bluuebunny/crossref_metadata_2025_split huggingface dataset:
Prostaglandin release and luteolysis associated with physiological and pathological conditions of the reproductive cycle of the mare: a review
Authors: DAELS P. F. , STABENFELDT G. H. , KINDAHL H. , HUGHES J. P. 
Published: June 2010

SummaryThe advent of radioimmunoassay for the major metabolite of prostaglandin F2α(PGF2α), 15‐keto‐13, 14‐dihydro‐PGF2α(15‐ketodihydro‐PGF2α), has allowed the dynamics of PGF2α, secretion to be studied in a variety of physiological and pathological situations in domestic animals, including the mare. In the non‐pregnant cyclic mare, PGF2αis responsible for the regression of the corpus luteum. In the pregnant mare, pulsatile secretion of PGF2αis blocked by the presence of the conceptus and the corpus luteum continues to secrete progesterone, essential to the support of pregnancy. At term, the massive increase in PGF2αsynthesis is the major stimulus for uterine contractions during delivery. The endometrium of the non‐pregnant mare secretes PGF2αin response to inflammatory changes caused by bacterial infection, intra‐uterine infusion of saline (low pH) or other irritants; the amount of PGF2αreleased is often sufficient to initiate luteolysis. In the pregnant mare, stimuli that can initiate PGF2αsecretion by the endometrium include uterine and cervical manipulation, chronic uterine inflammation, surgical manipulation of the uterus in conjunction with removal of one of twin conceptuses and manual rupture of one embryonic vesicleper rectumin mares carrying twins. Prostaglandin F2αcan be released by tissues other than the uterus. Systemic administration of endotoxin will induce the synthesis and release of PGF2α. The secretion of PGF2αin this situation can result in a decrease of luteal function or complete luteolysis in both the non‐pregnant and pregnant mare. In mares less than 55 days pregnant, compromised luteal activity following the administration of endotoxin results in death of the conceptus. Ongoing studies indicate that flunixin meglumine, a non‐steroidal anti‐inflammatory drug, effectively blocks PGF2αsecretion and can be used to prevent embryonic death in the event of endotoxaemia. Altrenogest can be used as an alternative treatment for the prevention of embryonic death. To be effective, flunixin meglumine must be administered soon after the onset of endotoxaemia whereas altrenogest treatment can be initiated up to 12 h later and still prevent pregnancy loss.
Growth rates of male and female equine embryos between Days 6 and 15 of pregnancy
Authors: ROMAGNANO A. , BETTERIDGE K. J. , RICHER C. L. , SIROIS J. , KING W. A. 
Published: June 2010

SummaryTo see whether any indication could be found that male conceptuses might develop more rapidly than females in the horse, as they do in several other mammals, pre‐attachment growth rates of female and male conceptuses were estimated from composite curves derived from the diameters of 36 female and 39 male conceptuses each measured once when collected at known times between six and 15 days after ovulation. The conceptuses were sexed cytogenically during the course of a previously reported study. The overall rates of growth (increase in conceptus diameter) were not significantly different for males and females. However, on any given day there was great variation in size amongst embryos and much overlap between the sizes of males and females. It is concluded that comparison of the growth rates of individual embryos, obtained by repeated echographic measurements, might reduce this variability and be a more useful means of continuing this investigation.
The development of Polish ponies born after embryo transfer to large recipients
Authors: TISCHNER M. , KLIMCZAK M. 
Published: June 2010

SummaryEmbryos from Polish pony mares (387 to 400 kg) were transferred to larger draught‐type mares (561 to 780 kg). Upon confirmation of pregnancy in the recipients, the donor mares were mated again to the same stallions. Six pairs of full sibling foals were obtained from which three pairs with matching gender were selected for long‐term developmental studies. All the foals born to recipient draught mares were larger and heavier than their siblings born to the genetic mothers. They also developed more rapidly during the nursing period. After weaning, the differences between individuals of each pair gradually became less evident. However, even at 53 months of age, there were still distinct differences in height at the withers (4 to 6 cm), length of front legs (4 cm) and length of cannon bones (1 to 2 cm).
Use of two‐year‐old mares as embryo donors in a commercial embryo transfer programme
Authors: SAVAGE N. C. , WOODCOCK L. A. , de GANNES G. 
Published: June 2010

