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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.
Repulsion of maxillary and mandibular cheek teeth in standing horses. To report the technique and results of cheek teeth repulsion in standing, sedated horses. Methods: Case series. Methods: Horses (n = 12), ponies (6). Methods: Medical records (2006-2009) of horses that had cheek tooth repulsion while standing were reviewed. Inclusion criteria included: maxillary or mandibular cheek tooth disease diagnosed by clinical and radiographic examination where attempted oral extraction failed necessitating repulsion. Horses were sedated and a local nerve block performed. Intraoperative radiographs facilitated instrument positioning and ensured repulsion of all dental r...
Seroprevalence of Anaplasma phagocytophilum in horses in the Czech Republic. Anaplasma phagocytophilum is the aetiological agent of equine granulocytic anaplasmosis (EGA). The aim of this survey was to assess the prevalence of anti-A. phagocytophilum antibodies in the horse population of the Czech Republic (CZ) and to investigate possible links between seropositivity and the geographic origin, age, and/or sex of the tested horses. Antibodies against A. phagocytophilum were screened using an indirect fluorescent antibody method (IFA). Serum samples from 96 healthy horses from 8 localities (7 within the CZ and one control upland/tick-free locality in Ukraine) were examin...
Immunolocalization of estrogen receptor alpha, estrogen receptor beta and androgen receptor in the pre-, peri- and post-pubertal stallion testis. In various species, androgens and estrogens regulate the function of testicular Leydig, Sertoli, peritubular myoid, and germ cells by binding to their respective receptors and eliciting a cellular response. Androgen receptor (AR) is expressed in Sertoli cells, peritubular myoid cells, Leydig cells and perivascular smooth muscle cells in the testis depending on the species, but its presence in germ cells remains controversial. Two different estrogen receptors have been identified, estrogen receptor alpha (ERα) and estrogen receptor beta (ERβ), and their localization and function in testicular...
Spread of West Nile virus in Iran: a cross-sectional serosurvey in equines, 2008-2009. We report the first large-scale serosurvey for West Nile virus (WNV) conducted in the equine population in Iran. Blood samples were obtained in 2008-2009 from 1054 equines collected from 260 districts located in 27 provinces. The overall seroprevalence rate for WNV neutralizing antibodies was 23·7%. Marked geographical variations were observed as province-specific seroprevalence rates ranged from 1% to 88%, the highest values being observed in the southern and western parts of the country. The presence of IgM-positive animals (n=9) indicated a recent circulation of WNV in several provinces. L...
A multicenter retrospective study of 151 renal biopsies in horses. Renal biopsies are uncommonly performed in horses and little is known about their diagnostic utility and associated complication rate. Objective: To describe the techniques, the complication rate, risk factors, and histopathology results; as well as evaluate the safety and diagnostic utility of renal biopsy in the horse. Methods: One hundred and forty-six horses from which 151 renal biopsies were obtained. Animals ranged in age from 48 hours to 30 years. Methods: Multicenter retrospective study, with participation of 14 institutions (1983-2009). Results: Renal biopsy in horses was associated w...
Use of BAER to identify loss of auditory function in older horses. To use the brainstem auditory evoked response (BAER) to test the hypothesis that auditory function could be worse in older horses than in younger horses. Methods: BAER waveforms in response to click stimuli were measured in five younger horses (5-8 years) and four older horses (17-22 years). Results: Compared with the younger horses, the older horses showed significantly (P < 0.02) worse BAER thresholds and significantly (P < 0.02) worse BAER wave V amplitudes to the 90 decibels above normal hearing level stimulus. These results were consistent with partial deafness in the older horse gr...
Prevalence of non-strongyle gastrointestinal parasites of horses in Riyadh region of Saudi Arabia. This study aimed to provide recent data on the occurrence of non-strongyle intestinal parasite infestation in horses in the Riyadh region of Saudi Arabia as a basis for developing parasite control strategies. We conducted necropsy for 45 horses from September 2006 to November 2007 in the Riyadh region, Saudi Arabia. 39 out of 45 horses were infected with intestinal parasites with an infestation rate of 86.6%. Infestations with seven nematode species and two species of Gasterophilus larva were found. The most prevalent parasites were Strongyloides westeri (64.4%) and Parascaris equorum (28.8%) ...
Determination of the correlation between stallion’s age and number of sex chromosome aberrations in spermatozoa. The aim of this study was a cytogenetic analysis of stallions semen to find sex chromosome aberrations and to determine if there was an association between stallion's age and aberration frequency for the sex chromosomes. Sperm samples were collected from 22 stallions of various age from 3 to 23 years. Multicolour FISH was performed on each sample, using probes for the sex chromosomes and EGFR gene, localized on 4p12 in domestic horse. A total of 26199 sperm cells were analysed (from 1 070 to 1 532 per animal). Among the analysed cells, there were 50.318% with X chromosome, 48.543% with Y chrom...
