Topic:Abdominal
Research in the abdominal health and conditions category examines digestive physiology, gastrointestinal disorders, and treatment protocols in horses. This page compiles peer-reviewed studies and journal articles on the pathophysiology of common digestive issues, diagnostic techniques for conditions like colic and gastric ulcers, and evaluations of various treatment strategies.
Gonadotroph-lactotroph associations and expression of prolactin receptors in the equine pituitary gland throughout the seasonal reproductive cycle. An interaction between gonadotroph and lactotroph cells of the pituitary gland has long been recognized in several species. The current study was conducted to investigate whether an association between gonadotrophs and lactotrophs occurs in mares and whether prolactin receptors are expressed within the pituitary gland of this species. The effects of both reproductive state and season on these variables were examined in pituitary glands obtained from sexually active mares in July (breeding season), sexually active mares in November (non-breeding season) and anoestrous mares in November. Pituita...
Selection of the dominant follicle in cattle and horses. The nature of selection of the dominant follicle is reviewed by comparing research results between cattle and horses. In both species, emergence of a follicular wave is stimulated by an FSH surge. The surge reaches a peak by the time the follicles attain 4 mm in diameter in cattle and 13 mm in mares. In cattle, all of the growing follicles >/=5 mm contribute to the decline in FSH concentrations. However, the declining FSH concentrations are still needed by the growing follicles. Several days after the peak of the FSH surge and emergence of the wave, the two largest follicles reach means of 8.5...
Chronic idiopathic inflammatory bowel diseases of the horse. A review of reported cases of inflammatory bowel diseases (IBDs) of horses for which no etiology was identified included cases of granulomatous enteritis (GE), multisystemic eosinophilic epitheliotropic disease (MEED), lymphocytic-plasmacytic enterocolitis (LPE), and idiopathic eosinophilic enterocolitis (EC). The terms EC and MEED were both used to describe a disease in horses characterized by infiltration of intestine and extraintestinal tissues with eosinophils. We use EC to describe IBD characterized by only intestinal infiltration by eosinophils. Horses with GE, MEED, or LPE are usually e...
Reproductive hormone profiles in mares during the autumn transition as determined by collection of jugular blood at 6 h intervals throughout ovulatory and anovulatory cycles. The aim was to define precisely the FSH secretion pattern in mares during the two ovulatory cycles before, and for 24 days after, the last ovulation of the season and to compare this with the profiles of other reproductive hormones and follicular growth to identify changes which may lead to the termination of follicular cycles. Jugular blood was collected every 6 h from ten light horse mares for 6 weeks in autumn. Samples were assayed for FSH, LH, prolactin, inhibin, oestrone conjugates and progesterone. Luteolysis occurred earlier and periovulatory oestrone, but not inhibin, concentrations we...
Effect of carboxymethylcellulose and a hyaluronate-carboxymethylcellulose membrane on healing of intestinal anastomoses in horses. To evaluate the effect of sodium carboxymethylcellulose (SCMC) or a hyaluronate-carboxymethylcellulose membrane (HA membrane) on healing of the small intestine in horses. Methods: 18 healthy adult horses. Methods: Midline celiotomy and 2 jejunal resection-and-anastomosis surgeries were performed. In treated horses, SCMC (n = 6) or a HA membrane (6) was applied to the jejunum to cover the anastomosis. There were 6 untreated control horses. Horses were euthanatized 10 days after surgery. For each horse, 1 anastomosis was used for histologic examination, and the second was used to determine intes...
Immunolocalization of P450C17 in the mare corpus luteum. Although the mare corpus luteum (CL) is capable of aromatization, the expression of other enzymes involved in estradiol synthesis is not yet clear. This study examined the localization of P450C17 in the mare CL at different stages of its functional development. In ovaries from follicular phase mares P450C17 was localized in the theca cells of ovarian follicles. Following ovulation, no immunostaining for P450C17 was detected in the mature CLs of nonpregnant mares. In pregnant mares, no immunostaining for P450C17 was identified in the corpus luteum prior to secretion of eCG by the feto placental...
Effects of melatonin implants in pony mares. 1. Acute effects. The effects of melatonin implant treatment over a four week period on LH, estradiol (E2) and progesterone (P4) secretion during the breeding season were studied in ovary-intact and ovariectomized pony mares. Mares with melatonin implants had significantly higher daytime melatonin concentrations than mares with sharm implants (P = 0.0065). In ovariectomized mares, LH secretion did not differ between mares with melatonin and sham implants. In ovary-intact mares, melatonin implants altered the pattern of LH secretion (P = 0.0023) in such a way that an increase in LH secretion was observed during ...
