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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.
Prevalence, risk factors and clinical signs predictive for equine pituitary pars intermedia dysfunction in aged horses. Equine pituitary pars intermedia dysfunction (PPID) is an ageing-related neurodegenerative disorder. The prevalence and risk factors for PPID using seasonally adjusted basal adrenocorticotropic hormone (ACTH) concentrations in aged horses have not been previously reported. Objective: To determine the prevalence, risk factors and clinical signs predictive for PPID in a population of horses aged ≥ 15 years in Queensland, Australia. Methods: Owner-reported data was obtained using a postal questionnaire distributed to an equestrian group. A subgroup of surveyed owners were visited and a veterina...
Evaluation of basal plasma α-melanocyte-stimulating hormone and adrenocorticotrophic hormone concentrations for the diagnosis of pituitary pars intermedia dysfunction from a population of aged horses. The sensitivity and specificity of basal plasma α-melanocyte-stimulating hormone (α-MSH) and adrenocorticotrophic hormone (ACTH) for the diagnosis of pituitary pars intermedia dysfunction (PPID) has not been evaluated in a population-based study. Objective: To evaluate basal plasma α-MSH and ACTH concentrations for the diagnosis of PPID in a population of horses aged ≥ 15 years. Methods: Owner-reported data were obtained using a postal questionnaire distributed to an equestrian group. A subgroup of surveyed owners was visited and veterinary examination performed on horses aged ≥ 15 year...
Reversibility of the effects of GnRH-vaccination used to suppress reproductive function in mares. Active immunisation against gonadotrophin-releasing hormone (GnRH) provides a reversible method for control of oestrous behaviour and fertility in mares. Previous reports failed to demonstrate the interval to resumption of cyclic ovarian activity after GnRH-vaccination. Objective: Administration of the GnRH-vaccine Improvac in a large group of mares of various ages will result in effective, reliably reversible suppression of ovarian activity within a 2 year period. Methods: The mares, subdivided into 3 age categories, were vaccinated twice (with a 35 day interval) using 400 µg Improvac and mo...
Relationship of heart rate and electrocardiographic time intervals to body mass in horses and ponies. To investigate the relationship of heart rate (HR) and ECG time intervals to body weight (BWT) in healthy horses and ponies. We hypothesized that HR and ECG time intervals are related to BWT. Methods: 250 healthy horses of >30 breeds; 5.5 (1-30) y [median (range)]; 479 (46-1018) kg. Methods: Prospective study. Standard base-apex ECGs were recorded while the horses were standing quietly in a box stall. Mean HR over 15 s was calculated and RR interval, PQ interval, QRS duration, and QT interval were measured by a single observer.QT was corrected for differences in heart rate using Fridericia'...
Detection of Neospora sp. antibodies in cart horses from urban areas of Curitiba, Southern Brazil. Neospora caninum is a protozoan parasite which affects dogs as definitive hosts and several mammalian species as intermediate hosts mainly causing abortions and central nervous system disorders. The reemerging population of cart horses for carrying recycling material in urban areas of major cities in Brazil may have an impact on disease spreading, and these animals may be used as sentinels for environmental surveillance. Thus, the present study investigated the frequency of Neospora sp. antibodies in cart horses from Curitiba and surrounding areas, Paraná State, Southern Brazil. IgG antibodie...
Retrospective study of 103 presumed cases of tick (Ixodes holocyclus) envenomation in the horse. Review 103 cases of presumed tick envenomation in horses. Methods: Retrospective study. Methods: Variables, including date of presentation, age, breed, weight, presence of ticks, gait and respiration scores, duration of recumbency, treatment, outcome and complications were recorded. A series of univariable screening tests were performed and used in a multivariable logistic regression model. Results: There were a total of 103 cases affecting 10 breeds, aged between 1 week and 18 years of age. Horses >6 months old and weighing >100 kg had a higher odds of death than those...
Investigation into the morphology of the third metacarpal bone in the horse. To describe key morphological attributes of the third metacarpal bone (Mc3) of horses and to determine whether or not the symmetry of the Mc3 varied significantly between limbs of the same horse. Methods: Ten pairs of metacarpi were collected from slaughter facilities. The age and breed of the horses were recorded. Fixed points and axes that could be easily reproduced between bones were identified on high-quality photographic images of each bone. Using image analysis, three angles were measured. Angle gamma measured the rotation around the long axis of the diaphysis of Mc3, angle delta the ang...