The equine neonatal intensive care laboratory: point-of-care testing. Rapid evaluation and intervention is a requirement and a characteristic of patient management in neonatal intensive care units, and this applies for equine neonates also. Appropriate interventions are based on solid knowledge of age, maturity, and species-specific differences in reference ranges. Point-of-care (POC) testing devices speedup decision making regarding treatments and interventions. However, there are potential limitations of these devices when applied to age groups and species beyond those they were specifically developed for. This article discusses the age-specific differences in...
Glanzmann thrombasthenia in a 17-year-old Peruvian Paso mare. A 17-year-old Peruvian Paso mare was evaluated for bilateral epistaxis that had been present for at least 3 years. The mare had mild anemia, platelet count within the reference interval, unremarkable coagulation times, and a negative Coggins test. On endoscopic examination, structural abnormalities were not observed in the nasal cavities, pharynx, larynx, trachea, or either guttural pouch, but petechiation was noted in the nasal mucosa. Additional tests revealed prolonged cutaneous bleeding time, normal concentration of von Willebrand factor antigen, an abnormal clot retraction test, and failu...
Serum free cortisol fraction in healthy and septic neonatal foals. Relative cortisol insufficiency occurs in septic foals and impacts survival. Serum free (biologically available) cortisol concentration might be a better indicator of physiologic cortisol status than serum total cortisol concentration in foals. Objective: In septic foals, (1) low free cortisol concentration correlates with disease severity and survival and (2) predicts disease severity and outcome better than total cortisol concentration. Methods: Fifty-one septic foals; 11 healthy foals; 6 healthy horses. Methods: In this prospective clinical study, foals meeting criteria for sepsis at admiss...
The effect of age on thoroughbred racing performance. Using a dataset of 274 male Thoroughbred racehorses in the United States, we study the effect of age on racing performance. Beyer speed figures, which are uniform measures of racing performance across distance and racing surface, are utilized in this study. A system of equations is estimated to determine quadratic improvement and decline in racing performance. We find that a typical horse's peak racing age is 4.45 years. The rate of improvement from age 2 to 4 1/2 is greater than the rate of decline after age 4 1/2. A typical horse will improve by 10 (horse) lengths in sprints (less than 1 mil...
The effect of age on thoroughbred racing performance. Using a dataset of 274 male Thoroughbred racehorses in the United States, we study the effect of age on racing performance. Beyer speed figures, which are uniform measures of racing performance across distance and racing surface, are utilized in this study. A system of equations is estimated to determine quadratic improvement and decline in racing performance. We find that a typical horse's peak racing age is 4.45 years. The rate of improvement from age 2 to 4 1/2 is greater than the rate of decline after age 4 1/2. A typical horse will improve by 10 (horse) lengths in sprints (less than 1 mil...
Prevalence of Theileria equi and Babesia caballi infection in horses from northern Italy. Babesia caballi and Theileria equi are the causative agents of equine piroplasmosis. In this epidemiological study, 294 horses reared in a rural area of northern Italy were studied. During January 2008-January 2009, blood samples were taken for serology (indirect fluorescent antibody test) and for polymerase chain reaction (PCR). Data on the geographical area, sex, and age were collected for statistical analysis of risk factors associated with infection. A seroprevalence of 8.5% was found: 8.2% of the animals were positive for anti-T. equi antibodies and 0.3% for anti-B. caballi antibodies. No...
Brother of CDO (BOC) expression in equine articular cartilage. Brother of CDO (BOC) is a cell surface receptor that derives its name from the structurally related protein, cell adhesion molecule-related/down-regulated by oncogenes (CDO, sometimes CDON). High levels of BOC mRNA and protein expression have been described in embryonic tissues with active cell proliferation and ongoing cellular differentiation(1,2). A microarray-based screen of RNA isolated from 11 different adult equine tissues unexpectedly identified BOC as having an expression pattern restricted to articular cartilage. The objective of this study was to further investigate BOC expression i...
Epithelioid haemangiosarcoma in the ocular tissue of horses. Haemangiosarcomas (HSAs) are malignant tumours of endothelial cell origin. Epithelioid HSA is a variant of the histologically conventional HSA that has little or no morphological evidence of a vascular origin and has been reported rarely in domestic animals. The following report documents six cases of equine epithelioid HSA occurring in the ocular tissues of horses with a mean age of 19.8 years at the time of diagnosis. Microscopically, all of the lesions consisted of solid sheets or cords of epithelioid cells with rare narrow clefts or small spaces containing erythrocytes that were often the ...
