Analyze Diet

Topic:Physiology

The physiology of horses encompasses the study of the biological functions and processes that occur within the equine body. This includes the examination of various systems such as the cardiovascular, respiratory, musculoskeletal, digestive, and nervous systems. Understanding equine physiology is essential for comprehending how horses adapt to different environmental conditions, perform physical activities, and respond to health challenges. Research in this field often focuses on the mechanisms of energy metabolism, thermoregulation, and muscle function during exercise, as well as the physiological responses to stress and disease. This page compiles peer-reviewed research studies and scholarly articles that explore the diverse aspects of equine physiology, providing insights into the biological processes that support the health and performance of horses.
Inflamm-aging and arachadonic acid metabolite differences with stage of tendon disease.
PloS one    November 14, 2012   Volume 7, Issue 11 e48978 doi: 10.1371/journal.pone.0048978
Dakin SG, Dudhia J, Werling NJ, Werling D, Abayasekara DR, Smith RK.The contribution of inflammation to the pathogenesis of tendinopathy and high prevalence of re-injury is not well established, although recent evidence suggests involvement of prostaglandins. We investigated the roles of prostaglandins and inflammation-resolving mediators in naturally occurring equine tendon injury with disease stage and age. Levels of prostaglandins E(2) (PGE(2)), F(2α) (PGF(2α)), lipoxin A(4) (LXA(4)) and its receptor FPR2/ALX were analysed in extracts of normal, sub-acute and chronic injured tendons. To assess whether potential changes were associated with altered PGE(2) ...
Pharmacokinetics and selected pharmacodynamic effects of tramadol following intravenous administration to the horse.
Equine veterinary journal    November 12, 2012   Volume 45, Issue 4 490-496 doi: 10.1111/j.2042-3306.2012.00688.x
Knych HK, Corado CR, McKemie DS, Steffey EP.Both the potential analgesic effect and the conflicting reports describing tramadol disposition in the horse warrant further study of the pharmacokinetics of tramadol in this species. Objective: To describe the pharmacokinetics of tramadol and its metabolites, O-desmethyltramadol and N-desmethyltramadol, following i.v. administration of 3 doses to the horse. Methods: Nine adult horses received a single i.v. dose of 0.5, 1.5 and 3 mg/kg bwt tramadol. Blood samples were collected prior to and at various times up to 72 h post administration. Plasma samples were analysed using liquid chromatograph...
Comparison of different treatments for oestrous induction in seasonally anovulatory mares.
Reproduction in domestic animals = Zuchthygiene    November 9, 2012   Volume 48, Issue 3 463-469 doi: 10.1111/rda.12098
Vizuete G, Diez E, Galisteo J, Agüera E, Aguilera-Tejero E, Perez-Marín CC.The aim of this study was to evaluate the effects of different treatments for induction and synchronization of oestrus and ovulation in seasonally anovulatory mares. Fifteen mares formed the control group (C), while 26 mares were randomly assigned to three treatment groups. Group T1 (n = 11) were treated with oral altrenogest (0.044 mg/kg; Regumate(®) ) during 11 days. Group T2 (n = 7) was intravaginally treated with 1.38 g of progesterone (CIDR(®) ) for 11 days. In group T3 (n = 8), mares were also treated with CIDR(®) , but only for 8 days. All mares received PGF2α 1 day afte...
Heart rate, heart rate variability and behaviour of horses during air transport.
The Veterinary record    November 9, 2012   Volume 172, Issue 1 15 doi: 10.1136/vr.100952
Munsters CC, de Gooijer JW, van den Broek J, van Oldruitenborgh-Oosterbaan MM.Heart rate (HR), HR variability (HRV) and behaviour score (BS) of nine horses were evaluated during an eight-hour air transport between The Netherlands and New York. HR and HRV parameters were calculated every five minutes during the air transport. Compared with transit (40±3), mean HRs were higher during loading into the jet stall (67±21, P<0.001), loading into the aircraft (47±6, P=0.011), taxiing (50±8, P=0.001), and during periods of in-flight turbulence (46±7, P=0.017). During the flight, individual horses showed differences in mean HR (P=0.005) and peak HR (P<0.001). By contra...
Crystal structures of wild-type and mutated cyclophilin B that causes hyperelastosis cutis in the American quarter horse.
