Five field trials on the efficacy of a bovine respiratory syncytial virus vaccine

Five field trials evaluated whether immunization of beef cattle prior to weaning, at weaning, or immediately upon arrival at the feedlot with a commercial bovine respiratory syncytial virus (BRSV) vaccine would reduce subsequent treatment for respiratory disease.

Bovine respiratory syncytial virus vaccination was associated with a significant (p<0.05) reduction in treatment rate in one of three groups of calves immunized prior to weaning (−12%) and in calves immunized upon arrival at the feedlot (−4%).

There was no significant (p>0.05) effect of the BRSV vaccine on treatment rate in calves immunized at weaning, in calves immunized upon arrival at the Saskatoon bull test station, or in yearlings immunized upon arrival at the feedlot.

Although the trend in these field trials was to a sparing effect of the BRSV vaccine, the small reduction in treatment rate may not justify the cost of the vaccination program.

     

Nephrotoxicity in dogs associated with methoxyflurane anesthesia and flunixin meglumine analgesia

Uremia unexpectedly developed in five dogs 24 hours after undergoing thoracotomy in a student laboratory. In all dogs general anesthesia had been maintained with methoxyflurane, muscle relaxation had been induced with gallamine, and each dog received a single intravenous dose of 1.0 mg/kg flunixin meglumine for analgesia upon termination of anesthesia. In a subsequent group of dogs undergoing an orthopedic procedure, we assessed the effects on renal function of methoxyflurane anesthesia plus oxymorphone, or of methoxyflurane or halothane anesthesia in combination with a single IM 1.0 mg/kg dose of flunixin meglumine. Significant elevations in serum urea and creatinine values, and necrosis of collecting ducts and loops of Henle, were noted only in the dogs receiving methoxyflurane and flunixin meglumine.

We conclude that the use of combination of methoxyflurane and flunixin meglumine is contraindicated in dogs.

     

A small animal clinical and epidemiological relational database

A mainframe relational database management system (RDBMS), ORACLE, has been applied to small animal clinical records to facilitate storage and querying of case data for clinical and epidemiological use. Coded records are entered into the computer via a “user-friendly” interface which validates the input. Clinicians' queries similarly utilise an interface that generates query commands from four simple queries. Epidemiologists' queries, in contrast, require considerable flexibility and so use the main RDBMS language, SQL*Plus. A data administrator manages the security and integrity of the RDBMS.     

Type-I hypersensitivity as a component of eosinophilic myositis (muscular sarcocystosis) in cattle

Eight bovine hearts with lesions of eosinophilic myositis (EM) and 2 bovine hearts without EM lesions were collected at slaughter. Blood samples from these 10 hearts, and the heart of a newborn calf also were collected. Histologically, Sarcocystis cruzi was identified in the 8 hearts with EM lesions and the 2 hearts without EM lesions, but not in the heart of the newborn calf. Serum was harvested from the 10 blood samples and was used in homologous, modified, passive cutaneous anaphylaxis tests. Antigen was prepared from S cruzi bradyzoites isolated from the 2 hearts without EM lesions. Serum samples from the 8 cattle with EM lesions reacted positively to S cruzi antigen. When heat-inactivated IgE in serum (56 C for 4 hours) was used, all passive cutaneous anaphylaxis responses were considered negative. Using ELISA, serum IgE concentrations from the 10 cattle with and without EM lesions were 2.2 to 9 U/ml. As determined by radial immunodiffusion, IgM concentrations were 80 to 215 mg/dl. Immunoglobulin G concentrations were 420 to 2,050 mg/dl, but most were less than or equal to 1,700 mg/dl. Immunoglobulin A concentrations were 0 to 62 mg/dl; 1 steer with EM lesions had 0 mg/dl. Double-gel immunodiffusion confirmed the presence of Sarcocystis-specific precipitating antibodies. Sera from the 10 cattle with and without EM lesions formed at least 1 precipitin band.     

Disorders of potassium homeostasis

Hypokalemia and hyperkalemia are common problems that may be artifactual, iatrogenic, or due to altered body homeostatic mechanisms. ECG may help one to recognize hyperkalemia but not hypokalemia. Excessive K supplementation is a common iatrogenic cause of hyperkalemia whereas fluid therapy is a common cause of iatrogenic hypokalemia. The most common causes of spontaneous hyperkalemia are renal failure and hypoadrenocorticism whereas the most common causes of spontaneous hypokalemia are vomiting, diarrhea, and renal wasting. Symptomatic therapy is usually done until the underlying cause(s) is resolved.     