Evaluation of two treatments in superovulation of mares. The efficiency of superovulating mares with an enriched fraction of equine follicle-stimulating hormone (feFSH) and an equine pituitary extract (EPE) with similar FSH content but differing in the LH amount was compared. Mares were randomly assigned to an feFSH (n = 5) or EPE (n = 5) treatment. The experimental period was of 2 successive estrous cycles, with the first cycle as the control. At Days 6 and 7 of the estrous cycle, the mares received 250 micrograms i.m. cloprostenol. The treatments consisted of daily injections of 25 mg feFSH or EPE beginning on Day 6 post ovulation. Mares were inse...
Effects of melatonin implants in pony mares. 2. Long-term effects. The effects of melatonin implant treatment over a 4 wk period at the summer solstice on the transition into and out of the following anovulatory season were evaluated in ovary-intact and ovariectomized mares. Melatonin implants tended to delay the timing of the final ovulation of the breeding season (P = 0.0797) in the ovary-intact mares. Although the decline in LH secretion associated with the end of the breeding season was parallel between treatments and ovarian statuses, the rate of LH secretion, as expressed by its mathematical accumulation, was lower in ovariectomized, melatonin-treated m...
Temporal interrelationships among luteolysis, FSH and LH concentrations and follicle deviation in mares. The effect of altered LH concentrations on the deviation in growth rates between the 2 largest follicles was studied in pony mares. The progestational phase was shortened by administration of PGF2alpha on Day 10 (Day 0=ovulation; n=9) or lengthened by daily administration of 100 mg of progesterone on Days 10 to 30 (n=11; controls, n=10). All follicles > or = 5 mm were ablated on Day 10 in all groups to initiate a new follicular wave. The interovulatory interval was not altered by the PGF2alpha treatment despite a 4-day earlier decrease in progesterone concentrations. Time required for growt...
Regulation of seasonal reproductive activity in the stallion, ram and hamster. This review considers seasonal reproduction in male animals with emphasis on the stallion, ram and hamster. The pineal hormone melatonin is the common link between photoperiod and reproduction. An increase in the daily diurnal period of melatonin secretion is associated with a decrease in GnRH release in long-day breeders, but an increase in GnRH release in short-day breeders. Melatonin influences GnRH release within or close to the mediobasal hypothalamus in rams; whereas melatonin receptors have not been found in the hypothalamus of horses. Prolactin release is positively correlated with day...
Opioidergic and dopaminergic effects on LH and prolactin release in pony mares at different times of the year. The effects of dopaminergic and opioidergic systems on LH and prolactin release in Pony mares were investigated. Experiments were performed in intact mares during the non-breeding and the breeding seasons and in ovariectomized mares in November, March and May. Mares were treated with the dopamine D2-antagonist sulpiride, the opioid antagonist naloxone and naloxone plus sulpiride and saline. Naloxone alone and in combination with sulpiride increased plasma LH concentrations in intact anovulatory mares and in cyclic luteal phase mares, whereas sulpiride alone had no effect. None of the treatment...
Uncoupling of the equine reproductive axes during transition into anoestrus. The reproductive activity of light horse mares (n=12) was monitored each day from 3 September until 29 January, or until the mares entered anoestrus, by behaviour evaluation, ultrasonography and blood sampling. Follicles, corpora lutea and ovulation, as well as oestradiol, progesterone, and LH and FSH concentrations, were analysed to determine a reproductive profile for the transition into anoestrus. The results of the present study indicate that light horse mares progress through four phases during the autumn transition into anoestrus: (i) normal cycles; (ii) aberrant cycles; (iii) anovulatio...
Ovarian secretion of inhibin in mares. In mares, circulating immunoreactive inhibin concentrations increase during the follicular phase and decrease at the start of the LH surge. Thereafter, sharp increases in circulating immunoreactive inhibin concentrations, the 'ovulatory increase', are observed during ovulation. In the present study, the cellular sources and molecular form of ovarian inhibin were investigated to determine the mechanism responsible for this unique ovulatory increase. Three sizes of ovarian follicles (small, 30 mm in diameter) were selected. Inhibin alpha-subunit was localized by immunohistochemistry to the gran...
