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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.
Patient variation in veterinary medicine: part I. Influence of altered physiological states. In veterinary medicine, the characterization of a drug's pharmacokinetic (PK) properties is generally based upon data that are derived from studies that employ small groups of young healthy animals, often of a single breed. These are also the data from which population predictions are often generated to forecast drug exposure characteristics in the target population under clinical conditions of use. In veterinary medicine, it is rare to find information on the covariates that can influence drug exposure characteristics. Therefore, it is important to recognize some of the factors that can alter...
Age-related differences in prostaglandin E2 synthesis by equine cartilage explants and synoviocytes. Time- and concentration-related actions of lipopolysaccharide (LPS) on the synthesis of prostaglandin E(2) (PGE(2)) were investigated in cartilage explants and synoviocytes harvested from 3 age groups of horses, all with clinically normal joint function: group A 20 years. Cartilage explants from group A horses were least and those from group C were most sensitive to LPS. Significant increases in PGE(2) concentration (P <or= 0.01) were obtained in group C horses in response to LPS concentrations of 1.0 microg/mL (and higher) after exposure for 24, 36 and 48 h, whereas explants from group A h...
Demographic characteristics of horses donated to the North Carolina State University Equine Health Center, 1996-2008. To determine demographic characteristics of horses donated to the North Carolina State University Equine Health Center (EHC) between 1996 and 2008. Methods: Retrospective cohort study. Methods: 122 horses donated to the EHC between January 1996 and December 2008, and 246 horses offered for donation to the EHC between January 2007 and December 2008. Methods: Telephone and medical records were examined. Data were collected in 5 categories: age, sex, breed, reason for donation, and use prior to donation. Results: From January 1996 through December 2008, 122 horses were donated to the EHC (median,...
Localization of insulin-like growth factor-I (IGF-I) and IGF-I receptor (IGF-IR) in equine testes. The insulin-like growth factor-I (IGF-I) is a key regulator of reproductive functions. IGF-I actions are primarily mediated by IGF-IR. The main objective of this research was to evaluate the presence of IGF-I and IGF-I Receptor (IGF-IR) in stallion testicular tissue. The hypotheses of this study were (i) IGF-I and IGF-IR are present in stallion testicular cells including Leydig, Sertoli, and developing germ cells, and (ii) the immunolabelling of IGF-I and IGF-IR varies with age. Testicular tissues from groups of 4 stallions in different developmental ages were used. Rabbit anti-human polyclona...
A 15-year survey of reproductive efficiency of Standardbred and Finnhorse trotters in Finland–descriptive results. The major horse breeds in Finland are the Finnhorse (FH) and the American Standardbred (SB). The foaling rates of the FH have consistently been lower than those of the SB. During the last years, a decreasing trend in foaling rates of both breeds has been observed. The purpose of this study was to describe and compare the structure of these two mare populations for age, reproductive history and mating type. In addition, changes over the years were studied that could explain the decline in foaling rates. Methods: In Finland, the mating statistics and foaling rates per stallion are published year...
Meckel’s diverticulum as a cause of colic: 2 cases with different morphological features. Persistent Meckel's diverticulum is an uncommon embryonic developmental anomaly of the distal small intestine created by a portion of the vitelline duct adjacent to intestine that remains patent. This portion can form a diverticulum (Meckel's diverticulum) or a fibrous band, called vitelloumbilical band, and can be associated with colic after local impaction or strangulation of the small intestine around the remnant. This report describes two cases of Meckel's diverticulum with different morphological features in older horses. This congenital disorder should be considered as a reason for abdom...
Relationships between race earnings and horse age, sex, gait, track surface and number of race starts for Thoroughbred and Standardbred racehorses in North America. There is no consensus on objective outcome measures that can be used to determine if a medical or surgical treatment affects race performance. Objective: To determine the association between 2 commonly used outcome measures (total starts and total earnings) and age, sex, gait and race surface. Methods: A cross-sectional study was performed using the race performance data for all Thoroughbred horses age 2, 3, 4 and 5 years racing in the United States, and Standardbred horses of the same ages racing in the United States and Canada during the year 2006. Median earnings and starts were determined ...
Ultrasonographic morphometric measurements of digital flexor tendons and ligaments of the palmar metacarpal region in Haflinger horses. The aim of the study was to determine morphometric values of the superficial and deep digital flexor tendon, the inferior check ligament and the suspensory ligament in the palmar metacarpal region of sound Haflinger horses using ultrasonography and to assess the influence of different factors on them. The findings were compared with the literature. A total of 30 sound Haflinger mares aged 4-20 years were used. Transverse ultrasound images were obtained with an 8-10 linear MHz transducer and the cross-sectional area, the circumference and the dorsopalmar and lateromedial width were determined f...