Endogenous opioid suppression of release of luteinizing hormone during suckling in postpartum anestrous beef cows

Beef cows were used to determine if suckling influences release of LH via endogenous opioids at 28 +/- 4 d after parturition. Cows of similar weight and body condition (6.8 +/- .1, 1 = emaciated, 9 = obese) were assigned randomly to five groups (n = 6 to 7): 1) control-suckled/saline (suckled 15 min every 6 hr for 48 hr); 2) control-suckled/naloxone; 3) calf-removal/saline (calf removal for 52 hr); 4) calf-removal/naloxone; and 5) control-suckled/GnRH (Gonadotropin-Releasing Hormone). At 0 hr, saline was administered to all cows. This treatment was continued at 6 hr intervals for 24 hr. Either naloxone (0.5 mg/kg), GnRH (40 ng/kg) or saline was administered to cows in their respective groups every 6 hr during the ensuing 24-hr period in calf-removal groups, or immediately preceding each suckling episode in the control-suckled groups. Blood samples for analysis of luteinizing hormone (LH) were collected at 15-min intervals for 1 hr prior to and 3 hr after treatment at 0, 24, 36 and 48 hr. Cows were observed for estrus twice daily. All cows in the control-suckled/GnRH group released LH (P less than .05) in response to exogenous GnRH, indicating the presence of releasable quantities of the gonadotropin. Mean concentrations of LH were not effected (P greater than .05) by the control-suckled regime. However, calf-removal alone, or in combination with naloxone, increased (P less than .05) mean concentrations of LH by 48 hr.(ABSTRACT TRUNCATED AT 250 WORDS)     

Enzyme-linked immunosorbent assay for the detection of circulating antigens of Toxoplasma gondii in the serum of cats

An ELISA was developed to detect circulating antigens of Toxoplasma gondii in the serum of cats. For the experiment, toxoplasmosis was induced in a group of cats by oral administration of bradyzoites. An ELISA that detects anti-Toxoplasma IgG, an ELISA to detect circulating antigens, and fecal examinations were performed on samples from each cat for 1 year after inoculation. When coupled with IgG-class antibody measurement, antigen detection can aid in the diagnosis of some cases of subclinical feline toxoplasmosis.     

A structural equation model for describing relationships between somatic cell score and milk yield in dairy goats

The relationship between milk yield and somatic cell score (log-transformed somatic cell count) in dairy goats may involve complex pathways with recursive or simultaneous effects. Structural equation models were fitted to longitudinal data on milk yield and on somatic cell scores. Data consisted of 4 repeated records of milk production and of somatic cell score from left and right halves of the udder in each of 47 dairy goats; infection status of each of the halves at each test day was also available. Results strongly suggest the existence of a within-half, first-order autoregressive process and of simultaneity of effects between somatic cell scores from the left and right halves of the udder. This indicates that the immune response to an infection is not restricted to the half of the udder in which the infection takes place and that it tends to propagate over time. The existence of a negative effect of somatic cell score on milk yield was also supported by the results; however, evidence in favor of an effect in the opposite direction, a dilution effect, was not strong.     

A case of "watery mouth" in a New Zealand Romney lamb

Watery mouth was diagnosed as the cause of illness and subsequent death in a 3-day-old Romney lamb which had not received early colostrum. The history, clinical signs and post-mortem findings were typical of the disease as seen in other countries, including Great Britain. The diagnosis was based on the clinical signs and was supported by an absence of post-mortem findings of other specific neonatal diseases. The potential importance of watery mouth under conditions of intensive husbandry in New Zealand is discussed.     

Restoration of the anterior dentition of a Canadian beaver (Castor canadensis)

An eight-year-old beaver lost one of its upper central incisors through unknown causes. As the anterior teeth of this species continually erupt in a similar manner to rodents' teeth, the unopposed lower incisor had over-erupted perforating the palate and entered the nasal cavity. The height of the lower incisor tooth was reduced and a cobaltchromium alloy bridge was constructed which was attached to the remaining upper incisor. The occlusal surface of the bridge was of sufficient width that both incisors could contact it. It was cemented into place with composite resin cement and cross-pinned through the labial surface of the metal into the tooth substance. It is unknown how such treatment will affect the biological processes underlying the continually erupting incisor and the animal is being monitored for any adverse effects.