Regression analysis is a statistical method used to examine the relationship between variables, often employed to predict outcomes or understand associations in equine studies. In the context of horses, regression analysis can be applied to a variety of research areas, including performance metrics, health parameters, and genetic traits. By analyzing data, researchers can identify patterns or correlations that may inform breeding decisions, training regimens, or health interventions. This page compiles peer-reviewed research studies and scholarly articles that explore the application of regression analysis in equine research, focusing on methodologies, findings, and implications for horse management and care.
Porter MB, Cleaver BD, Peltier M, Robinson G, Sharp DC.Hourly pulses of gonadotropin-releasing hormone (GnRH) or bi-daily injections of estradiol (E2) can increase luteinizing hormone (LH) secretion in ovariectomized, anestrous pony mares. However, the site (pituitary versus hypothalamus) of positive feedback of estradiol on gonadotropin secretion has not been described in mares. Thus, one of our objectives involved investigating the feedback of estradiol on the pituitary. The second objective consisted of determining if hourly pulses of GnRH could re-establish physiological LH and FSH concentrations after pituitary stalk-section (PSS), and the th...
Buchner HH, Savelberg HH, Schamhardt HC, Barneveld A.The complete set of three-dimensional inertial properties (mass, density, centre of mass, inertial tensor) was determined in 26 segments of six Dutch Warmblood horses. The measurements were performed with frozen segments similar to the procedure described by Lephart (1984, J. Biomechanics 17, 537-543). Based on these data linear regression models were developed for the estimation of inertial properties in living horses. The reproducibility of the dissection procedure was found to range between 2 and 9%. Both mean values and regression models are presented for all parameters. The mean standard ...
Martin GS, Strand E, Kearney MT.To determine the relationship between prediction errors of a regression model of racing finish times and earnings or finish position; the relationship between standardized finish times, determined by use of this model, and earnings or finish position; and whether this model was valid when applied to data for horses that underwent surgical treatment. Methods: Survey. Methods: Records of 6,700 healthy Thoroughbreds racing in Louisiana and of 31 Thoroughbreds with idiopathic left laryngeal hemiplegia that underwent surgical treatment. Methods: Predicted and standardized finish times were calculat...
Furr M, Tinker MK, Edens L.This study was conducted to develop an equation for the prediction of outcome in neonatal foals undergoing treatment in an intensive care unit (ICU). Fifty-three physical examination, historical, and clinicopathologic variables were analyzed from the records of 99 neonatal foals (< 14 days of age) treated in the neonatal ICU of the Equine Medical Center. The outcome was recorded and the results were categorized into either surviving or nonsurviving groups. The mean values for the 2 groups were compared, and variables that differed significantly between the two groups were retained and used ...
Studer U, Marti E, Stornetta D, Lazary S, Gerber H.20 sarcoid-affected horses from a practice in the northern Jura were used in this experiment. The mean age of the 20 horses was 3.9 years at the time of the first observation of sarcoid tumors. On the average, 4.4 tumours were noted per horse. 10 of the horses were treated in a double-blind study with an unspecific immunostimulant (Baypamun P), 10 others received a placebo. One single tumour only was treated per horse. The injections were given under and around the sarcoid. In eight out of the 20 horses all tumours regressed totally or for more than 50% of their initial size. Five of these had...
Martin GS, Strand E, Kearney MT.To develop a statistical model to evaluate the influence of specific parameters on racing performance in Thoroughbreds. Methods: Survey. Methods: Racing records of Thoroughbreds performing in Louisiana from 1981 to 1985. Methods: Race results for 20 randomly selected days from 5 racetracks during 5 years were analyzed, using regression analysis. Results: The most influential parameter was distance raced. There were significant differences in racing performance among horses at different tracks. At the tracks examined, fast racing surfaces resulted in significantly faster finish times than good ...
Caron JP, Kaneene JB, Miller R.To determine the patterns of use and perceived efficacy of polysulfated glycosaminoglycan (PSGAG) for the treatment of degenerative joint disease in horses. Methods: Cross-sectional mail survey. Methods: 1,522 equine practitioners. Methods: Information was obtained on frequency and route of administration of PSGAG for the treatment of each of 4 forms of degenerative joint disease, the efficacy of PSGAG, and its efficacy compared with that of sodium hyaluronate. Data were analyzed by nonparametric and multivariate regression methods. Results: Response rate was 40.5%. Of practitioners responding...
