bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of stride characteristics in a cantering horse on a flat and inclined treadmill
Authors: KAI M. , HIRAGA A. , KUBO K. , TOKURIKI M. 
Published: June 2010

SummaryThe purpose of this study was to determine whether there was any difference in the stride characteristics between cantering on a flat or inclined treadmill. Five 2‐year‐old Thoroughbred horses were cantered on a treadmill at 3 different velocities and at 3 different slopes. The sequence of speeds at each slope was chosen at random and 16 mm cine‐films at 300 frames/s were taken from a lateral view at a distance of 15 m from the treadmill to record the linear and temporal data. On the slope, stride length, stride duration, stance duration and swing duration did not change. However, midstep length increased significantly and the airborne step length decreased significantly as slope increased from a 3% slope to a 8% slope at 12 m/s. The airborne duration increased significantly from a 0% slope to a 3% slope, and inversely decreased significantly from a 3% slope to a 8% slope. The advanced placement (AP) between trailing hindlimb and leading hindlimb (APTH‐LH) and between trailing forelimb and leading forelimb (APTF‐LF) and the overlap between LH and TF (LH‐TF) tended to decrease and the AP between LH and TF (APLH‐TF) and the overlap between TH and LH (TH‐LH) inversely tended to increase as the slope increased, though these tendencies were not significant. These findings indicated that in slope locomotion, the stride length might be maintained by sacrificing the length of the airborne period as the workload became more intense.
Kinematics in horses at the trot before and after an induced forelimb supporting lameness
Authors: GALISTEO A. M. , CANO M. R. , MORALES J. L. , MIRÓ F. , VIVO J. , AGÜERA E. 
Published: June 2010

SummaryThe aim of this study was to analyse the biokinematic alterations caused by an induced lameness in the right forelimb of Dutch Warmblood (DWB) horses using a system of computer‐aided normal videography. Five mature DWB were recorded with a videocamera (frame rate 1/25) from a lateral view before and after an induced lameness. Before videotaping, passive markers were placed on the skin, over easily identifiable anatomical references to determine the joint angles in the forelimb (always on the flexor side). Lameness was induced using special horseshoes. The lameness was evident at the trot and mild at walk. The images were analysed using a real time digitalising system combined with a previously designed spreadsheet. Linear, temporal and angular parameters (maximum, minimum and angular range of motion) along the stride were calculated as well as the moments of highest extension (Pmax) and flexion (Pmin), expressed as a percentage of the whole stride. Results before and after the induced lameness were compared by a paired Student'sttest at a significance level of P<0.05. No differences in speeds before and after the induced lameness were found. Stride length was significantly shorter in the lameness condition. Stride duration was slightly shorter in lameness. The diagonal stance phase increased, while the swing phase decreased. Angular parameters changed mainly in elbow, carpus, fetlock and retraction‐protraction angles. This indicated that the angular range of motion in the elbow and carpal joints decreased, and the elbow Pmin occurred later in the stride. The results are useful in the development of video‐based equine lameness diagnostics.
Fetal pulmonary development: the role of respiratory movements
Authors: HARDING R. 
Published: June 2010

SummaryThe lung develops before birth as a collapsible, liquid‐filled, organ. Throughout the later stages of gestation the fetal lungs are maintained at a level of expansion that is considerably greater than the level achieved as a result of passive equilibration between lung recoil and the chest wall. Fetal breathing movements (FBM) are a feature of normal fetal life and, as such, are used clinically in the assessment of fetal wellbeing. By opposing lung recoil, FBM help to maintain the high level of lung expansion that is now known to be essential for normal growth and structural maturation of the fetal lungs. During ‘apnoeic’ periods between successive episodes of FBM, active laryngeal constriction has the effect of opposing lung recoil by resisting the escape of lung liquid via the trachea. The prolonged absence or impairment of FBM is likely to result in a reduced mean level of lung expansion which can lead to hypoplasia of the lungs. There is clinical evidence, disputed by some, that the absence of FBM exacerbates the effects of other factors that are associated with lung hypoplasia, such as premature rupture of fetal membranes and oligohydramnios. Even in the absence of such factors, prolonged or repeated reductions or abolition of FBM may contribute to impairments of fetal lung development; FBM can be inhibited by fetal hypoxaemia, hypoglycaemia, maternal alcohol consumption, maternal smoking, intra‐amniotic infection and maternal consumption of sedatives or narcotic drugs. Abnormal growth of the fetal lungs has relevance for postnatal respiratory health as it is now recognised that there may be only a limited capacity after birth for the restoration of normal pulmonary architecture following impaired intra‐uterine lung development.
Systemic and luminal influences on the perinatal development of the gut
Authors: TRAHAIR J. F. , SANGILD P. T. 
Published: June 2010