Gene expression of proteolytic systems and growth regulators of skeletal muscle in horses with myopathy associated with pituitary pars intermedia dysfunction. To investigate gene expression of the major proteolytic systems and growth regulators in skeletal muscle of horses with myopathy associated with pituitary pars intermedia dysfunction (PPID). Methods: 14 horses with PPID-associated myopathy and 7 healthy control horses. Methods: Horses with PPID and controls were age matched (15 to 28 years old). Muscle biopsy specimens were collected from both groups and processed for RNA and cDNA extraction. Validation of the most stable housekeeping genes for skeletal muscle was performed and used to compare gene expression of the following proteolytic syste...
A survey of equine oral pathology. Dental abnormalities in horses can lead to weight-loss, poor performance, pain, behavioral abnormalities, and illness. Despite this impact, the occurrence and type of dental disease in horse populations is infrequently reported in veterinary medicine. The purpose of this cross-sectional survey of horses presented for slaughter at a processing plant in Western Canada was to measure the prevalence of equine oral abnormalities, examine associations between the most common abnormalities, and consider the relationship between the age of horse and types of abnormalities observed. The horses used in ...
Genetic variation in competition traits at different ages and time periods and correlations with traits at field tests of 4-year-old Swedish Warmblood horses. For many years, the breeding value estimation for Swedish riding horses has been based on results from Riding Horse Quality Tests (RHQTs) of 4-year-olds only. Traits tested are conformation, gaits and jumping ability. An integrated index including competition results is under development to both get as reliable proofs as possible and increases the credibility of the indexes among breeders, trainers and riders. The objectives of this study were to investigate the suitability of competition data for use in genetic evaluations of horses and to examine how well young horse performance agrees with ...
Maxillofacial fractures sustained by unmounted equestrians. Facial injuries caused by horses are relatively common among riding enthusiasts, but little is known about the nature of maxillofacial fractures sustained by those not mounted. We collected data on patients' characteristics, fractures sites, mechanisms of injury, and treatment of these fractures from the departmental records of the oral and maxillofacial unit at Christchurch Hospital, New Zealand between 1996 and 2008. Of 49 patients with equine-related facial fractures, 35 (mean (SD) age 35.8 (16.7) years) had sustained their injuries while unmounted (71%). Most of the fractures occurred in w...
Reproductive performance measures among Thoroughbred mares in central Kentucky, during the 2004 mating season. To improve efficiency at the farm level, a better understanding of how farm management factors impact reproductive performance is important. Objective: To assess reproductive efficiency and effectiveness among Thoroughbred mares in central Kentucky. Methods: A cohort of 1011 mares on 13 farms in central Kentucky was followed during the 2004 mating and 2005 foaling season. Information on farm level practices was collected via interviews with farm managers. Reproductive records were collected for each mare mated to obtain information on mare characteristics. The influence of mare age and status ...
Evaluation of a new enzyme-linked immunosorbent assay to detect keratan sulfate in equine serum. This study aimed to evaluate a system that identifies cartilage turn over and/or degradation through measurement of a new keratan sulfate (KS) epitope concentration in equine sera. Blood samples were collected from 30 horses, 1 (n = 15) and 2 year-olds (n = 15). Serum samples were analyzed for an epitope of keratan sulfate by 1/20/5D4 (KS5D4) and new epitopes of keratan sulfate using high sensitive keratan sulfate (HSKS), measured by two respective enzyme-linked immunosorbant assays (ELISAs). There was no correlation in serum concentration of KS evaluated using 5D4 and HSKS. Age had no signifi...
Induration of the cricoid cartilage complicates prosthetic laryngoplasty in a horse. To report intraoperative complications during needle penetration and suture placement through the cricoid cartilage during a prosthetic laryngoplasty procedure. Methods: Case report. Methods: An 11-year-old American Paint gelding with grade IV left laryngeal hemiplegia underwent a terminal prosthetic laryngoplasty for teaching purposes. Passage of the needle through the cricoid cartilage was difficult and resulted in needle breakage before eventual success using a new needle. The larynx was examined postmortem. Results: Palpation of the larynx revealed hardening of the cricoid cartilage. Radio...