Dart AJ, Peauroi JR, Hodgson DR, Pascoe JR.In this retrospective study, postoperative ileus was studied in horses having resection of the small intestine followed by a jejunojejunal (n = 35) or a jejunocaecal (n = 35) anastomosis. Twenty-six horses received no metoclopramide, 27 received metoclopramide as an intermittent intravenous infusion and 17 horses received metoclopramide as a continuous intravenous infusion (0.04 mg/kg/hour). Horses receiving a continuous infusion of metoclopramide had a reduced total volume (P < 0.001), shorter duration (P < 0.001), and a slower rate (P < 0.001) of postoperative gastric reflux, and a ...
Skedros JG, Mason MW, Nelson MC, Bloebaum RD.Functionally induced strains provide epigenetic signaling for bone modeling and remodeling activities. Strain gauge documentation of the equine third metacarpal reveals a neutral axis passing through the craniolateral cortex, resulting in a narrow band of cortex loaded predominantly in tension, with the remainder of the cortex experiencing a wide range of compression strain magnitudes that are maximal in the caudomedial cortex. This predictable strain pattern provides a model for examining the hypothesis that strain mode, magnitude, and strain energy density are potential correlates of compact...
Cohen ND, Honnas CM.To determine the incidence of the risk factors for developing diarrhea in horses after celiotomy for colic. Methods: Retrospective cohort study. Methods: 357 adult horses that had celiotomy for colic at the teaching hospital between Jan 1, 1990 and Sep 1, 1994. Methods: Medical records of horses that had celiotomy for colic were reviewed to abstract information regarding development of diarrhea, signalment, history, and treatment. Results: In horses that had celiotomy for colic, the incidence of diarrhea was 53.2% (190/357). Using multiple logistic regression, horses with a disorder of the lar...
Guhl A, Lindner A, von Wittke P.Eight thoroughbred horses, trained for racing competition, were subjected to a standardised incremental speed test to determine the relationship between their blood lactate concentrations and running speed. Between 14 days before and 14 days after completing the standardised exercise test, the horses were timed for runs of 2000 to 6000 m. The blood lactate concentration after each run was measured and compared with the blood lactate concentration predicted from the individual horse's blood lactate-running speed relationship curve determined from the standardised exercise test. The relationship...
Guhl A, Lindner A, von Wittke P.To examine the reproducibility of blood lactate-running speed curve parameters derived by a curve-fit equation and by linear interpolation from the results of 4-speed tests of sport horses under field conditions. Methods: Thoroughbreds completed 10 test pairs with 3 to 11 days between tests and retest. Methods: 7 Thoroughbreds. Methods: The 4-speed test consisted of 4 runs over a distance of 2,110 m. Exercise intensity was increased by 1 m/s for each run. Blood lactate concentration measured after each run was plotted against running speed to determine the blood lactate-running speed relation....
Pearson RA, Ouassat M.The age, sex, liveweight and body measurements (heart girth, umbilical girth, height, length from elbow to tuber ischii and circumference of the foreleg cannon bone) of 516 donkeys used to transport goods in Morocco were recorded. There were few donkeys over 12 years of age. For adult donkeys weighing from 74 to 252 kg, the best equation with only one variable for predicting liveweight was: liveweight (kg) = heart girth (cm)2.65/2188. The inclusion of two variables improved the prediction marginally, but the addition of further variables gave little further improvement. The best prediction equ...
Yvorchuk-St Jean K, Gaughan E, St Jean G, Frank R.To evaluate the effect of a porous bovine-derived collagen membrane (PBCM) on the rates of wound healing, cellular events, presence of granulation tissue, and appearance at termination of the study in surgically created full-thickness cutaneous wounds of the distal portion of the extremities of horses. Methods: Treated wounds (n = 12) received a PBCM dressing and control wounds were covered with a nonadherent dressing. Forelimbs and hind limbs were cross paired; the right forelimb and left hind limb always received the same dressing application, as did the left forelimb and right hind limb. Li...
de la Rúa-Domènech R, Mohammed HO, Atwill ER, Cummings JF, Divers TJ, Summers BA, deLahunta A, Jackson C.To examine the regional variations in the distribution of equine motor neuron disease (EMND) in the United States and the factors that might explain those variations. Methods: Cluster investigation and case-control study. Methods: The study population consisted of 97 horses with histopathologically confirmed EMND and 698 controls with diagnosis of other spinal cord disorders at 21 US veterinary teaching hospitals participating in the Veterinary Medical Data Base. Methods: The total horse population of the United States was divided into 21 regions, and the regional incidence rates of EMND from ...
