Omneity® Pellets
All-In-One Vitamin & Mineral Pellet
Topic:Age Factors
Age factors in horses encompass a range of physiological and developmental changes that occur as horses mature from foals to adults and eventually into their senior years. These factors include variations in metabolic rate, immune function, and musculoskeletal development, which can influence a horse's health, performance, and nutritional needs. Age-related changes can also affect how horses respond to medications, recover from injuries, and maintain overall vitality. Researchers study these aspects to understand better how age impacts equine health and management. This page compiles peer-reviewed research studies and scholarly articles that explore the effects of age on equine physiology, health management, and disease susceptibility.
Performance analysis after prosthetic laryngoplasty and bilateral ventriculectomy for laryngeal hemiplegia in horses: 70 cases (1986-1991). Medical records of 70 horses diagnosed with left laryngeal hemiplegia that were treated by use of prosthetic laryngoplasty combined with bilateral ventriculectomy were examined. Degree of arytenoid cartilage abduction that had resulted from the prosthesis had been graded before the horse was discharged from the hospital. Follow-up information through owner/trainer questioning was acquired for 55 horses. Information concerning the type and frequency of complications, if any, was recorded, along with a determination of owner/trainer satisfaction regarding surgical results. Race records were acqu...
Right hepatic lobe atrophy in horses: 17 cases (1983-1993). The case records of 17 horses with atrophy of the right hepatic lobe were reviewed. Fifteen horses had signs of colic. Two horses had clinical problems that were unassociated with gastrointestinal tract disease. Ages ranged from 5 to 30 years (mean, 12.6 years) and there was no breed or sex predisposition. In clinically normal horses, the right hepatic lobe constitutes half of the total liver weight. The right hepatic lobe in the 17 horses in this study ranged from 11.0 to 38.3% of the total liver weight (mean, 27.8%). Findings on histologic examination of hepatic tissue from horses in the stu...
Epidemiological observations on sarcoids in a population of donkeys (Equus asinus). An epidemiological study of equine sarcoid in a population of 4126 donkeys showed that the peak incidence of the disease was 15.2 cases per 100 animal-years and occurred in animals in their fourth year of life. The crude incidence of the disease was 0.6 cases per 100 animal-years. The disease occurred most frequently in younger, male animals during their first five years in the population. The lesions were observed most commonly in the paragenital region. Pre-entry quarantine procedures did not appear to play a significant role in the spread of the disease but there was an indication that clos...
Genetics of racing performance in the Japanese Thoroughbred horse:: II. Environmental variation of racing time on turf and dirt tracks and the influence of sex, age, and weight carried on racing time. Data collected by the Japan Racing Association (JRA) were individual horse racing times at eight racecourses (Hakodate, Fukushima, Niigata, Tokyo, Nakayama, Chukyo, Kyoto and Hanshin) and at five distances (1000 m, 1200 m, 1400 m, 1600 m, and 1800 m) from 1982 to 1990. Important sources of variation in racing time were examined using a nested model and expressing the variance components as percentages of the total on both turf and dirt. At all racecourses and at all distances where races were on both turf and dirt, racing times were less on turf than dirt. Differences were from 2.09s to 3.91s ...
Epidemiology of equine motor neuron disease. Equine motor neuron disease (EMND) is a newly recognized neurodegenerative disorder of bulbospinal motor neurons in the horse. We conducted a case-control study to identify intrinsic factors associated with the risk of this disorder. Seventy-four cases and 160 controls were assembled. Controls included horses diagnosed with equine protozoal myelitis, equine degenerative myeloencephalopathy, and cervical stenotic myelopathy during the same time period as the cases. Logistic regression analysis was used to evaluate the association of each hypothesized factor while simultaneously controlling for ...
Age-related storage of iron in the liver of horses. The non-haem iron concentration was estimated in post-mortem liver samples from 51 horses (age range 1-25 years). Two were normal and 49 had been suffering from conditions that were not expected to have had long-term effects on iron metabolism. Muscle samples (splenius and biceps femoris) from 23 of these horses were also analysed. There was a highly significant age-related increase in the non-haem iron concentration in the liver (r = 0.635, p < 0.001), but not in the muscles, in which the iron concentration was much lower than in the liver.
