Etiologic studies on late-term swine abortions

One hundred thirty-eight swine abortions were studied in detail in an effort to identify an etiologic agent. A viral agent was implicated in 7 cases. Bacteria were isolated in less than half of the examined cases: however, in 61% of the cases, motile, filamentous organisms were observed in tissues and fluids. Although swine sera from farms experiencing reproductive problems had a high reactor rate to Leptospira bratislava antigen, electron microscopy of the observed organism revealed a wall-free prokaryote morphologically typical of the class Mollicutes.     

Observations on the treatment of necrobacillosis in wallabies

Clinical experience of 73 cases of necrobacillosis in red-necked wallabies (Macropus rufogriseus) over a 6-year period is reviewed. Diagnostic methods and the medical and surgical treatment options are detailed. It is suggested that survival curves are necessary to assess the outcome of treatment.     

A selective procedure for the field isolation of pathogenic Streptococcus spp. of rainbow trout (Salmo gairdneri)

A procedure established for the selective isolation of the species of Streptococcus responsible for rainbow trout streptococcosis in South Africa, consisted of the inoculation of samples into nutrient broth which had been supplemented with 100 micrograms/ml of nalidixic acid, 160 micrograms/ml of oxolinic acid or 200 micrograms/ml of sodium azide. After incubation, the sample was plated onto tetrazolium agar on which the rainbow trout pathogenic Streptococcus species grew as a red colony. The colonies were isolated from the tetrazolium agar and identified as rainbow trout pathogenic isolates by biochemical and serological tests. In the laboratory the selective procedure is capable of detecting about 2 bacteria per ml. This procedure was used in the field and biochemically identical Streptococcus species were found in the mud and a freshwater crab from the water source of a site with a history of streptococcosis.     

Effect of colostrum intake on plasma glucose, non-esterified fatty acid and glucoregulatory hormone patterns in the neonatal pig

The effect of colostrum on endocrine and metabolic factors affecting glucose homeostasis was evaluated in 60 neonatal pigs that were fasted, fed (nursed ad libitum) or limit-fed colostrum (25% ad libitum, 4-hr interval feeding). Plasma acquired at birth (t0), and after 10, 20 and 30 hr (t10, t20 and t30, respectively) was analyzed for glucose, non-esterified fatty acids (NEFA), and the glucoregulatory hormones--insulin, glucagon, cortisol, growth hormone and catecholamines. The concentration of glucose and NEFA was similar among treatment groups at birth and increased in proportion to the quantity of colostrum consumed. Pigs fed ad libitum achieved and maintained a higher (greater than or equal to 40%; P less than .01) glucose concentration when compared to fasted neonates. Limit-fed counterparts also achieved and maintained higher levels, with glucose concentration being approximately 20% higher throughout (P less than .05). Fed pigs maintained NEFA concentrations which were approximately 2.5-fold to 4-fold greater than that of fasted pigs (P less than .05). Likewise, limit-fed pigs tended (P = .19) to have elevated NEFA concentrations and a lower (P less than .05) insulin:glucagon molar ratio. An inverse relationship was observed between colostrum intake and plasma concentrations of cortisol and growth hormone. Concentrations of epinephrine and norepinephrine tended (P greater than .10) to be elevated in fed pigs, relative to those of fasted counterparts. Provision of even limited quantities of colostrum is therefore beneficial to the glucoregulatory response in newborn pigs.     