Richardson JD, Cripps PJ, Lane JG.The prediction of the age of a horse from its dentition has been widely accepted as an accurate technique, but recent reports have questioned this belief. In this study the dental features of 434 thoroughbreds of known age were documented and a multiple regression equation was calculated from the 13 dental features which had the highest correlation with true age. The accuracy of the ages assessed by a computer model were compared with the ages estimated by experienced equine clinicians. There was little difference between the accuracy of the computer model and the human observers, and neither ...
Back W, Schamhardt HC, Hartman W, Bruin G, Barneveld A.The gait of 24 horses was recorded on a treadmill when they were trotting at 4 m sec-1, first when they were four months old and again when they were 26 months. The data recorded at four months were used to predict the locomotion of the adult horses, and the predictions were assessed against the data recorded at 26 months. The locomotion of the foals and the adults appeared to be closely related, when the differences in segment length and joint angles due to growth were taken into account. The duration of swing, the total range of protraction and retraction, and the maximum tarsal flexion coul...
Grøndahl AM, Engeland A.The tarsocrural, metacarpophalangeal, and metatarsophalangeal joints of 753 Standardbred yearlings were radiographed. On the basis of radiographic findings, the horses were allotted into 4 groups. Group-1 horses had osteochondrosis in the tarsocrural joints. Group-2 horses had palmar/plantar bony fragments in the metacarpo- and metatarsophalangeal joints. Group-3 horses had radiographic changes in the metacarpo- and metatarsophalangeal joint region, such as bony fragments located at the dorsoproximal end of the proximal phalanx, osteochondrosis of the sagittal ridge of the third metacarpus/met...
Reid SW, Mair TS, Hillyer MH, Love S.Multiple logistic regression was used to assess epidemiological risk factors associated with the diagnosis of cyathostomiasis in 87 cases of chronic diarrhoea in the horse. Age, season and the period since last receiving anthelmintics were identified as important risk factors using chi-square and two-sample t test analyses, whereas access to grazing, shared grazing with other horses and recurrence of signs were only weakly associated with a diagnosis of cyathostomiasis. Multivariate analysis of the parameters using logistic regression was performed. The final model included age, season and tim...
McGreevy PD, Cripps PJ, French NP, Green LE, Nicol CJ.A greater knowledge of the effect of management factors is required to investigate the ontogeny of abnormal behaviour in the stabled horse. A postal survey of racehorse (flat) trainers yielded information about 22 yard and management factors. The relationship of the factors to the prevalence of abnormal behaviour was analysed by logistic regression. Management factors related to the time spent in the stable showed the strongest associations with stereotypic behaviour. The risk of horses performing abnormal behaviour increased: 1) as the amount of forage fell below 6.8 kg/day, 2) when bedding t...
Tomizawa N, Nishimura R, Sasaki N, Hayashi Y, Senba H, Hara S, Kadosawa T, Takeuchi A.Morphological differences between cervical vertebrae were statistically analyzed in ataxic foals to clarify abnormal structural factors in the pathogenesis of this problem. At first, multiple regression analysis and cluster analysis were performed with 28 variables in C3-C7 of 39 control foals without lameness. As a result, there were no sex differences in the growth of all cervical vertebral sites, and the most suitable categorization of the age of the foals was 3 clusters of 8 months old or younger, 9-12 months old and 13 months old or older in any sites in the cervical vertebrae. Twenty-eig...
Sims D, Horne MM, Creighan M, Donald A.The objective of this ultrastructural investigation was to determine if populations of pericytes in equine dermal and skeletal muscle capillaries increase in a head-to-foot direction, as has been reported in human skeletal muscles. Samples of equine microvessels were obtained from the longissimus dorsi skeletal muscle 150 cm. from the ground, from the dermis above this muscle, from the extensor carpi radiali muscle at 55 cm. from the ground, from the dermis adjacent to that muscle, and from dermis 15 cm. from the ground, just above the hoof wall. Tissues were processed for transmission electro...
