Omneity® Pellets
All-In-One Vitamin & Mineral Pellet
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.
Changes in luteinizing hormone bioactivity associated with gonadotrophin pulses in the cycling mare. Equine plasma luteinizing hormone (LH) possesses both biological (in vitro bioassay, B) and immunological (radioimmunoassay, I) activities and the ratio of B:I varies with stage of the oestrous cycle. To estimate the contribution made by pituitary secretion and peripheral metabolism to changes in the B:I ratio, pituitary venous effluent and circulating plasma from 5 dioestrous and 2 oestrous mares were analyzed using both an in vitro bioassay and a radioimmunoassay. During dioestrus, LH was released in a pulsatile fashion with a frequency of 1.4 pulses/24 h and a pulse duration of 20-40 min (c...
[The estimation of platelet factor 3 activity in horses, cattle, sheep and pigs by the use of synthetic chromogenic tripeptide substrates]. The aim of this study was to investigate the platelet factor 3 activity in platelet-rich plasma of horse, cattle, sheep and pig, by the use of chromogenic tripeptide substrate H-D-Phenylalanyl-Pipecolyl-Arginyl-p-nitroanilide. Among species examined the highest activity of this factor was stated in pig, the lowest one in sheep. Chromogenic substrate test was 10 times more sensitive that Stypven clotting time test. Thus, the use of chromogenic tripeptide substrate is fully valuable in platelet factor 3 activity estimation in domestic animals.
Influence of pregnancy on diurnal and seasonal changes in glucose level and activity of FDPA, AlAT and AspAT in mares. 1. The diurnal changes in the glucose level and in activity of FDPA, A1AT and AspAT in four pregnant standard-bred mares were studied. 2. As a control four barren mares, were kept and examined in the same conditions. 3. Blood samples were taken every 4 hr for one day, each month, throughout pregnancy, or one year. 4. A diurnal rhythm in activity of A1AT and AspAT in barren mares was found. The pregnancy masked diurnal rhythm in activities of both transaminases. 5. No diurnal rhythm in glucose level and FDPA activity in both groups of mares was observed. 6. Seasonal cyclicity was found in all i...
Galactosyltransferase activity is restricted to the plasma membranes of equine and bovine sperm. beta 1, 4-Galactosyltransferase (GalTase) is localized to the plasma membrane of mouse sperm, in which it mediates the binding of sperm to glycoconjugate residues in the egg zona pellucida. In this study, the presence of subcellular distribution of sperm GalTase were determined in two other mammalian species that yield sufficient sperm for subcellular fractionation. Equine and bovine semen were collected, and the plasma membranes (PM), outer acrosomal membranes (OAM), and inner acrosomal membranes (IAM) were sequentially removed. The purities of the isolated membrane preparations were determin...
Characterization of hydrophobic cores in apomyoglobin: a proton NMR spectroscopy study. A proton nuclear magnetic resonance spectroscopic study of horse apomyoglobin was undertaken in order to define the regions of myoglobin that are and that are not structurally affected by the binding of the prosthetic group. It was found that, in spite of the poor spectral resolution, a number of spin systems could be identified by using standard correlated methods. Four clusters consisting mostly of hydrophobic residues were detected by nuclear Overhauser spectroscopy, two of which involved the tryptophan side chains. Extensive similarities to nuclear Overhauser spectroscopy data collected on...
Haem binding to horse spleen ferritin. Horse spleen ferritin, a spherical protein shell of 24 subunits, contains no haem when extracted. This contrasts with ferritins isolated from bacterial sources which have the capacity to bind up to 24 haem groups [(1990) FEBS Lett. 271, 141-143] via two methionine residues [(1990) Nature 341, 771]. Here it is shown that horse spleen ferritin can bind between 15 and 17 haems per 24 subunits with an apparent association constant of 2.2-3.2 x 10(4) M-1. The strength of haem binding appears to be unaffected either by the presence of the core or by the oxidation state of the haem. The demonstration...
