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Topic:Comparative Study

Comparative studies in equine research involve the systematic analysis of different horse breeds, management practices, or physiological responses to identify variations and similarities. These studies are instrumental in understanding how different factors influence health, performance, and behavior in horses. Common areas of comparison include genetic traits, nutritional requirements, disease resistance, and response to training. By evaluating these differences, researchers can develop targeted strategies for breeding, healthcare, and training. This page aggregates peer-reviewed research studies and scholarly articles that focus on the methodologies, findings, and implications of comparative studies in the context of equine science.
Anti-Müllerian hormone as an indicator of hemi-castrated unilateral cryptorchid horses.
Journal of equine science    March 31, 2015   Volume 26, Issue 1 15-20 doi: 10.1294/jes.26.15
Murase H, Saito S, Amaya T, Sato F, Ball BA, Nambo Y.Anti-Müllerian hormone (AMH), a glycoprotein secreted from the fetal testis, is responsible for regression of the Müllerian duct in the male fetus. The aim of this study was to evaluate the usefulness of serum AMH as a biomarker for diagnosis of cryptorchidism in horses. Serum AMH concentrations were measured in intact stallions, hemi-castrated unilateral cryptorchid stallions, and geldings. In addition, expression of AMH was characterized in cryptorchid testes by immunohistochemistry. Serum AMH was detected in intact stallions (n=11, 13.3 ± 1.8 ng/ml) and in hemi-castrated cryptorchid stal...
Characterization of discrete equine intestinal epithelial cell lineages.
American journal of veterinary research    March 31, 2015   Volume 76, Issue 4 358-366 doi: 10.2460/ajvr.76.4.358
Gonzalez LM, Kinnin LA, Blikslager AT.To characterize epithelial cells of the small intestine and colon in horses without clinical gastrointestinal abnormalities with an emphasis on the stem cell niche constituents. Methods: Mucosal biopsy specimens from small and large intestines obtained from 12 horses euthanized for reasons unrelated to gastrointestinal disease or systemic disease. Methods: Intestinal biopsy specimens were collected by sharp dissection immediately following euthanasia. Specimens were prepared for immunohistochemical, immunofluorescence, and transmission electron microscopic imaging to detect and characterize ea...
An analysis of the effect of thermometer type and make on rectal temperature measurements of cattle, horses and sheep.
New Zealand veterinary journal    March 31, 2015   Volume 63, Issue 3 171-173 doi: 10.1080/00480169.2014.967325
Hine L, Laven RA, Sahu SK.To compare the variation in rectal temperature measurement by digital, mercury and ethanol thermometers in cattle, horses and sheep. Methods: Seven different makes of thermometer (four digital, two mercury, and one ethanol; (n=27) were tested individually in a calibrated water bath to identify whether there was an effect of thermometer make on recorded temperature. In addition, rectal temperatures of four cattle, four sheep and four horses were recorded using the same thermometers, by seven persons, with each person being assigned to one thermometer make. Results: In the water bath test, mean ...
Two variants in the KIT gene as candidate causative mutations for a dominant white and a white spotting phenotype in the donkey.
Animal genetics    March 27, 2015   Volume 46, Issue 3 321-324 doi: 10.1111/age.12282
Haase B, Rieder S, Leeb T.White spotting phenotypes have been intensively studied in horses, and although similar phenotypes occur in the donkey, little is known about the molecular genetics underlying these patterns in donkeys. White spotting in donkeys can range from only a few white areas to almost complete depigmentation and is characterised by a loss of pigmentation usually progressing from a white spot in the hip area. Completely white-born donkeys are rare, and the phenotype is characterised by the complete absence of pigment resulting in pink skin and a white coat. A dominant mode of inheritance has been demons...
Comprehensive protein profiling of synovial fluid in osteoarthritis following protein equalization.
Osteoarthritis and cartilage    March 26, 2015   Volume 23, Issue 7 1204-1213 doi: 10.1016/j.joca.2015.03.019
Peffers MJ, McDermott B, Clegg PD, Riggs CM.The aim of the study was to characterise the protein complement of synovial fluid (SF) in health and osteoarthritis (OA) using liquid chromatography mass spectrometry (LC-MS/MS) following peptide-based depletion of high abundance proteins. Methods: SF was used from nine normal and nine OA Thoroughbred horses. Samples were analysed with LC-MS/MS using a NanoAcquity™ LC coupled to an LTQ Orbitrap Velos. In order to enrich the lower-abundance protein fractions protein equalisation was first undertaken using ProteoMiner™. Progenesis-QI™ LC-MS software was used for label-free quantification. ...