Scudamore CL, Pemberton AD, Miller HR, McDonnell AM, Thomson SR, Dawson A, Watson ED.An enzyme linked immunosorbent assay (ELISA) was developed and used to estimate the concentrations of the serine proteinase inhibitor, alpha-1 proteinase inhibitor (API), in uterine flushings recovered from mares at different stages of the oestrous cycle and before and after the induction of experimental endometritis. There was a significant increase in the concentrations of API and albumin relative to total protein in flushings recovered during oestrus compared with dioestrus but no difference was observed in the concentrations of these proteins relative to total protein before and after the ...
Hanson CM, Kline KH, Foreman JH.Heart scores (the arithmetic mean of the QRS durations of the three bipolar limb leads for 10 cycles) and heart weights were determined from five draft type horses and five racing type horses, and evaluated for relationships between heart score and heart size within and between the two different types of horses. Horses were killed using a captive bolt gun, and actual heart weights were recorded using an electronic digital scale. The linear regression equation for heart weight versus heart score had a significant (P < 0.05) negative slope for racing types. The regression coefficients for heart ...
Furr MO, Bender H.To determine the effects of age on each analyte, CSF variables were evaluated in healthy foals from birth through 42 days of age. Cerebrospinal fluid was collected from 14 clinically normal, naturally delivered cross-bred foals and was analyzed for glucose, sodium, potassium, magnesium, and total protein concentrations, total and differential WBC counts, RBC count, and lactate dehydrogenase, aspartate transaminase, and creatine kinase activities. Samples were collected in 3 foals < 48 hours old, and at 11 to 14 days of age in 4 foals, 21 to 22 days of age in 3 foals, and 31 to 42 days of ag...
Sewell DA, Harris RC, Marlin DJ.Skeletal muscle samples were obtained by needle biopsy from two depths of the m. gluteus medius of 50, young race-trained thoroughbred racehorses. Histochemical and biochemical characteristics of the muscle samples were analysed. Fibres were classified as type I, type IIa or type IIb on the basis of the pH dependent lability of the myosin ATPase reaction. The activities of citrate synthase (CS) and glycogen phosphorylase (Phos) were determined. Muscle fibre composition varied markedly between deep and superficial muscle samples and this was reflected in differences in the activities of citrate...
Misumi K, Sakamoto H, Shimizu R.To investigate the validity of swimming training, the following matters were considered: 1) changes in the performance capacity, 2) changes in the constitution and 3) frequency of locomotor diseases. These were evaluated during a training program including both conventional exercise on a track and swimming. In this study, 24 two-year-old thoroughbred horses were studied, and divided into the following three groups: Group A, trained by only running; Group B, trained by running plus a gradual increase in swimming; Group C, trained by running plus constant swimming. As a result of standardized ex...
Atwill ER, Mohammed HO, de la Rua-Domenech R.A total of 2,579 serum samples from horses in New York state during 1985-1986 were examined for seropositivity to Ehrlichia risticii using the indirect fluorescent antibody technique. Cluster analysis statistical technique was used to group counties according to their estimated EME-disease rate (seropositive proportion of sampled horses). Counties were clustered into 4 groups of different EME-disease rates, representing high (86% seropositive), medium (66% seropositive), medium-low (47% seropositive) and low (6% seropositive) risk regions. The logistic regression statistical technique was used...
Hoshi F, Satho M, Koyama S, Nakadaka K, Chiba M, Ikeda N, Hakamada R, Higuchi S, Kawamura S.The usefulness of a dry-chemistry blood analyzer, Spotchem SP-4410 (SP-4410) in a veterinary clinic for analysis of bovine and equine blood chemistry was studied. We quantitated total protein (TP), albumin (Alb), total bilirubin (T-Bil), blood urea nitrogen (BUN), total cholesterol (T-Cho), glucose (Glu), calcium (Ca), aspartate aminotransferase (AST), gamma-glutamyltransferase (GGT), creatinine phosphokinase (CPK), and alkaline phosphatase (ALP) in bovine sera. Each sample was assayed with both the SP-4410 and an automated blood analyzer which served as a wet-chemistry reference system, and t...
Mohammed HO, Cummings JF, Divers TJ, de la Rua-Domenech R, de Lahunter A.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 ...
de Tonnerre DJ, Medina Torres CE, Stefanovski D, Robinson MA, Kemp KL, Bertin FR, van Eps AW.Sirolimus, a mechanistic target of rapamycin inhibitor, suppresses insulin production in other species and has therapeutic potential for hyperinsulinemia in horses. Objective: Determine the pharmacokinetics (PKs) of sirolimus and evaluate its effect on insulin dynamics in healthy and insulin dysregulation (ID) horses. Methods: Eight Standardbred geldings. Methods: A PK study was performed followed by a placebo-controlled, randomized, crossover study. Blood sirolimus concentrations were measured by liquid chromatography-mass-spectrometry. PK indices were estimated by fitting a 2-compartment mod...
