Pyrolysis mass spectrometry of Listeria monocytogenes isolates from sheep.

Forty-eight isolates of Listeria monocytogenes from sheep and silage, involved in five small outbreaks of listeriosis, were compared by pyrolysis mass spectrometry (PyMS). The method clustered isolates from single animals, and showed that epidemiologically associated isolates were closely related to each other. PyMS is a simple technique capable of analysing large numbers of samples daily, and its application in veterinary studies should help to elucidate the epidemiology of listeriosis.     

Ectopia cordis thoracoabdominalis in a piglet

A congenital anomaly characterised by displacement of the heart through a ventral body wall fissure involving the thoracic and cranial abdominal regions was recorded in a female Yorkshire-cross piglet. Dissection to assess the morphology of the developmental defect and a summary review of the literature on ectopia cordis were made. This case appears to be one of only three of ectopia cordis thoracoabdominalis reported in swine.     

Cervical esophagostomy to permit extraoral feeding of the horse.

An indwelling stomach tube was placed through a cervical esophagostomy in 5 clinically normal horses and in 3 horses requiring artificial alimentation. In all but one case, surgery was performed on conscious horses following tranquilization and infiltration of the surgical sites with a local anesthetic. Six horses were fed liquid rations through the indwelling tubes, which were left in place from 3 to 26 days. After the tubes were removed, the stomas healed rapidly and with minimal complications. Cervical esophagostomy proved to be a safe, easy, and effective method for the provision of extraoral feeding of the horse.     

Loop colostomy for management of rectal tears and small-colon injuries in horses: 10 cases (1976-1989).

Loop colostomy was performed in 10 horses as treatment for grade-III rectal tears (n = 6 horses), small-colon infarction (n = 2 horses), perirectal abscess and stenosis (n = 1 horse), and small-colon stricture (n = 1 horse). In 7 horses, the colostomy was constructed through a single incision low in the left flank, with closure of the incision around the stoma (single-incision technique). In 3 horses, 2 of which had colostomy performed as a standing procedure, the selected segment of small colon was placed from a flank incision into a separate, small incision low in the left flank (double-incision technique). Five horses underwent colostomy reversal (at 18 to 63 days) and 2 of these horses, both with grade-III rectal tears, recovered completely. Of 8 horses that did not survive, 6 died from the primary disease or associated complications. Technical problems associated with colostomy accounted for death of 2 horses. One horse had gastric rupture attributable to suture occlusion of the small intestine after colostomy reversal, and another horse had complications of incisional infection after repair of a peristomal hernia. Small-colon prolapse through the stoma necessitated premature reversal of the colostomy in a horse that was euthanatized because of worsening laminitis. Minor complications of the colostomy procedure were partial stomal dehiscence (n = 4 horses), partial dehiscence of the flank wound after colostomy reversal (n = 2 horses), and small ventral midline hernia after colostomy reversal (n = 1 horse). Loop colostomy may be of benefit to horses with rectal tears, provided it is done soon after the tear occurs.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of dietary cation-anion balance in mineral balance in anaerobically exercised and sedentary horses