Pituitary response to steroid replacement therapy in fertile, subfertile and infertile stallions after castration. Recent studies in our laboratory investigating plasma gonadotrophin concentrations before and after castration indicate that the hypothalamic-pituitary axis is not the original site of dysfunction in stallions with idiopathic infertility. In the present study, fertile, subfertile and infertile stallions were subjected to replacement therapy with oestradiol and testosterone 1 year after castration to investigate hypothalamic-pituitary axis function further. Fertile (n=5), subfertile (n=3) and infertile (n=2) castrated stallions of Light horse breeds, aged 11-23 years, were given either oestradi...
Differential expression of steroidogenic enzymes by the primary corpora lutea of pregnant mares during equine chorionic gonadotrophin secretion. At the onset of equine chorionic gonadotrophin (eCG) secretion, eCG stimulates luteal androgen and oestrogen production. Although eCG concentrations increase exponentially from day 37 to day 60 of gestation and eCG is detectable in maternal serum until about day 120-150 of gestation, luteal androgen and oestrogen production peaks between 5 and 10 days after initial exposure to eCG and then decreases gradually. It is not clear how eCG regulates luteal androgen and oestrogen production. In the present study, the steady-state mRNA expression of 3beta-hydroxysteroid dehydrogenase (3beta-HSD), cyto...
Influence of the dopamine antagonist domperidone on the vernal transition in seasonally anoestrous mares. The aim of the present study was to determine the effect of prolonged administration of the dopamine antagonist domperidone on follicular development, ovulation and endocrine profiles in anoestrous mares. Anoestrous mares (n=16) were maintained under natural photoperiod and ambient temperature. Eight of the mares were treated with domperidone each day from 15 January until the first ovulation of the year. The mean number and size of follicles > or =20 mm in diameter were significantly greater in domperidone-treated mares than in control mares by day 14 of treatment. The day of first ovulati...
Effect of oestradiol on LH secretion and pituitary responsiveness to GnRH in ovariectomized mares. Long-term ovariectomized Pony mares were treated with oestradiol (0.2-5.0 mg; i.m.) at 12 h intervals for 10 days. Blood samples were collected by jugular venepuncture three times a day throughout the experiment and additional blood samples were collected at 15 min intervals for 12 h on days 0 and 10 (sampling periods 1 and 2, respectively). There were significant effects of oestradiol treatment (P < 0.05) and oestradiol treatment x day (P < 0.0001) on the mean LH concentrations each day. Regression analysis of LH time trends each day indicates that there is heterogeneity (P < 0.001) ...
The role of endogenous opioids in the ovulatory LH surge in mares. Removal of opioid inhibition of GnRH neurones is thought to be a critical event in generating the ovulatory surge in some species. In the present study, a nonsurgical technique was used to collect pituitary venous blood samples from eight mares every 0.5-1.0 min for 1 h before and after administration of the opioid receptor antagonist naloxone (0.2 mg kg(-1), i.v.), to investigate whether opioid inhibition is also important in mares. Jugular blood samples were taken at 10-15 min intervals. Mares were studied 0, 1 or 2 days before ovulation. Naloxone administration increased mean rates of GnRH ...
Ovulation synchrony after follicle ablation in mares. Two experiments were performed to determine the efficacy of ultrasound-guided transvaginal follicle ablation for synchronizing ovarian function in mares. The experiments were initiated at random stages of the oestrous cycle in control (nonablated) and follicle-ablated mares. On day 0, all follicles > or =10 mm in diameter were punctured, aspirated and curettaged in ablated mares, and, on day 4, two doses of PGF2alpha were administered with a 12 h interval between the doses to both ablated and nonablated (control) mares. In Expt 1, hCG was administered to the ablated mares on the first or se...
Comparison of incisional bursting strength of simple continuous and inverted cruciate suture patterns in the equine linea alba. To determine the bursting strength of ventral median abdominal incisions closed by either simple continuous or inverted cruciate suture patterns. Methods: Experimental. Methods: Twelve equine cadavers. Methods: A 25 cm ventral median incision was made through the linea alba and a 200 L polyurethane bladder was placed within the abdomen. Either a simple continuous or an inverted cruciate pattern using 3 polyglactin 910 with a bite size and suture interval of 1.5 cm was used to close linea incisions. Closure time was recorded for each pattern. The bladder was inflated with air at 40 L/min, and t...