Malalana F, Ireland JL, Pinchbeck GL, McGowan CM.Risk factors for a first episode of primary uveitis in horses have not been determined. In addition, disease progression and the proportion of horses that develop recurrence following the original episode are not known. Objective: To determine the risk factors for the development of a first episode of primary uveitis in horses in the UK and to document the proportion of cases that experience recurrence following this first episode. Methods: Prospective case-control longitudinal study. Methods: Horses with a first episode of primary uveitis between July 2014 and August 2018 were recruited to th...
Soma LR, Stefonovski D, Robinson MA, Tsang DS, Haughan J, Boston RC.A retrospective study was conducted to establish the prerace venous acid-base and blood gas values of Standardbred horses at rest using big data analytics. Methods: Venous blood samples (73,382) were collected during seven racing seasons from 3 regional tracks in the Commonwealth of Pennsylvania. Horses were detained 2 hours prior to race time. Methods: A mixed-effects linear regression model was used for estimating the marginal model adjusted mean (marginal mean) for all major outcomes. The interaction between age and gender, track, and the interaction between month, treatment (furosemide), a...
O'Brien TJ, Rosanowski SM, Mitchell KD, Carrick JB, Butt TD, Adkins AR.There is little consensus on factors associated with survival in foals with septic arthritis and limited data on long-term racing performance of Thoroughbred foals treated for septic arthritis. A more thorough understanding of short- and long-term outcome is necessary to help inform owners, and subsequently guide treatment. Objective: To investigate factors associated with survival, and to analyse racing performance of foals with septic arthritis compared with their maternal siblings. Methods: Retrospective cohort and a case-control study. Methods: Veterinary clinical records of Thoroughbred f...
Nagy A, Dyson SJ, Murray JK.Information acquired from endurance riders and its relationship with the results of the ride has not been investigated. The aims of this study were to assess associations between data provided by riders and data obtained from the Fédération Equestre Internationale (FEI) website at FEI endurance rides and to identify whether data provided by riders in pre- and post-ride questionnaires was subject to response and/or information bias. Variables were collected from the FEI website and from self-completed pre-ride and post-ride questionnaires at 20 FEI endurance rides in 2011 and 2012. Kappa stat...
Solter PF, Farner S.The purpose of this study was to compare 2 different nonradioactive assay methods with a conventional radioimmunoassay (RIA) measuring the concentration of serum thyroxine (T4) in horses. Serum was obtained from 85 adult standardbred horses. The T4 concentration of each sample was analyzed by RIA, chemiluminescent enzyme immunoassay (CEI), and homogeneous enzyme immunoassay (HEI). The correlation between the HEI method and RIA method was significantly greater (r = 0.89) than the correlation between the CEI and the reference method (r = 0.53). In addition, the precision of the HEI method was si...
Blanchard TL, Thompson JA, Love CC, Brinsko SP, Ramsey J, O'Meara A, Varner DD.Records (years 2005-2007) were analyzed from a Thoroughbred stud farm in central Kentucky. Data from all breeding cycles of foaling mares were tabulated (3184 cycles of 2003 foaling mares bred between 7 and 163 days postpartum). A multiple logistic regression model employing Bayesian statistics was used to adjust for factors that significantly affected outcome; odds ratios (ORs) for pregnancy rate, pregnancy loss rate, and foaling rate were determined to examine the influence of day of postpartum breeding on these parameters. Mares bred before Day 22 (Day 0 = day of foaling) postpartum had a d...
Rodriguez MH, Chavez B, Hernandez-Avila JE, Orozco A, Arredondo-Jimenez JI.Light and scanning electron microscopy were used to compare the eggs of Anopheles vestitipennis Dyar & Knab females collected from human and animal baits in 9 villages of southern Mexico. An. vestitipennis eggs are boat-shaped, with lateral floats extending the length of the egg. Both the deck and dorsal surface are covered with hexagonal and pentagonal chorionic cells that contain round tubercles in the cell field. Crowns that enclose 3-5 lobed tubercles are present at both egg poles. By light microscopy, the mean length/width ratio of eggs of females caught at human bait were statistical...