Factors affecting the incidence of postpartum oestrus, ovarian activity and reproductive performance in Thoroughbred mares bred at foal heat under Indian subtropical conditions. Decreased reproductive performance due to summer stress is a well known phenomenon in farm livestock. Whether this occurs in the mare and specifically how this might affect postpartum reproductive activity and performance, especially at Foal Heat (FH), is unknown. This study, therefore, aims to investigate this and the factors that might affect postpartum reproductive activity. Reproductive records of 228 Thoroughbred mares (694 mare years) bred in subtropical north-western India were retrospectively analysed. Overt oestrous activity occurred within 21 d postpartum in 92.94% (645/694) of mares...
The relationship between concentrations of vitamin D-binding protein (DBP) in serum and colostrum of mares and in serum of their foals in the neonatal period. Vitamin D-binding protein (DBP) participates in the actin scavenger system, it is a carrier of vitamin D and its derivatives, it manifests the capacity to bind mainly monounsaturated and saturated fatty acids, it binds to the surface of several cells and enhances chemotactic activity of C5a of the complement. The present study was aimed at answering the question whether serum DBP level in mares is related to levels of this protein in colostrum and in serum of its progeny. For this purpose, sera from 77 mares, colostra from 72 mares and sera from 69 Thoroughbred foals were collected. Mother's a...
A study of the thickness of cheek teeth subocclusal secondary dentine in horses of different ages. There is limited knowledge on the thickness of subocclusal secondary dentine in equine cheek teeth (CT). Objective: Subocclusal secondary dentine is of consistent thickness above different pulp horns in individual horses and its thickness increases with age. Methods: 408 permanent CT were extracted post mortem from 17 horses aged 4-30 years, with no history of dental disease. The CT were sectioned longitudinally in the medio-lateral (bucco-palatal/lingual) plane through each pulp horn, and the thickness of the secondary dentine overlying each pulp horn was measured directly. Results: The suboc...
Morphological study of tracheal shape in donkeys with and without tracheal obstruction. There is limited information on the gross tracheal morphology of donkeys with or without tracheal abnormalities. Objective: To: 1) examine the morphology of tracheas of donkeys with and without clinical and/or post mortem evidence of tracheal obstruction; 2) record the cross-sectional dimensions and shapes of tracheal rings at fixed sites; and 3) document prevalence, sites and characteristics of detected tracheal abnormalities. Methods: The tracheas of 75, predominantly aged (median age 30 years, range 7-48 years) donkeys that died or were subjected to euthanasia on humane grounds were examine...
Return to work following unilateral enucleation in 34 horses (2000-2008). REASONS FOR STUDY: The effect of unilateral enucleation on vision and potential loss of performance in horses has received little study. Objective: To evaluate the likelihood of return to prior discipline following unilateral enucleation in horses, assessing the role of age at enucleation, equine discipline, reason for enucleation, time to vision loss and eye enucleated. Objective: Unilateral enucleation has no significant effect on likelihood of return to work in horses, for both right and left eyes, across age and discipline. Methods: A retrospective review of medical records identified 92 h...
Retrospective study of 108 foals with septic osteomyelitis. To determine the clinical characteristics, short-term outcome and future athletic performance of foals with septic osteomyelitis. Methods: Retrospective clinical study of 108 Thoroughbred foals with radiographic evidence of bone infection that were presented at the Scone Veterinary Hospital between August 1995 and December 2001. Medical records were reviewed and information concerning signalment, the clinical, laboratory and radiographic findings, treatment and outcome was obtained. Racing records were obtained and evaluated for surviving foals that had reached racing age. Results: Mean age of...
Factors affecting the relationship between arterial and end-tidal carbon dioxide pressures in the anaesthetised horse. To assess the effects of the duration of anaesthesia, position of recumbency, mode of ventilation, anaesthetic drug protocol, patient age and type of surgical procedure on the usefulness of capnometry as a measure of the partial pressure of arterial carbon dioxide (P(a)co(2)) during general anaesthesia in horses. Methods: A prospective study compared the P(a)co(2) values with those of partial pressure of end-tidal carbon dioxide (ETco(2)) in horses anaesthetised for elective or emergency surgical procedures. The difference between P(a)co(2) and ETco(2) (P(a)co(2)- ETco(2)) and the physiologica...
Anatomical studies of maxillary cheek teeth infundibula in clinically normal horses. Although clinical disorders of equine maxillary cheek teeth (CT) infundibula are common, anatomical knowledge of these structures is poor. Objective: Anatomical examinations of sectioned CT infundibula will better define their shapes and sizes and allow identification of infundibular cemental variations and changes. Methods: Cheek teeth were extracted post mortem from 33 horses, aged 3-30 years, without a clinical history of dental disease. The CT were sectioned longitudinally in the bucco-palatal plane through the widest aspects of both infundibula. The infundibular surfaces were then assesse...