SummaryAt birth, the mammalian gastrointestinal tract (GIT) must be able to support a shift from mainly parenteral nutrition in the fetus (via the placenta) to enteral nutrition in the neonate. In the perinatal period the GIT therefore undergoes enhanced growth as well as morphological and functional differentiation, and this maturational programme is influenced by a complex interplay of local, systemic and luminal factors. This review shows how systemic and luminal factors may influence GIT development in the perinatal period of the pig and sheep, two long‐gestation species. Adrenocortical hormones play a pivotal role in the prepartum maturation of the GIT in addition to their better known effects on the development of many other tissues and body systems. More particularly, in the fetal pig and sheep, the prenatal development of gastric acid and gastrin secretion, and of GIT hydrolase activities (chymosin, pepsin, amylase, lactase, aminopeptidases) is influenced by Cortisol. Additionally, glucocorticoids exert effects throughout the GIT by influencing morphological, cytological, and functional differentiation. Since the GIT epithelial cells comprise a renewing cell population there are also changes in cell kinetics. In addition to systemic factors, the presence of growth factors, hormones and nutrients from swallowed amniotic fluid (fetus) and colostrum (neonate) may influence GIT development In utero, fetal fluid ingestion has been shown to modulate tissue growth, macromolecule and immunoglobulin transport, enterocyte differentiation, cell turnover and activity of brush‐border hydrolases. These effects may be mediated via regulatory peptides (e.g. insulin‐like growth factor I, gastrin‐releasing peptides, insulin, epidermal growth factor, gastrin). A physiological role of luminally derived growth factors is supported by a number of unique structural and functional adaptations of the GIT in the fetus and neonate (low luminal proteolysis, intestinal macromolecule transport). Thus, in the pig and sheep, both systemic and luminal factors appear to play critical roles in GIT development in the perinatal period.
Stimulation of the switch in myometrial activity from contractures to contractions in the pregnant sheep and nonhuman primate
Authors: NATHANIELSZ P. W. , GIUSSANI D. A. , WU W. X. 
Published: June 2010

SummaryThe process of parturition is regulated by a set of interrelated endocrine, paracrine, and autocrine systems. Many of these systems demonstrate positive feed‐forward characteristics. The sequential recruitment of signals that promote the labour process demonstrates that it is not possible to attribute the designation of the factor responsible for the ‘initiation of parturition’ uniquely to any one signalling mechanism. For this reason we prefer to avoid the term initiation of parturition since, mechanistically, each cellular and molecular mechanism that contributes to the process is itself initiated by an earlier process. In a very real sense, the initiation of parturition can be considered to be fertilisation. Therefore we prefer to describe the key mechanisms involved as promoting, rather than initiating, the process of labour and delivery. Despite many interspecies differences, an increase in maternal plasma oestrogen in late gestation appears to play a central role in promotion of parturition. In both sheep and monkeys signals from the fetal hypothalamo‐pituitary‐adrenal axis increase oestrogen production by the placenta. We propose that the key fetal adrenal product is Cortisol in the sheep and androgen in the monkey. Oestrogen then recruits a range of stimulators, uterotonins, that act on the prepared myometrium to initiate the switch in myometrial activity from contractures to contractions. The various mechanisms central to the process can be considered to be either, or both, activators and/or stimulators of one or more of the key terminal steps involved.
Biosynthesis and possible biological roles of progestagens during equine pregnancy and in the newborn foal
Authors: CHAVATTE PASCALE , HOLTAN D. , OUSEY JENNIFER C. , ROSSDALE P. D. 
Published: June 2010

