Search Results

You are looking at 71 - 80 of 1,083 items for :

  • Refine by Access: All Content x
Clear All

Abstract

Objective

To protect neonatal calves against fatal salmonellosis within the first 2 weeks after birth, using chicken egg yolk antibodies specific against Salmonella typhimurium or S dublin.

Animals

38 neonatal Holstein calves from Salmonella-free farms.

Procedure

After removal of the lipid components with hydroxypropylmethylcellulose phthalate, egg yolk antibodies were spray dried. At 4 days of age, calves were challenge exposed by oral inoculation with 1011 virulent S typhimurium (experiment 1) or S dublin (experiment 2). Starting from the challenge-exposure day, egg yolk antibody preparations were administered orally 3 times a day for 7 to 10 days.

Results

In passive immunization trials, the orally administered antibodies conferred dose-dependent protection against infection with each of the homologous strains of Salmonella. Within 7 to 10 days after challenge exposure, all control calves died, whereas low-titer antibody-treated calves had 60 to 100% mortality. Only fever and diarrhea, but no deaths (P < 0.01), were observed in calves given the highest titer of antibody.

Conclusions and Clinical Relevance

Compared with that in control calves, survival was significantly higher among calves given antibodies with titers of 500 (P < 0.05) and 1,000 (P < 0.01) homotypic for S typhimurium and with titer of 5,000 (P < 0.01) for S dublin. Egg yolk antibodies specific for whole cell S typhimurium or S dublin are protective against fatal salmonellosis when given in sufficiently high concentration, and may be clinically useful during a salmonellosis outbreak. (Am J Vet Res 1998;59:416–420)

Free access
in American Journal of Veterinary Research

Summary

The cellular response induced in the host animal by endotoxin contributes greatly to the morbidity and mortality of gram-negative infections in bovine neonates. We characterized the temporal sequence, magnitude, and duration of mediator release during endotoxemia and evaluated the effect of endotoxin dose and method of administration. Thromboxane B2 (TxB2), and 6-keto prostaglandin F (PGF) concentrations and tumor necrosis factor (tnf), and interleukin-1β (il-1β) activities were measured in 34 newborn calves given Escherichia coli endotoxin at dosage of 0 (saline solution), 0.2, 2.0, or 20 μg/kg of body weight, either by iv administered bolus or infusion over 50 minutes. In all groups and at each lipopolysaccharide dosage, mediators peaked in this sequence: TxB2 and tnf, followed by PGF, then il-1β. Neither dose nor method of administration affected the sequence of mediator release. The magnitude of eicosanoid reponse to endotoxin was dose-dependent. During induced endotoxemia, duration and/or magnitude of mediator response reflected the dose of endotoxin administered, indicating that the outcome of endotoxemia, in neonatal calves, may be related to the amount of circulating endotoxin.

Free access
in American Journal of Veterinary Research
Author:

Summary

Saline (0.9% NaCl) solution or 1 of 3 nonsteroidal anti-inflammatory drugs (nsaid) was administered iv to 5 neonatal calves 15 minutes after the start of a 3-hour iv infusion of Escherichia coli lipopolysaccharide (lps; 2 µg/kg/h). Four additional calves were given a 3-hour iv infusion of saline solution alone. Clinical attitude, mean arterial blood pressure, pcv, wbc, and plasma lactate, glucose, and eicosanoid concentrations (thromboxane B2, 6-keto-PGF) were monitored for 12 hours.

Flunixin meglumine (1.1 mg/kg of body weight, iv), ketoprofen (2.2 mg/kg, iv), and ketorolac tromethamine (1.1 mg/kg, iv) each ameliorated the clinical signs of endotoxemia and lps-induced lacticemia, but failed to significantly alter the degree of leukopenia or hypoglycemia associated with infusion of lps. Although the 3 nsaid prevented eicosanoid production, they provided only partial protection against lps-induced hypotension. Each nsaid modified the response to lps, but none was clearly superior to the others in modulating the clinical signs or physiologic alterations induced by infusion of lps in neonatal calves.

Free access
in American Journal of Veterinary Research

Summary

Labor and delivery stimulate increased release of catecholamines and endogenous opioid peptides in neonates. Catecholamines promote adaptation to the extrauterine environment after birth. Enkephalins are stored together with catecholamines in the adrenal medulla and have an inhibitory effect on catecholamine release. We investigated the influence of labor and neonatal hypoxia on epinephrine, norepinephrine, and met-enkephalin release in calves. Blood samples were taken from the umbilical artery before rupture of the umbilical cord and from the jugular vein repeatedly after birth. Highest plasma norepinephrine concentration was found in calves delivered at the end of gestation (term calves) before umbilical cord rupture. In calves delivered before the physiologic end of gestation (preterm calves), norepinephrine values increased after cord rupture, but remained lower than values in term calves. Epinephrine release followed a similar pattern, but norepinephrine was clearly predominant. In term calves, met-enkephalin values were significantly higher than values in preterm calves. In calves of both groups, met-enkephalin release increased after cord rupture. During birth, the increase in catecholamine release seems to take place earlier than that of enkephalins. Norepinephrine-dominated stimulation during expulsion of the calf might be followed by increasing enkephalinergic inhibition after cord rupture and onset of respiration. Reduced release of catecholamines and enkephalins in preterm calves may be connected with delayed adaptation to the extrauterine environment.

