of a concentric (tube within a tube) cannula into the area of the medial basal hypothalamus and perfusing a carrier medium (artificial cerebrospinal fluid) through the inner tube whilst aspirating from the outer tube so that the flow rate within the hypothalamic tissue was essentially constant. The perfusion rate was 0.5 ml/10 min and samples were collected at 10-min intervals for 10-15 h. The carrier medium, which co...
Influence of follicular status on twinning rate in mares. Between 1982 and 1985, 1015 mares were evaluated using the following parameters: age, mare status (maiden, barren, lactating), Caslick index, Caslick operation, ovarian cycle, ovarian and follicular size, treatments (hCG and intrauterine infusions), number of ovulations after mating (184 mares), number of conceptuses present, dimensions of embryonic vesicles, and pregnancy status 45 days after mating. Mares were examined ultrasonographically between Days 12 and 25 to detect the presence of embryonic vesicles and measure the dimensions of each vesicle. The data were analysed by a stepwise logis...
In-vitro biosynthesis of C18 neutral steroids in horse testes. Deuterium, 14C- and 3H-labelled steroid substrates were incubated with minced testicular tissue from stallions of different ages. After extraction and separation of the neutral and phenolic fractions the metabolites were identified by gas chromatography-mass spectrometry. The presence of the expected C19 neutral and C18 phenolic steroids was confirmed. An isomer of 5(10)-oestrene-3,17-diol was also identified.
Analysis of the equine lymphocyte antigen system by Southern blot hybridization. Fourteen Standardbred horses homozygous for one of six equine lymphocyte antigen (ELA) specificities (A1, A3, A4, A5, A6, or A10) were analyzed by Southern blot hybridization using DNA probes derived from the mouse major histocompatibility complex (MHC). Total genomic DNA from peripheral lymphocytes was digested with the restriction enzymes Hind III, Pvu II, or Eco RI. Twenty-three to thirty-three bands were generated for individual horses with the class I cDNA probe. The resulting band patterns revealed 12-14 nonpolymorphic fragments, which is consistent with the highly conserved Qa/Tla genes...
Factors affecting uterine clearance of inoculated materials in mares. Twelve acyclic mares of various ages (2-29 years) and parity (maiden-multiparous) were given oestradiol-17 beta i.m. (winter 1982) or progesterone i.m. (winter 1983) to induce changes in the endometrium consistent with oestrus and dioestrus, respectively. After hormone treatment, mares were inoculated intrauterine with 50 ml saline containing 5 X 10(5) Streptococcus zooepidemicus bacteria, 51Cr-labelled 15-micron microspheres, and 500 mg charcoal (Groups E + B and P + B) or microspheres and charcoal only (Groups EC and PC). At 5 h after inoculation uteri were flushed with 50 ml saline containi...