An analysis of 75 cases of intestinal obstruction caused by pedunculated lipomas. A retrospective study of 75 cases of pedunculated lipoma obstruction (PLO) of the intestine was conducted. Age, breed and sex distributions were compared to the non-PLO colic population. Horses in the PLO group were significantly older than in the non-PLO colic group (P < 0.001). A significant increase in risk of PLO was associated with geldings (O.R. 2.32) and with ponies (O.R. 3.75). Of the 75 PLO cases analysed, 69 were strangulating, 70 involved small intestine and 5 involved small colon. Cases of strangulation obstruction tended to have lipomas originating distant to the mesenteric bor...
[Hematological reference values for foals in the first two months of life]. Hematologic reference values were established in 18 healthy foals in the first two months of life. Blood samples were collected prior to colostrum consumption and at 30 hours, 1 week, 3, 5, 7 and 9 weeks of age. PCV, Hb and RBC decreased during the first week and RBC, but not PCV and Hb, increased toward the end of the second month. With the exception of the sample at 1 week, the foals had mean RBC values significantly higher than those of controls. Mean MCV and MCH did not change during the first week, but decreased slightly thereafter; all means were smaller than in controls. The numbers of ...
Respiratory mechanics of the horse during the first year of life. This study investigated the developmental changes in the mechanical properties of the respiratory system in growing horses. Pulmonary mechanics and lung volumes were serially measured in anesthetized foals during the first year of life. Quasi-static pressure-volume curves were generated, and functional residual capacity (FRC) was measured using a closed nitrogen equilibration technique. At birth, chest wall compliance normalized to body weight was substantially less than that reported in other less precocious newborn species, while lung compliance normalized to body weight was similar to value...
Glucose transport and glycolytic enzyme activities in erythrocytes of two-year-old thoroughbreds undergoing training exercise. D-Glucose transport and cytosolic enzyme activities were measured in erythrocytes from 2-year-old thoroughbreds under continuous training exercise (race horses) and compared with those from untrained horses of various ages (sires, mares and untrained 2-year-old thoroughbreds). The activities of the glucose transport and glycolytic enzymes, hexokinase and pyruvate kinase, in the race horses' erythrocytes were elevated to 2-3.5 times above those of untrained horses. There were no significant differences in plasma glucose, triglyceride or IRI concentrations between the horses in training and untr...
[The discovery of a horse skeleton from the 17th century in Kiesen in Bern canton]. In 1968 a skeleton of a horse was found in Kiesen (Switzerland). This discovery could be dated by radiocarbon method: According to that this 13 years old gelding with a withers-height of 135 to 140 cm must have lived during the first third of the 17th century. Apparently it died by an accident. The bones are fully documented with pictures and scales and the findings described and discussed in detail.
Effect of interleukin 1 on articular cartilage from young and aged horses and comparison with metabolism of osteoarthritic cartilage. The effect of interleukin 1 (IL-1) on equine articular cartilage was investigated, using a cartilage explant culture system. Measurement of [35S]O4 incorporation revealed synthesis of matrix proteoglycan by cartilage to be decreased 45, 59.7, and 37.5% after 1, 3, and 5 days, respectively, in culture in the presence of 5 U of IL-1/ml. There was no change in proteoglycan degradation as determined by measurement of [35S]O4 release into the culture medium. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of cartilage-conditioned medium indicated that exposure of cartilage to IL-1 caused ...
Histochemical and morphometric study of the cricoarytenoideus lateralis muscle in the horse. Histochemical and morphometric parameters of the cricoarytenoideus lateralis muscle of the horse are presented. Using myosin ATPase staining after acid preincubation, 3 fibre types (I, IIA and IIC) were identified. Using NADH-TR staining, type I fibres showed high oxidative capacity, whereas type II fibres had high or low oxidative capacity. The type I to type II ratio was of 35:65. This ratio remained constant in the age range examined. Statistically significant (p < 0.01) differences were found in values for fibre size between groups of horses weighing more than 500 kg and less than 400 k...
Equine pituitary neoplasia: a clinical report of 21 cases (1990-1992). The records of 21 horses with an adenoma of the pars intermedia of the pituitary gland were reviewed. The animals comprised nine Dutch warmblood horses and 12 ponies. They ranged in age from 12 to 30 years (mean +/- sem 21 +/- 1.3 years) for 20 of the horses, and comprised 13 geldings and eight mares. All the animals showed hirsutism. In 1991, nine horses were diagnosed as having the adenoma, equivalent to 0.5 per cent of the horses examined in 1991. The mean +/- sem survival time of four of the horses (from discharge to the development of complications which required euthanasia) was 192 +/- 5...