Jönsson L, Madsen P, Mark T.Genetic evaluations of sport performance typically consider competition records of ranking points in each competition, accumulated lifetime points or annual earnings. Repeated observations have the advantage of allowing for adjustment of effects associated with each competition such as rider experience, judge and competing horses, but also demands more computer capacity than single-trait records, which could prohibit multiple-trait evaluations. The aim of the study was to compare CPU times, estimated breeding values (EBVs), reliabilities and model prediction abilities when modelling repeated c...
Riber C, Cuesta I, Muñoz A, Gata J, Trigo P, Castejón FM.Fatigue during endurance rides might induce changes in gait pattern that could be difficult to distinguish from subtle lameness. Objective: To assess changes in gait pattern en route, in fore(FL) and hindlimbs (HL) and establish differences between excellent (EP) and good performers (GP). Methods: Seventy-five sound and fit horses that completed endurance rides of 80 km were filmed at trot in the vet-gates (VGs) prior to competitions (VGO), and at 29 km (VG1), 59 km (VG2) and 80 km (VG3). Mean gait velocity (V), stride length (SL), duration (SD) and frequency (SF) were measured. Also, stance (...
Visser HE, Diehl KA, Whitley RD, Myrna KE.To compare Schirmer tear test I (STTI) values collected in normal horses with and without an auriculopalpebral nerve block. Methods: Schirmer tear test I values were measured in 20 clinically normal horses (38 eyes) with a median age of 12 years. The order of eyes tested was randomized. Within 24-48 h, at the same time of day, tear measurements were collected again after administration of an auriculopalpebral nerve block. Each block was performed a minimum of 5 min prior to each STT I. A repeated-measures model was used to analyze differences between STT I values in eyes with and without nerve...
Nequin LG, King SS, Roser JF, Soderstrom BL, Carnevale EM, Neumann KR.The reproductive activity of light horse mares (n=12) was monitored each day from 3 September until 29 January, or until the mares entered anoestrus, by behaviour evaluation, ultrasonography and blood sampling. Follicles, corpora lutea and ovulation, as well as oestradiol, progesterone, and LH and FSH concentrations, were analysed to determine a reproductive profile for the transition into anoestrus. The results of the present study indicate that light horse mares progress through four phases during the autumn transition into anoestrus: (i) normal cycles; (ii) aberrant cycles; (iii) anovulatio...
Clutton RE, Chase-Topping M, Squires R, Lawson H, Minard H, Rose S.The dimensions of anaesthetised hobbled horses during suspension and transfer onto the operating table are unknown. These data are required for the cost-effective construction of equine surgical facilities. Objective: To measure the distance from the toe to dependent back margin (Bsusp) and poll (Psusp) of anaesthetised suspended horses and correlate them with readily obtained measures from standing animals. Methods: Digital photographs of suspended horses were taken in the anaesthesia induction box at a fixed position that allowed trigonometric determination of Bsusp and Psusp. These values w...
Sugita S, Oki H, Hasegawa T, Ishida N.Estimation formulas for the morbidity of horses infected with equine influenza virus by linear regression, logistic regression and probit transformation were developed, using data from the outbreak at the Sha Tin Racing Track in Hong Kong in 1992. Using these formulas, we estimated the equine influenza virus morbidity rates at training centers belonging to the Japan Racing Association (JRA) in October 1997 and in October 1998. In 1998 JRA started a new vaccination program, and every horse must now be vaccinated twice per year. At that time, the vaccine included two US lineage virus strains, th...
Tabar-Rodriguez JJ, Cruz AM, Monteith G, Gordon K, Hurtig MB.OBJECTIVE-To use quantitative ultrasonography to evaluate the association between the speed of sound (SOS) at 9 sites in the third metacarpal bone (MCIII) of racing Thoroughbreds with workload accumulation and the effect that MCIII failure has on this association. ANIMALS-Sixty-two 2- and 3-year-old Thoroughbreds in racing condition. PROCEDURES-Cumulative work index (CWI) was used to calculate total workload (CWI(total)) and also 3 independent CWIs for the various gaits (ie, trot [CWI(trot)], gallop [CWI(gallop)], and race [CWI(race)]) used during training and racing. Speed of sound was monito...
