bluuebunny/crossref_metadata_2025 huggingface dataset:
Cryopreservation procedures for Day 7–8 equine embryos
Authors: YOUNG C. A. , SQUIRES E. L. , SEIDEL G. E. , KATO H. , McCUE P. M.
Published: June 2010

Larger grade 1 or 2 (1 = excellent, …. 4 = degenerate) equine embryos that ranged in diameter from 300 to 680 μm and were recovered from mares on Day 7 or 8 after ovulation, were randomly assigned to 3 widely divergent cryopreservation treatments. Treatment 1 consisted of cooling from −6°C to –35°C at 0.5°C per min followed by plunging into liquid nitrogen, with a one‐step addition and a 4‐step removal of 1.0 M glycerol. Treatment 2 (step‐down equilibration) consisted of a 2‐step addition of glycerol to 4.0 M followed by a decrease to 2.0 M prior to freezing, with galactose present in the final step and in all glycerol removal steps and with a cooling protocol identical to Treatment 1. Treatment 3 was a standard vitrification protocol with step‐wise addition of ethylene glycol up to 11.9 M, and step‐wise removal of cryoprotectant with decreasing concentrations of galactose in the dilution medium.

The cryoprotectants were removed at 20–21°C. After the final dilution, the embryos were cultured in 5% CO2‐in‐air for 36 h at 38.5°C on equine oviductal epithelial cell monolayers. Their morphology was then evalued, their capsules were removed mechanically, and they were fixed prior to staining with 1% w:v orcein in 45% acetic acid to assess the morphology of their nuclei and cytoplasm.

All 7 embryos in Treatment 1 degenerated during thawing or culture. Of the 6 embryos included in Treatment 2, 4 were graded 1, one was graded 2 and one graded 3 after culturein vitro.Of the 7 embryos in Treatment 3, one was graded 2, one was graded 3 and the remaining 5 were degenerate (P < 0.01 among treatments). The average changes in initial diameter exhibited by the frozen/thawed embryos during culture after thawing were: Treatment 1, –91 μm; Treatment 2, +179 μm; Treatment 3, +20 μm (P < 0.05). Two 26‐day pregnancies were established following transfer of 6 Treatment 2 embryos (step‐down equilibration method) to recipient mares.
Digital perfusion, evaluated scintigraphically, and hoof wall growth in horses with chronic laminitis treated with egg bar‐heart bar shoeing and coronary grooving
Authors: RITMEESTER A. M. , BLEVINS W. E. , FERGUSON D. W. , ADAMS S. B.
Published: June 2010

Nuclear scintigraphy was used to assess digital perfusion before and after treatment in 10 horses with clinical and radiographic evidence of chronic laminitis. Horses were evaluated for lameness, degree of distal phalanx rotation, and heel‐toe hoof wall growth ratio, and randomly divided into two treatment groups.Group 1horses received only egg bar‐heart bar shoeing;Group 2underwent egg bar‐heart bar shoeing and coronary grooving. Horses were re‐evaluated for digital perfusion, lameness, degree of distal phalanx rotation, and hoof wall growth at 6 week intervals over the 18 week follow‐up period. Prior to treatment, relative scintigraphic activity at the dorsal laminar area was decreased and relative scintigraphic activity at the toe and adjacent solar area was increased. Egg bar‐heart bar shoeing was associated with significantly increased dorsal laminar scintigraphic activity and significantly decreased solar scintigraphic activity over the 18 week period. Coronary grooving, in combination with egg bar‐heart bar shoeing, resulted in a significantly lower heel‐toe hoof wall growth ratio but did not enhance digital perfusion. Seven of 10 (70%) horses were responsive to treatment, defined as an improvement in lameness by at least one grade. Horses that were refractory to treatment had significantly lower dorsal laminar scintigraphic activity and higher palmar coronary scintigraphic activity prior to treatment than horses that responded to treatment. Our results are the first to demonstrate that egg bar‐heart bar shoeing is associated with improved dorsal laminar perfusion, and support the use of this technique. In addition, we found that pre‐treatment nuclear scintigraphy was predictive of clinical outcome in horses with chronic laminitis treated with corrective shoeing.
The effect of administration of a beta blocker in periparturient mares
Authors: INGARDEN J. , DUBIEL A. , RAULUSZKIEWICZ S.
Published: June 2010

