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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.
Extra-adrenal paraganglioma of the equine orbit: six cases. At The Ohio State University from 1994-2006 six of seven horses evaluated for primary orbital disease were diagnosed with extra-adrenal paraganglioma (EAPG). The horses ranged in age from 14 to 24 years, with a mean of 16.8 years. Duration of clinical signs was 1.5 years to 5 years, with a mean of 2.8 years. Clinical signs varied, but all six had non-painful exophthalmus of the right eye. Five horses had complete ocular exams reported; three of five had decreased to absent vision, two of five had pale optic nerves, and in three of five, difficulty of retropulsion of the globe was noted. Diagno...
Comparative skeletal muscle histopathologic and ultrastructural features in two forms of polysaccharide storage myopathy in horses. Polysaccharide storage myopathy (PSSM) has been found in more than 35 different horse breeds through identification of abnormal storage of polysaccharide in muscle biopsies. A dominant mutation in the glycogen synthase 1 gene (GYS1) accounts for a substantial proportion of PSSM cases in at least 17 breeds, including Quarter Horses, but some horses diagnosed with PSSM by muscle histopathologic analysis are negative for the mutation. We hypothesized that a second distinct form of glycogen storage disease exists in GYS1-negative horses with PSSM. The objectives of this study were to compare the h...
Characteristics of equine summer eczema with emphasis on differences between Finnhorses and Icelandic horses in a 11-year study. Summer eczema, allergic dermatitis of the horse, was studied on 275 affected horses in Finland in 1997-2007. Features of the horses, clinical signs of the disease and owners' opinions of aggravating factors were recorded. Differences, especially, between two of the native Scandinavian horse breeds, the Finnhorse and the Icelandic horse, were evaluated. The study was based on clinical examination and information from the owners. Of the horses, 50% were Finnhorses, 26% Icelandic horses and 24% consisted of different breeds of ponies and other horses. Of the Finnhorses, 76% had summer eczema by t...
Prevalence of and risk factors for postoperative ileus after small intestinal surgery in two hundred and thirty-three horses. To determine the incidence of postoperative ileus (POI) in a population of horses after small intestinal surgery and the effect of multiple variables on development of POI. Methods: Case series. Methods: Horses (n=233) aged > or =1 year that had exploratory celiotomy for small intestinal disease that recovered from surgery from 1995 to 2005. Methods: Sixty-eight variables were collected from medical records (1995-2005) for each horse. POI was defined as nasogastric reflux volume >20 L over 24 hours or >8 L at any single time after surgery. Results: Twenty-seven percent (64/233) of hor...
Clinical dental examinations of 357 donkeys in the UK. Part 1: prevalence of dental disorders. Dental disorders have a high prevalence in older donkeys and horses, but the nature and pathogenesis of many of these disorders have yet to be established. Objective: The identification and determination of the prevalence of important dental disorders in different age groups in a large single population of donkeys, to establish a better understanding of the nature and pathogenesis of these disorders. Methods: A prospective cross-sectional study was performed on the donkey population at The Donkey Sanctuary with detailed oral examinations of 357 donkeys within 7 different age groups (age range ...
Descriptive epidemiology of fracture, tendon and suspensory ligament injuries in National Hunt racehorses in training. While fractures and tendon injuries are known to be important diseases in National Hunt (NH) racehorses during racing, there are no accurate estimates of their incidence in NH training yards. Objective: To estimate the incidence of fractures and tendon and suspensory ligament injuries (TLIs) in NH racehorses in training; to describe the injuries incurred and to compare injury incidence rates by horse age, trainer, gender and background (ex-flat vs. ex-store horses). Methods: Cohort data were collected from 14 UK NH training yards for 2 racing seasons. Daily exercise regimens and details of fra...
Clinical dental examinations of 357 donkeys in the UK. Part 2: epidemiological studies on the potential relationships between different dental disorders, and between dental disease and systemic disorders. Dental disease has been shown to be a risk factor for weight loss and colic in horses. No extensive clinical studies in donkeys have investigated the potential relationship between different dental disorders, or between dental disease and systemic disorders. Objective: To determine possible associations between dental disease and body condition score, weight loss, the need for supplemental feeding and prevalence of colic in donkeys of all ages, and to gain a better understanding of the pathogenesis of dental disease by the determination of associations between different dental disorders. Metho...
Effect of age and mitogen on the frequency of interleukin-4 and interferon gamma secreting cells in foals and adult horses as assessed by an equine-specific ELISPOT assay. Peripheral blood mononuclear cells (PBMCs) were obtained from 6 foals <1 week of age, 6 foals between 3 and 4 months of age, and 10 adult horses. PBMCs were stimulated with concanavalin A (ConA) or calcium ionomycin-phorbol myristate acetate (CaI-PMA) and the frequency of interferon IFN-gamma and IL-4 secreting cells was measured using an equine-specific ELISPOT assay. The number of IFN-gamma secreting cells was significantly lower in both groups of foals than in adult horses regardless of the mitogen used for stimulation. The number of IFN-gamma secreting cells was significantly higher in ...
