Evaluation of surgical treatment for signs of acute abdominal pain in draft horses: 72 cases (1983-2002)

OBJECTIVE: To determine whether heavy (> or = 680 kg [> or = 1,500 lb]) draft horses undergoing surgical treatment for acute signs of abdominal pain were at a greater risk for anesthetic and postoperative complications and lower postoperative survival rates than light (< 680 kg) draft horses. DESIGN: Retrospective case series. ANIMALS: 72 draft horses. PROCEDURES: Medical records of draft horses that underwent exploratory celiotomy for signs of acute abdominal pain from October 1983 to December 2002 were reviewed. Medical records of draft horses in which a celiotomy was performed for correction of reproductive abnormalities were not included in the study. RESULTS: When compared with light draft horses, heavy draft horses had longer durations of anesthesia, more postoperative complications, and lower survival rates. Seventy-six percent of horses that recovered from anesthesia had postoperative complications. Postoperative complications associated with low survival rates included myopathy and neuropathy, ileus, diarrhea, and endotoxemia. All horses with postoperative myopathy and neuropathy died or were euthanized. The short-term survival rate for horses that recovered from anesthesia was 60%. Horses undergoing small intestinal surgery had a worse prognosis for short-term survival than those undergoing large intestinal surgery. The survival rate for horses for which long-term (> 1 year) follow-up information was available was 50%. CONCLUSIONS AND CLINICAL RELEVANCE: Draft horses weighing > 680 kg that underwent surgery because of acute signs of abdominal pain had longer durations of anesthesia, more postoperative complications, and higher mortality rates than draft horses weighing < 680 kg.     

Assessment of Meiotic Spindle Configuration and Post‐Warming Bovine Oocyte Viability Using Polarized Light Microscopy

The objectives of this study were to assess the efficiency of polarized light microscopy (PLM) in detecting microtubule‐polymerized protein in in vitro‐matured bovine oocytes; to examine its effects on oocyte developmental competence; and to assess the meiotic spindle of in vitro‐matured oocytes after vitrification/warming and further assessment of oocyte developmental competence. In the first experiment, the presence of microtubule‐polymerized protein (MPP) was confirmed as a positive PLM signal detected in 99.1% of analysed oocytes (n = 115), which strongly correlated (r = 1; p < 0.0001) with the presence of MPP as confirmed by immunostaining. In the second experiment, oocytes (n = 651) were exposed or not (controls) to PLM for 10 min and then fertilized and cultured in vitro. Oocytes exposed to PLM did not significantly differ from controls with regard to cleavage, total blastocyst and expanded blastocyst rates and cell numbers. In the third experiment, meiotic spindles were detected in 145 of 182 oocytes (79.6%) following vitrification and warming. Interestingly, after parthenogenetic activation and in vitro culture, oocytes that displayed a positive PLM signal PLM(+) differed significantly from PLM(?) in cleavage and Day 8 blastocyst rates. These results suggest that polarized light microscopy is an efficient system to detect microtubule‐polymerized protein in in vitro‐matured bovine oocytes and does not exert detrimental effects on bovine oocyte developmental competence. Moreover, PLM could be used as a tool to assess post‐warming viability in vitrified bovine oocytes.     

Gastric squamous cell carcinoma in three horses

Gastric squamous cell carcinoma was diagnosed in three horses. Clinical signs observed in all cases were weight loss, anorexia and lethargy. Respiratory signs were prominent in one case. All three horses had depressed albumin and elevated globulin and fibrinogen concentrations. Two horses were mildly anaemic. Inflammatory exudates were present in peritoneal cavities in all cases, and cytological evaluation provided a positive diagnosis of squamous cell carcinoma in two cases. Pleural fluid samples taken from two cases were also classified as inflammatory exudates, but no neoplastic cells were detected on initial examination. In all cases the neoplasms had arisen from the oesophageal region of the stomach, and had metastised throughout the abdomen. Two cases had metastatic lesions within the pleural cavity.     

Development of a Staphylococcus aureus vaccine against mastitis in dairy cows. I. Challenge trials

A vaccine composed of three field isolates of Staphylococcus aureus (S. aureus) derived from cases of mastitis in cows was developed. The vaccine was administered to nine uninfected cows while 10 other cows were used as controls. All cows were challenged with a highly virulent S. aureus strain administered into two quarters of each cow. Quarters were tested for clinical signs, secretion of S. aureus, and somatic cell count (SCC). No systemic effects were observed in any of the cows, vaccinated or control. Vaccinated cows had 70% protection from infection compared with fewer than 10% in the controls. Moreover, all quarters challenged in the vaccinated cows, regardless of whether they were successfully infected or not with S. aureus, exhibited very mild inflammatory reactions, identified by their low SCCs (<100,000).     