SummaryIn a commercial embryo transfer programme between 1985 and 1988, using two‐year‐old donor mares to achieve greater productivity and economic return, embryos were collected non‐surgically and transferred by transcervical technique. Embryo collection was performed on 19 mares on 31 occasions between 6.5 and 7.5 days post‐ovulation. Over the four years, 77.4 per cent (24 of 31) of the collections resulted in embryo recovery and there was no significant effect of year on recovery rate. Repeated recovery attempts in successive cycles showed no adverse effects on recovery rates. Using transcervical transfer, the pregnancy rate per recovery attempt was 12.9 per cent (range 10 to 57 per cent) and the pregnancy rate per transferred embryo was 30.4 per cent (range 14 to 80 per cent). Pregnancy data were calculated from ultrasound evaluations at 12 to 15, 20, 30, 45, 60 and 90 days. No pregnancy loss from recipient mares was recorded throughout the study. Non‐surgical embryo collection and transcervical transfer techniques can be considered useful management strategies to improve productivity from two‐year‐old donor mares.
Viability of inner cell mass versus trophectodermal cells of frozen‐thawed horse embryos
Authors: BARRY B. E. , THOMPSON D. L. , WHITE K. L. , WOOD T. C. , HEHNKE K. E. , RABB M. H. , COLBORN D. R. 
Published: June 2010

SummaryFluorescein diacetate (FDA), a fluorogenic vital stain, was used in conjunction with a silicon‐intensified target (SIT) camera and computer‐based image analysis to estimate the viability of cells of the inner cell mass (ICM) and trophectoderm (TE) of freshly collected and frozen‐thawed horse embryos. Fluorescence intensities were greater (p<0.02) for fresh ICM (0.1500) and TE (0.1686) than for frozen‐thawed ICM (0.0323) and TE (0.0694). Fluorescence intensity ratios (ICM:TE) also differed (p<0.004) between fresh (0.966) and frozen‐thawed (0.482) embryos. These results indicate that 1) the use of FDA coupled with SIT camera image analysis is a repeatable, objective method for assessing embryo viability and 2) the freeze‐thaw process is more detrimental to ICM cells than to TE cells of horse embryos.
Embryo technology applied to the conservation of equids
Authors: FARINASSO A. , DE FARIA C. , MARIANTE A. DA S. , DE BEM A. R. 
Published: June 2010

SummaryWith the aim of starting a programme to conserve the Wild Horse of Roraima and the Northeastern Donkey, we adapted techniques used on bovine embryos to these equids. During the breeding season of 1987/88, 120 embryo collection attempts were performed on 11 crossbred donor mares between Days 6 and 8 after ovulation. Most attempts (107) were carried out on Day 6 to give an overall recovery rate of 48.3 per cent. Of 20 Day 6 embryos that were frozen in liquid nitrogen and subsequently thawed, 17 (85 per cent) appeared viable and were transferred non‐surgically to recipient mares synchronised to within +1 to −5 days of the embryo donors. This resulted in four pregnancies at Day 60 (23.5 per cent) compared to three pregnancies resulting from the transfer of seven ‘fresh’ unfrozen embryos (43 per cent). Transfer of 10 bisected demi‐embryos to individual recipients resulted in one live foal.
Pregnancies following 24‐hour co‐culture of equine embryos on foetal bovine uterine monolayer cells
Authors: WIEMER K. E. , CASEY P. L. , MITCHELL P. S. , GODKE R. A. 
Published: June 2010

SummaryA total of 77 embryo collection attempts from 28 donor mares resulted in 50 embryos (64.9 per cent recovery rate) ranging from Day‐6 morulae to Day‐7 expanded blastocysts. Thirty‐five of these embryos, classified as quality grades 1 and 2, were allotted randomly by developmental stage (Stage‐I, precapsulate and Stage‐II, postcapsulate) to a control group transferred non‐surgically within 1 h to synchronised recipients, and a treated group, cultured on a monolayer of foetal uterine fibroblast cells for 24 h prior to non‐surgical transfer to recipient mares. There was no significant difference in pregnancy rates between Stage‐I and Stage‐II embryos, nor between the control group (53.3 per cent) and the 24 h co‐cultured group (42.1 per cent). The use of a co‐culture system may provide a viable alternative to cryopreservation for the transport of equine embryos from one station to another.
A simple method for bisecting horse embryos
Authors: MÜLLER Z. , CIKRYT P. 
Published: June 2010

