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Topic:Comparative Study
Comparative studies in equine research involve the systematic analysis of different horse breeds, management practices, or physiological responses to identify variations and similarities. These studies are instrumental in understanding how different factors influence health, performance, and behavior in horses. Common areas of comparison include genetic traits, nutritional requirements, disease resistance, and response to training. By evaluating these differences, researchers can develop targeted strategies for breeding, healthcare, and training. This page aggregates peer-reviewed research studies and scholarly articles that focus on the methodologies, findings, and implications of comparative studies in the context of equine science.
Carbohydrate composition of horse spleen ferritin. The carbohydrate composition of horse spleen ferritin was studied. 1 mol of the apoferritin, the protein moiety of ferritin, contains 25 mol of hexose, 3 mol of hexosamine and 10 mol of fucose. Same carbohydrate composition was detected in the apoferritin from iron rich ferritins. These results indicate that horse spleen ferritin is composed of non-identical subunits as regards its carbohydrate composition.
Hereditary multiple exostosis. A comparative genetic evaluation in man and horses. Comparative studies are being conducted on hereditary multiple exostosis in man and the horse. In both, there is an unquestionable inheritance pattern of a typical single, dominant, autosomal gene. Those who carry the gene have a one-half chance of transmitting it to each offspring, whereas, those who do not carry the gene do not transmit this abnormality to their progeny. The lesions are clinically and histologically similar; no persistent chromosomal irregularities have been associated with the abnormality in either man or the horse and no single evidence of malignancy in either man or anima...
[Estimation of the concentration of urea in the blood of horses, cattle, goats and dogs using the “Merckognost Harnstoff” method compared with an enzymatic, photometric method (author’s transl)]. To examine the suitability and reliability in field use of the "Merckognost Harnstoff" method in estimating the concentration of urea in the blood of horses, cattle, goats and dogs, the levels determined by this procedure were compared with those determined by an enzymatic (urease) photometric method widely used in laboratories. It was concluded from the results obtained that estimation using the "Merckognost Harnstoff" is sufficiently reliable for the rapid assay of urea in the blood under field conditions.
Oxygen affinity responses to 2,3-diphosphoglycerate, and methaemoglobin formation in horse and human haemoglobins. The oxygen affinities of horse and human haemoglobins were compared in the absence and presence of the allosteric effector 2,3-diphosphoglycerate (2,3-DPG). Horse haemoglobin solutions showed significantly smaller responses to the presence of 2,3-DPG, and this difference may be due to different amino acid substitutions at position NA2(2)beta. Horse haemoglobin solutions from erythrocytes containing different ratios of the two different haemoglobin types showed similar oxygen affinities in the absence and presence of 2,3-DPG. Horse haemoglobins in solution were found to autoxidise to methaemogl...
Cardiopulmonary measurements in nonanesthetized, resting normal ponies. Cardiopulmonary measurements were determined in 19 nonanesthetized, normal ponies. Mean values for arterial pressure, pulmonary arterial pressure, cardiac output, heart rate, packed cell volume, and hemoglobin are reported, as well as acid-base determinations of arterial blood and cerebrospinal fluid. Respiratory function test data include total ventilation, respiratory rate, alveolar ventilation, oxygen uptake, and carbon dioxide output. The data compare favorably with the available data from previous reports on ponies. Because of large day-to-day variations in total ventilation, alveolar ven...
Efficacy studies with three formulations of cambendazole in horses. Treatment with 3 formulations of cambendazole (paste, pellets, and suspension) was compared with thiabendazole treatment in 181 Quarter Horses (females and intact and altered males) of different ages in 2 experiments. The mean output of strongyle eggs, as measured by eggs per gram of feces (epg), was reduced by at least 95% by the 3 formulations of cambendazole compared with pretreatment epg and epg in simultaneously nonmedicated horses. Eggs of Parascaris equorum were seen in 19 of the younger horses in experiment I. Parascaris eggs were not seen in postmedication fecal samples from 14 horses...
[Plasma progesterone in mares showing oestrus during early pregnancy (author’s transl)]. Sixtyfour mares were examined 3 and 6 weeks after mating. Progesterone was measured in 22 mares 3 weeks after mating in order to see if this could be of any help in the oestrous diagnosis. None of the pregnant mares had plasma progesterone below 2 ng/ml. Pregnant mares that did not show oestrus had higher levels of plasma progesterone than pregnant mares showing signs of oestrus 3 weeks after mating. Clinical findings in pregnant and nonpregnant mares 3 weeks after mating is compared, and oestrus in pregnant mares is discussed.
Comparative electrophysiology and pharmacology of mammalian (including one marsupial) intercostal muscle biopsy preparations. Characteristics of minature end-plate potentials (MEPP) of isolated external intercostal muscle preparations of 7 mammalian species (dog, cat, pig, horse, cow, and goat) including 1 marsupial (opossum, Didelphis marsupialis) were determined with intracellular microelectrodes. Mean amplitude (+/- standard error of MEPP for all species was 0.60 +/- 0.06 mV, and the range was 0.28 mV (opossum) to 1.07 mV (pig). Amplitude was inversely correlated (P less than 0.01) with muscle fiber diameter which ranged from 93 mum (opossum) to 51 mum (pig). Mean values for rise time, half-decay time, and frequen...