SummaryMajor progress on the endocrinology of the pregnant mare has been possible thanks to the catheterised equine fetal preparation developed by Marian Silver. In particular, these preparations led to the identification of the source of progestagens within the feto‐placental unit and provided the impetus for further work on their biosynthesis and biological activities. The biosynthesis of the progestagens involves close interaction between the fetus, the endometrium and the placenta, and gives rise to some fundamental biochemical questions. The biological role of the progestagens is also discussed: these compounds may have progestagenic activities but may also play a role in the onset of parturition.
Long term exposure to T‐2 Fusarium mycotoxin fails to alter luteal function, follicular activity and embryo recovery in mares
Authors: JUHÁSZ JUDIT , NAGY P. , HUSZENICZA G. , SZIGETI G. , REICZIGEL J. , KULCSÁR M. 
Published: June 2010

SummaryThe effect of long term administration of T‐2 toxin was studied in 6 Trotter mares during the summer and early autumn. After one complete oestrous cycle (Cycle 1) each mare was given 7 mg purified T‐2 toxin perosdaily (1 mg/ml in ethyl alcohol) beginning on Day 10 after ovulation in Cycle 2. Exposure to toxin was continued for 32–40 days, until Day 7 of Cycle 4. During this period all the animals remained in good physical condition, but skin lesions were observed around the mouth in 3 cases. Toxin administration had no effect on the length of the interovulatory interval or on the lengths of the luteal and follicular phases. It also had no effect on peripheral plasma progesterone profiles or follicular kinetics, including the growth rate and maximum size of ovulatory follicles and the maximum number, and time of first increase in number, of follicles larger than 1 and 2 cm.Uterine flushing was attempted in 5 mares and yielded 3 embryos (60%). These were of normal size and morphology and one was transferred nonsurgically to a recipient mare; a conceptus developed initially but it subsequently died and was resorbed. The results of the study allowed the conclusion that the administration of 7 mg/day T‐2 toxin to mares in good body condition has no detrimental effect on ovarian activity, fertilisation or oviductal transport.
Effects of follicular aspiration and flushing, and the genotype of the fetus on circulating progesterone levels during pregnancy in the mare
Authors: MEINTJES M. , GRAFF K. J. , PACCAMONTI D. , EILTS B. E. , PAUL J. B. , THOMPSON D. L. , KEARNEY M. T. , GODKE R. A. 
Published: June 2010

SummaryWhen aspirating ovarian follicles in pregnant mares to obtain oocytes for in vitro fertilisation (IVF), the effect of the manipulation on circulating concentrations of progesterone may be an important consideration in terms of the maintenance of pregnancy. The object of this study was to compare the effects of 3 different forms of transvaginal ultrasound‐guided follicle aspiration (Treatment 1, no aspiration, n = 4; Treatment 2, aspirate only follicles >20 mm in diameter, n = 7; Treatment 3, aspirate all visible follicles, n = 7) on peripheral plasma progesterone concentrations between Days 21 and 150 of gestation in 9 mares carrying intraspecies horse and 9 mares carrying interspecies mule conceptuses. The 3 follicle aspiration treatments were applied at the peak of each follicular wave as determined by follicular mapping by means of transrectal ultrasonography on alternate days. The plasma progesterone profile in mares undergoing Treatment 1 was in close agreement with those reported previously in pregnant mares. A decline in plasma progesterone levels occurred after Day 53 of gestation in Treatments 2 and 3 mares, indicating that the follicular aspiration procedures did interfere with the formation of secondary corpora lutea. However, the levels in individual mares never dropped low enough to endanger the pregnancy. Mares carrying mule pregnancies exhibited higher mean plasma progesterone concentrations between Days 39 and 45 of gestation than mares carrying horse pregnancies, equivalent levels between Days 46 and 66 despite the lower circulating concentrations of chorionic gonadotropin (mule CG) in their blood during this period and lower progesterone levels between Days 67 and 150 of gestation. The results indicate that the primary corpus luteum in the pregnant mare may be more sensitive to mule CG than horse CG. Furthermore, the earlier disappearance of CG from the circulation in mares carrying mule fetuses is reflected by an earlier decline in plasma progesterone concentrations in this type of equine pregnancy.
Timing of in vivo maturation of equine preovulatory oocytes and competence for in vitro maturation of immature oocytes collected simultaneously
Authors: BÉZARD JACQUELINE , MEKARSKA ANNA , GOUDET GHYLENE , DUCHAMP G. , PALMER E. 
Published: June 2010