SummaryLate morulae and blastocysts were recovered non‐surgically on Days 6 to 8 after ovulation (Day 0) from Czech warm‐blood mares which had been inseminated with fresh or frozen stallion semen. Three morulae and three early blastocysts were bisected using a microblade attached to a simple bisection tool fixed to the objective of a phase contrast microscope. The 12 resulting demi‐embryos and 13 intact (non‐bisected) blastocysts were transferred surgically via flank laparotomy to recipient mares which had ovulated +1 to −3 days with respect to the embryo donor. Pregnancy was established in nine of the 13 mares (69 per cent) which received intact embryos and in tow of the six mares (33 per cent) which received demi‐morulae. However, none of the six mares which received demi‐blastocysts became pregnant.
Micromanipulation of equine embryos to produce monozygotic twins
Authors: SKIDMORE JULIAN , BOYLE M. S. , CRAN D. , ALLEN W. R. 
Published: June 2010

SummaryThe uteri of Welsh Pony donor mares were flushed non surgically late on Day 5 after ovulation (at 18.00 h or midnight) or on Day 6 (between 06.00 h and 12.00 h) to recover morulae or early blastocysts. Twenty‐six embryos were recovered from 63 flushing attempts (41 per cent). To investigate the effects of in vitro culture and micromanipulation on the development of the acellular equine blastocyst capsule, intact and manipulated embryos were cultured for varying times before being fixed and stained for histological examination. The capsule developed normally on two non‐manipulated morulae and one blastocyst cultured for 12 to 48 h. However, no development or redevelopment of the capsule occurred during 48 to 96 h in culture of the 18 demi‐embryos which resulted from the bisection of two morulae and seven blastocysts. The remaining 14 embryos were also bisected and the demi‐embryos transferred surgically to synchronised recipient mares within 4 h. All eight pregnancies which developed, including two sets of monozygotic twins, originated from bisected morulae. No pregnancies developed following transfer of bisected blastocysts.
Peripheral corneal ulcers in the horse
Authors: DICE P. F. , COOLEY PENNIE L. 
Published: June 2010

SummaryThis report involves a retrospective study of five horses with an unusual form of progressive peripheral corneal ulcers. These ulcers were located at the perilimbal region of the cornea and spread both centripetally to mid periphery and circumferentially. Lipping of the epithelial edge was observed often. The depth ranged from superficial to mid stroma. Patients ranged from two and a half to eight years, both sexes, and were referred after a variety of antibacterial therapy. Histories were similar in that all ulcers were initially located adjacent to the limbus in one or more quadrants. No trauma was known to antedate the corneal disease and the patients were in good general health. Conjunctivectomy was performed in three patients which revealed an abundance of plasma cells and lymphocytes. All five cases were negative for a specific bacterial pathogen. Patients responded to a variety of treatment modalities: topical corticosteroid, surgical debridement, therapeutic soft contact lens (TSCL), and/or conjunctivectomy.
Aniridia in a Thoroughbred horse
Authors: UEDA Y. 
Published: June 2010

SummaryAniridia presents with very characteristic typical signs and has been reported in man (Newell and Ernest 1974), calves (Saunders and Fincher 1951) and horses (Ericksson 1955; Joyce 1983). This case report records aniridia in a Thoroughbred.The animal, a two‐month‐old brown colt, presented with a history of unusual brightness in both eyes and strange behaviour. Clinical examination revealed curtain‐like pigmentation in the upper part of the cornea from the superior limbus which was thickened and poorly demarcated. Some vascularisation was present in the affected corneal region. The iris was absent and the tips of the ciliary body processes were apparent around the lens equator. A small central cataract was present. Intraocular pressure was normal and there were no abnormalities detected on ophthalmoscopic examination of the fundus (Fig 1). The condition was bilateral. Examinations at three and five years of age revealed no further abnormalities.The colt was well developed from birth and although behaving as the other colts, photophobia was evident in the paddock at all times. The horse was quiet in the stable and would sometimes stare in one direction for long periods. It was nervous outside; training was carried out in the early morning as the animal exhibited certain wild behaviour in bright sunshine and reacted sharply to reflected light from pools of water. However, it was placed first on four occasions, second on five occasions and third on one occasion from 37 starts. The colt was gelded at 16 months and was the eighth foal from a mare imported from Ireland; none of the other offspring were affected and the mare showed no evidence of illness during pregnancy.
Methodology and repeatability of a standardised treadmill exercise test for clinical evaluation of fitness in horses
Authors: SEEHERMAN H. J. , MORRIS ELISABETH A. 
Published: June 2010