Serum antibody immunoreactivity to equine zona protein after SpayVac vaccination.
Theriogenology    March 24, 2015   Volume 84, Issue 2 261-267 doi: 10.1016/j.theriogenology.2015.03.012
Mask TA, Schoenecker KA, Kane AJ, Ransom JI, Bruemmer JE.Immunocontraception with porcine ZP (pZP) can be an effective means of fertility control in feral horses. Previous studies suggest that antibodies produced after pZP vaccination may both inhibit fertilization and cause follicular dysgenesis. Zonastat-H, PZP-22, and SpayVac are three pZP vaccines proposed for use in horses. Although all these vaccines contain the pZP antigen, variations in antigen preparation and vaccine formulation lead to differences in antigenic properties among them. Likewise, despite numerous efficacy and safety studies of Zonastat-H and PZP-22, the contraceptive mechanism...
Age-dependent expression of osteochondrosis-related genes in equine leukocytes.
Veterinary record open    March 24, 2015   Volume 2, Issue 1 e000058 doi: 10.1136/vetreco-2014-000058
Mendoza L, Piquemal D, Lejeune JP, Vander Heyden L, Noguier F, Bruno R, Sandersen C, Serteyn D.Osteochondrosis (OC) is a developmental disease in horses which has a significant impact on the horse's welfare and performance. The early disturbance in the process of endochondral ossification progresses to inflammatory and repair processes in older horses. Previously, differentially expressed genes in leukocytes of OC-affected horses have been identified. The aim of the present study is to detect age-related changes in these differentially expressed genes. Methods: The expression of OC-related genes was analysed by real-time PCR and subsequent statistical analysis (ΔΔCT) in the leukocytes...
The role of microRNAs in equine medicine: a review.
The veterinary quarterly    March 24, 2015   Volume 35, Issue 2 88-96 doi: 10.1080/01652176.2015.1021186
van der Kolk JH, Pacholewska A, Gerber V.The search for new markers of diseases in human as well as veterinary medicine is ongoing. Recently, microRNAs (miRNAs or miRs) have emerged as potential new biomarkers. MiRNAs are short sequences of RNA (∼22 nucleotides) that regulate gene expression via their target messenger RNA (mRNA). Circulating miRNAs in blood can be used as novel diagnostic markers for diseases due to their evolutionary conservation and stability. As a consequence of their systemic and manifold effects on the gene expression in various target organs, the concept that miRNAs could function as hormones has been suggest...
Cytoskeletal alterations associated with donor age and culture interval for equine oocytes and potential zygotes that failed to cleave after intracytoplasmic sperm injection.
Reproduction, fertility, and development    March 24, 2015   Volume 27, Issue 6 944-956 doi: 10.1071/RD14468
Ruggeri E, DeLuca KF, Galli C, Lazzari G, DeLuca JG, Carnevale EM.Intracytoplasmic sperm injection (ICSI) is an established method to fertilise equine oocytes, but not all oocytes cleave after ICSI. The aims of the present study were to examine cytoskeleton patterns in oocytes after aging in vitro for 0, 24 or 48h (Experiment 1) and in potential zygotes that failed to cleave after ICSI of oocytes from donors of different ages (Experiment 2). Cytoplasmic multiasters were observed after oocyte aging for 48h (P<0.01). A similar increase in multiasters was observed with an increased interval after ICSI for young mares (9-13 years) but not old (20-25 years) mares...
Characterization and comparison of the bacterial microbiota in different gastrointestinal tract compartments in horses.
Veterinary journal (London, England : 1997)    March 23, 2015   Volume 205, Issue 1 74-80 doi: 10.1016/j.tvjl.2015.03.018
Costa MC, Silva G, Ramos RV, Staempfli HR, Arroyo LG, Kim P, Weese JS.The advance of new sequencing technologies has allowed more comprehensive characterization of complex microbial communities, including the ones inhabiting the intestinal tract. The presence of extreme environmental filters, such as low pH, digestive enzymes and anaerobic conditions along the tract, acts on the selection of unique bacteria in each compartment. The intestinal microbiota has an enormous impact on the maintenance of health. However, data about the bacteria present in the different intestinal compartments of horses are sparse. In this study, high throughput sequencing was used to c...