Role of luteinizing hormone in follicle deviation based on manipulating progesterone concentrations in mares. The effects of several doses of progesterone on FSH and LH concentrations were used to study the role of the gonadotropins on deviation in growth rates of the two largest follicles during the establishment of follicle dominance. Progesterone was given to pony mares at a daily dose rate of 0 mg (controls), 30 mg (low dose), 100 mg (intermediate dose), and 300 mg (high dose). All follicles > or = 6 mm were ablated at Day 10 (Day 0 = ovulation) to initiate a new follicular wave; prostaglandin F(2alpha) was given to induce luteolysis, and progesterone was given from Days 10 to 24. The low dose ...
Detection and comparison of nitric oxide in clinically normal horses and those with naturally acquired small intestinal strangulation obstruction. The purpose of this study was to determine whether nitric oxide (NO) is present in clinically normal horses under basal conditions and if it increases secondary to naturally acquired small intestinal strangulation obstruction. Thirty-one horses were used; 20 horses with naturally acquired small intestinal strangulation obstruction and 11 clinically normal horses with no signs of gastrointestinal tract disease. Jugular venous blood, abdominal fluid, and urine were collected for NO quantification. Plasma, abdominal fluid, and urine were stored at -70 degrees C until analyzed for NO using a chemi...
Tumor necrosis factor and interleukin-6 activity and endotoxin concentration in peritoneal fluid and blood of horses with acute abdominal disease. The purpose of this study was to evaluate the diagnostic and prognostic significance of tumor necrosis factor-alpha (TNF) and interleukin-6 (IL-6) activities and endotoxin concentration in blood and peritoneal fluid of 155 adult horses with acute abdominal disease (colic). Samples also were obtained from 20 healthy adult horses. Blood and peritoneal fluid supernatant TNF and IL-6 activities and endotoxin concentration were significantly greater in horses with colic, compared with healthy horses. In horses with colic, the peritoneal fluid endotoxin concentration and TNF and IL-6 activities were...
Small intestine strangulation by components of the spermatic cord in two geldings. Two adult Quarter Horse geldings were evaluated for signs of abdominal pain. Both horses had signs of depression and distended small intestines on abdominal palpation per rectum. Abdominal exploratory surgery was performed on both horses. In each instance, small intestine was found to be strangulated by components of the spermatic cord. Both horses were euthanatized because of a poor prognosis. Although not commonly observed, incarceration of intestine by components of the spermatic cord should be considered as a cause of small intestine strangulation in male horses. Early recognition of this ...
Chyloperitoneum and abdominal adhesions in a miniature horse. Chyloperitoneum is a potential cause of colic in horses. Although rare in horses, chyloperitoneum can develop secondary to tearing of mesenteric adhesions and rupture of mesenteric lymphatic vessels. The prognosis for horses with chyloperitoneum depends on the underlying cause and the response to treatment.
Drug disposition and dosage determination of once daily administration of gentamicin sulfate in horses after abdominal surgery. To evaluate pharmacokinetics of once daily i.v. administration of gentamicin sulfate to adult horses that had abdominal surgery. Methods: Prospective study. Methods: 28 adult horses that underwent abdominal surgery for colic. Methods: 14 horses were treated with each dosage of gentamicin (i.e., 6.6 or 4 mg/kg, i.v., q 24 h) and blood samples were collected for pharmacokinetic analysis. Plasma gentamicin concentrations were measured by use of a fluorescence polarization immunoassay. Pharmacokinetic analysis measured the elimination half-life, volume of distribution, and gentamicin total systemi...
Experimental assumption of dominance by a smaller follicle and associated hormonal changes in mares. A two-follicle model was used to study the nature of selection of the dominant follicle in mares by ablating neither or one of the two follicles on the day the larger follicle reached >/= 20 mm (Day 0). The larger follicle became the dominant follicle in all mares in which both follicles (n = 8) or only the larger follicle (n = 10) was retained. When only the smaller follicle (n = 9) was retained, it became dominant and ovulated in six mares and became atretic in three mares; the difference in diameter between the two follicles on Day 0 was less (p < 0.01) in mares in which the retained ...
Abdominal spindle cell sarcoma of probable myofibroblastic origin in a horse. No abstract available
Surgical repair of a diaphragmatic hernia in a racehorse. A 9-year-old Thoroughbred was evaluated for clinical signs of acute abdominal pain. During laparotomy, a rent in the diaphragm and herniation of the small intestine into the thoracic cavity were detected. Because edges of the rent were smooth and fibrous, which suggested the defect was chronic, the abdomen was closed without repairing the rent. After recurrence of clinical signs, a second laparotomy was performed, during which the intestines were found to have reherniated. The diaphragmatic rent was repaired, using a polypropylene mesh secured with stainless steel staples. The horse recovered ...