SummaryThe objects of this study were to monitor the development of the cumulus complex and nuclear maturation in oocytes recovered from preovulatory follicles following treatment to induce ovulation and to investigate the in vitro maturation competence of oocytes recovered from smaller nonpreovulatory follicles of varying size. All follicles ≤5 mm in pony mares were individually punctured at 0, 6, 12, 24 and 35 h after an injection of LH to induce ovulation. The recovery rates of oocytes were 64% from 55 preovulatory follicles, 22% from 32 subordinate follicles and 52% from 227 small follicles. Cumulus expansion of the preovulatory oocytes occurred at 12 h post LH treatment while the metaphase I and II components of nuclear maturation were not completed until 24 and 35 h post LH respectively. For nonpreovulatory follicles, the frequency of atresia and oocyte competence for in vitro nuclear maturation both increased with increasing follicular size.
Comparison of different methods for the recovery of horse oocytes
Authors: ALM H. , TORNER H. , KANITZ W. , BECKER F. , HINRICHS K. 
Published: June 2010

SummaryThe object of this study was to compare 4 different methods of oocyte recovery from mares; 1) transvaginal follicle aspiration in vivo; 2) follicle aspiration in vitro; 3) oocyte recovery by isolation of follicles in vitro and 4) follicle scraping in vitro. Oocyte recovery was highest after follicle scraping (71.1%) and follicle isolation and rupture (61.3%). Follicle aspiration in vitro and in vivo yielded oocytes on 31.2% and 19.3% of occasions, respectively. The output of different types of cumulus‐oocyte‐complexes was different among the methods; the portion of compact cumulus‐oocyte‐complexes was significantly higher with follicle scraping (50.7%) and follicle isolation (44.5%) than with aspiration in vivo (31.9%) and in vitro (23.7%). The recovery rate of oocytes from small follicles (<15 mm) was significantly higher than from larger follicles (P < 0.05) using transvaginal follicle aspiration. The proportion of oocytes that were degenerate (exhibited shrunken, dense or visibly damaged ooplasm) ranged from 1.2% after follicle scraping, to 17.2% after aspiration in vivo. These results indicate that, for the recovery of horse oocytes in vitro, follicle scraping and follicle isolation give the highest recoveries of cumulus‐intact oocytes.
Success rates when attempting to nonsurgically collect equine embryos at 144, 156 or 168 hours after ovulation
Authors: BATTUT I. , COLCHEN S. , FIENI F. , TAINTURIER D. , BRUYAS J.‐F. 
Published: June 2010

SummaryThe purpose of this study was to evaluate the exact age when the equine embryo reaches the uterus. The time of ovulation was determined by hourly ultrasound examinations starting 32 h after an injection of crude equine pituitary gonadotrophin or human chorionic gonadotrophin, or after the first of 4 injections of buserelin. Nonsurgical uterine flushings were carried out 144 h (Day 6), 156 h (Day 6.5) or 168 h (Day 7) after ovulation. Induction of ovulation was attempted in 101 oestrous cycles and 61 of 101 mares (60.4%) ovulated 32–44 h post injection. Sixty embryo collections were performed which yielded: 0/20 embryos at 144 h, 9/17 embryos (53%) at 156 h and 12/23 embryos (52%) at 168 h. The mean (± s.e.m.) diameter of the embryo was significantly greater (P < 0.01) at Day 7 (244 ± 15 μm) than at Day 6.5 (186 ± 9.1 μm), and variability in size was observed among embryos collected from the same mare after synchronous natural multiple ovulations.These results suggest that; i) horse embryos enter the uterus between 144 and 156 h after ovulation, and ii) the time interval between ovulation and fertilisation in mares is inconsistent and/or embryonic development rate may differ between individual embryos.
Parentage testing of Day 10 equine embryos by amplified PCR analysis of microsatellites
Authors: GUÈRAND MATHILDE , MAHLA R. , LAGNEAUX D. , AMIGUES Y. , PALMER E. , BÉZARD JACQUELINE 
Published: June 2010