Free access
in American Journal of Veterinary Research

Summary

In contrast to the net absorption of Na and Cl ions observed in vivo, porcine small intestine had a net secretion of these ions in vitro. These discrepancies between in vivo and in vitro results have led to difficulties in interpretation of studies investigating mechanisms of intestinal secretion and diarrhea in this species. To examine the influence of endogenous prostanoids on ion transport in neonatal porcine ileum in vitro, tissues were prepared and studied in indomethacin. Net absorption of Na, reversal of net Cl secretion to net absorption, and decreased short circuit current were observed. Conversely, addition of prostaglandins to indomethacin-treated tissues reversed these effects and reestablished conditions similar to those observed in control tissues. Control tissue was essentially refractory to the effects of exogenous prostaglandins. Results indicate that under in vitro conditions, ion transport in neonatal porcine ileum is tightly regulated by endogenous prostanoids that abolish the neutral NaCl absorptive mechanism and elicit electrogenic Cl secretion. However, concentrations of these prostanoids may have been artificially high as a result of tissue preparation for in vitro study.

Free access
in American Journal of Veterinary Research

Summary

A study was performed to determine prevalence of tumor necrosis factor (tnf) activity in serum of equine neonates with presumed sepsis and to determine correlation between serum tnf activity and severity and outcome of disease. Twenty foals <21 days old were considered suitable for inclusion in this study by satisfying clinical and laboratory criteria suggestive of septicemia. At admission, blood samples were collected from all foals for determination of serum tnf activity, then clinical course and outcome of disease were recorded. Thirty-one clinically normal foals <21 days old served as controls for serum tnf activity. Serum tnf activity was estimated by use of an in vitro cytotoxicity bioassay and WEHI 164 clone-13 murine fibrosarcoma cells. Of the 20 foals with presumed sepsis, 5 had high serum TNF activity. Mean heart rate (P < 0.005), mucosal petechial hemorrhages (P = 0.06), and death rate (P = 0.06) were greater in the group of foals with high serum TNF activity. These foals also had a lower mean neutrophil count (P < 0.001), greater band-to-segmented neutrophil ratio (P < 0.0001), and more prevalent neutrophil toxic changes (P = 0.07) than did foals without serum tnf activity (P = 0.02). Joint swelling was more prevalent in foals without serum tnf activity. Results of the study indicate that serum tnf activity is correlated with clinical criteria of sepsis in equine neonates. An association was apparent between disease severity and serum tnf activity in this group of foals with presumed septicemia.

Free access
in Journal of the American Veterinary Medical Association

Abstract

Objective

To evaluate antigen recognition patterns of serum IgM, IgG, and IgA from queens and their kittens as a method of diagnosing neonatal toxoplasmosis.

Animals

5 pregnant queens were inoculated orally with Toxoplasma gondii tissue cysts during gestation (18 to 44 days). On various days after parturition (0 to 97), serum was obtained from queens and kittens (n = 19).

Procedure

Tissues from most kittens were assessed for T gondii infection by bioassay in mice. Serum samples were evaluated by IgM, IgG, and IgA western blot immunoassays for the presence of T gondii antibodies. Antigens recognized by kitten serum samples, but not by the corresponding queen serum sample, were considered to indicate neonatal infection with T gondii.

Results

Using the results of western blot immunoassay, 8 of 19 kittens (age, 2 to 97 days) were determined to be infected with T gondii. Western blot immunoassay results correlated well with bioassay results, identifying 7 of 8 bioassay-positive kittens. Western blot immunoassay additionally identified 1 kitten as infected, but tissues from the kitten had not been bioassayed. In each of the 5 kittens that developed clinical signs of toxoplasmosis, the diagnosis of neonatal toxoplasmosis was supported by results of the western blot immunoassays.

Conclusion and Clinical Relevance

Comparison of queen and kitten T gondii antigen recognition patterns of IgM, IgG, and IgA can be used for antemortem diagnosis of neonatal toxoplasmosis. (Am J Vet Res 1996;57: 1327-1330)

Free access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate therapeutic efficacy of a high extralabel dose of ceftiofur for treatment of experimental salmonellosis in neonatal calves.

Animals—Forty-two 1- to 4-day-old Holstein bull calves.

