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Biomedical subjects

D C Van Metre

Publications and source records attributed to D C Van Metre.

16 recordsLinked to original sources
PubMed2001

Virulence factors in Escherichia coli isolated from the blood of bacteremic neonatal calves.

Twenty-five Escherichia coli isolates from the blood of critically ill bacteremic calves sampled in two separate studies on a calf-rearing farm housing over 15,000 calves, in the San Joaquin Valley, California were studied. Isolates were characterized for O serogroups and for pathotypes as determined by the presence of specific virulence factors including heat-labile enterotoxin (LT), heat-stable enterotoxins a and b (STa, STb), verotoxins 1 and 2 (VT1, VT2), cytotoxic necrotizing factor (CNF), aerobactin, intimin Eae and P, F17 and CS31A fimbrial adhesins, and resistance to bactericidal effects of serum. These isolates constituted a heterogeneous group. However, isolates were mostly aerobactin positive and often resistant to the bactericidal effects of serum. Isolates of pathotypes O78 (n=6), O119:CS31a (n=3), and P positive but O non-typeable (n=3) were associated with a high mortality rate. The remaining isolates belonged to diverse pathotypes, often possessing the adhesins P, F17, CS31A and Eae but belonging to O serogroups other than O78 and O119, and were less frequently associated with mortality. Although no virulence factor common to all isolates was identified, the capacity to use iron by the presence of aerobactin which is important to the capture of iron was a predominant factor. Moreover, certain pathotypes appear to be associated with primary colisepticemia whereas other pathotypes may cause a bacteremia without necessarily leading to septicemia.

Adhesins, Bacterial↗
PubMed2001

Selenium and vitamin E.

Deficiency of selenium and vitamin E has recently been identified as a major health concern of sheep producers in certain regions of the United States, and familiarity with published data on these nutrients seems to be of value to small ruminant practitioners. This article begins with a description of the biochemical roles and metabolism of selenium and vitamin E. A literature review follows in which the influence of these nutrients on the musculoskeletal, reproductive, and immune systems, as well as on flock productivity, is discussed. Methods for detection of deficiency and supplementation strategies are also described.

Animal Feed↗
PubMed2000

Diagnosis of enteric disease in small ruminants.

Diagnosis of gastrointestinal disease in small ruminants requires integration of information obtained in the signalment, history, physical or necropsy examination, and ancillary diagnostic tests. The purpose of this article is to provide the practitioner with a review of the clinical features of several common gastrointestinal diseases of sheep and goats. Rumen acidosis, enterotoxemia, gastrointestinal parasitism, neonatal diarrhea, and salmonellosis are discussed, and where appropriate, reviews of the pathophysiology, prevention, and control of these diseases are cited for further reading.

Animals↗
PubMed1999

Brucellosis induced by RB51 vaccine in a pregnant heifer.

Brucellosis developed in a 14.5-month-old Gelbvieh heifer after the animal was vaccinated with the calfhood dose of strain RB51 Brucella abortus vaccine s.c. during the fourth month of its first pregnancy. The heifer experienced dystocia and was euthanatized during cesarean section because of a large uterine tear. The fetus was dead at delivery. Suppurative placentitis and fetal pneumonia were evident at necropsy. Brucella abortus strain RB51 was isolated from the placenta and the fetus' lung.

Agglutination Tests↗
PubMed1999

Treatment of hypernatremia in an acidotic neonatal calf.

A 7-day-old Jersey calf was evaluated because of diarrhea and pneumonia. The calf was hypernatremic, hypoproteinemic, and acidemic, and was treated initially with i.v. administration of fluids with sodium concentration (175 mEq/L) similar to the calf's serum sodium concentration. Sodium concentration of the administered fluids was gradually decreased over the following days, but the calf's serum sodium concentration decreased too rapidly, and the calf developed neurologic signs attributed to cerebral edema. Treatment with mannitol and i.v. administration of fluids with a higher concentration of sodium resulted in abatement of clinical signs. In calves, hypernatremia may develop over several days. Prescribing traditional isotonic or hypotonic fluids in such cases will be harmful, because during chronic hypernatremia, the brain's adaptive mechanisms involve accumulation of organic osmoles that may take several days to equilibrate across cell membranes, and cerebral edema may result. Administration of fluids containing sodium concentration approximately equal to the patient's measured serum sodium concentration is required to decrease serum sodium concentration more slowly than is possible with traditional isotonic fluids.