Pharmacokinetics of and serum thromboxane suppression by flunixin meglumine in healthy foals during the first month of life. Age and species reportedly affect the pharmacokinetic variables of nonsteroidal anti-inflammatory drugs. We determined the effect of age on flunixin pharmacokinetic variables in foals during the first month of life. We also estimated the physiologic activity of the drug in neonatal foals by determining the effect of flunixin on thromboxane production during clotting of blood taken from the foals. Flunixin disposition and clearance were determined after IV administration of 1.1 mg of drug/kg of body weight to 5 healthy foals when they were 24 to 28 hours, 10 to 11 days, and 27 to 28 days old. T...
Equine bronchoalveolar lavage cytology: survey of thoroughbred racehorses in training. Sixty-two Thoroughbred horses aged between 1 and 7 years in training in Sydney had bronchoalveolar lavage (BAL) samples collected for cytological examination. All horses, except the yearlings and those with a cough, had raced at the time of the examination and the trainers reported satisfactory performance. Free erythrocytes were found in 73% of samples and haemosiderophages in 90% of the samples, indicating immediate or past occurrences of exercise-induced pulmonary haemorrhage (EIPH). Bronchoalveolar fluid from the yearlings contained significantly less (P < 0.05) erythrocytes and haemosi...
Age-related characteristics of gastric squamous epithelial mucosa in foals. Specimens of grossly normal gastric stratified squamous epithelial mucosa adjacent to the margo plicatus on the right side and along the greater curvature were obtained from 7 foetuses, 10 term foals and 12 foals 2-35 days old. Gastric squamous epithelium from the foetuses changed markedly during gestation. At 150-270 days, the epithelium was 8-10 cells thick, with a single layer of basal cells. Epithelial cells were polyhedral and had abundant clear or slightly stained cytoplasm. In the 300-day foetus the basal layer was thicker, epithelial cells were polyhedral, and there was a flattened 1 c...
Muscle fiber type composition and fiber size in successfully and unsuccessfully endurance-raced horses. Triplicate biopsies from three different depths of the gluteus medius muscle were obtained in 36 endurance-raced horses, aged 8.42 +/- 2.85 yr. Twenty of the horses were considered excellent endurance performers according to the mean speed of their three fastest records in endurance events for the past 2 or 3 years, whereas 16 were moderate performers, with a mean racing speed < 12.5 km/h (in 120- to 180-km endurance rides), < 14 km/h (in 80- to 120-km endurance rides), or < 13.5 km/h (in 40- to 60-km endurance rides). Significant differences in muscle fiber type composition and fiber...
Equine cricoid cartilage densitometry. The density of the cricoid cartilage from 29 equine larynges collected from an abattoir was determined by dual photon absorptiometry (DPA). Densities of the right and left cricoid cartilages were highly correlated. No correlation was found between age of the horse and the density of the cricoid cartilage.
Radiographic evaluation of ossification of the collateral cartilages of the third phalanx in Finnhorses. Of 462 Finnhorses (age 1-20 years) evaluated and graded (scale 0-5) radiographically for ossification of the collateral cartilages of the 3rd phalanx of the front feet, 22.9% were totally free from sidebones (Grade 0), and 49.1% had minimal or mild ossification (Grade 1 or 2) at the base of 1 or more of the cartilages. Moderate ossification (Grade 3) was present in 10.2% of the horses, whereas ossification was advanced (Grade 4) or extensive (Grade 5) in 17.8%. In most horses > 1 cartilage was affected and 7.6% of the horses had separate centres of ossification in 1 or more of the cartilage...
Desmitis of the accessory ligament of the deep digital flexor tendon in the horse: clinical and ultrasonographic features. A report of 24 cases. The clinical and ultrasonographic features of desmitis of the accessory ligament of the deep digital flexor tendon (carpal check ligament) are reported in a series of 24 horses. Lameness associated with the carpal check ligament especially was found in Warmblood riding horses ranging in age from 6 to 18 years with a mean age of 11.3 years. The most striking clinical feature was a firm, painful swelling medially and laterally in the proximal and/or mid metacarpal region, corresponding with the dorsoproximal-palmarodistal oblique direction of the carpal check ligament. Sonographically swelling o...