Procedure—36 calves were orally challenged with Salmonella enteritica serovar Typhimurium (6.5 × 108 colony-forming units). Six additional calves were retained as nonmedicated nonchallenged control calves. Four days following Salmonella challenge, surviving calves were randomly allocated to ceftiofurtreated (5 mg/kg, IM, q 24 h) or nonmedicated control groups. Calves assigned to the treated group were medicated daily for 5 days starting on day 4 after challenge. Calves were monitored for 18 days following Salmonella challenge. Outcome assessments included clinical parameters (attitude, appetite, fecal characteristics, and rectal temperature), mortality rate, and quantitative Salmonella culture of fecal samples, mesenteric lymph nodes, and cecal contents.

Results—Ceftiofur treatment was associated with a significant decrease in rectal temperature and diarrhea. Three of 15 medicated calves and 4 of 14 nonmedicated calves died or were euthanatized between days 4 and 18. A significant decrease in fecal shedding of Salmonella organisms was observed in treated calves, compared with non-medicated calves. Salmonella organisms were isolated from all 10 nonmedicated calves at necropsy, whereas no Salmonella organisms were isolated from 5 of 12 medicated calves.

Conclusions and Clinical Relevance—Treatment of salmonellosis in neonatal calves with a high extralabel dose of ceftiofur (5 mg/kg, IM, q 24 h) promotes animal welfare, reduces fecal shedding of Salmonella organisms, and may promote clearance of Salmonella infections when plasma ceftiofur concentrations are maintained above minimal inhibitory concentrations. (Am J Vet Res 2003;64:918–925)

Full access
in American Journal of Veterinary Research

Objective

To determine whether treatment with a commercially available nonspecific immunomodulating biologic product would alter the clinical course of disease in neonatal calves.

Design

Systematically randomized, controlled cohort study.

Animals

200 Holstein bull calves 1 to 5 days old.

Procedure

Assessments were performed that included evaluation of fecal consistency, attitude, appetite, and hydration status. Calves with abnormal results were enrolled in the study. Calves were systematically assigned to control or treatment groups (100 calves/group). Calves in the treatment group were given a single IV injection of the biologic product at the time of enrollment, whereas control calves were not given the product. Calves were assessed daily for 5 days to evaluate fecal consistency, attitude, appetite, hydration status, and rectal temperature. Assessments were made without knowledge of group assignment.

Results

Treatment with the immunomodulating product was not associated with a decrease in the number of calves that had moderate or severe departures from clinically normal conditions for attitude, appetite, or hydration on days 1 though 5, compared with control calves. Fecal consistency scores were significantly greater for treated calves on days 1 (P = 0.03) and 5 (P = 0.02), compared with scores for control calves.

Clinical Implications

Administration of the nonspecific immunomodulating biologic product did not significantly affect outcome of clinical disease for calves in the treated group, compared with calves in the control group. On the basis of results of this study, we cannot recommend use of the nonspecific immunomodulating biologic product for the treatment of undifferentiated diarrheal disease in neonatal calves. (J Am Vet Med Assoc 1998;213:1308-1311)

Free access
in Journal of the American Veterinary Medical Association

Summary

Total protein (tp), albumin, and IgG concentrations were measured in csf from the atlanto-occipital (ao) and lumbosacral (ls) sites and in serum of 15 clinically normal neonatal foals ≤ 10 days old (mean, 7.0 days). The albumin quotient (aq; csf albumin/serum albumin × 100) and IgG index ([csf IgG/serum IgG] × [serum albumin/csf albumin]), indicators of blood-brain barrier permeability and intrathecal IgG production, respectively, were then calculated.

Mean ± sd values obtained from the foals of this study were: serum albumin, 2,900 ± 240 mg/dl; serum IgG, 1,325 ± 686 mg/dl; ao csf total protein (tp), 82.8 ± 19.2 mg/dl; ls csf tp, 83.6 ± 16.1 mg/dl; ao csf albumin, 52.0 ± 8.6 mg/dl; ls csf albumin, 53.8 ± 15.7 mg/dl; ao csf IgG, 10.2 ± 5.5 mg/dl; ls csf IgG, 9.9 ± 5.7 mg/dl; ao aq, 1.86 ± 0.29; ls aq, 1.85 ± 0.51, ao IgG index, 0.52 ± 0.28; and ls IgG index, 0.48 ± 0.27. Significant difference between values for the ao and ls sites was not found. A csf albumin concentration > 85.2 mg/dl or aq > 2.4, as determined by mean ± 2 sd, may indicate increased blood-brain barrier permeability. An IgG index value >1.0 may indicate intrathecal IgG production.

Values obtained for foals of this study should serve as baseline for comparison in the evaluation of blood-brain barrier permeability and intrathecal IgG production in neonatal foals with neurologic disease.

Free access
in American Journal of Veterinary Research