Long-term characteristics of idiopathic persistent corpus luteum in the mare.
Theriogenology    March 23, 2015   Volume 84, Issue 2 242-251 doi: 10.1016/j.theriogenology.2015.03.015
Santos VG, Bettencourt EM, Ginther OJ.Persistent CL (PCL; n = 10) in mares was studied daily from Day 20 (Day 0 = ovulation) to the ending ovulation. In addition, the 10 days before ovulation at the end of a PCL were compared with the end of an interovulatory interval (IOI; n = 28) during the same months. Concentration of P4, cross-sectional area of CL, and percentage of CL with Doppler signals of blood flow during PCLs remained constant from 64 to about 33 days before the end of luteolysis and then decreased linearly. Concentration of LH between Day 20 and beginning of the ovulatory LH surge increased linearly. A dominant follicl...
Reduced high intensity training distance had no effect on VLa4 but attenuated heart rate response in 2-3-year-old Standardbred horses.
Acta veterinaria Scandinavica    March 20, 2015   Volume 57, Issue 1 17 doi: 10.1186/s13028-015-0107-1
Ringmark S, Lindholm A, Hedenström U, Lindinger M, Dahlborn K, Kvart C, Jansson A.Training of Standardbred race horses aims to improve cardiovascular and metabolic functions but studies on the effects of different training strategies from breaking till racing are lacking. Sixteen horses with the goal to race as 3-year-olds were studied from breaking (1-year-olds) to December as 3-year-olds. Horses were allocated to either a control (C) or reduced (R) training program from 2 years of age. The aim was to evaluate the effect of reducing the distance of high intensity exercise by 30% with respect to velocity at lactate concentration 4 mmol/l (VLa4), blood lactate and cardiovasc...
Regulatory T cells in early life: comparative study of CD4+CD25high T cells from foals and adult horses.
PloS one    March 19, 2015   Volume 10, Issue 3 e0120661 doi: 10.1371/journal.pone.0120661
Hamza E, Mirkovitch J, Steinbach F, Marti E.The immune system of mammals is subject to continuous development during the postnatal phase of life. Studies following the longitudinal development of the immune system in healthy children are limited both by ethical considerations and sample volumes. Horses represent a particular valuable large animal model for T regulatory (Treg) cells and allergy research. We have recently characterised Treg cells from horses, demonstrated their regulatory capability and showed both their expansion and induction in vitro. Insect bite hypersensitivity (IBH) is a common allergy in horses resembling atopic de...
The transcriptome of equine peripheral blood mononuclear cells.
PloS one    March 19, 2015   Volume 10, Issue 3 e0122011 doi: 10.1371/journal.pone.0122011
Pacholewska A, Drögemüller M, Klukowska-Rötzler J, Lanz S, Hamza E, Dermitzakis ET, Marti E, Gerber V, Leeb T, Jagannathan V.Complete transcriptomic data at high resolution are available only for a few model organisms with medical importance. The gene structures of non-model organisms are mostly computationally predicted based on comparative genomics with other species. As a result, more than half of the horse gene models are known only by projection. Experimental data supporting these gene models are scarce. Moreover, most of the annotated equine genes are single-transcript genes. Utilizing RNA sequencing (RNA-seq) the experimental validation of predicted transcriptomes has become accessible at reasonable costs. To...
Using epidemics to map H3 equine influenza virus determinants of antigenicity.
Virology    March 19, 2015   Volume 481 187-198 doi: 10.1016/j.virol.2015.02.027
Woodward A, Rash AS, Medcalf E, Bryant NA, Elton DM.Equine influenza is a major cause of respiratory infections in horses and causes widespread epidemics, despite the availability of commercial vaccines. Antigenic drift within the haemagglutinin (HA) glycoprotein is thought to play a part in vaccination breakdown. Here, we carried out a detailed investigation of the 1989 UK outbreak, using reverse genetics and site-directed mutagenesis, to determine the individual contribution of amino acid substitutions within HA. Mutations at positions 159, 189 and 227 all altered antigenicity, as measured by haemagglutination-inhibition assays. We also compa...
Species-specific effects on non-enzymatic metmyoglobin reduction in vitro.