Acidosis↗
PubMed1999

Treatment of sodium balance disorders. Water intoxication and salt toxicity.

Electrolyte disorders are commonly identified in food animal medicine. Some of these electrolyte disturbances require that the veterinarian be aware of the potential for causing harm during routine fluid therapy. Hyponatremia (water intoxication) and hypernatremia (salt toxicity) are two such disorders. Both create osmolar disturbances that effect changes in the brain's osmolar state. During fluid resuscitation it is possible to cause iatrogenic central nervous system damage in these cases. It is important to recognize those cases where sodium imbalance may complicate routine therapy, understand the underlying mechanisms for osmolar changes in the plasma and brain, and know the appropriate steps to take for safe correction of the sodium disturbance.

Animals↗
PubMed1999

Miniature pigs.

Miniature pigs have become popular pets in North America, and veterinarians of a variety of clinical specialties may be called on for their care. Successful collection of blood from these animals requires familiarity with the location of sites for venipuncture and knowledge of adequate methods of restraint. In this article, restraint and techniques for venipuncture are described, as well as techniques for cerebrospinal fluid collection, semen collection, and vaginal cytologic examination. Interpretation of hematologic, serum biochemical, and urinalysis data are also discussed. Methods for diagnosis of skin diseases, gastrointestinal parasitism, and enteric infectious diseases are included in order to provide the practitioner with the essential knowledge and skills for a variety of clinical pathologic studies of this unique pet.

Anesthesia↗
PubMed1997

Allergic respiratory disease.

Allergic rhinitis and extrinsic allergic alveolitis are the most common allergic disorders of the bovine respiratory system. Environmental and management factors play significant roles in the pathogenesis of these disorders. When compared to infectious or toxic respiratory disease, allergic respiratory disease is relatively rare and of far less economic importance in North American cattle; however, the environmental and management conditions conducive to these diseases exist in many regions. Therefore, familiarity with the clinical and epidemiologic features of these unique diseases will aid the veterinarian in establishing an accurate diagnosis. Signs of respiratory dysfunction are common to anaphylactic and anaphylactoid reactions. Early recognition of these adverse reactions will provide the practitioner with the greatest chance of successful treatment.

Alveolitis, Extrinsic Allergic↗
PubMed1997

Bacteriological culture of blood from critically ill neonatal calves.

The objectives of this study were to estimate the prevalence of bacteremia in critically ill, neonatal calves with severe diarrhea or depression, and to describe the variety of bacteria involved. Two studies were conducted in the summers of 1991 and 1993 involving 190 neonatal calves, 1-day to 19-days-old. Bacteremia was detected by blood culture in 31% (28/90) of calves in study 1, and in 24% (19/79) of ill calves and 0% (0/21) of control calves in study 2. Bacteria cultured from blood included Escherichia coli (51% of all isolates), other gram-negative enterics (25.5%), gram-negative anaerobes (5.9%), gram-positive cocci (11.8%), and gram-positive rods (5.9%). Among clinically ill calves, the average age was significantly lower in the blood culture-negative group (5.5 d) than in the blood culture-positive group (7.5 d) (P = 0.004). Mean serum IgG concentration was significantly (P = 0.0001) lower in blood culture-positive calves (1.146 g/L) than in blood culture-negative calves (3.077 g/L). The mortality rate was significantly (P < 0.0001) higher in the blood culture-positive group (57.4%) than in the blood culture-negative group (15.1%). Bacteremia appeared to be a frequent entity in this particular rearing situation. Early recognition of the problem, as well as appropriate treatment, may be beneficial in increasing survival rates. Results also support the need to address the failure of passive transfer of maternal antibodies to prevent bacteremia in calves.

Aging↗
PubMed1997

Use of a clinical sepsis score for predicting bacteremia in neonatal dairy calves on a calf rearing farm.