Evaluation of dual energy x-ray absorptiometry for in situ measurement of bone mineral density of equine metacarpi

OBJECTIVE: To determine the accuracy and precision of dual energy x-ray absorptiometry (DEXA) for measuring bone mineral density in horses in situ. Sample Population-12 randomly selected forelimbs from 12 horses. PROCEDURE: Metacarpi were scanned in 2 planes and DEXA measurements obtained for 6 regions of interest (ROI). Each ROI was isolated and bone density measured by Archimedes' principle. Linear regression analysis was used to determine the correlation between the 2 measurements at each ROI. An additional metacarpus was measured 10 times to determine the coefficient of variation for both techniques. RESULTS: Dual energy x-ray absorptiometry and bone density were significantly associated at multiple ROI. The addition of age, weight, and soft tissue or bone thickness improved these associations. Repeated measurements had a low coefficient of variation. CONCLUSIONS AND CLINICAL RELEVANCE: Dual energy x-ray absorptiometry can be used to accurately and precisely measure the bone density in the equine metacarpus. Dual energy x-ray absorptiometry appears suitable for serial in vivo measurement of bone density of the equine metacarpus. Dual energy x-ray absorptiometry may be used for studies to evaluate the effects of diet or drugs on bone density or density changes from bone remodeling that develop prior to stress fractures.     

Evaluation of treatment with doxorubicin and piroxicam or doxorubicin alone for multicentric lymphoma in dogs

OBJECTIVE: To evaluate the antitumor and toxic effects of treatment with doxorubicin combined with piroxicam or doxorubicin alone for multicentric lymphoma in dogs. DESIGN: Nonrandomized clinical trial. ANIMALS: 75 dogs with multicentric lymphoma. PROCEDURE: 33 dogs were treated with doxorubicin (30 mg/m2, IV, q 21 d, for 3 doses) and piroxicam (0.3 mg/kg [0.14 mg/lb], PO, q 24 h); results were compared with a historical control group of 42 dogs treated with doxorubicin (30 mg/M2, IV, q 21 d, for 3 doses) alone. Results-The percentages of dogs that had remission with doxorubicin-piroxicam treatment (79%) or doxorubicin treatment alone (74%) were not significantly different. Median duration of first remission was 130 days with doxorubicin-piroxicam and 147 days with doxorubicin alone; these values were not significantly different. Severe toxicosis was observed in 22% of dogs treated with doxorubicin-piroxicam and 17% of dogs treated with doxorubicin alone. CONCLUSIONS AND CLINICAL RELEVANCE: Both treatment protocols were efficacious and well tolerated. The doxorubicin-piroxicam treatment was no more effective regarding response rate, remission duration, or survival duration, compared with the control group treated with doxorubicin alone.     

Non-dietary risk factors for gastric dilatation-volvulus in large and giant breed dogs

OBJECTIVE: To identify non-dietary risk factors for gastric dilatation-volvulus (GDV) in large breed and giant breed dogs. DESIGN: Prospective cohort study. ANIMALS: 1,637 dogs > or = 6 months old of the following breeds: Akita, Bloodhound, Collie, Great Dane, Irish Setter, Irish Wolfhound, Newfoundland, Rottweiler, Saint Bernard, Standard Poodle, and Weimaraner. PROCEDURE: Owners of dogs that did not have a history of GDV were recruited at dog shows, and the dog's length and height and the depth and width of its thorax and abdomen were measured. Information concerning the dog's medical history, genetic background, personality, and diet was obtained from the owners, and owners were contacted by mail and telephone at approximately 1-year intervals to determine whether dogs had developed GDV or died. Incidence of GDV, calculated on the basis of dog-years at risk for dogs that were or were not exposed to potential risk factors, was used to calculate the relative risk of GDV. RESULTS AND CLINICAL RELEVANCE: Cumulative incidence of GDV during the study was 6% for large breed and giant breed dogs. Factors significantly associated with an increased risk of GDV were increasing age, having a first-degree relative with a history of GDV, having a faster speed of eating, and having a raised feeding bowl. Approximately 20 and 52% of cases of GDV among the large breed and giant breed dogs, respectively, were attributed to having a raised feed bowl.     

Administration of Thyroxine Affects the Morphometric Parameters and VEGF Expression in the Uterus and Placenta and the Uterine Vascularization but does Not Affect Reproductive Parameters in Gilts During Early Gestation

The aim of this study was to evaluate the effects of thyroxine administration on morphometric parameters, expression of vascular endothelial growth factor (VEGF) and vascularization in the uterus and placenta and reproductive parameters in gilts at 70 days of gestation. At 150 days of age, i.e., before first heat, 20 gilts were randomly divided into two experimental groups: treated (n = 10) and control (n = 10). The treated group received a daily dose of 400 μg of l ‐thyroxine (T₄) in their diet until slaughter and the control group received only typical meals. Before artificial insemination, blood was collected to determine plasma total T₄. The gilts were inseminated in the second oestrus and slaughtered at 70 days of gestation. The foetal thyroid follicular epithelium height, number, size and weight of foetuses; foetal myogenesis, corpora lutea number, embryonic mortality rate, uterine weight, placental weight and placental fluid volume were measured. Histomorphometric and immunohistochemical analysis of uterus and placenta were determined. The averages of all variables were compared by the Student’s t‐test. The gilts treated with thyroxine showed significant increase of plasma total T₄. At 70 days of gestation, the heights of the trophoblastic epithelium, endometrial epithelium and endometrial gland epithelium were significantly higher in the group treated with T₄. The expression of cytoplasmatic and nuclear VEGF in trophoblastic cells and the number of blood vessels per field in endometrial stroma were significantly higher in the gilts treated with T₄. No other significant differences between groups were obtained with respect to other parameters (p > 0.05). We conclude that oral administration of T₄ up to 70 days of pregnancy in gilts affects the morphometric parameters, the expression of placental VEGF and the uterine vascularization but does not affect reproductive parameters in gilts during early gestation.