Injuries due to falls from horses. This study describes the epidemiology of injuries due to falls from horses in New Zealand. There were 54 fatalities from 1977 to 1986 (0.17 per 100,000 persons per year). There were 773 hospitalisations in 1987 (23.7 per 100,000 persons per year). Head injuries were predominant among both fatal and nonfatal injuries. The incidence of nonfatal head injury in the 10 to 19 age group was significantly higher than the incidence in all older groups (P = 0.003). Young people, particularly females, were the segment of the population most affected by the problem of falls from horses. Reference to data ...
Reproductive performance of thoroughbred mares on six commercial stud farms. The records of 1630 mare years from 6 Thoroughbred stud farms in south eastern Australia were analysed for the years 1981 to 1986. Overall pregnancy and foaling rates were 83.9% and 69.3%, respectively. When calculated per served oestrous cycle, pregnancy and foaling rates were 54.7% and 43.1%, respectively. Pregnancy and foaling rates were higher (P < 0.001) for mares 3 to 10 years of age than for older mares. There was no difference in the pregnancy rates of maiden, barren and foaling mares. The foaling rate was significantly higher (P < 0.001) in mares that became pregnant during the ...
Effect of intramuscularly administered polysulfated glycosaminoglycan on articular cartilage from equine joints injected with methylprednisolone acetate. Intra-articularly administered, long-acting corticosteroids are a beneficial treatment for many equine joint disorders because they alleviate inflammation and signs of pain, but they also exert detrimental effects on the biochemical composition and morphologic features of articular cartilage. Chondroprotective drugs have been shown to mitigate some of the deleterious effects of intra-articularly administered corticosteroids on articular cartilage of laboratory animals. Twenty-one ponies were assigned at random to receive 1 of 3 treatments in the right middle carpal joint. Group-1 ponies (n = 8...
Growth hormone secretion in the horse: unusual pattern at birth and pulsatile secretion through to maturity. A heterologous radioimmunoassay was developed and validated for the measurement of horse GH in plasma. It utilized recombinant-derived bovine GH as the radiolabelled ligand, a guinea-pig anti-porcine GH serum as first antibody and pituitary-derived horse GH as standard. Cross-reactivities were high with all of the pituitary and recombinant-derived GH preparations tested (49-140%) and very low (< 0.3%) with horse FSH, LH and prolactin. A synthetic analogue of GH-releasing factor(1-29) stimulated the expected pattern of GH release in foals. Plasma GH concentrations in foals were low at birth (< ...
Repetitive injectable anesthesia in a 27-year-old horse. A 27-year-old horse was anesthetized 3 times a week for 4 weeks, to facilitate cobalt therapy of a squamous cell carcinoma in the left paranasal sinus. Limitations of facilities required transport of the anesthetized horse to and from the cobalt therapy room, therefore, injectable anesthesia was used. Initially, the horse was preanesthetized with xylazine (at 1.1 mg/kg IV) and butorphanol (0.04 mg/kg IV). After 3 anesthetic episodes, the xylazine dose was reduced to 0.4 mg/kg IV and the butorphanol was deleted from the regimen. Tiletamine-zolazepam (1.1 mg/kg IV) was used for induction and mai...
Streptococci and Pasteurella spp. associated with disease of the equine lower respiratory tract. The likelihood of finding evidence of inflammation in 551 tracheal washes collected endoscopically from 278 Thoroughbred racehorses increased with the number of bacterial colony forming units (cfu) per ml of wash (P < 0.001). The aerobic bacteria Streptococcus zooepidemicus, Pasteurella/Actinobacillus-like species and Streptococcus pneumoniae were significantly associated with lower airway inflammation whereas coagulase-negative Staphylococcus spp., alpha-haemolytic Streptococcus spp., Acinetobacter spp., Bacillus spp., Escherichia coli, Pseudomonas aeruginosa, non-haemolytic Streptococcus ...
Ovarian follicles, ovulations and progesterone concentrations in aged versus young mares. The objectives of this study were: 1) to document age-related ovulation failure in mares and 2) to contrast the number of ovarian follicles, occurrence of ovulations, and postovulatory concentrations of progesterone in aged versus young mares. In Experiment 1, 4 of 10 aged (25- to 33-years-old) mares were anovulatory between July 1 and September 1, 1989. In Experiment 2, two of 25 aged (20- to 30-years-old) and none of 21 young (3- to 12-years-old) mares were anovulatory between February 1 and June 30, 1990. The average (+/- SEM) day of the first ovulation was later (P<0.05) for aged versus...