In human, equine, and bovine neonates, early diagnosis of bacteremia remains a challenge for the internist. The objective of this study was to develop a predictive model for risk of bacteremia, based on a clinical evaluation system called the clinical sepsis score. Blood from 90 ill calves, 1- to 14-days-old from a calf-raising farm in the San Joaquin Valley of California was cultured. The calves were also scored according to a clinical score for hydration status, fecal appearance, general attitude, appearance of scleral vessels, and umbilical abnormality. Age, rectal temperature, heart rate, respiratory rate, and presence or absence of a focal site of infection were recorded. Prevalence of bacteremia was 31% (28/90). A logistic regression model indicated that high clinical score, presence of a focal infection, and increased age were associated with an increased risk of bacteremia in ill calves (P < 0.06). Calves for which the model predicted bacteremia with a probability > or = 40.8% were considered bacteremic, yielding acceptable sensitivity (75%) and specificity (71%) estimates. The predictive model was validated through a 2nd sampling of 100 calves (79 ill calves and 21 controls), of which 17 calves were bacteremic. The classification was 75% correct using the model, with an estimated sensitivity of 76% and specificity of 75%. Overall, results indicated that the model could be a useful tool for predicting bacteremia in ill calves in a clinical setting.

Aging↗
PubMed1994

Delivery of a live calf after in vitro maturation and fertilization of oocytes obtained from ovaries removed from a moribund cow.

An aged Holstein cow of high genetic merit and economic value was determined to have a squamous cell carcinoma of the tarsus. Treatment was unsuccessful, as was an attempt at superovulation and embryo collection; thus, the owner elected euthanasia. On day 17 of the estrous cycle, the ovaries were removed via laparotomy and the cow was immediately euthanatized. Oocytes were aspirated from ovarian follicles and subjected to in vitro maturation and fertilization procedures. Seven morulae that developed in culture were transferred nonsurgically to 3 recipient females, resulting in birth of a full-term healthy male calf. In vitro maturation and fertilization procedures can be used to obtain offspring from valuable, terminally ill cows for which conventional embryo collection techniques have proven unsuccessful.

Animals↗
PubMed1992

A case report of the treatment of an overdose of xylazine in a cow.

An adult Holstein cow was inadvertently administered an overdose of xylazine hydrochloride. The cow became weak, collapsed, and developed severe bradycardia and intermittent heart block. Initial therapy for cardiovascular collapse consisted of rapid infusion of large volumes of intravenous fluids and intravenous injection of atropine sulfate. Yohimbine, an alpha 2-adrenergic antagonist, and tolazoline hydrochloride, an alpha 1- and alpha 2-adrenergic antagonist, were administered intravenously as antidotes for xylazine overdose. The cow recovered but calved prematurely 4 days later.

Animals↗
PubMed1991

Otitis media/interna and suppurative meningoencephalomyelitis associated with Listeria monocytogenes infection in a llama.

Listeria monocytogenes was found to be the cause of fatal suppurative meningoencephalomyelitis in a 3.5-month-old cria. The cria initially had clinical signs of unilateral peripheral vestibular disease, but on the following day, the cria developed progressive signs of encephalitis. Treatment with antibiotics, flunixin meglumine, and anticonvulsant drugs failed to stop progression of the disease, and the cria was euthanatized. Post-mortem examination revealed otitis media-interna and diffuse suppurative meningoencephalomyelitis. Listeria monocytogenes was isolated from CSF and brain tissue.

Animals↗
PubMedDate not supplied

Detection of low serum immunoglobulin concentrations in clinically ill calves.

The sensitivity, specificity, and accuracy of classification of 4 tests for failure of passive transfer (FPT) were examined in clinically ill neonatal calves. Comparisons were made with serum IgG1 concentrations determined by radial immunodiffusion. Serum samples were obtained from 27 clinically ill calves < or = 21 days of age. The results of 4 commonly used assays, the sodium sulfite turbidity test, the zinc sulfate turbidity test, refractometry, and the serum gamma-glutamyl transferase (GGT) activity test, were compared with radial immunodiffusion determinations of serum IgG1 concentration. Serum GGT activity using a 50 IU/L threshold resulted in correct classification of the highest percentage of calves (93%) with regard to their passive transfer status. The sodium sulfite test with a 1+ end point and refractometry using a 5.5 g/dL end point resulted in correct classification of 85% of the calves studied. When using the sodium sulfite test, the 2+ and 3+ test end points had lower specificity, 0.58 and 0.00, respectively, than the 1+ end point. This loss in specificity resulted in misclassification of calves with adequate serum immunoglobulin concentrations as having FPT. The zinc sulfate turbidity test was inadequately specific (0.33) and resulted in misclassification of 33% of calves.

Animals↗