Meat science    March 19, 2015   Volume 105 108-113 doi: 10.1016/j.meatsci.2015.03.010
Elroy NN, Rogers J, Mafi GG, VanOverbeke DL, Hartson SD, Ramanathan R.Our objectives were to determine the non-enzymatic metmyoglobin reduction properties of bovine, porcine, and equine myoglobins and to characterize the effects of pre-incubation of 4-hydroxy-2-nonenal (HNE) with myoglobins on non-enzymatic metmyoglobin reduction in vitro. Purified bovine, porcine, and equine metmyoglobins (0.05 mM) were reduced at pH 5.6 and 7.4 in the presence or absence of HNE. Rates of metmyoglobin reduction were monitored by spectrophotometry, and myoglobin adducts were characterized by high-resolution mass-spectrometry. Results showed that the species origins of individual...
Relationships among nitric oxide metabolites and pulses of a PGF2α metabolite during and after luteolysis in mares.
Theriogenology    March 18, 2015   Volume 84, Issue 2 193-199 doi: 10.1016/j.theriogenology.2015.03.010
Ginther OJ, Wolf CA, Baldrighi JM, Greene JM.Hourly circulating concentrations of a PGF2α metabolite (PGFM), progesterone (P4), and LH were obtained from a reported project, and concentrations of nitric oxide (NO) metabolites (NOMs; nitrates and nitrites) were determined in eight mares. Unlike the reported project, hormone concentrations were normalized to the peak of the first PGFM pulse of luteolysis (early luteolysis), second PGFM pulse (late luteolysis), and a pulse after luteolysis. The duration of luteolysis was 23.1 ± 1.0 hours, and the peak of the first and second PGFM pulses occurred 6.5 ± 0.9 and 14.8 ± 0.8 hours after the ...
Carotenoids and fat-soluble vitamins in horse tissues: a comparison with cattle.
Animal : an international journal of animal bioscience    March 17, 2015   Volume 9, Issue 7 1230-1238 doi: 10.1017/S1751731115000415
Álvarez R, Meléndez-Martínez AJ, Vicario IM, Alcalde MJ.Carotenoids are important for human health because of their provitamin A function among other biological actions. Their implication on consumer point of view of cattle products have been widely studied, but very little information is available for horse products. The aim of this study was to study the accumulation of carotenoids, retinoids and tocopherol by HPLC and HPLC-MS analysis in different horse tissues (plasma, milk, adipose tissue and liver) and compare it with that of cattle. Fat color was also studied. Four groups of animals were studied (15 animals within each group): lactating mare...
Effects of sodium citrate and acid citrate dextrose solutions on cell counts and growth factor release from equine pure-platelet rich plasma and pure-platelet rich gel.
BMC veterinary research    March 14, 2015   Volume 11 60 doi: 10.1186/s12917-015-0370-4
Giraldo CE, Álvarez ME, Carmona JU.There is a lack information on the effects of the most commonly used anticoagulants for equine platelet rich plasmas (PRPs) elaboration on cell counts and growth factor release from platelet rich gels (PRGs). The aims of this study were 1) to compare the effects of the anticoagulants sodium citrate (SC), acid citrate dextrose solution A (ACD-A) and ACD-B on platelet (PLT), leukocyte (WBC) and on some parameters associated to platelet activation including mean platelet volume (MPV) and platelet distribution width (PDW) between whole blood, pure PRP (P-PRP) and platelet-poor plasma (PPP); 2) to ...
Genetic evolution of equine influenza strains isolated in France from 2005 to 2010.
Equine veterinary journal    March 13, 2015   Volume 47, Issue 2 207-211 doi: 10.1111/evj.12244
Legrand LJ, Pitel PH, Cullinane AA, Fortier GD, Pronost SL.REASON FOR PERFORMING THIS STUDY: Equine influenza virus (EIV) is considered the most economically important equine respiratory pathogen worldwide. The H3N8 subtype, responsible for all outbreaks of equine influenza globally, evolves perpetually. Mutations in the genome of these viruses have the potential to modify their antigenic properties and recognition by pre-existing antibodies. Objective: The aim of this study was to determine the genetic evolution of EIV strains in France and to compare it with the evolution of strains isolated globally. Analysis of the sequence data was performed to i...
Molecular identification of Cryptosporidium isolates from exotic pet animals in Japan.