Pascoe RR, Pascoe DR, Wilson MC.Between 1982 and 1985, 1015 mares were evaluated using the following parameters: age, mare status (maiden, barren, lactating), Caslick index, Caslick operation, ovarian cycle, ovarian and follicular size, treatments (hCG and intrauterine infusions), number of ovulations after mating (184 mares), number of conceptuses present, dimensions of embryonic vesicles, and pregnancy status 45 days after mating. Mares were examined ultrasonographically between Days 12 and 25 to detect the presence of embryonic vesicles and measure the dimensions of each vesicle. The data were analysed by a stepwise logis...
Solar Diaz IDP, Strauss Borges Junqueira G, Aparecida Rocha Cruz V, Albano Araújo de Oliveira C, Nunes de Oliveira H, Miguel Ferreira de Camargo G....Principal component analysis (PCA) was applied to evaluate the genetic variability and relationship between 15 morphometric traits in 91,483 Campolina horses, as well as to propose an index based on an aggregate genotype that promotes a particular selection objective. PCA was applied to the genetic (co)variance matrix among variables. After calculation of the principal components, the breeding values were estimated to obtain an index related to the component that explained most of the variation. The first principal component (PC1) accounted for 97.8% of the total additive genetic variance of t...
Önder H, Şen U, Piwczyński D, Kolenda M, Drewka M, Abacı SH, Takma Ç.This work aimed to compare the fitting performance of the random regression models applied to the different order orthogonal Legendre polynomials on the race completion speed (m/s) of Arabian racing horses. Legendre polynomial function for additive genetic, permanent environmental variances and heritability values with the L(2,2), L(2,3), L(3,2) and L(3,3) models (where L(i,j) means L(order of fit for additive genetic effects, order of fit for permanent environmental effects)) was estimated. A total of 233,491 race speed records (m/s) of Arabian horses were taken from the Jockey Club of Turkey...
Salamanca-Carreño A, Parés-Casanova PM, Monroy-Ochoa NI, Vélez-Terranova M.This study examined paedomorphosis in PAH and F1 crossbreds. A sample of 99 horses was selected from 40 different breeders and consisted of three groups: stallions ( = 16), mares ( = 53), and geldings ( = 30), ranging from 10 months to 27 years in age. All horses presented a concave celloid lateral left head profile in the acquired photographic images. The hypothesis proposed in this study suggested the lateral profile of the head in juveniles was representational in the adult form due to the neonate's facial bones (part of the splanchnocranium) developing at a different rate to those of the s...
Sánchez-Guerrero MJ, Ripollés-Lobo M, Bartolomé E, Perdomo-González DI, Valera M.The Arabian horse is a generally reliable sport horse, and continues to be a remarkable endurance horse, so the relevance of the expected value of the proportion of Arabian genes (EV%AG) in horses participating in eventing could be a relevant factor. A total of 1089 horses participating in eventing (8866 records) were used. A GLM revealed that the EV%AG was significant in dressage, show jumping and cross-country. A BLUP genetic evaluation was computed with five genetic models (without the EV%AG (0) using as a covariate (A), as a fixed effect (B), with variance heterogeneity, and in genetic gro...
Kaps M, Curik I, Baban M.Heterogeneity of variance of growth traits over age is a common issue in estimating genetic parameters and is addressed in this study by selecting appropriate variance structure models for additive genetic and environmental variances. Modeling and partitioning those variances connected with analyzing small data sets were demonstrated on Lipizzan horses. The following traits were analyzed: withers height, chest girth, and cannon bone circumference. The measurements were taken at birth, and at approximately 6, 12, 24, and 36 mo of age of 660 Lipizzan horses born in Croatia between 1948 and 2000....
Salamanca-Carreño A, Parés-Casanova PM, Crosby-Granados RA, Vélez-Terranova M, Bentez-Molano J.The skull is divided into neurocranium and splanchnocranium, and its variation allows ecomorphological studies to learn about possible evolutionary and adaptive characteristics. The basicranial organization of the neurocranium and splanchnocranium modules was studied in a sample of 31 skulls from adult Araucanian horses by means of 2D geometric morphometric techniques. The neurocranium and splanchnocranium modules on the ventral aspect were analyzed separately using a set of 31 landmarks. The RV coefficient (the multivariate analog of a correlation) was estimated to analyze the independence of...
Kovár J.The possibility of using the test for pulse-rate response to gradated load in the evaluation of the endurance component of horse performance (in other words, response to the degree of horse adaptation to load) is discussed in detail. A mathematic-statistical analysis of regression coefficients is performed in the equations of the dependence of pulse rate on speed obtained in 278 three years old horses in the period following the termination of the basic training (145 Bohemian Warm-Blooded horses, 115 Kladrub Black horses and 18 English Half-Breds). A ten-score scale is calculated on the basis ...