BMC research notes    November 8, 2012   Volume 5 626 doi: 10.1186/1756-0500-5-626
Boudko SP, Ishikawa Y, Lerch TF, Nix J, Chapman MS, Bächinger HP.Hyperelastosis cutis is an inherited autosomal recessive connective tissue disorder. Affected horses are characterized by hyperextensible skin, scarring, and severe lesions along the back. The disorder is caused by a mutation in cyclophilin B. Results: The crystal structures of both wild-type and mutated (Gly6->Arg) horse cyclophilin B are presented. The mutation neither affects the overall fold of the enzyme nor impairs the catalytic site structure. Instead, it locally rearranges the flexible N-terminal end of the polypeptide chain and also makes it more rigid. Conclusions: Interactions of th...
Flow-mediated K(+) secretion in horses intoxicated with lolitrem B (perennial ryegrass staggers).
New Zealand veterinary journal    November 8, 2012   Volume 61, Issue 3 159-164 doi: 10.1080/00480169.2012.731682
Johnstone LK, Mayhew IG.To investigate the effects of lolitrem B intoxication on renal K(+) secretion in response to increased tubular flow rates. Methods: Results are derived from a repeated measure pilot study of seven horses fed non-perennial ryegrass feed for a week prior to exposing them to perennial ryegrass seed and hay that contained an average of 2 ppm lolitrem B. At the end of the control and treatment period frusemide (1 mg/kg I/V) was administered and serial fractional excretion of K(+)(FEK(+)) and fractional excretion of Na(+)(FENa(+)) calculated. Baseline concentration of aldosterone in plasma, serum K(...
Crystal structures of wild-type and mutated cyclophilin B that causes hyperelastosis cutis in the American quarter horse.
BMC research notes    November 8, 2012   Volume 5 626 doi: 10.1186/1756-0500-5-626
Boudko SP, Ishikawa Y, Lerch TF, Nix J, Chapman MS, Bächinger HP.Hyperelastosis cutis is an inherited autosomal recessive connective tissue disorder. Affected horses are characterized by hyperextensible skin, scarring, and severe lesions along the back. The disorder is caused by a mutation in cyclophilin B. Results: The crystal structures of both wild-type and mutated (Gly6->Arg) horse cyclophilin B are presented. The mutation neither affects the overall fold of the enzyme nor impairs the catalytic site structure. Instead, it locally rearranges the flexible N-terminal end of the polypeptide chain and also makes it more rigid. Conclusions: Interactions of th...
Sperm motility is lost in vitro as a consequence of mitochondrial free radical production and the generation of electrophilic aldehydes but can be significantly rescued by the presence of nucleophilic thiols.
Biology of reproduction    November 8, 2012   Volume 87, Issue 5 110 doi: 10.1095/biolreprod.112.102020
Aitken RJ, Gibb Z, Mitchell LA, Lambourne SR, Connaughton HS, De Iuliis GN.The prolonged incubation of human spermatozoa in vitro was found to induce a loss of motility associated with the activation of mitochondrial reactive oxygen species generation in the absence of any change in mitochondrial membrane potential. The increase in mitochondrial free radical production was paralleled by a loss of protein thiols and a concomitant rise in the formation of 4-hydroxynonenal, an electrophilic product of lipid peroxidation that was found to directly suppress sperm movement. These results prompted a search for nucleophiles that could counteract the action of such cytotoxic ...
Steroid diffusion into the navicular bursa occurs in horses affected by palmar foot pain.
The Veterinary record    November 7, 2012   Volume 171, Issue 25 642 doi: 10.1136/vr.101075
Manfredi JM, Boyce M, Malone ED, Anderson C, Anderson LB, Trumble TN.Palmar foot pain is frequently treated by steroid injections into the distal interphalangeal joint (DIPJ) in the anticipation that the steroid will diffuse to the navicular bursa and palmar foot structures. The object of this study was to determine if triamcinolone acetonide (TA) would in fact be able to locally diffuse from the DIPJ into the navicular bursa in horses affected by palmar foot pain. Both forelimb DIPJs (nine horses) were injected with 10 mg of TA. Navicular bursa fluid samples, both forelimb and one hind limb (systemic control), were analysed for TA with high-performance liquid ...
Effect of butorphanol on thermal nociceptive threshold in healthy pony foals.
Equine veterinary journal    November 5, 2012   Volume 45, Issue 4 503-506 doi: 10.1111/j.2042-3306.2012.00673.x
McGowan KT, Elfenbein JR, Robertson SA, Sanchez LC.Pain management is an important component of foal nursing care, and no objective data currently exist regarding the analgesic efficacy of opioids in foals. Objective: To evaluate the somatic antinociceptive effects of 2 commonly used doses of intravenous (i.v.) butorphanol in healthy foals. Our hypothesis was that thermal nociceptive threshold would increase following i.v. butorphanol in a dose-dependent manner in both neonatal and older pony foals. Methods: Seven healthy neonatal pony foals (age 1-2 weeks), and 11 healthy older pony foals (age 4-8 weeks). Five foals were used during both age ...