Veterinary parasitology    March 12, 2015   Volume 209, Issue 3-4 254-257 doi: 10.1016/j.vetpar.2015.02.035
Abe N, Matsubara K.The Cryptosporidium horse genotype, a zoonotic protozoan parasite first found in a Prezewalski wild horse, has not been found in any other mammal but calves, horses, and humans. Hedgehogs, popular exotic pet animals in Japan, are a reservoir of two zoonotic Cryptosporidum: C. parvum and C. erinacei (previously known as the hedgehog genotype). Recently, after finding Cryptosporidium infection in a four-toed hedgehog (Atelerix albiventris), we identified the isolate genetically as the Cryptosporidium horse genotype. Its subtype (VIbA13) was the same as that of an isolate from a pet shop employee...
Effects of acceleration on gait measures in three horse gaits.
The Journal of experimental biology    March 12, 2015   Volume 218, Issue Pt 9 1453-1460 doi: 10.1242/jeb.113225
Nauwelaerts S, Zarski L, Aerts P, Clayton H.Animals switch gaits according to locomotor speed. In terrestrial locomotion, gaits have been defined according to footfall patterns or differences in center of mass (COM) motion, which characterizes mechanisms that are more general and more predictive than footfall patterns. This has generated different variables designed primarily to evaluate steady-speed locomotion, which is easier to standardize in laboratory conditions. However, in the ecology of an animal, steady-state conditions are rare and the ability to accelerate, decelerate and turn is essential. Currently, there are no data availa...
Impact of karyotype organization on interlocus recombination between T cell receptor genes in Equidae.
Cytogenetic and genome research    March 11, 2015   Volume 144, Issue 4 306-314 doi: 10.1159/000377712
Drbalova J, Musilova P, Kubickova S, Sebestova H, Vahala J, Rubes J.The T cell receptor (TCR) genes (TRA, TRB, TRD and TRG) reside in 3 different chromosomal regions. During the maturation of T lymphocytes, the TCR genes are rearranged by site-specific recombination, a process that also predisposes T cells to aberrant rearrangements. Illegitimate recombination between the TCR genes occurs at a low level in healthy individuals, but this frequency may correlate with the risk of lymphoma. The aim of this work was to investigate interlocus recombination in equids. Illegitimate rearrangements were studied in peripheral blood lymphocytes by FISH with painting and BA...
Group C Streptococcus dysgalactiae subsp. equisimilis in south-east Brazil: genetic diversity, resistance profile and the first report of human and equine isolates belonging to the same multilocus sequence typing lineage.
Journal of medical microbiology    March 9, 2015   Volume 64, Issue Pt 5 551-558 doi: 10.1099/jmm.0.000052
Silva LG, Genteluci GL, Corrêa de Mattos M, Glatthardt T, Sá Figueiredo AM, Ferreira-Carvalho BT.Streptococcus dysgalactiae subsp. equisimilis (SDSE) isolates are the most common group C streptococci in humans and reports of invasive infections associated with SDSE have been increasing. Molecular epidemiology studies are an important strategy to trace the emergence and spread of possible well-fit bacterial pathogens of humans and animals. In this work, we analysed the antimicrobial and clonal profiles of 115 SDSE infection and colonization isolates of human and equine origin. PFGE revealed the spread of two main clusters: clone A (57.4%) and clone A (26.1%). Remarkably, two isolates from ...
Energy-related parameters and their association with age, gender, and morphometric measurements in healthy donkeys.
Veterinary journal (London, England : 1997)    March 6, 2015   Volume 204, Issue 2 201-207 doi: 10.1016/j.tvjl.2015.03.004
Mendoza FJ, Estepa JC, Gonzalez-De Cara CA, Aguilera-Aguilera R, Toribio RE, Perez-Ecija A.Donkeys are commonly afflicted by endocrine and metabolic disturbances but few studies have investigated endocrine variables involved in energy regulation and their association with morphometric indices, age or gender in this species. Hemostatic and clinical differences have been demonstrated between horses and donkeys, so to consider both species as metabolically and endocrinologically similar could lead to misdiagnosis. In this study, plasma concentrations of glucose, triglycerides and endocrine factors involved in energy homeostasis (insulin, glucagon, leptin, adiponectin, ghrelin and insul...
Molecular identification of Cryptosporidium spp. and Giardia duodenalis in grazing horses from Xinjiang, China.