The origin and foot condition of horses slaughtered in Australia for the human consumption market. There are ethical concerns regarding the loss of horses from various equine industries and their corresponding slaughter. However, to date, no empirical evidence regarding the extent of this loss, nor of the condition of horses involved, exists within Australia. Objective: To determine the approximate ages, brand type and condition of feet of horses relinquished to an export abattoir in Australia. Methods: Data were collected from 340 horses processed at an Australian abattoir from November 2007-January 2008. Foot abnormalities, injuries and hoof indicators of overgrown and untrimmed hooves we...
Surgical thrombectomy in horses with aortoiliac thrombosis: 17 cases. Aortoiliac thrombosis (AIT) is a progressive vascular disease characterised by an exercise-induced hindlimb lameness. After developing a surgical technique, a follow-up study was required. Objective: To assess the surgical results of a surgical thrombectomy in horses with AIT, a chronic arterial occlusive disease of the aorta and its caudal arteries. Methods: Seventeen cases showed the typical signs of AIT and diagnosis was confirmed by Doppler-ultrasonography. Average age of the horses was 12 years. Seven stallions, 6 mares and 4 geldings were included. Results: The thrombus was located in th...
Pituitary pars intermedia dysfunction (Equine Cushing’s disease) in an onager (Equus hemionus onager). Pituitary pars intermedia dysfunction (PPID), also known as Equine Cushing's disease, is most often diagnosed in older horses and ponies. To the authors' knowledge, there have been no reports of its diagnosis in captive nondomestic equids. A 13-yr old onager (Equus hemionus onager) at the Zoological Society of London (ZSL) Whipsnade Zoo showed clinical signs suggestive of PPID, including hirsutism, fat redistribution, weight loss, laminitis, and chronic infections. A dexamethasone suppression test was performed to confirm PPID. Subsequently, adenomatous hyperplasia and microadenoma of the pars...
Temporal changes in concentrations of branched-chain amino acids in plasma on healthy mares and foals from birth to 24 weeks of age. The concentrations of branched-chain amino acids (BCAA; valine, leucine, isoleucine) were determined in plasma of 7 healthy thoroughbred mares and their foals from birth (0 week) to 24 weeks of age, using automated high-performance liquid chromatography. In foals, the concentrations of plasma valine were significantly high (p<0.05) at 16, 20 and 24 weeks. The concentrations of plasma leucine were significantly high (p<0.05) at 1 and 3 weeks. The concentrations of plasma isoleucine were significantly high (p<0.05) from 1 to 24 weeks. In mares, the concentrations of plasma valine were s...
Lameness and effusion of the tarsocrural joints after arthroscopy of osteochondritis dissecans in horses. The presence and degree of tarsocrural joint effusion and lameness, and the result of a hindlimb flexion test were scored subjectively in 79 horses before, and six weeks to 20 months after, arthroscopic surgery to remove osteochondritis dissecans fragments. The scores of all three variables improved significantly after surgery. The score reductions for the right and left hindlimbs, respectively, were 82 per cent and 95 per cent for lameness, 48 per cent and 41 per cent for joint effusion, and 89 per cent and 84 per cent for reaction to flexion (P < or = 0.01). The oldest horses reacted more fa...
The effect of age on the immune response of horses to vaccination. Few studies have investigated immunosenescence in the horse, but it is accepted that the primary and secondary (anamnestic) immune responses may differ between aged and younger horses. The aim of the present study was to determine whether aged horses have a protective immune response post-vaccination. Thirty-four aged healthy horses (> or =20 years) and 29 younger adult horses (4-12 years) of various breeds were vaccinated with commercially produced killed rabies and influenza vaccines. Rabies serum neutralizing antibody titres and equine influenza virus specific antibody subclasses (immunoglo...
Seroprevalence of Leptospira spp. in clinically healthy racing horses in Korea. Leptospirosis is a zoonotic disease of global importance, and has a worldwide distribution. The present study aimed to determine leptospiral seroprevalence in clinically healthy racing horses from all three racecourses in Korea. Serum samples from 1,226 racing horses were examined using a microscopic agglutination test to detect the presence of antibodies against 18 Leptospira serovars. Of the tested samples, 307 (25.0%) were found to be positive. The distribution of seroprevalence differed significantly by racecourse (P=0.004); the Jeju course had the highest incidence (31.1%), followed by th...