Miller PJ, Holmes JR.Transaortic blood pressures were recorded in seven horses using catheter mounted transducers during various types of supraventricular arrhythmia. Changes in left ventricular (LV) and aortic (Ao) pulse contours were associated with variation in pulse interval (PI). When PI lengthened there was a rise in LV end diastolic pressure (LVEDP) associated with a prolonged filling time. In contrast, a long PI resulted in a reduced end diastolic Ao pressure (AoEDP) due to a prolonged arterial 'run off'. LVdP/dt max representing the peak rate of rise of pressure during the isovolumic contraction period wa...
Leach DH, Sprigings EJ, Laverty WH.Standard univariate and bivariate statistical methods and two multivariate methods, stepwise regression and factor analyses, were used to analyze 17 stride-timing measurements of 22 racing Thoroughbreds filmed at the beginning of races. All horses were in a right-lead transverse gallop. Data were extracted from frame-by-frame analysis of 16-mm film taken with a high-speed camera. The mean stride duration was 0.405 s and the mean stride frequency was 2.47 strides/s. Stride duration had a higher correlation to the suspension-phase duration (r = 0.864) than to stride-stance-phase duration (r = 0....
Cymbaluk NF, Christison GI, Leach DH.Eighteen Quarter Horse and Paint weanling colts were assigned to two treatments, either limit or ad libitum feeding. Nutrient digestibilities of diets were evaluated between 6 and 12 mo, 12 and 18 mo and 18 and 24 mo of age. From 6 to 12 mo, energy digestibility (64 to 68%) was unaffected by feed intake level. Ad libitum-fed horses had energy digestibilities 9 to 10% greater (P less than .05) than limit-fed horses between 12 and 24 mo of age, but adjustment for DM intake removed these differences. Limit-fed, mature ponies used dietary energy similarly to growing horses from 6 to 18 mo of age, ...
Beech DJ, Roche ED, Sibbons PD, Rossdale PD, Ousey JC.Mean glomerular volume has previously been estimated, using stereological techniques, specifically the point-sampled intercept (PSI), either from isotropic or from vertical sections. As glomeruli are approximately spherical structures, the same stereological technique was carried out on vertical and arbitrary sections to determine whether section orientation had any effect on mean glomerular volume estimation. Equine kidneys from 10 individuals were analysed using the PSI method of estimating volume-weighted mean glomerular volume (MGV); for each kidney, arbitrary and vertical sections were an...
Russold E, Ambrisko TD, Schramel JP, Auer U, Van Den Hoven R, Moens YP.To compare tidal volume estimations obtained from Respiratory Ultrasonic Plethysmography (RUP) with simultaneous spirometric measurements in anaesthetized, mechanically ventilated horses. Methods: Prospective randomized experimental study. Methods: Five experimental horses. Methods: Five horses were anaesthetized twice (1 week apart) in random order in lateral and in dorsal recumbency. Nine ventilation modes (treatments) were scheduled in random order (each lasting 4 minutes) applying combinations of different tidal volumes (8, 10, 12 mL kg(-1)) and positive end-expiratory pressures (PEEP) (0,...
Guhl A, Lindner A, von Wittke P.To examine the reproducibility of blood lactate-running speed curve parameters derived by a curve-fit equation and by linear interpolation from the results of 4-speed tests of sport horses under field conditions. Methods: Thoroughbreds completed 10 test pairs with 3 to 11 days between tests and retest. Methods: 7 Thoroughbreds. Methods: The 4-speed test consisted of 4 runs over a distance of 2,110 m. Exercise intensity was increased by 1 m/s for each run. Blood lactate concentration measured after each run was plotted against running speed to determine the blood lactate-running speed relation....
Boorman S, Richardson DW, Hogan PM, Stefanovski D, Levine DG.To report the performance of thoroughbred racehorses after surgical repair of a medial condylar fracture of the third metacarpal/metatarsal bone. Methods: Retrospective cohort study. Methods: Forty-three horses surgically treated for medial condylar fractures, 30 with previous racing experience, 13 without previous racing experience (nonexperienced). Methods: Medical records (2009-2017) were reviewed for signalment, radiographic fracture characteristics, repair technique, and postoperative morbidity and mortality. Each experienced horse was matched with two horses randomly selected from its mo...