Long-term outcome in 44 horses with stifle lameness after arthroscopic exploration and debridement. To (1) examine the outcome in horses with osteoarthritis or intra-articular soft tissue injuries of the stifle after arthroscopic exploration and debridement and (2) to determine any imaging or surgical findings that may influence prognosis. Methods: Case series. Methods: Horses (n=44) with lameness referable to the stifle, diagnosed with osteoarthritis, meniscal tears, or other intra-articular soft tissue injuries based on arthroscopic examination. Methods: Medical records of horses with stifle lameness that had arthroscopic exploration were reviewed. Horses with osteochondrosis lesions, intr...
Tendinitis of the proximal aspect of the superficial digital flexor tendon in horses: 12 cases (2000-2006). To determine clinical signs, ultrasonographic findings, and outcome of horses with tendinitis of the proximal portion of the superficial digital flexor tendon (SDFT; group A horses) and to compare signalment, horse use, and outcome in these horses with that of horses with tendinitis of the midmetacarpal region of the SDFT (group B horses). Methods: Retrospective case series. Methods: 12 group A horses and 22 group B horses. Methods: Medical records were reviewed for signalment, horse use, and outcome information; data for group A horses also included severity of lameness, diagnostic results, a...
Left ventricular radial and circumferential wall motion analysis in horses using strain, strain rate, and displacement by 2D speckle tracking. Noninvasive assessment of left-ventricular (LV) function is clinically relevant, but is incompletely studied in horses. Objective: To document the feasibility, describe the techniques, and determine the reliability of 2D speckle tracking (2DST) for characterization of LV radial and circumferential wall motion in horses. Methods: Three Standardbreds, 3 Thoroughbreds; age 8-14 years; body weight 517-606 kg. Methods: Observational study. Repeated 2-dimensional echocardiographic examinations were performed in unsedated horses by 2 observers and subsequently analyzed by 2DST. Test reliability was d...
Body mass index and serum gamma-glutamyltransferase level as risk factors for injuries related to professional horse racing: a prospective study. Prevention of horse-related injuries is considered difficult because horse behavior is unpredictable. Therefore, risk factors for injuries related to professional horse racing need to be investigated. We conducted a study to determine whether body mass index (BMI) and gamma-glutamyltransferase (GGT) levels are associated with professional horse racing-related injuries. Methods: A baseline healthy survey of 546 male grooms and exercise riders aged 40-70 yr working at Miho Training Center, the largest racing-horse training facility in Japan, was performed in May 2003. A total of 93 occupational ...
Reproductive efficiency of Thoroughbred mares under Indian subtropical conditions: A retrospective survey over 7 years. Service records of 253 mares (1181 mare-years) spanning over 7 consecutive years, from nine organized Thoroughbred stud farms, situated in the subtropical northwestern India were retrospectively analyzed to assess their reproductive performance. The overall per cycle pregnancy rate at Day 16 and overall foaling rates were 50.30% and 68.95%, respectively, and were significantly higher in mares aged 3-7 years than > or =18 years old mares. The late embryonic losses (9.86%) that occurred between Days 16 and 39 post-ovulation contributed more than 50% of the overall detected pregnancy losses (19.1...
Influence of foot conformation on duration of competitive life in a Dutch Warmblood horse population. Warmblood horse studbooks aim to breed horses with a conformation that will enable elite future sports performance, but reduce the risk of early retirement due to lameness. Negative conformational traits, such as asymmetrical or 'uneven' forefeet may possibly shorten the career of sporthorses. Objective: To investigate the significance of foot conformation at young age to duration of the career of sporthorses. Methods: Databases of the Royal Dutch Warmblood Studbook (KWPN) and of the Royal Dutch Equestrian Sports Federation (KNHS) were matched and resulted in a dataset comprising 23,116 record...
Chronology and sequence of emergence of permanent premolar teeth in the horse: study of deciduous premolar ‘cap’ removal in Thoroughbred racehorses. There are few published data to support the ages of emergence of permanent dentition widely reported in horses. Objective: To clarify the chronology and sequence of permanent premolar (PM) tooth emergence in Thoroughbred racehorses. Methods: A prospective study was undertaken in which records were kept of deciduous PM 'cap' extractions performed during routine dental examinations in Thoroughbred racehorses. Mixed effects multiple regression analysis was used to relate the observed ages, measured in days, for PM 'cap' extractions simultaneously with different predictive variables. Care was take...