Progestin treatment does not affect expression of cytokines, steroid receptors, oxytocin receptor, and cyclooxygenase 2 in fetal membranes and endometrium from pony mares at parturition.
Theriogenology    November 2, 2012   Volume 79, Issue 1 59-68 doi: 10.1016/j.theriogenology.2012.09.009
Palm F, Walter I, Nowotny N, Budik S, Helmreich M, Aurich C.In most mammalian species, progestins have a major function in maintaining pregnancy. In humans, the physiologic initiation of parturition bears similarities with inflammatory processes and anti-inflammatory effects of progestins have been suggested to postpone birth until term. To examine if comparable effects exist in the horse, mares were treated with the synthetic progestin altrenogest from day 280 of gestation until parturition (N = 5) or were left untreated as controls (N = 7). Tissue from the amnion (AMN), allantochorion (AC), and endometrium (EM) was collected at foaling and mRNA expre...
Lateralized suckling in domestic horses (Equus caballus).
Animal cognition    November 2, 2012   Volume 16, Issue 3 343-349 doi: 10.1007/s10071-012-0575-x
Komárková M, Bartošová J.Brain lateralization enables preferential processing of certain stimuli and more effective utilization of these stimuli in either the left or the right cerebral hemisphere. Horses show both motor and sensory lateralization patterns. Our aim was to determine whether a lateralized response could be detected in foals during the naturally side-biased behaviour, suckling. The foals' preferred suckling side could be the effect of either visual or motor lateralization. In the case of a visual lateralized response, foals are expected to suck more often from the mother's right side, so potential danger...
Stimulatory effect of PGF2α on PRL based on experimental inhibition of each hormone in mares.
Theriogenology    November 1, 2012   Volume 78, Issue 9 1960-1968 doi: 10.1016/j.theriogenology.2012.08.002
Ginther OJ, Pinaffi FL, Rodriguez MB, Duarte LF, Beg MA.During the luteolytic period in mares, the peak of 65% of pulses of a PGF2α metabolite (PGFM) and the peak of a pulse of PRL have been reported to occur at the same hour. It is unknown whether the synchrony reflects an effect of PGF2α on PRL or vice versa. Controls, a flunixin meglumine (FM)-treated group (to inhibit PGF2α), and a bromocriptine-treated group (to inhibit PRL), were used at 14 days postovulation in June and in September (n = 6 mares/group/mo). Blood samples were collected hourly from just before treatment (Hour 0) to Hour 10. Concentrations of PGFM in the FM group were lower ...
Exogenous L-lactate clearance in adult horses.
Journal of veterinary emergency and critical care (San Antonio, Tex. : 2001)    November 1, 2012   Volume 22, Issue 5 564-572 doi: 10.1111/j.1476-4431.2012.00800.x
De Pedro P, Wilkins PA, McMichael MA, Dirikolu L, Lascola KM, Clark-Price SC, Boston RC.To determine endogenous production of L-lactate and the clearance of exogenous sodium L-lactate (ExLC) in healthy adult horses. Methods: A sodium L-lactate solution (1 mmol/kg body weight qs to 500 mL final volume in 0.9% NaCl) was adminstered IV over 15 minutes. Blood samples for L-lactate concentration [LAC] measurement were collected immediately prior to infusion, at 5, 10, and 15 minutes during infusion and at 1 minute intervals for 15 minutes, at 30, 45, 60, 120, and 180 minutes postinfusion. Disposition modeling and pharmacokinetic analysis was performed using proprietary software. Metho...
The horse as a model of naturally occurring osteoarthritis.
Bone & joint research    November 1, 2012   Volume 1, Issue 11 297-309 doi: 10.1302/2046-3758.111.2000132
McIlwraith CW, Frisbie DD, Kawcak CE.Osteoarthritis (OA) is an important cause of pain, disability and economic loss in humans, and is similarly important in the horse. Recent knowledge on post-traumatic OA has suggested opportunities for early intervention, but it is difficult to identify the appropriate time of these interventions. The horse provides two useful mechanisms to answer these questions: 1) extensive experience with clinical OA in horses; and 2) use of a consistently predictable model of OA that can help study early pathobiological events, define targets for therapeutic intervention and then test these putative thera...
Evaluation of growth models for follicle development and ovulation in Lusitano mares.