SummaryThis paper describes the methodology necessary to perform a clinical exercise test and the expected variability in an individual horse's exercise test measurements based on comparing the results of two repetitions of the test with six horses. The exercise test measurements were obtained with an open flow respiratory gas analysis system, fast time response lactate analyser and an on‐board heart rate monitor during an incremental inclined treadmill exercise test. With the exception of peak venous lactate concentration (LACpeak), the results indicate that the mean variability in peak oxygen consumption (V̇O2peak) peak carbon dioxide production (V̇CO2peak), peak respiratory exchange ratio (Rpeak), peak heart rate (HRpeak), peak packed cell volume (PCVpeak), peak total plasma protein (TPPpeak) and the maximum number of steps completed during the exercise test (STEPmax) was less than 5 per cent. Variation in the regression analysis of V̇O2, V̇CO2 and HR versus velocity was also less than 5 per cent. Slightly higher variation was recorded for LAC and R. Mean variation in the regression analysis of PCV and TPP versus velocity was more than 16 per cent. Mean variation for all of the post exercise test measurements was less than 10 per cent at 1, 5 and 15 mins post exercise. Therefore, the results obtained during a single exercise test are a reliable assessment of a horse's metabolic capability.
Investigation of the vertical hoof force distribution in the equine forelimb with an instrumented horseboot
Authors: BARREY E. 
Published: June 2010

SummaryA greater knowledge of the biomechanics is necessary in equine orthopaedics, therapeutics, farriery and for the selection of athletic horses. The purpose of this study was to determine the normal distribution of the vertical component of the hoof force using a measuring boot. The measurements were carried out using 20 sound horses walking and trotting on a straight hard track. A force measuring horseshoe, attached to the foot with a boot, provided continuous recording of vertical forces at four locations on the hoof. For each measuring location, a computer program produced curves and calculated gait and force parameters. The position of the resultant force moved cranially during the stance phase. The vertical component was not distributed uniformly over the whole hoof surface. Thus the mechanical loading was greater in the caudal area than in the cranial area, especially after the foot impact on the ground. It was concluded that the heels and the quarters seemed to take a prominent part in dampening concussion and supporting bodyweight. More investigations are necessary to establish the relationships between the two functions and the frequent pathology of the caudal region of the foot.
Cardiorespiratory drift during exercise in the horse
Authors: THOMAS D. P. , FREGIN G. F. 
Published: June 2010

SummaryThe purpose of the present study was to measure the time‐course and degree of cardiovascular and respiratory ‘drift’ during constant submaximal exercise in the horse. One Thoroughbred and four Morgan mares were instrumented for simultaneous measurement of respiratory and blood gases which also enabled cardiac output (Q̇) to be calculated. Data were collected at rest, and at 10, 20 and 30 mins during a constant workload which elicited an initial exercising heart rate (HR) of 150 beats/min, and an approximate 15‐fold increase in oxygen consumption (VO2). Significant cardiac and respiratory drift during exercise were observed over time so that ventilation increased from 750 ± 58 to 910 ± 49 litres/min (21 per cent increase) from the 10 to 30 min time‐point (P<0.05) and HR went from 154 ± 4 to 173 ± 9 beats/min (mean ± se) over the same time period (P<0.05). Q̇ also rose from 142 ± 5 to 177 ± 17 litres/min (P<0.05) during the same interval while stroke volume (SV) was maintained. Rectal temperature (TR) and mixed venous lactate (LA) also showed significant increases during exercise while PaO2and PaCO2remained constant. The results indicate a significant degree of cardiac and respiratory drift in the horse in response to strenuous submaximal exercise. At the constant exercise work rate chosen, a levelling off, or plateauing of the selected parameters of interest was not observed. Therefore if a true exercising ‘steady‐state’ was achieved, it must have occurred very early in the exercise bout.
Alterations in plasma volume, plasma constituents, renin activity and aldosterone induced by maximal exercise in the horse
Authors: MASRI MARIA , FREESTONE J. F. , WOLFSHEIMER K. J. , SHOEMAKER K. 
Published: June 2010