SummaryPaternity analysis was performed on the DNA of 21 equine embryos collected nonsurgically 10 days after ovulation from known mares, but involving 3 possible sires. After extraction, the DNA of each embryo was typed by radioactive PCR amplification using 10 characterised microsatellites; HMS 1, 2, 5, 6, 7 and 8 (Guérin et al. 1994) and HTG 3, 4, 6 and 10 (Marklund et al. 1994). The 21 dams and 3 sires were genotyped using DNA extracted from blood and amplified by PCR. After electrophoresis and autoradiography of the PCR products of the embryo and parents, the alleles of the embryo were compared to those of the dam to identify those of maternal origin. The paternal alleles were then searched for within the genotype of the 3 sires, and the stallion(s) that exhibited the particular allele was said to be compatible with the embryo for this microsatellite. In this way, the true sire was identified correctly for all 21 embryos.
The effect of propanediol on the morphology of fresh and frozen equine embryos
Authors: BRUYAS J‐F. , MARTINS‐FERREIRA C. , FIÉNI F. , TAINTURIER D. 
Published: June 2010

SummarySeventeen horse embryos recovered on the sixth day after spontaneous ovulation were; 1) washed in PBS (n = 6), 2) treated with 1.5 M 1–2 propanediol (n = 6) or, 3) frozen and thawed using 1.5 M propanediol as the cryoprotectant (n = 5). After treatment, the embryos were incubated for 6 h in medium before they were fixed, serially sectioned and examined microscopically to count the total numbers of interphase, mitotic and pycnotic nuclei. Significant differences were measured only in the mean proportions of pycnotic cells (± s.d.), both between the control (9.2 ± 7.3%) and frozen‐thawed embryos (52.8 ± 37.1%; P < 0.05) and between the propanediol‐treated (10.8 ± 4.6%) and the frozen‐thawed embryos (P < 0.01). Propanediol appears to be minimally toxic to equine embryos but it is a poor cryoprotectant.
Effect of anti‐freeze protein (AFP) on the cooling and freezing of equine embryos as measured by DAPI‐staining
Authors: LAGNEAUX D. , HUHTINEN M. , KOSKINEN E. , PALMER E. 
Published: June 2010

SummaryEquine embryos recovered on Day 6 after ovulation were cooled to +4°C, or frozen with AFP alone or together with glycerol. Twenty embryos (140–200 μm in diameter) were randomly assigned to 6 treatment groups. In the first 3 groups, the embryos were cooled from room temperature to +4°C at a rate of 3°C/min and warmed again at a rate of 32°C/min in a programmable freezer. In the second 3 groups, the embryos were frozen using a standard protocol, stored in liquid nitrogen for 5–7 days and then thawed in a 37°C waterbath. After cooling/warming or freezing/thawing all the embryos were stained with DAPI. The percentage of dead cell area was significantly lower in the cooling groups than in the freezing groups and no significant differences were apparent between the cryoprotectants used in the study.
Cryopreservation of equine embryos with glycerol plus sucrose and glycerol plus 1,2‐propanediol
Authors: FERREIRA J. C. P. , MEIRA C. , PAPA F. O. , e ALVARENGA F. C. LANDIN , ALVARENGA M. A. , BURATINI J. 
Published: June 2010

SummarySix or 7‐day‐old equine embryos were divided into 4 groups;Group 1, n = 15, Day 7 embryos destined for immediate transfer;Group 2, n = 15, Day 6 embryos destined for deepfreezing with glycerol plus sucrose as cryoprotectant;Group 3, n = 10, Day 6 embryos destined for deep‐freezing with glycerol plus 1,2‐propanediol as cryoprotectant andGroup 4, n = 3, fresh embryos destined for ultrastructural analysis. All the frozen/thawed embryos were transferred to recipient mares, except 3 embryos inGroup 3that were subjected to ultrastructural analysis. After thawing the cryoprotectants were removed by successive dilutions in PBS + 15% v:v fetal calf serum (FCS) containing decreasing concentrations of the cryoprotectants. Pregnancy was diagnosed ultrasonographically in 53.3%, 13.3% and 0% of the mares inGroups 1, 2 and 3respectively.Ultrastructural analysis showed differences between frozen/thawed and fresh embryos. In the former, embryonic cells were deformed and showed dilation of the intercellular and perivitelline spaces, a decrease of desmosome number in the junctional complexes, few microvilli on the apical surface of the trophectoderm and an almost total absence of pinocytotic vesicles. Most of the mitochondria showed regions containing dilation and irregularities on the cristae, which appeared electron‐dense. The results obtained withGroups 2and3embryos showed that the cryoprotectants employed were not effective in protecting the embryos against damage during freezing and thawing. Indeed, the ultrastructural changes observed in theGroup 3embryos explained the absence of any established pregnancies in this group of mares.