This study investigated the effect of a beta blocker on parturition, fetal membrane retention and subsequent fertility in mares. The animals were divided into an experimental group (ISO mares treated during second stage labour with propranolol [50 mg i.v.]) and a control group (180 mares with no treatment). Administration of propranolol was associated with a significant decrease in time of expulsion of fetal membranes, and an increase in both exhibition of foal heat and pregnancy rates at this heat.
Comparative learning theory and its application in the training of horses
Authors: COOPER J. J.
Published: June 2010

Training can best be explained as a process that occurs through stimulus‐response‐reinforcement chains, whereby animals are conditioned to associate cues in their environment, with specific behavioural responses and their rewarding consequences. Research into learning in horses has concentrated on their powers of discrimination and on primary positive reinforcement schedules, where the correct response is paired with a desirable consequence such as food. In contrast, a number of other learning processes that are used in training have been widely studied in other species, but have received little scientific investigation in the horse. These include: negative reinforcement, where performance of the correct response is followed by removal of, or decrease in, intensity of a unpleasant stimulus; punishment, where an incorrect response is paired with an undesirable consequence, but without consistent prior warning; secondary conditioning, where a natural primary reinforcer such as food is closely associated with an arbitrary secondary reinforcer such as vocal praise; and variable or partial conditioning, where once the correct response has been learnt, reinforcement is presented according to an intermittent schedule to increase resistance to extinction outside of training.
Role of duodenal reflux in nonglandular gastric ulcer disease of the mature horse
Authors: BERSCHNEIDER HELEN M. , BLIKSLAGER A. T. , ROBERTS M. C.
Published: June 2010

Gastric contents were sampled in horses via nasogastric tube to determine changes in pH and bile salt concentrations during feeding and fasting periods. The horses were rotated through 4 feeding protocols. (1) hay; (2) hay with twice daily grain meals; (3) and (4) fasting preceded by either hay only or hay and grain. Sequential, hourly samples were collected from 3 horses prepared with gastric cannulas. Horses were fed hay twice daily and grain mix either twice daily or in small aliquots dispensed every 90 min. The horses were sampled during normal feeding or after 14 h of feed deprivation. Gastric pH values varied with time, but there was no significant difference between the feeding protocols or the fasting period on mean pH. Bile salt concentrations in fasted animals averaged 0.23–0.44 mmol/1 with individual samples greater than 0.9 mmol/1. The bile salt concentrations in fed animals were consistently below 0.2 mmol/1.

The effect of bile salt and acid on the stratified squamous gastric mucosa was testedin vitro.Mucosa, stripped of muscle and serosal layers, was mounted in Ussing chambers and the electrical potential difference (PD) across the tissue recorded. Sodium taurocholate or deoxycholate (0.3 mmol/1, bile salt) and/or HCl were added to the mucosal bathing solutions. The bile salt alone had no significant effect. Addition of acid (pH 2.5) to control tissues caused a decrease in the PD, which recovered within 20 min. Addition of acid to tissues exposed to bile salts resulted in a significant decrease in the PD, which did not recover.

We conclude that combinations of bile salts and acid are more injurious to the stratified squamous gastric mucosa of the equine than acid alone. Concentrations of bile salts and acid sufficient to alter the electrolyte transport function of this mucosa can be found in the gastric contents of horses deprived of feed for as little as 14 h.
Radiographic development of osteochondral abnormalities, in the hock and stifle of Dutch Warmblood foals, from age 1 to 11 months
Authors: DIK K. J. , ENZERINK E. , van WEEREN P. R.
Published: June 2010

In a longitudinal study the hocks and stifles of Dutch Warmblood foals were radiographed at age 1 month and subsequently at intervals of 4 weeks. Forty‐three foals were radiographed until age 5 months and 19 foals until age 11 months. The chance for the development of osteochondrosis was enhanced by using only offspring from diseased sires with radiographically proven OC at either the intermediate ridge of the distal tibia or the lateral ridge of the femoral trochlea.

The radiographic appearances of the intermediate ridge of the distal tibia, the distal aspect of the lateral trochlear ridge of the talus and the midregion of the lateral ridge of the femoral trochlea were classified on a 0–4 scale using a standardised radiographic classification.