Eight geldings and four mares were randomly assigned treatments within three 4x4 Latin square design experiments to study the effects of dietary cation-anion balance (DCAB) on mineral balance and dry matter digestibility in sedentary and anaerobically exercised horses. Four diets with an average DCAB (calculated as meq ((Na+K+) - Cl-)/kg of diet dry matter) of +24 (Low, L), +127 (Medium Low, ML), +227 (Medium High, MH) and +352 (High, H) were fed for a 21 day adjustment period followed by a 72 hour collection period. Diets consisted of a pelleted base concentrate of com, soybean meal and cottonseed hulls fed with either native prairie grass or bermuda grass hay in a 60:40 ratio. Diet L was formed by adding calcium chloride and ammonium chloride to the base concentrate, diet ML was formed by adding calcium chloride, and diet H was formed by adding potassium citrate and sodium bicarbonate. Diet MI-I received no supplementation and served as the control. Representative samples of feed, feces and urine were analyzed for mineral content and mineral balances were calculated by difference. Fecal output was greater (p <.05), and thus, dry matter digestibility was lower in exercised homes consuming diet L versus diet H. Sodium balance was greater (p <.05) in sedentary horses consuming diet MH as compared to those consuming diets ML and L Sodium balance was greater (p <.05) in exercised homes consuming diet H as compared to those consuming diets ML and L Potassium balance was greater (p <.05) in sedentary horses consuming diet H as compared to those horses consuming diet ML, however, potassium balance was not affected by DCAB in exercised horses. No significant differences were detected in chloride or magnesium balances in the sedentary horses, although chloride balance was greater (p <.05) and magnesium balance was lower (p <.05) in exercised homes consuming diet L as compared to all other diets. In sedentary homes, phosphorus balance was reflective of intake with differences (p <.05) observed between all treatments. However, in exercised homes, phosphorus balance was lower (p <.05) oniy for those consuming diet L. Calcium balance decreased significantly as DCAB decreased between all treatments in sedentary horses, while calcium balance in exercised homes was greater (p <.05) for homes consuming diet H as compared to those consum- ing diet L.Previous research from our laboratory has shown that both exercised and sedentary horses consuming diets with a low DCAB experience a nutritionally induced metabolic acidosis. The current data indicate that anaerobically exercised and sedentary horses consuming these diets excrete significantly more calcium in the urine resulting in decreased calcium balances. Prolonged consumption of diets with a low DCAB may lead to a significant demineralization of bone and a subsequent weakening of the skeleton.     

Comparison of natural transmission of bovine leukemia virus in Holstein cows of two genetic lines selected for high and average milk production.

One hundred and fifty lactating Holstein cows from 2 genetic lines selected for high and average milk production were used in the study. Sera from 6 annual herd tests were analyzed by agar-gel immunodiffusion test for antibodies to bovine leukemia virus. Odds of being seropositive were analyzed by use of stepwise and backward logistic regression procedures. Analysis within birth year revealed that estimated in odds increased by 0.19/year of age among cows of the high genetic line and by 0.43 among cows of the average genetic line. This was accompanied by a more important cohort effect among high producers than among average producers.     

Effect of D-glucose on in vitro short-circuit current in neonatal calf jejunum and rabbit ileum

Thin sheets of mucosa from small intestine of neonatal calves were mounted in incubation chambers for in vitro studies. These mucosal sheets generated a potential difference (PD) of 2.05 +/- 0.02 mV (mean +/- SEM), short-circuit current (SCC) of 23.32 +/- 3.81 microA x cm2, and tissue resistance of 86.22 +/- 4.41 ohms x cm2 (n = 6). Ouabain in the serosal bathing solution caused a sharp decrease in the SCC (P less than 0.01) and PD (P less than 0.005), a decrease in tissue K content (P less than 0.05), and an increase in tissue Na content (P less than 0.05). The mucosa responded to D-glucose by an increase in PD (P less than 0.001) and SCC (P less than 0.001). In vitro methods used in the calf were validated in similar experiments on rabbit ileum.     

Physiological aspects of growth promotion in poultry

Growth promotants used in poultry production fall into two categories: those which increase the utilization of food (e.g. antibiotics) and those which have anabolic activity.The mode of action of antibiotics is not certain. Several interacting factors may be involved: altered gut microflora, reduced ammonia production, thinner intestinal walls, reduced epithelial cell turnover and improved nutrient absorption. It has been suggested that antibiotics have a systemic action but evidence of gross physiological change is difficult to find. Thyroid function was not affected after feeding aureomycin but penicillin-fed chickens had a greater plasma growth hormone concentration than control birds. The plasma corticosterone responses to a stressor, corticotrophin, were similar in control and penicillin-fed birds.Goitrogenic substances cause lipid deposition and thyroactive substances improve feather cover but neither consistenly improve growth.Oestrogenic substances tend to stimulate energy consumption and lipogenesis at the expense of protein deposition. Use is made of them to improve carcass quality of capons and turkeys. Androgenic substances have either no effect or depress growth.Growth hormone improves weight gain, increases protein and decreases fat in the carcass. It may be of use in the production of older table birds.