The equine practice laboratory. The authors discuss the value of a practice laboratory to the equine clinician and its priorities. Laboratory examinations of particular value are described in relation to their clinical application. The need to establish normal values according to laboratory and horse population is stressed. Tables of normal parameters related to age groups of horses in the authors' practice are presented.
Isolation and partial characterization of the major glycoproteins of horse and swine erythrocyte membranes. The major glycoproteins of horse and swine erythrocyte membranes were isolated and examined chemically and immunologically. The major glycoprotein of horse erythrocyte membranes had a molecular weight of 33 000 and consisted of 46.2% protein and 53.8% carbohydrate, of which 9.4% was hexose, 10.1% hexosamine and 33.7% sialic acid. This glycoprotein was associated with activity for the infectious mononucleosis heterophile antigen. There were two different major glycoproteins in swine erythrocyte membranes. One major glycoprotein had a molecular weight of 46 200 and consisted of 34.2% protein and...
Effect of season on some characteristics of stallion semen. Season had a pronounced effect upon seminal pH and refractometer 'protein', total carbohydrate, dry weight, total N2 and lactic acid in seminal plasma of first and second ejaculates. In addition, total seminal volume, spermatozoa per ml and per ejaculate, non-protein sulphhydryl and glycerylphosphorylcholine of second ejaculates were also influenced. There was a season difference in the concentrations of lactic acid in spermatozoa from first and in total N2 from spermatozoa in second ejaculates. The effects of season on seminal plasma were greater than those on spermatozoa. Spermatozoa in firs...
Transfer of gases and metabolites in the equine placenta: a comparison with other species. Mares and fetuses with indwelling catheters in the umbilical and uterine vessels have been used to monitor transplacental blood gas tensions, pH, O2 affinities and the concentration of various metabolites in fetal and maternal blood during late gestation. Measurements of umbilical and uterine blood flows and arterio-venous differences enabled the uptake of O2 and glucose by the fetus and the uterus to be estimated. The present findings are compared with those from other species in comparable conditions.
Androgens and oestrogens in normal and cryptorchid stallions. Total androgens, testosterone and total oestrogens were measured in twenty-one intact, nine unilaterally cryptorchid, three bilaterally cryptorchid stallions and four geldings. Total oestrogens were significantly higher (P less than 0-005) and total androgens significantly lower (P less than 0-05) in the bilateral cryptorchid compared to other groups. There was a significant (P less than 0-025) day and night variation in total androgen levels. Thyroidectomized and intact animals showed a marked decrease in total androgen as well as testosterone levels during the winter period thus showing an e...
Gonadal dysgenesis in the mare. Five phenotypically normal but infertile mares were studied; four had karyotypes of 63XO, and one was a 25,64XX/13,63XO mosaic. The mares exhibited small uteri and has small ovaries that lacked germ cells and consisted primarily of undifferentiated ovarian stroma. These cases demonstrate that chromosome analysis is an important technique for the diagnosis of some forms of equine infertility.
Some aspects of endometrial cup formation and PMSG production. Two females of heterosexual pairs of chimaeric horse twins were fertilized by their co-twin brother and PMSG production examined during gestation. Four pregnancies developed in one mare and two in the other. The levels of PMSG were high in both mares and remained detectable in the peripheral blood until 220 and 265 days of gestation. The fetal membranes of one mare contained remnants of cup secretion with PMSG activity at term. The findings support the thesis of Allen & Moor (1972) that the endometrial cups are of fetal origin and that they are destroyed by immunological mechanisms.
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.
A survey of eggs in the oviducts of mares. A total of 424 eggs was recovered from flushings of 176 pairs of oviducts. Of these eggs, 324 were in a state of advanced degeneration (Type 4) and ten appeared to have been recently ovulated (Type 1). The number of eggs/oviduct varied from 0 to 13, most being up to 3 eggs, but fifty oviducts contained no eggs. It is widely believed that unfertilized ova are selectively retained in the oviducts but an alternative explanation for their presence is put forward.
Surfactant studies in the fetal and neonatal foal. Phospholipids in embryonic lung tissue, pulmonary washings and amniotic fluid were measured to study the development of lyng surfactant in the horse. A significant increase in the concentration of total phospholipids in lung tissue and a concomitant rise in the amount of dipalmitoyl lecithin in amniotic fluid between 100 and 150 days of gestation indicated the initial formation of surfactant in the fetal lung during this period.
Aspects of respiration in anaesthetized newborn foals. The arterial oxygen tension (PaO2) in clinically normal newborn foals at 1300 m above sea-level is considerably lower (less than 60 mmHg) than in similarly aged foals at lower altitudes. This figure is further reduced to less than 50 mmHg without adverse effect in newborn foals at 1300 m maintained under pentobarbitone anaesthesia for prolonged periods. Measurement of O2 dissociation curves indicates that haemoglobin becomes saturated at a lower blood O2 tension in newborn foals than adult horses.
Ontogeny of equine haemoglobins. Studies were made of the O2 affinities of fetal and maternal haemoglobins in the horse, and correlations were found with erythrocytic levels of 2,3-diphosphoglycerate.
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.
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...
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.
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 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.