At age 1 month the appearance of the intermediate ridge of the distal tibia was frequently abnormal (grades 1–3: 67%; grade 4: 1%). Abnormal appearances of the distal aspect of the lateral trochlear ridge of the talus were less common (grades 1–3: 25%; grade 4: 6%). The midregion of the lateral ridge of the femoral trochlea was predominantly normal (grade 0: 98%; grade 1: 2%). Initial abnormalities of the intermediate tibial ridge showed a marked tendency for regression. Progression was less common. Normal appearances rarely turned into abnormal. Only 18% of the hocks were still abnormal at this site at age 11 months. Abnormalities of the distal aspect of the lateral trochlear ridge of the talus showed a strong tendency towards resolution. Progression never occurred. Normal appearances seldom turned into abnormal. Only 3% of the hocks were still abnormal at this site at age 11 months. For both predilection sites in the hock normal and abnormal appearances were permanent from age 5 months. In the stifle, abnormal appearances of the midregion of the lateral ridge of the femoral trochlea became obvious from age 3 or 4 months. Subsequent progression was usually followed by regression and resolution, the appearance returned in most cases to normal at age 8 months. At 5 months, 20% of the stifles were abnormal, but at 11 months this percentage had decreased to 3%. Normal and abnormal appearances were permanent from age 8 months.

Osteochondrosis of the main predilection sites in the hock and stifle develops very early in life. The majority of the lesions were temporary, the ‘age of no return’ was 5 months for the hock and 8 months for the stifle.
Changes in bone morphogenic enzymes and lipid composition of equine osteochondrotic subchondral bone
Authors: van de LEST C. H. A. , van den HOOGEN BIANCA M. , van WEEREN P. R. , BROUWERS J. F. H. M. , van GOLDE L. M. G. , BARNEVELD A.
Published: June 2010

Osteochondrosis (OC) is a disturbance in the process of endochondral ossification, a process in which cartilage is mineralised and transformed into bone. In this process different biochemical events occur, of which the cartilage component has been studied so far almost exclusively. In this study we concentrated on the biochemical characterisation of normal and osteochondrotic subchondral bone, by analysis of enzyme activities, DNA content and phospholipids (PL).

In subchondral bone, lysyl oxidase and both total and bone alkaline phosphatase activity were significantly increased in all degrees of OC. DNA content was increased only in the most established grade of OC investigated (grade 4). Furthermore, lactate dehydrogenase activity was significantly lower ingrades 2and3OC, but was normal ingrade 4OC, indicating that severe cell damage is not probable. Nonbuffer extractable PL content was substantially higher in osteochondrotic subchondral bone. The phosphatidylethanolamine (PE) to phosphatidylcholine (PC) ratio in both normal and OC subchondral bone was very low (typically 0.21 w/w, PE/PC), which indicates that these PLs were not from cellular origin and could be important in the maturation process of mineralised cartilage into bone and hence in the pathogenesis of OC.
Effect of age, exercise and growth rate on bone mineral density (BMD) in third carpal bone and distal radius of Dutch Warmblood foals with osteochondrosis
Authors: FIRTH E. C. , van WEEREN P. R. , PFEIFFER D. U. , DELAHUNT J. , BARNEVELD A.
Published: June 2010

This sutdy aimed a the determining bone mineral density (BMD) in the 3rd carpal bone and distal radius of foals age 5 and 11 months that had been subjected to different exercise regimens from birth until age 5 months. It was hypothesised that BMD would be greater in older animals, and that differences in exercise regimens before age 5 months would be associated with differences in BMD at both age 5 and 11 months.

Epiphyseal bone tissue was available from 5 and 11 month old Warmblood foals bred from sires known to have radiographic evidence of osteochondrosis (OC). The foals were in a clinical trial which assessed the effect of exercise up to age 5 months on osteochondrosis (OC). Until age 5 months, foals were either box confined, box confined and sprint trained daily, or kept at pasture. Half the horses in each group were then confined together in a large stall, with access to pasture for 2 h daily, from age 6 to 11 months. BMD was assessed by dual x‐ray absorptiometry in 4 areas of interest (AOIs) of excised third carpal bone (C3) and 5 in the distal radius. Volumetric BMD was determined in C3, only surface BMD was analysed in the radius. Across age groups, exercise had an effect on BMD in the mediodorsal and mediopalmar areas of C3. In the 5‐month‐old animals, the training exercise had similar effect to constant pasture exercise. In all AOIs, BMD was significantly greater in 11‐month than in 5‐month‐old animals. Between age groups there was a difference ineffect of exercise regimen before 5 months, in mediodorsalC3 and medial aspect of the radius, and the difference observed between exercise groups at age 5 months was no longer present in horses age 11 months, indicating no residual effect of early exercise. BMD was lower in the group with high OC scores. In the group of horses with the most severe OC, monthly growth rate did not fall uniformly with age over the first 5 months, as it did in groups with lower OC scores.