Factors influencing conception rates of Arab mares in Tunisia. In order to investigate the factors affecting the reproduction efficiency of Arab breeding mares in Tunisia, breeding data corresponding to 2340 mated cycles, over 5 years (from 2000 to 2004), from 555 mares offspring of 50 sires and bred with 17 stallions were analysed using a multivariate logistic regression. We chose logit link function and binomial distribution and we used log-likelihood-ratio (LL) and Wald tests (X(2)Wald) to test the mean values. The factors of variation included in the model were the year, the stallion, the age of the mare at mating, the sire and the category of the mar...
Developmental changes in the concentrations of glutamine and other amino acids in plasma and skeletal muscle of the Standardbred foal. Glutamine is concentrated within skeletal muscle, where it has been proposed to play a regulatory role in maintaining protein homeostasis. The work presented here addressed the hypothesis that glutamine would be the most abundant free alpha-AA in plasma and skeletal muscle in the foal during the first year of life. Glycine, however, was the most abundant free alpha-AA in plasma at birth and between 3 and 12 mo of age. The concentration of glutamine, the second most abundant AA at birth, increased through the first 7 d (P < 0.05) and then returned to values similar to those at birth. This re...
Effects of age and equine follicle-stimulating hormone (eFSH) on collection and viability of equine oocytes assessed by morphology and developmental competency after intracytoplasmic sperm injection (ICSI). Young (4 to 9 yr) and old (>or=20 yr) mares were treated with equine follicle-stimulating hormone (eFSH), and oocytes were collected for intracytoplasmic sperm injections (ICSI). Objectives were to compare: (1) number, morphology and developmental potential of oocytes collected from young v. old mares from cycles with or without exogenous eFSH and (2) oocyte morphology parameters with developmental competence. Oocytes were collected from preovulatory follicles 20 to 24 h after administration of recombinant equine LH and imaged before ICSI for morphological measurements. After ICSI, embryo d...
Change in Morphology of Spermatozoa from Dismount Semen during the Breeding Season in Thoroughbred Stallions in Japan. To clarify the physiological changes of sperm morphology in active Thoroughbred stallions during the breeding season, we examined the dismount semen collected from the penile urethra immediately after service. The spermatozoa were analyzed for relationships between the morphology and the stallion's age or the number of services. Seasonal variation was apparent in the rate of the sperm tail abnormalities, spermatozoa with cytoplasmic droplets, appearance of medusa cells, and sperm head length. Area and width of the sperm head correlated negatively with age (P<0.05). The rate of appearance of...
Identification of risk factors for lameness in dressage horses. The aim of this study was to describe the prevalence of illness and lameness at different anatomical sites in registered United Kingdom dressage horses and to identify risk factors for lameness. A questionnaire was sent to all 11,363 registered members of British Dressage in 2005, with one questionnaire assigned per horse. Four multivariable logistic regression models were developed for each section of the questionnaire. A final mixed effects logistic regression model was developed which combined the results from all prior models. Owners reported that 33% of horses had been lame at some time d...
[Characterization of age dependent alterations of the cup of the incisor on the basis of data from Hungarian and German horses]. The authors give a short orientation about the age related parameters of the incisors based on the literature. They examined the question of breed differences with respect to the age determination of horses in the different counties, especially in regard to the English Thoroughbred. In this context they present a new parameter as well as a new approach in data-processing. The cup depth and the yearly abrasion showed high breed-specificity. The relative abrasion indicated that the most intensive wear out is typical for the Thoroughbred. The cup depth and the yearly wear out were different accor...
Intrinsic Factors Influencing the Infection by Helminth Parasites in Horses under an Oceanic Climate Area (NW Spain). A coprological survey to determine the influence of some intrinsic factors (breed, age, and sex) on the infection by helminth parasites in equine livestock (n = 418) under an oceanic climate area (NW Spain) was conducted. Faecal samples were individually collected and analyzed by the coprological techniques. The main strongylid genera identified were Trichonema and Cyalocephalus spp (small strongyles) and Strongylus and Triodontophorus (large strongyles). The prevalence of gastrointestinal nematode was 89% (95% CI 86, 92) and 1% cestoda (0, 2). The percentage of horses with strongyloid parasit...
Characterization of hypertriglyceridemia and response to treatment with insulin in horses, ponies, and donkeys: 44 cases (1995-2005). To characterize signalment, clinical signs of disease, and clinical response to insulin in equids with hypertriglyceridemia. Methods: Retrospective case series. Methods: 20 horses, 17 ponies, and 7 donkeys with hypertriglyceridemia. Methods: For analysis of medical record data, horses, donkeys, and ponies with multiple serum or plasma triglycerides measurements were separated into groups. Hypertriglyceridemic equids that were (HT-I; n = 14) or were not (HT-N; 10) treated with insulin consisted of equids with an initial triglycerides concentration > 44 mg/dL but < 500 mg/dL. Equids with an init...