Susceptibility to persistent breeding-induced endometritis in the mare: relationship to endometrial biopsy score and age, and variations between seasons. The objectives were to: (1) investigate the associations of age and endometrial biopsy score with uterine fluid retention after insemination; and (2) determine if a strict classification of susceptibility to persistent breeding-induced endometritis (PBIE) based on biopsy score, endometrial cytology, and fluid retention after inseminations, is consistent over subsequent breeding seasons. In Experiment 1, 57 mares were inseminated with 10(9) freeze-killed sperm during estrus and evaluated for uterine fluid retention 48 h and 96 h after insemination. Comparisons were made between fluid retention ...
The association between jockey experience and race-day falls in flat racing in Australia. Apprentice thoroughbred racing jockeys have a higher fall rate than their more experienced counterparts. The authors describe rates of occurrence and investigate risk factors for falls among less-experienced thoroughbred flat racing jockeys in Australia who commenced their race riding career between August 2002 and July 2009. Methods: Data on race-day falls were extracted from stewards' reports. Denominator data were provided by Racing Information Services Australia on races conducted in Australia. HRs were estimated using time-to-event (survival analysis) methods. Results: Factors found to be...
Finite element analysis in 3-D models of equine cheek teeth. Periodontal diseases occur frequently in equine dentistry and excessive strain in biological tissues is assumed to be a predisposing factor in their development. Finite element (FE) analysis enables strains and stresses occurring in the periodontium to be calculated and is a useful tool for testing this hypothesis. The current study aimed to establish reliable 3-D models from equine maxillary and mandibular cheek teeth for use in FE simulations, with particular attention to the detailed construction of the periodontal ligament (PDL). Age-related morphological aspects of the teeth and the perio...
Myosin heavy chain pattern in the Akhal-Teke horses. This study investigates the myosin heavy chain (MyHC) isoform composition in the gluteus medius muscle of the Akhal-Teke horses using SDS-PAGE (sodium dodecyl sulfate polyacrylamide gel electrophoresis). Fifteen horses aged between 1.5 and 23.5 years were used in this study and divided into three age groups: 1.5 to 4 (n = 6), 9 to 13 (n = 5) and 18.5 to 23.5 years (n = 4). The average content of the MyHC I isoform was 11.72 ± 1.07% (variation between individuals: 7.09% to 20.14%). The relative content of the MyHC IIa and IIx isoforms was subsequently 38.20 ± 1.46% (30.73% to 48.78%) and 50.0...
Sexual dimorphism in Hucul horses using discriminant analysis. The purpose of this study has been to evaluate the applicability of discriminant function analysis to determine gender dimorphism in Hucul horses, based on morphological indices obtained in different stages of life. A total of 243 horses, divided into six age groups, have been examined in its course. For each horse we have measured 12 metric traits, which were then used to calculate 13 biometric indices commonly used in horse breeding in Poland. These have become the basis for defining functions classifying the animals by gender in each of the six age groups. This study answers the question of...
Electrophysiological studies in American Quarter horses with neuroaxonal dystrophy. Neuroaxonal dystrophy (NAD) is a disease characterized by the sudden onset of neurologic signs in horses ranging from 4 to 36 months of age. Equine degenerative myeloencephalopathy (EDM), a disease that has been associated with low vitamin E concentrations, is considered a more advanced form of NAD. The objective of this report is to describe the electrophysiological features of NAD/EDM in American Quarter horses (QHs). HORSES: Six NAD/EDM-affected QHs and six unaffected QHs were evaluated by ophthalmic examination and electroretinography. Five of the NAD/EDM-affected QH and five unaffected QH...
Cell-secreted vesicles in equine ovarian follicular fluid contain miRNAs and proteins: a possible new form of cell communication within the ovarian follicle. Proper cell communication within the ovarian follicle is critical for the growth and maturation of a healthy oocyte that can be fertilized and develop into an embryo. Cell communication within the follicle involves many signaling molecules and is affected by maternal age. Recent studies indicate that cell communication can be mediated through secretion and uptake of small membrane-enclosed vesicles. The goals of this study were to 1) identify cell-secreted vesicles (microvesicles and exosomes) containing miRNAs and proteins within ovarian follicular fluid and 2) determine if miRNA level differ...
Frequency distributions of 174 fractures of the distal condyles of the third metacarpal and metatarsal bones in 167 Thoroughbred racehorses (1999-2009). Although fractures of the metacarpal and metatarsal condyles are the most common long-bone fractures of Thoroughbred horses in training, limited data on variations in morphology and incidence have been published. Additionally, grouped analyses of previous studies from the UK and USA would permit comparison between study groups and the creation of a substantial pool of international data. Methods: Retrospective analysis of case records of horses with fractures of the distal condyles of third metacarpal/metatarsal bones seen over the last 10 years at Newmarket Equine Hospital. The current series...