Animal reproduction science    November 1, 2012   Volume 136, Issue 1-2 81-84 doi: 10.1016/j.anireprosci.2012.10.026
Mata F.Several growth models are commonly used in the biological sciences, to model the follicle growth occurring in the estrous cycle. The aim of this project was to find the model that best fit the follicular size growth data for Lusitano mares. Retrospective data collected from reproduction book records of n=84 mares and n=124 cycles was used to find the series to be fitted to the models. The exponential, Gompertz, logistic, von Bertalanffy, Richards and Weibull models were used, and the most parsimonious and best fit was achieved with the logistic model (r(2)=0.999). The logistic model fits the L...
Sex-dependent insulin like growth factor-1 expression in preattachment equine embryos.
Theriogenology    November 1, 2012   Volume 79, Issue 1 193-199 doi: 10.1016/j.theriogenology.2012.10.004
Beckelmann J, Budik S, Helmreich M, Palm F, Walter I, Aurich C.An adjustment of sex ratio of offspring to the conditions present at conception is seen in many mammals including horses. This depends on preferential survival of male embryos under conditions of high energy intake. In several species, growth factors including insulin like growth factor (IGF)-1 have been shown to promote embryonic development by decreasing apoptosis and increasing cell proliferation. We hypothesized that sex-related differences in IGF-1 expression in equine embryos during the phase of maternal recognition of pregnancy might exist and thus contribute to preferential survival of...
Induction of double ovulation in mares using deslorelin acetate.
Animal reproduction science    November 1, 2012   Volume 136, Issue 1-2 69-73 doi: 10.1016/j.anireprosci.2012.10.015
Nagao JF, Neves Neto JR, Papa FO, Alvarenga MA, Freitas-Dell'Aqua CP, Dell'Aqua JA.This study aimed to determine whether deslorelin acetate could induce double ovulation in mares. In Experiment 1, eight mares were treated with prostaglandin on Day 8 (D8) after ovulation, then treated with saline or with 100 μg of a controlled-release formulation of deslorelin acetate vehicle intramuscularly (IM) every 12h from D8 after ovulation until at least two follicles reached 33 mm. At this time, ovulation was induced with 2500 IU of hCG. Artificial insemination was performed 24h after induction, and embryos were collected on the eighth day after ovulation was first detected. In Exper...
Secondary osteon size and collagen/lamellar organization (“osteon morphotypes”) are not coupled, but potentially adapt independently for local strain mode or magnitude.
Journal of structural biology    November 1, 2012   Volume 181, Issue 2 95-107 doi: 10.1016/j.jsb.2012.10.013
Skedros JG, Keenan KE, Williams TJ, Kiser CJ.In bone, matrix slippage that occurs at cement lines of secondary osteons during loading is an important toughening mechanism. Toughness can also be enhanced by modifications in osteon cross-sectional size (diameter) for specific load environments; for example, smaller osteons in more highly strained "compression" regions vs. larger osteons in less strained "tension" regions. Additional osteon characteristics that enhance toughness are distinctive variations in collagen/lamellar organization (i.e., "osteon morphotypes"). Interactions might exist between osteon diameter and morphotype that repr...
Where does it hurt?
Equine veterinary journal    October 31, 2012   Volume 44, Issue 6 627-628 doi: 10.1111/j.2042-3306.2012.00661.x
Barr AR.No abstract available
Endocrinological aspects of the pathophysiology of equine laminitis.
Equine veterinary journal    October 31, 2012   Volume 44, Issue 6 735-737 doi: 10.1111/j.2042-3306.2012.00663.x
Menzies-Gow N.No abstract available
The present state and future of laminitis research.
Equine veterinary journal    October 31, 2012   Volume 44, Issue 6 749-751 doi: 10.1111/j.2042-3306.2012.00669.x
Belknap J, Geor R.No abstract available
Progress towards effective prevention and therapy for laminitis.
Equine veterinary journal    October 31, 2012   Volume 44, Issue 6 746-748 doi: 10.1111/j.2042-3306.2012.00667.x
van Eps AW.No abstract available
Respiratory responses to exercise in the horse.
Equine veterinary journal    October 31, 2012   Volume 44, Issue 6 726-732 doi: 10.1111/j.2042-3306.2012.00666.x
Franklin SH, Van Erck-Westergren E, Bayly WM.Horses are elite athletes when compared with other mammalian species. In the latter, performance is limited by cardiovascular or musculoskeletal performance whereas in athletic horses it is the respiratory system that appears to be rate limiting and virtually all horses exercising at high intensities become hypoxaemic and hypercapnoeic. This is due to both diffusion limitation and a level of ventilation inadequate for the metabolic level that enables horses to exercise at these intensities. In conjunction with these blood gas changes, total pulmonary resistance increases and the work of breath...