[Reference values for cortisol, T4 and T-uptake in different horse groups using the fluorescence polarization immunoassay (FPIA)]. Reference values for Cortisol, T4 and T-Uptake, determined with the Fluorescence-Polarization-Immunoassays (FPIAs) in blood-plasma of different horse groups were established. The highest Cortisol values were measured in blood samples from thoroughbred racehorses and riding horses taken between 7 and 8 a.m. (181 +/- 37 and 268 +/- 43 nmol/l), the lowest gained between 5 and 6 p.m. (69 +/- 45 and 85 +/- 32 nmol/l respectively). Peak values for T4 in riding horses were found in blood samples collected between 1 and 2 p.m. (28.2 +/- 5.7 nmol/l) followed by the samples taken at 5-6 p.m. and 7-8 a.m...
Comparative anatomy of the tracheobronchial circulation. This review considers the similarities and difference between several animal species to determine which are most appropriate for studies of the human bronchial circulation in health and disease. The subgross anatomy of the sheep, cow, pig and horse appear to be similar to that of humans. These species have a major bronchial artery with a consistent location. In humans and other species, there is evidence of anastomoses between the bronchial and coronary circulations. The bronchial circulation provides nutrient supply to the neural structures of all species. The bronchial arteries themselves ar...
Maximum velocity of shortening of three fibre types from horse soleus muscle: implications for scaling with body size. 1. To explore how maximum velocity of shortening (Vmax) of fibres varies within one muscle and how Vmax varies with body size, we measured Vmax of muscle fibres from soleus muscle of a large animal, the horse. 2. Vmax was determined by the slack test on skinned single muscle fibres at 15 degrees C during maximal activation (pCa = 5.2). The fibre type was subsequently determined by a combination of single-cell histochemistry and gel electrophoresis of the myosin light chains. 3. Vmax values for the type I, IIA and IIB muscle fibres were 0.33 +/- 0.04 muscle lengths/s (ML/s) (+/- S.E.M., n = 6),...
[The diagnosis of adrenal cortical function in animals using hormone analysis]. This paper describes the use of hormone analysis in the diagnosis of adrenal cortex dysfunction in the dog, cat and horse. Analytical problems concerning the determination of corticosteroid levels are discussed and the pathology of adrenal dysfunction is briefly presented. The paper focuses on the problems in establishing physiological norms for adrenal function based on the established assays. Own experiences and other reported data are referred to.
Pharmacokinetics of gentamicin in newborn to 30-day-old foals. Gentamicin sulfate, equivalent to 4 mg of gentamicin base/kg of body weight, was administered IV to 6 Thoroughbred foals on day 1 (12 to 24 hours of age) and at 5, 10, 15, and 30 days after birth. On day 40 after parturition, gentamicin was given to the mares at a dosage similar to that used in foals. Decay of serum gentamicin concentrations was best described by a 2-compartment model. Among foals, the overall elimination rate constant at 30 days of age was significantly (P less than 0.05) greater than at days 1, 10, and 15. There was, however, no difference in the overall elimination rate con...
Bioavailability of ascorbic acid in horses. The bioavailability of ascorbic acid administered to thoroughbreds by intramuscular injection was investigated. For intramuscular injection two preparations were studied, and the percentage bioavailability up to 24 h of 10 g of ascorbic acid was 95% +/- 22 in four horses and 60% in two horses with preparations A and B, respectively. Bioavailability at 24 h in three horses injected subcutaneously with 10 g of preparation B was 82%. Intramuscular injection of both preparations was apparently well tolerated while subcutaneous injection of preparation B (pH 6.0) was associated with marked irritanc...
Cleavage line patterns of the skin in the horse. In 6 equine specimens of both sexes, the morphological features of the cleavage lines of the skin over the entire body were examined using a metal probe with a sharp conical point. Wounds were produced on the skin with the probe and painted with Chinese white or Indian ink. The direction of running of the cleavage lines was determined from their relationship to the long axis of each region or area of the physical structure. The cleavage lines of the head and face revealed a fixed pattern in all specimens. They were similar to those of equine fetuses of 6 to 7 months of age. A transverse patter...
Immunohistochemical detection of papillomavirus structural antigens in animal hyperplastic and neoplastic epithelial lesions. One hundred and seventy-two hyperplastic and neoplastic epithelial lesions from 8 different mammalian and 1 avian species have been tested with an immunohistochemical technique to detect papillomavirus structural antigens. Selected lesions were diagnosed histologically as papilloma, fibropapilloma, equine sarcoid, squamous cell carcinoma, basalioma, epulis, keratoacanthoma, trichoepithelioma, pilomatrixoma, epidermal inclusion cyst, and hyperkeratotic or acanthotic epidermal lesions. Positive nuclear staining was detected in 14 out of 23 papillomas, 8 out of 32 fibropapillomas and in 1 out of ...