SummaryPlasma volume (PV) decreased by 13 per cent following the completion of 1,000 m of maximal exercise in the horse. This study demonstrated that the critical reduction in PV following maximal exercise occurred within 10 mins of completion of exercise, as previously reported in man. Total plasma protein (TPP) increased by 23 per cent at 2 and 5 mins, and by 21 per cent at 10 mins post exercise. Therefore, it does not appear to be an accurate measurement to assess the degree of PV contraction in the horse. Protein was apparently added to the intravascular space either during or following exercise. The changes in osmolality correlated strongly with those in sodium, which is the primary determinant of alterations in plasma tonicity. The increase in osmolality (12 per cent) was similar to the reduction in PV (13 per cent) concluding that a transient hypotonic fluid loss had occurred. The increase in plasma renin activity (PRA) following maximal exercise was followed by an increase in aldosterone (ALD) concentration in both magnitude and time course. Alterations in PV should be considered when interpreting electrolyte and serum enzyme activity data collected following maximal exercise.
Effect of show jumping on heart rate, blood lactate and other plasma biochemical values
Authors: ART TATIANA , AMORY HELENE , DESMECHT D. , LEKEUX P. 
Published: June 2010

SummaryThis study investigated some physiological responses to exercise performed by a horse during show jumping. The effects of jumping on heart rate (HR), blood lactate (LA) and some other blood values were studied in nine normal horses participating at the Belgian Junior Championship. Venous blood was sampled before and immediately after the show jumping and was analysed for packed cell volume, LA, blood glucose (GLU), total plasma protein, bicarbonate, sodium, potassium (K+), chloride, calcium and activities of plasma lactate dehydrogenase, creatine phosphokinase (CK) aspartate amino transferase and gamma glutamyl transferase (GGT). A heart rate recorder placed under the saddle allowed the continuous recording of HR from the warm‐up until 2 mins after the event. The completion of the jumping induced significant changes in all values, except in K, GLU and GGT. Resting values of LA and HR were 0.53 ± 0.05 mmol/litre and 43.9 ± 1.9 beats/min respectively. Post exercise LA reached a mean value of 9.04 ± 0.9 mmol/litre, and, during the jumping, HR rose to a peak of 191.4 ± 3.8 beats/min. The results of this study demonstrate that, although the speed and duration of such an exercise are low, show jumping represents a severe exertion which requires the use of anaerobic metabolism. This implies that the training schedule of jumpers must include power training in order to improve their anaerobic capacity.
Bicarbonate loading in the Thoroughbred: Dose, method of administration and acid‐base changes
Authors: GREENHAFF P. L. , SNOW D. H. , HARRIS R. C. , ROBERTS C. A. 
Published: June 2010

SummaryTwo studies were undertaken in an attempt to investigate the optimal dose, route and time course required to ‘bicarbonate load’ the Thoroughbred. During the first study a test solution of sodium bicarbonate (NaHCO3) and a control solution of water were administered via a nasogastric tube to six horses. Blood acid‐base status was determined immediately prior to and for 24 h following intubation. During the second study a standardised feed was given to four horses, with and without NaHCO3 supplementation. This was followed by a further trial involving the addition of glucose and NaHCO3 to a standardised feed. During Study 1, plasma pH peaked 8 h after NaHCO3 intubation (7.433 ± 0.020) and levels were still elevated above control values 12 h post intubation. Although there was a trend for blood PCO2 to be elevated above control values at all times after NaHCO3 administration, values were only significantly different at 4 and 5 h post intubation. The patterns of change in plasma HCO3− and blood base‐excess after NaHCO3 administration were similar. Values peaked between 3 and 6 h post intubation and were still above control values 12 h post intubation. In Study 2 attempts to alter acid‐base status by presenting NaHCO3 mixed with feed were unsuccessful because horses failed to consume the total mix, despite attempts to mask the unpalatable nature of the feed by adding glucose. The results suggest that future studies investigating the influence of NaHCO3 on exercise performance and metabolism should possibly involve administration of NaHCO3 in a greater quantity than is administered conventionally (0.3g/kg). More meaningful results may be obtained if NaHCO3 is administered as a solution, via a nasogastric tube, at least 3 h prior to exercis