Change of Ferritin-binding Activity in the Serum of Foal after Birth. In mammal circulation, various ferritin-binding proteins (FBPs) are thought to be involved in the clearance of circulating ferritin after complex formation with it. However, horse FBPs are known to cause inhibitory effects on ferritin immunoassay due to the concealment of the ferritin molecule to anti-ferritin antibodies used in the ferritin immunoassay. These inhibitory effects are eliminated by heat treatment of horse serum at 75°C for 15 min. The inhibitory effects on ferritin immunoassay in the sera of ten foal sera (5 females and 5 males) from 1 to 18 months were detected during all peri...
Demographic and environmental risk factors for infection by Theileria equi in 590 horses in Israel. The prevalence of Theileria equi infection as well as the environmental and demographic risk factors for infection was studied in 590 healthy horses from 46 farms in Israel. The prevalence of T. equi DNA was assessed using a polymerase chain reaction for a segment of the Theileria 18S rRNA gene. The overall prevalence was 26.4% (156/590). There was a significant geographical variation in the prevalence of T. equi infection, ranging from 9.3% (25/270) in the central lowlands to 81.7% (49/60) in the Golan Heights. The prevalence of T. equi infection was found to be significantly associated with ...
The influence of temperature and age on the T1 relaxation time of the equine distal limb. The extent of fat suppression using short tau inversion recovery (STIR) imaging is variable between horses. Our aim was to determine if patient's age and/or hoof temperature have an influence on the T(1) relaxation time of bone marrow in the equine distal limb, thereby affecting the suppression of fat signal. Magnetic resonance imaging was conducted on standing horses and cadaver samples using a low-field magnet (0.27 T). The hoof temperature was measured at the lateral side of the coronary band. A modified inversion recovery fast spin-echo (IR-FSE) sequence was used to measure the signal inte...
Age- and gender-related variations in hematology, clinical biochemistry, and hormones in Spanish fillies and colts. In order to assess which laboratorial parameters need specific age- and/or gender-related reference values, hematological and biochemical profiles (including hormones) were performed in 205 Spanish foals of 5 groups: A (1-2 months; 20 fillies, 10 colts), B (2-3 months; 24 fillies, 18 colts), C (3-6 months; 25 fillies, 16 colts), D (6-9 months; 20 fillies, 23 colts) and E (9-12 months; 25 fillies, 15 colts). Additionally, 120 adult horses were sampled in order to establish baseline data for this breed in our laboratory. Group E had lower red blood cell number and mean cell volume than B, C and ...
Examination of the depth of the equine hard palate. Equine behavioral problems and loss of optimum performance have been associated with musculoskeletal injury and, more recently, dental disease. Injuries to a horse's tongue and bars of the mandible due to bitting have been documented. However, another point of contact of the bit, the hard palate, has thus far been virtually ignored. The objective of the study was to determine if there was a significant range associated with the depth of the equine hard palate and if this range was associated with a certain breed, age, or sex of the horse. Oral examinations were performed on 52 horses and a mea...
Gestation length and occurrence of daytime foaling of Standardbred mares on two stud farms in New Zealand. To examine the gestation lengths and occurrence of daytime foaling of Standardbred mares foaling outdoors at stud farms in Southland, New Zealand (latitude 45˚S). Methods: Data were collected prospectively at two commercial Standardbred stud farms (Farms A and B), during the 2008/9 and 2009/10 breeding seasons (October to February). For each foaling, the identity of the mare, date and time of foaling, gender of foal, time the mare passed the fetal membranes, time the foal stood, and foaling problems including dystocias, were recorded. The effect of farm, season, gender of foal, month of artif...
Investigation of strongyle EPG values in horse mares relative to known age, number positive, and level of egg shedding in field studies on 26 farms in Central Kentucky (2010-2011). A parasite study was done in 1,300 horse mares on 26 farms in Central Kentucky over a 5-month period in 2010 and 2011. The mares included 1,114 Thoroughbreds (TB) on 24 farms, 64 Standardbreds (SB) on 1 farm, and 122 mixed light horse types (MLH) on 1 farm. The objective of this research was to determine strongyle eggs per gram of feces (EPG) counts for evaluation by known age, number positive, and level of egg shedding by the mares. This was done to establish strongyle EPG profiles for the mares to aid in determining whether antiparasitic treatment was necessary. Eggs found were considered th...