Anatomical validation of two-dimensional echocardiography in the horse. This study was performed on 15 horses to validate the cardiac anatomy as imaged with two dimensional echocardiography (2DE) and to determine the accuracy of intracardiac measurements. 2DE images were recorded in five horses in life with a Diasonics DRF100 ultrasound system and a 3.5 MHz transducer in different tomographic planes. After slaughter, the hearts were fixed in 10 per cent formalin. To compare in vivo and in vitro results, the specimens were suspended in a water-filled tank and 2DE images were made using the same transducer positions as in life. In vitro 2DE and autopsy measurements ...
The distribution of ventilation-perfusion ratios in the lungs of a dysmature foal. The distribution of ventilation-perfusion (VA/Q) ratios, before and after 100 per cent oxygen, was studied in an induced-premature foal at 4 h and again at eleven days of age, using the multiple inert gas elimination technique. The major finding was an absence of low VA/Q ratios when breathing air, indicating that low PaO2 in the neonatal period was totally attributable to the right-to-left shunt. At 4 h of age the PaO2 was 5.48 kPa and the right-to-left shunt represented 33.4 per cent of the cardiac output. At eleven days of age the PaO2 was 9.76 kPa and right-to-left shunt was 10.1 per cent ...
A comparison of xylazine-diazepam-ketamine and xylazine-guaifenesin-ketamine in equine anesthesia. After sedation with xylazine (0.3 mg/kg intravenously [IV]), anesthesia was induced in six healthy horses with ketamine (2.0 mg/kg IV) and guaifenesin (100 mg/kg IV), diazepam (0.05 mg/kg IV), or diazepam (0.10 mg/kg IV). Anesthesia was maintained with halothane for 30 minutes. Heart rate, respiratory rate, direct arterial blood pressure, arterial blood gas, and pH measurements were made before, and at set intervals after, induction of anesthesia. Quality and characteristics of induction and recovery were evaluated objectively by an independent observer unaware of the protocol used. There were...
A comparison of inulin, para-aminohippuric acid, and endogenous creatinine clearances as measures of renal function in neonatal foals. The glomerular filtration rate (GFR) was estimated in eight full-term neonatal foals by the single injection inulin plasma clearance method at two days of age, the continuous infusion plasma and urinary clearance methods at three days of age, and the 12-hour endogenous creatinine clearance method at four days of age. The effective renal plasma flow (ERPF) was estimated simultaneously by the single injection para-aminohippuric acid (PAH) plasma clearance method in the eight two-day old foals and the continuous PAH infusion plasma and urinary clearance method in the eight three-day old foals. Th...
Efficacy of avermectin B1 given orally against equine intestinal strongyles and Onchocera microfilaria. Three groups of horses and ponies (N = 13, 13 and 12) were treated with ivermectin paste (0.2 mg/kg p.o.), avermectin B1 solution (0.2 mg/kg p.o.), or fenbendazole suspension (10 mg/kg via nasogastric tube). The avermectin B1 was a 1% solution in a propylene glycolglycerol formal base. Faecal strongyle egg counts were performed before, and 14, 28, 42, 56 and 70 d, after treatment. Full-thickness skin biopsies from the neck, pectoral and umbilical regions were examined for Onchocera microfilaria before treatment, and again 14 and 70 d later. Ivermectin therapy produced a significant (P less tha...
Left ventricular volume determination in the horse by two-dimensional echocardiography: an in vitro study. This study was designed to evaluate the accuracy of two-dimensional echocardiography (2DE) in determining the left ventricular volume (LVV) of the horse in vitro. After examining the shape of the left ventricular silicon rubber casts of four equine hearts, two modified Simpson's rule methods (Model A and Model B) as combinations of conical shapes and one biplane area-length method as a single cone (Model C) were chosen for volume calculations. One long axis and three short axis planes were used for linear and area 2DE measurements, respectively. The ventricular length (L) was calculated from t...
Interspecies and interregional analysis of the comparative histologic thickness and laser Doppler blood flow measurements at five cutaneous sites in nine species. Studies in dermatology, cutaneous pharmacology, and toxicology utilize skin from different animal species and body sites. However, regional differences exist in topical chemical percutaneous absorption studies in man and in animal. The objective of this study was to compare epidermal thickness and number of cell layers across species and body sites using both formalin-fixed paraffin and frozen sections. Cutaneous blood flow determined by laser Doppler velocimetry (LDV) was compared to histologic data. Six animals of each of the following species were used: monkeys, pigs, dogs, cats, cows, hors...