Comparison of bovine and human platelet deformability, using micropipette elastimetry

We evaluated the deformability of bovine platelets and contrasted the effects of pharmacologic and thermal perturbations on cytoskeletal structure of human and bovine platelets. Platelets were aspirated into micropipettes (0.7 to 0.8 micron in diameter) by stepwise increments in tension. The resulting lengths of the cell extensions were recorded. The cell extensions aspirated from bovine platelets were shorter than the extensions drawn from human platelets. Disassembly of the circumferential microtubule coil allowed human platelets to pass through the pipette, but the same treatments only slightly increased the deformability of bovine platelets. Alteration of the actin filament cytoskeleton caused increased mechanical fragility of human platelets. In contrast, even the combined use of microtubule and actin filament-disrupting agents only modestly increased the deformability of bovine platelets and did not cause premature fragmentation of the cells. Unusual cytoskeletal structure, absence of an open canalicular system, and disparity in granule size may all contribute to the variance in deformability between the platelets of the 2 species. Reduced cell deformability may impair bovine platelet surface interactions by diminishing the ease of cell spreading and formation of areas of contact between the platelet and other cell surfaces.     

Structural and metabolic integrity of sheep external intercostal muscle during extended culture

The objectives of this study were to examine the structural and metabolic integrity of isolated sheep external intercostal muscle bundles following variable lengths of preincubation (0 to 192 h). Samples of intact external intercostal muscle (10 to 15 g), with tendons attached, were prepared from growing wethers and maintained at their resting lengths during preincubation for 0 to 192 h. Protein synthesis (PS), protein degradation (PD), acetate oxidation and ultrastructural integrity of muscle samples were examined at 0 to 192 h, 0 to 96 h, 0 to 48 h and 0 to 96 h following isolation, respectively. Additionally, the effects of variable fetal calf serum (FCS) concentrations (0 to 20%; w/v) on PS and PD and acetate oxidation were examined. Rate of PS increased as preincubation time increased to 192 h; however, most of this increase was due to the proliferation of fibroblasts on the surface of the muscle sample. Addition of cytosine arabinoside to the incubation media prevented the fibroblast-dependent increase in PS; however, it did not entirely prevent the preincubation time-dependent increase in PS. Rate of PD increased greatly upon preincubation. The nitrogen balance of incubated muscles was negative at all times examined. Acetate oxidation was maintained through 12 h of preincubation and thereafter declined. Relatively normal myofibrillar structure was maintained through 48 h of preincubation; however, loss of mitochondrial integrity and dissolution of Z-disks at 48 h and at 96 h of preincubation were evident. Isolated tissues were able to respond to FCS concentration in medium following 48 h of preincubation.     

The effect of pressure on turkey breast skin

In an attempt to experimentally reproduce focal ulcerative dermatitis (FUD) in turkeys, pressures of 94, 136, and 240 mmHg were applied for 2, 4, or 6 hr daily for 4 consecutive days to unfeathered breast skin of six 9-week-old toms. No gross lesions occurred either immediately after treatment or during a 10-day post-treatment period, and no microscopic changes were present in the skin at the conclusion of the trial. These findings suggest that avian skin is resistant to pressure-induced decubital ulceration and that pressure is unlikely to be either the cause of or a significant contributor to FUD.     

Biomicroscopy of the tear film: the tear film of the pekingese dog

Polarised light biomicroscopy was used to examine the normal pre-corneal tear film in 21 eyes of 12 pekingese dogs. The purpose of the study was to examine the influence of excessive exophthalmos on the pre-corneal tear film in the dog. The majority of the animals were found to have high levels of ocular surface contamination by particulate material and plaques of viscous mucus. Other abnormalities included surface lipid with an abnormal granular (three dogs) or 'curdled' (two dogs) appearance; excessive thinning of the lipid layer of the tear film; and the presence of dark globular structures in two dogs, which were presumed to be abnormal meibomian lipid. Break up of the tear film was observed in one dog. Grossly, a thread of viscous mucus was frequently observed along the margin of the lower eyelid. It is postulated that this thread forms because of the excessively exophthalmic conformation of the breed, which prevents the normal access of effete mucus and entrapped debris to the lower conjunctival fornix. The combination of the above factors in the pekingese is suggested as the mechanism whereby the tear film has a reduced stability, thus enhancing the risk from factors more usually considered to initiate corneal ulceration in the breed. The possible adverse effects of lid splitting for the mass removal of distichiae in exophthalmic dogs is discussed.