Risk factors for race-associated sudden death in Thoroughbred racehorses in the UK (2000-2007). Sudden death adversely affects racehorse welfare, jockey safety and the public perception of horseracing. Objective: To describe the risk of racing-associated sudden death in Thoroughbred racehorses in the UK from 2000 to 2007, to identify whether there were risk factors uniquely associated with sudden death and to improve the understanding of the pathogenesis of racing-associated sudden death by identification of risk factors for such cases. Methods: A sudden death was defined as an acute collapse and death, in an apparently healthy Thoroughbred racehorse, during or immediately after racing, ...
Neutrophil function of neonatal foals is enhanced in vitro by CpG oligodeoxynucleotide stimulation. Rhodococcus equi is an intracellular bacterium that causes pneumonia in foals and immunocompromised adult horses. Evidence exists that foals become infected with R. equi early in life, a period when innate immune responses are critically important for protection against infection. Neutrophils are innate immune cells that play a key role in defense against this bacterium. Enhancing neutrophil function during early life could thus help to protect foals against R. equi infection. The objective of our study was to determine whether in vitro incubation with the TLR9 agonist CpG 2142 would enhance d...
Seroprevalence of Toxoplasma gondii infection among horses in Tunisia. The present study was conducted to investigate the serological survey of Toxoplasma antibodies in local.horses from three major regions: a neighbourhood of a city in the North (Sidi Thabet), a neighbourhood of a city on the coast (Monastir) and a neighbourhood of a city in the middle (Battan) of Tunisia (North of Africa). Methods: A total of 158 serum samples were obtained from clinically healthy horses which consisted of 111 (32 female, 79 male) 2-10 years old and 47 (11 female, 36 male) older than 10 years. All of the horses were tested for antibodies to T. gondii using the Modified Agglutin...
Risk factors for equine laminitis: a systematic review with quality appraisal of published evidence. Epidemiological studies into the risk factors for naturally-occurring equine laminitis are limited. There are a small number of such studies, although the results are inconsistent and remain disputed. The reasons for the conflicting results remain unclear. The aim of this review was to critically evaluate previous research in order to identify publications which provide the best evidence of risk factors for naturally-occurring equine laminitis. A systematic review of English language publications was conducted using MEDLINE (1950-2010), CAB Direct (1910-2010) and IVIS (1997-2010). Additional p...
Relationship between dose of cloprostenol and age of corpus luteum on the luteolytic response of early dioestrous mares: a field study. The objective of this study was to establish and characterize the relationship between the dose of cloprostenol (37.5, 250, 500 and 750 μg) and the age of the early corpus luteum (CL) (80, 88, 96, 104 and 112 h) on the luteolytic response of mares. Behavioural oestrus and ultrasonographic signs of return to oestrus were considered as the occurrence of full luteolysis. A total of 298 mares were divided into groups according to dose of cloprostenol and CL age. There was an effect of dose of cloprostenol (p < 0.001) and age of the CL at the time of treatment (p 0.05); and that of 500 similar...
The relationship of training milestones with racing success in a population of Standardbred horses in New Zealand. To investigate the association between attainment of training milestones by 2-year-old horses with racing outcomes in a population of Standardbred racehorses in New Zealand. Methods: Retrospective records of the 2001/2002-born Standardbred foals were obtained. The three training milestones used were: registered with a trainer, entered in a trial, and competed in a race. The racing outcomes were length of career in years raced and number of race starts, and total earnings. Cox regression analysis was used to assess the association between attainment of the three milestones by 2-year-olds and th...
Welfare of Aged Horses. Horses form a unique and special part of their owners' lives and aged horses are no exception. This review considers the health and management of aged horses, including the role of the owner and their perceptions of aged horses, potential threats or risks to their welfare and finally, factors affecting quality of life and euthanasia of aged horses. Owners of aged horses are concerned about the health, welfare and quality of life of their aged animals. Yet surveys of management and preventive healthcare reflect that there may be some limitations to what owners are actually achieving in practice...
Comparison of plasma and peritoneal indices of fibrinolysis between foals and adult horses with and without colic. To identify hemostatic imbalances indicative of an increased risk of intra-abdominal adhesion formation in foals versus adult horses. Methods: Horses with colic undergoing exploratory laparotomy or abdominocentesis as part of a clinical examination (n = 16 foals ≤ 6 months of age and 19 adults ≥ 5 years of age) and horses without colic undergoing herniorrhaphy (15 foals) or euthanasia for noninflammatory and nongastrointestinal disease (10 foals and 20 adults). Methods: Paired abdominal fluid and blood samples were collected from each horse into buffered sodium citrate and centrifuged imme...