It was concluded that wxercise influenced significantly BMD at 5 months, suggesting that carefully designed training programmes to increase bone mineral could be employed in young animals. There was no residual effect at 11 months.
Influence of exercise on bone mineral density of immature cortical and trabecular bone of the equine metacarpus and proximal sesamoid bone
Authors: CORNELISSEN B. P. M. , van WEEREN P. R. , EDERVEEN A. G. H. , BARNEVELD A.
Published: June 2010

Bone mineral density (BMD) and cross‐sectional area (CSA), measured using peripheral quantitative computed tomography, were determined in the left third metacarpal bone (MCIII) and left medial proximal sesamoid bone (psb) in 3 differently exercised groups of foals. Groupbox(n = 14) was confined to a box stall from birth to age 5 months, Grouptraining(n = 14) was kept in similar box stalls but additionally given a daily exercise programme consisting of an increasing number of gallop sprints and Grouppasture(n = 15) remained at pasture. At 5 months of age, 8 foals from each group were randomly selected and subjected to euthanasia, the remaining 19 foals were given an identical light exercise regimen for an additional 6 months and were killed at age 11 months.

In MCIII CSA increased with age and was also significantly (P<0.05) larger in Grouppasturecompared to Groupboxat age 5 months. At 11 months this difference had disappeared. In the dorsal cortex, BMD was significantly (P<0.05) higher in Groupboxthan in both other groups. At age 11 months all significant differences had disappeared. In the psb, CSA increased with age, but there were no differences between the exercise groups. At the apical level, trabecular BMD was higher in Grouptrainingthan in Groupboxand GroupPasture(p<0.001 and P<0.01, respectively). At 11 months, trabecular BMD in the foals that had belonged to Grouptrainingwas less than in the foals that had belonged to Groupbox(P<0.05).

It is concluded that box‐rest during the first months of life results in a retardation of normal development which is compensated for when the restriction on exercise is lifted. Exercise during the first months of life induces an increase in CSA in the third metacarpal bone. In the psb exercise increases BMD, principally in trabecular bone. There is an indication that the specific training regimen used in this study led to an overstimulation of the bone resulting in less active mineral deposition in the longer term.
Age‐related changes and effect of exercise on the molecular composition of immature equine superficial digital flexor tendons
Authors: CHERDCHUTHAM W. , BECKER C. , SMITH R. K. W. , BARNEVELD A. , van WEEREN P. R.
Published: June 2010

To test the hypothesis that exercise at very young age may influence the eventual molecular composition (and hence the biomechanical properties) of tendon tissue in the horse, 43 Dutch Warmblood foals were allotted to 3 differently exercised groups (box‐rest, box‐rest with training and pasture exercise). Twenty‐four superficial digital flexor tendons (SDFTs) were collected at age 5 months (8 from each exercise group) and the others were obtained at 11 months after an additional period of light exercise that was equal for all remaining foals and was intended to see if any induced changes would be reversible or not. Significant changes in DNA content (cellularity), hyaluronic acid (HA) and polysulphated glycosaminoglycans (PSGAGs) were found after the 5 month period of different exercise regimens. There was a tendency towards an exercise‐related effect on hydroxylysine content and number of hydroxylysylpyridinoline (HP) crosslinks. Levels of Cartilage Oligomeric Matrix Protein (COMP), measured by homologous inhibition ELISA, showed significant differences at 5 months and were highest in foals kept at pasture and lowest in foals maintained in a box but given enforced exercise. At 11 months, the biochemical parameters of the tendons from the foals of the former box‐rest and pasture groups became similar, indicating the capacity of the immature tendon to recover from a retarded development. However, the ratio of PSGAGs per unit of DNA of the former training group was significantly lower than those from the other groups, suggesting that the training regimen in this study had a lasting negative effect on the tenocytes resulting in a decrease of the production of PSGAGs. Therefore, inappropriate or excessive exercise may damage developing tendon, with limited recovery after normalising the exercise level. These possibly deleterious effects of a training regimen on tendon development may be important for the management of young would‐be equine athletes.