Serological prevalence of Babesia caballi and Theileria equi in horses of Lara State, Venezuela. The main objective of this study was to demonstrate the occurrence of equine piroplasmosis (EP) in horses of Lara State, Venezuela, and to correlate it with the factors host's sex and age in order to know the epidemiology of this disease at the Venezuelan Centroccidental Region. Antibody levels to Babesia caballi and Theileria equi were assessed in 360 equine serum samples, collected from 9 municipalities of Lara State, using an ELISA technique with recombinant antigens and monoclonal antibodies (Mabs). Antibodies to B. caballi were found in 254 horses (70.6%), whereas 181 animals (50.3%) were...
Infrared spectroscopy reveals both qualitative and quantitative differences in equine subchondral bone during maturation. The collagen phase in bone is known to undergo major changes during growth and maturation. The objective of this study is to clarify whether Fourier transform infrared (FTIR) microspectroscopy, coupled with cluster analysis, can detect quantitative and qualitative changes in the collagen matrix of subchondral bone in horses during maturation and growth. Equine subchondral bone samples (n = 29) from the proximal joint surface of the first phalanx are prepared from two sites subjected to different loading conditions. Three age groups are studied: newborn (0 days old), immature (5 to 11 months ol...
Epidemiology of equine sarcoids in horses in western Canada. Sarcoids are the most common tumor of the equine skin but only 1 study describing the epidemiology of sarcoids in Canadian horses has been published. The records of 5 veterinary diagnostic laboratories in western Canada were searched to identify submissions of sarcoids from horses. The submission records and diagnostic reports of 802 separate submissions of equine sarcoids were reviewed for age, breed, and gender of the horse and the number, location, and clinical type of sarcoid. From these records, the 307 submissions to laboratories in Saskatchewan were compared to a reference group to test...
Influence of endemic goitre areas on thyroid hormones in horses. The aim of this study was to investigate thyroid hormone levels in horses stabled in two different locations on the island of Sicily. The study was carried out on a total of 72 clinically healthy Sanfratellano horses ranging in age from 5 to 9 years and weighing 585 ± 40 kg. The results showed higher thyroxine values (P < 0.02) in horses stabled in an endemic goitre area (group II) than those observed in horses in a non-endemic area (group I). Unexpectedly, the T(4)/T(3) and the fT(4)/fT(3) rations were both lower in group I than in group II. The percentages of fT(4) to T(4) and of fT(3) to T...
Na+, K(+)-ATPase activity and ATP concentration in horses of the Wielkopolski breed in relation to age. This study aimed at determining relationships between the age of the Wielkopolski horses, ATP in whole blood and in the erythrocytes, and between erythrocyte Na+, K(+)-ATPase activity, and serum concentrations of mineral components. ATP was measured in whole blood and in erythrocytes by HPLC method. Serum concentrations of Ca2+ and Mg2+ were measured spectrophotometrically, while Na+ and K+ by flame photometry. In horses aged from 4 to 48 months, a dynamic decrease in ATP activity was found. Erythrocyte Na+, K(+)-ATPase activity decreased proportionally with the decrease in ATP activity. The r...
Quantitative pertechnetate thyroid scintigraphy and the ultrasonographic appearance of the thyroid gland in clinically normal horses. We characterized the scintigraphic and sonographic appearance of the thyroid gland in clinically normal horses to establish the value of these modalities for assessment of the thyroid gland in this species. Horses were divided into two age groups. One group consisted of eight horses between 3 and 10 years of age and the other of seven horses between 11 and 20 years of age. Total T4 concentrations were within the laboratory reference interval in all horses. Thyroid to salivary (T/S) ratio, percent dose uptake of pertechnetate (Na99mTcO4) and thyroid lobe volume were calculated. The echogenicity...
Effects of age and altrenogest treatment on conceptus development and secretion of LH, progesterone and eCG in early-pregnant mares. The treatment of early pregnant mares with a history of repeated early embryonic loss with the progestin altrenogest has become routine; however no controlled studies on the efficiency of altrenogest to prevent embryonic losses are available so far. In the present study, we have investigated effects of altrenogest treatment in mares on conceptus development and the secretion of LH, progesterone, and eCG until day 100 of pregnancy. In addition, differences related to age of mares were assessed. Mares were treated with altrenogest (0.044 mg/kg per os once daily) or sunflower oil (10 ml per os on...