Veterinary parasitology    March 6, 2015   Volume 209, Issue 3-4 169-172 doi: 10.1016/j.vetpar.2015.02.030
Qi M, Zhou H, Wang H, Wang R, Xiao L, Arrowood MJ, Li J, Zhang L.A total of 262 fecal specimens collected from grazing horses at five locations in Xinjiang, China were examined by PCR for Cryptosporidium spp. and Giardia duodenalis. The Cryptosporidium and G. duodenalis infection rates were 2.7% and 1.5%, respectively. Seven Cryptosporidium-positive specimens were found in foals (16.3%), and four G. duodenalis-positive specimens were found in mares (2.5%). Sequence analyses of 18S rRNA and gp60 genes revealed that seven animals were positive for the subtype VIaA15G4 of Cryptosporidium horse genotype. G. duodenalis assemblages A and B were identified by mole...
[Morphological features of Bundleia spp. (Ciliophora: Entodiniomorphida: Buetschliidae) and ontogenesis in Bundleia Cunha and Muniz 1928].
Turkiye parazitolojii dergisi    March 4, 2015   Volume 38, Issue 4 239-247 doi: 10.5152/tpd.2014.3526
Gürelli G, Göçmen B.The aim of this study was to investigate the morphological features of 7 endocommensal ciliates, B. (s. str.) postciliata, B. (s. str.) piriformis, B. (s. str.) nana, B. (C.) elongata, B. (C.) triangularis, B. (F.) dolichosoma, and B. (F.) inflata belonging to the genus Bundleia, which exist in the hindgut of 15 Rahvan horses and 15 racing horses living in the vicinity of Izmir and to investigate the ontogenesis in the Bundleia genus. Methods: Specimens were obtained from 30 horses and were fixed with 10% formalin. The morphological features of the species were investigated with the pyridinate...
The efficacy of ELISA commercial kits for the screening of equine infectious anemia virus infection.
Revista Argentina de microbiologia    February 28, 2015   Volume 47, Issue 1 25-28 doi: 10.1016/j.ram.2014.12.001
Alvarez I, Cipolini F, Wigdorovitz A, Trono K, Barrandeguy ME.The most used and reliable indicator of Equine infectious anemia virus (EIAV) infection is the detection of its specific antibodies in horse serum. In the present study, the performance of two commercial ELISA tests for the detection of EIAV antibodies as well as the potential advantages of their use as an EIAV infection screening tool were evaluated in 302 horse serum samples. Both ELISA assays showed 100% diagnostic sensitivity, and 92.3-94.3% diagnostic specificity. Discordant results were analyzed by immunoblot. The results showed that both ELISA tests are very efficient at detecting EIAV ...
Association of catastrophic biaxial fracture of the proximal sesamoid bones with bony changes of the metacarpophalangeal joint identified by standing magnetic resonance imaging in cadaveric forelimbs of Thoroughbred racehorses.
Journal of the American Veterinary Medical Association    February 27, 2015   Volume 246, Issue 6 661-673 doi: 10.2460/javma.246.6.661
Peloso JG, Vogler JB, Cohen ND, Marquis P, Hilt L.To compare bony changes in the metacarpophalangeal joint (MCPJ) of racehorses with (cases) and without (controls) biaxial proximal sesamoid bone (PSB) fracture as determined by 2 grading scales applied to images of cadaveric forelimbs obtained by means of standing MRI (sMRI). Methods: Case-control study. Methods: Forelimbs from 74 Thoroughbred racehorses (21 cases and 53 controls) that were euthanized at a Florida racetrack. Methods: Both forelimbs were harvested from cases and controls. Each forelimb underwent sMRI to obtain images of the MCPJ. Two grading scales were described and used for i...
Horses fail to use social learning when solving spatial detour tasks.
Animal cognition    February 26, 2015   Volume 18, Issue 4 847-854 doi: 10.1007/s10071-015-0852-6
Rørvang MV, Ahrendt LP, Christensen JW.Social animals should have plenty of opportunities to learn from conspecifics, but most studies have failed to document social learning in horses. This study investigates whether young Icelandic horses can learn a spatial detour task through observation of a trained demonstrator horse of either the same age (Experiments 1 and 2, n = 22) or older (Experiment 3, n = 24). Observer horses were allowed to observe the demonstrator being led three times through the detour route immediately before being given the opportunity to solve the task themselves. Controls were allowed only to observe the d...