Adrenocorticotropic hormone stimulation tests in healthy foals from birth to 12 weeks of age. The purpose of this study was to investigate total baseline plasma cortisol and adrenocorticotropic hormone (ACTH) concentrations, and ACTH-stimulated cortisol concentrations in foals from birth to 12 wk of age. Plasma (baseline) cortisol and ACTH concentrations were measured in 13 healthy foals at birth and at 1, 2, 3, 4, 5, 7, 10, 14, 21, 28, 42, 56, and 84 d of age. Each foal received cosyntropin (0.1 microg/kg) intravenously. Plasma cortisol concentrations were measured before (baseline), and 30, and 60 min after cosyntropin administration at birth and at 3, 5, 7, 10, 14, 21, 28, 42, 56, a...
Leptospira seroprevalence and associations between seropositivity, clinical disease and host factors in horses. A cross-sectional study was carried out to determine the seroprevalence of different serovars of Leptospira spp. and their association with clinical disease and host factors in Swedish horses. Methods: Sera from 2017 horses brought to equine clinics during 1997-98 were investigated. The sera were examined by microscopic agglutination test for the presence of antibodies against the following L. interrogans serovars: Bratislava strain Jez, Icterohaemorrhagiae strain Kantorowicz and Pomona strain Pomona and also L. kirschneri sv Grippotyphosa strain Duyster and L. borgpetersenii sv Sejroe strain ...
Distal limb cast sores in horses: risk factors and early detection using thermography. There is a lack of evidence-based data on the prevalence, outcome and risk factors of distal limb cast sores, and no objective tool has been described for the early detection of cast sores. Objective: To investigate the prevalence, location, outcome and risk factors of cast sores after application of a distal limb cast and to determine whether static thermography of the cast is a valuable tool for the assessment of sores. Methods: A prospective study was conducted on horses treated with a distal limb cast. At each cast removal, cast sores were graded as superficial sores (SS), deep dermal sore...
Young foal and adult horse monocyte-derived dendritic cells differ by their degree of phenotypic maturity. Newborn foals are very susceptible to infections by opportunistic pathogens such as Rhodococcus equi. This susceptibility is thought to be due to the immaturity of their immune system, in particular their inability to produce interferon-gamma. This deficiency may result from an insufficiency in accessory signals. We therefore compared monocyte-derived dendritic cells (MoDC) from foals and from adult horses. CD172, MHC-I and MHC-II were generally expressed on more than 90% MoDC from foals and adults. CD1w2(+)CD86(+) cells tended to be less represented in 2-3-week-old foals than in adults. This ...
The influence of age and Rhodococcus equi infection on CD1 expression by equine antigen presenting cells. There is a distinct age-associated susceptibility of horses to Rhodococcus equi infection. Initial infection is thought to occur in the neonatal and perinatal period, and only foals less than 6 months of age are typically affected. R. equi is closely related and structurally similar to Mycobacterium tuberculosis, and causes similar pathologic lesions. Protective immune responses to M. tuberculosis involve classical major histocompatibility complex (MHC)-restricted T cells that recognize peptide antigen, as well as MHC-independent T cells that recognize mycobacterial lipid antigen presented by ...
Morphological characterization and meiotic competence of oocytes collected from filly ovaries. The effect of filly age on morphology of the ovaries, collected oocytes and their capacity for in vitro maturation (IVM) was examined. The ovaries of slaughtered fillies were classified into three groups, according to filly age: (I) <10 month old (<10MF); (II) approximately 1 year old (1YF); and (III) approximately 1.5 year old (1.5YF). The ovaries of mares were used as a control group. Ovarian morphology and collected oocytes were evaluated. Only oocytes with expanded (Ex) and compact (Cm) cumuli were used for IVM. In <10MF, 1YF, 1.5YF and mare groups, corpora lutea were found in the...
The relationship between consecutive pregnancies in Thoroughbred mares. Does the location of one pregnancy affect the location of the next, is this affected by mare age and foal heat to conception interval or related to pregnancy success. Delayed uterine involution is a major cause of early reproductive failure in mares. Involution is affected by mare age, and foaling to covering interval. Involution rates vary between the previously non-gravid horn (PNGH), which recovers the quicker, and the previously gravid horn (PGH). Location of a pregnancy and its likely success may, therefore, be affected by its location relative to the previous pregnancy. This study aimed to determine: (i) the location of concepti in consecutive pregnancies; (ii) whether this varies with mare age or foaling to conception interval; (iii) whether location...