Idiopathic granulomatous disease involving the skin in a horse. Clinical signs of generalized granulomatous disease in a horse included depression, generalized lymphadenopathy, scaly skin, and dependent edema. Diagnosis was confirmed histopathologically by diffuse granulomas in more than one organ system (lymph nodes and skin), and by ruling out etiologic agents. Response to treatment with corticosteroids was favorable. The clinical features and response to treatment in this horse were different from classic textbook descriptions of equine generalized granulomatous disease. Equine granulomatous disease appears to be comparable to human sarcoidosis. To avoi...
Intra-osseous pressure and pressure pulse gradients along the equine third metatarsal bone. Intra-osseous pressure measurements in the third metatarsal bone of anesthetised young and mature ponies demonstrated that a pressure gradient exists along the bone, the pressure being highest at the level of the nutrient foramen and decreasing distally and proximally from this point. The height of the intra-osseous pressure pulse also decreased toward the bone ends. It is concluded that the sites of measurement of the intra-osseous pressure in clinical and experimental studies should be standardized.
Measurement of endotoxic activity in feces of normal horses. Two chromogenic Limulus amebocyte lysate systems were evaluated for the measurement of endotoxic activity in feces of normal horses. Fecal extracts had neither non-specific nor inhibitory effect on the test reaction, and the two systems with different specificity showed equivalent results. Endotoxic activities in feces of healthy horses averaged 5.7 +/- 2.8 microns/g wet weight. Correlation between the endotoxin levels and the fecal microbial flora could not be determined.
Mast cells in normal and pathological specimens of the equine lung. In lungs from 22 horses, the number and type of mast cells in histologically normal specimens were compared with those in specimens with various histological lesions. Tissues fixed in Carnoy's solution were superior to those fixed in formalin for the identification of mast cells. Fixation of lung specimens from eight horses in Carnoy's solution and formalin allowed the identification of two subpopulations of mast cells: formalin-sensitive, which predominated and formalin-resistant. Specimens with mild chronic tracheitis and mild and moderate chronic bronchitis generally had slight increases in...
Effect of inositol hexakisphosphate on the spectroscopic properties of the nitric oxide derivative of ferrous horse and bovine hemoglobin. The effect of inositol hexakisphosphate (IHP) on the spectroscopic (EPR and absorbance) properties of the nitric oxide derivative of ferrous horse and bovine hemoglobin (Hb) has been investigated. In the absence of IHP, the nitric oxide derivative of ferrous horse Hb shows spectroscopic properties similar to those of the corresponding derivative of ferrous human Hb that are generally taken as typical of the high affinity state of tetrametric hemoproteins. Similar to human Hb, the addition of IHP to the nitric oxide derivative of ferrous horse Hb induces a transition toward a species characteri...
[The treatment basis for anticoagulants in horses]. The pharmacokinetics of racemic phenprocoumon were studied in 8 adult horses after the single intravenous and oral administration of 0.75 mg/kg. After i.v. administration the plasma concentration of phenprocoumon showed a biphasic decline in time. The pharmacokinetics were calculated on the two-compartment open model. The average plasma half-life (beta-phase) was 22 hours, the apparent volume of distribution was 0.61 l/kg, Cltot was 25.2 ml/kg/h (13.9-40.9 ml/kg/h). The systemic bioavailability of oral phenprocoumon was 97.6%, Tmax was found to be 4-12 hours. The effect of phenprocoumon on the...
Different combinations of regulatory elements may account for expression of the glycoprotein hormone alpha-subunit gene in primate and horse placenta. Expression of the glycoprotein hormone alpha-subunit gene occurs in the pituitaries of all mammals and in the placentas of primates and horses. In humans, tandem cAMP response elements (CREs), located in the proximal promoter-regulatory region of the alpha-subunit gene, act together with an adjacent upstream regulatory element to confer placenta-specific expression. Here, we report that the alpha-subunit genes of Old World Monkeys contain a single functional CRE. This suggests that tandem CREs are unique to higher primates and humans and are not absolutely required for placenta-specific expres...