The selenium and vitamin E status of horses in Prince Edward Island. Serum selenium (Se), vitamin E, and resting thyroid hormone concentrations were measured in 201 horses in Prince Edward Island (PEI). Selenium concentrations were either marginal (0.0053 to 0.1200 ppm) or deficient (< 0.0053 ppm) in 79% of horses based on current reference ranges for Se in serum. Aged and young adult pleasure horses had a higher prevalence of inadequate Se concentrations compared to racehorses and broodmares (82% and 97% versus 45% and 72%, respectively). Overall, 13% of horses had inadequate (< 200 μg/dL) serum vitamin E concentrations; most of these were young pleasure hors...
Assessment of ultrasonographic morphometric measurements of digital flexor tendons and ligaments of the palmar metacarpal region in Icelandic Horses. To obtain morphometric values for the superficial digital flexor tendon, deep digital flexor tendon, accessory ligament of the deep digital flexor muscle, and suspensory ligament in the palmar metacarpal region of Icelandic Horses. Methods: 50 nonlame Icelandic Horses in training. Methods: Horses included 2 stallions, 30 geldings, and 18 mares from 4 to 20 years of age with a body mass index from 149.1 to 250.11 kg/m2. Transverse ultrasonographic images were obtained with an 8- to 10-MHz linear transducer and a standoff pad. In both forelimbs, the cross-sectional area, circumference, dorsopalm...
Subpopulations of equine blood lymphocytes expressing regulatory T cell markers. Several distinct T lymphocyte subpopulations with immunoregulatory activity have been described in a number of mammalian species. This study performed a phenotypic analysis of cells expressing regulatory T cell (Treg) markers in the peripheral blood of a cohort of 18 horses aged 6 months to 23 years, using antibodies to both intracellular and cell surface markers, including Forkhead box P3 (FOXP3), CD4, CD8, CD25, interferon gamma (IFNγ) and interleukin 10 (IL-10). In peripheral blood, a mean of 2.2 ± 0.2% CD4+ and 0.5 ± 0.1% CD8+ lymphocytes expressed FOXP3. The mean percentage of CD4+FOXP...
Bilateral iatrogenic [corrected] maxillary fractures after dental treatment in two aged horses. This clinical report describes two horses with bilateral maxillary fractures following dental treatment. The fractures occurred during dental treatment by a veterinarian, and both had rostral, transverse, and complete bilateral maxillary fractures with instability and minimal displacement. The fractures were repaired using bilateral intraoral wiring with the patients under general anesthesia. The postoperative period was without complications and the fractures healed as expected. Maxillary fractures during or after routine dental treatment are rare, but can occur, especially in older horses. A...
Determination of the prevalence and severity of metacarpophalangeal joint osteoarthritis in Thoroughbred racehorses via quantitative macroscopic evaluation. To determine the prevalence and severity of osteoarthritis in the metacarpophalangeal joints of Thoroughbred racehorses via development and validation of a quantitative macroscopic evaluation system. Methods: Metacarpophalangeal joints from 50 Thoroughbred racehorses. Methods: Joints were collected from horses that died or were euthanized within 60 days of racing. Metacarpophalangeal joints were assessed for osteoarthritic degeneration by use of macroscopic and histologic scoring systems, polarized light microscopy, and cartilage biochemical analysis. The global macroscopic score for the entir...
Retrospective evaluation of crib-biting and windsucking behaviours and owner-perceived behavioural traits as risk factors for colic in horses. Although crib-biting (cribbing)/windsucking has previously been associated with 2 types of colic, additional research into the possible role of other behaviours on incidence of colic by type and severity has not been undertaken. Objective: To investigate: a relationship between cribbing/windsucking and colic; a relationship between cribbing/windsucking and different types of colic, both medical and surgical; and whether horses displaying specific behaviour traits were more likely to have had colic. Methods: A matched case-control retrospective study was conducted evaluating horses with various...
Ultrasonographic findings in the lumbosacral joint of 43 horses with no clinical signs of back pain or hindlimb lameness. The transrectal ultrasonographic appearance of the lumbosacral joint was assessed in 43 horses with no history or clinical evidence of back pain or hindlimb lameness. In the majority of horses (34/43, 79.1%) the lumbosacral disc had uniform or mildly heterogeneous echogenicity. However, variation in the ultrasonographic appearance of the lumbosacral joint was also identified, including hyperechogenic regions within the lumbosacral disc with or without an acoustic shadow, and mild or moderate irregularity of the opposing surfaces of the last lumbar and the first sacral vertebral bodies. Marked ...