Supporting limb laminitis: the four important ‘whys’.
Equine veterinary journal    October 31, 2012   Volume 44, Issue 6 741-745 doi: 10.1111/j.2042-3306.2012.00662.x
Orsini JA.No abstract available
A review of recent advances and current hypotheses on the pathogenesis of acute laminitis.
Equine veterinary journal    October 31, 2012   Volume 44, Issue 6 752-761 doi: 10.1111/j.2042-3306.2012.00664.x
Katz LM, Bailey SR.With the increasing number of studies being published on the different experimental models used to induce and study acute laminitis, the pathophysiological events associated with these various models (i.e. starch overload, oligofructose overload, black walnut extract and hyperinsulinaemia) can be compared more realistically. Within this review, the mechanisms for metabolic vs. inflammatory laminitis are discussed, and the question of how pasture laminitis may fit into any of the proposed mechanisms is addressed.
Investigation of forelimb hoof wall strains and hoof shape in unshod horses exercised on a treadmill at various speeds and gaits.
American journal of veterinary research    October 31, 2012   Volume 73, Issue 11 1735-1741 doi: 10.2460/ajvr.73.11.1735
Bellenzani MC, Merritt JS, Clarke S, Davies HM.To investigate forelimb hoof wall strains and shape changes in unshod horses undergoing regular moderate exercise on a treadmill at selected speeds and gaits. Methods: 6 horses of various body types. Methods: Each horse was exercised on a treadmill (walking, trotting, and cantering, with or without galloping at 12.5 m/s) 3 times a week for 4 consecutive weeks; duration of each exercise session ranged from 10 to 14 minutes. During the 4-week period, the proximal hoof circumference (PHC) and toe angle (TA) of each forelimb hoof were measured weekly with a flexible measuring tape and a hoof gauge...
Profound re-organization of cell surface proteome in equine retinal pigment epithelial cells in response to in vitro culturing.
International journal of molecular sciences    October 31, 2012   Volume 13, Issue 11 14053-14072 doi: 10.3390/ijms131114053
Szober CM, Hauck SM, Euler KN, Fröhlich KJ, Alge-Priglinger C, Ueffing M, Deeg CA.The purpose of this study was to characterize the cell surface proteome of native compared to cultured equine retinal pigment epithelium (RPE) cells. The RPE plays an essential role in visual function and represents the outer blood-retinal barrier. We are investigating immunopathomechanisms of equine recurrent uveitis, an autoimmune inflammatory disease in horses leading to breakdown of the outer blood-retinal barrier and influx of autoreactive T-cells into affected horses' vitrei. Cell surface proteins of native and cultured RPE cells from eye-healthy horses were captured by biotinylation, an...
Mechanical and morphological properties of trabecular bone samples obtained from third metacarpal bones of cadavers of horses with a bone fragility syndrome and horses unaffected by that syndrome.
American journal of veterinary research    October 31, 2012   Volume 73, Issue 11 1742-1751 doi: 10.2460/ajvr.73.11.1742
Symons JE, Entwistle RC, Arens AM, Garcia TC, Christiansen BA, Fyhrie DP, Stover SM.To determine morphological and mechanical properties of trabecular bone of horses with a bone fragility syndrome (BFS; including silicate-associated osteoporosis). Methods: Cylindrical trabecular bone samples from the distal aspects of cadaveric third metacarpal bones of 39 horses (19 horses with a BFS [BFS bone samples] and 20 horses without a BFS [control bone samples]). Methods: Bone samples were imaged via micro-CT for determination of bone volume fraction; apparent and mean mineralized bone densities; and trabecular number, thickness, and separation. Bone samples were compressed to failur...
Effects of high-intensity training on lipid metabolism in Thoroughbreds.
American journal of veterinary research    October 31, 2012   Volume 73, Issue 11 1813-1818 doi: 10.2460/ajvr.73.11.1813
Kitaoka Y, Mukai K, Aida H, Hiraga A, Masuda H, Takemasa T, Hatta H.To investigate the effects of high-intensity training (HIT) on carbohydrate and fat metabolism in Thoroughbreds. Methods: 12 Thoroughbreds (3 to 4 years old; 6 males and 6 females). Methods: Horses performed HIT for 18 weeks. They ran at 90% or 110% of maximal oxygen consumption ((V)O(2max)) for 3 minutes (5 d/wk) and were subjected to incremental exercise testing (IET) before and after training. Blood samples were collected during IET, and muscle samples were obtained from the gluteus medius muscle immediately after IET. Phosphofructokinase, citrate synthase, and β-3-hydroxyacyl CoA dehydrog...