Association between changes in eating and drinking behaviors and respiratory tract disease in newly arrived calves at a feedlot

OBJECTIVE: To investigate eating and drinking behaviors and their association with bovine respiratory disease complex (BRDC) and to evaluate methods of diagnosing BRDC. ANIMALS: 170 newly arrived calves at a feedlot. PROCEDURE: Eating and drinking behaviors of calves were recorded at a feedlot. Calves with clinical signs of BRDC were removed from their pen and classified retrospectively as sick or not sick on the basis of results of physical and hematologic examinations. Pulmonary lesions of all calves were assessed at slaughter. RESULTS: Calves that were sick had significantly greater frequency and duration of drinking 4 to 5 days after arrival than calves that were not sick. Sick calves had significantly lower frequency and duration of eating and drinking 11 to 27 days after arrival but had significantly greater frequency of eating 28 to 57 days after arrival than calves that were not sick. Calves at slaughter that had a higher percentage of lung tissue with pneumonic lesions had significantly lower frequency and duration of eating 11 to 27 days after arrival but had significantly higher frequency and duration of eating 28 to 57 days after arrival. Agreement for calves being sick and having severe pulmonary lesions at slaughter was adequate. Agreement for calves being removed and having pulmonary lesions at slaughter was low. CONCLUSIONS AND CLINICAL RELEVANCE: Eating and drinking behaviors were associated with signs of BRDC, but there was not an obvious predictive association between signs of BRDC in calves and eating and drinking behaviors. Fair to poor agreement was observed between antemortem and postmortem disease classification.     

Production of transgenic rabbits using centrifuged pronuclear zygotes

Superovulation of female rabbits was induced by subcutaneous injection(s) of porcine FSH. Zygotes were recovered 17 to 19 hr after hCG injection and were classified into two categories under a microscope equipped with Nomarski interference-contrast optics at x 200 magnification: (A) zygotes with clearly visible pronuclei, or (B) zygotes with visualized pronuclei after 10 min centrifugation at 12,000 x g. No significant difference between strains was found in the proportion of category-A zygotes (JW 72.6% vs NZW 79.3%). Pronuclei of category-A zygotes were located in the center of the cytoplasm, and the pronuclei of category-B zygotes were slightly moved by centrifugation toward the mass of cytoplasmic lipid droplets. Exogenous DNA solution (5 microg/ml of fusion gene composed of bovine alphaS1-casein promoter and human growth hormone structural gene) was microinjected into the pronucleus of the JW zygotes. The pronucleus of category-A zygotes with a mean volume of 7.4 pl swelled up to 16.6 pl (132% increase), while that of category-B zygotes with a mean volume of 6.1 pl swelled up to 15.9 pl (148% increase). Nevertheless, similar proportions of category-A and category-B zygotes developed into offspring after transfer to recipient females (11.1 and 11.2%, respectively). The efficiency to produce hGH-carrying transgenic rabbits was 0.9% (2/235) from category-A zygotes and 0.5% (1/215) from category-B zygotes (P>0.05). To date, transgenic rabbits have been produced without centrifugation of pronuclear zygotes. However approximately 25% of fertilized rabbit zygotes can be used for DNA microinjection after they have been centrifuged to visualize their pronuclei.     

The effect of intravenous administration of variable-dose midazolam after fixed-dose ketamine in healthy awake cats

The effects of intravenous administration of variable-dose midazolam and ketamine (3 mg/kg) were studied in twelve healthy unmedicated cats from time of administration until full recovery. A range of midazolam doses (0.0, 0.05, 0.5, 1.0, 2.0 and 5.0 mg/kg) was chosen, so that beneficial and/or detrimental effects could be documented and the therapeutic window for further study determined. One minute after administration of ketamine, all cats had assumed a lateral position, mostly with head up. Muscle tone was increased (100%), apneustic breathing pattern evident in 92% of cats, chewing without stimulation of the oropharyngeal area was observed in most cats (97%), but most cats did not salivate (87%). At 2.5 min after completion of ketamine injection and 1 min after administration of saline, a similar picture was observed, except that salivation was evident. All cats chewed or swallowed in response to a finger or laryngoscope placed in the oropharyngeal area and, while most cats were not aware of a noxious stimulus to the tail, some cats were aware of a noxious stimulus to the paw. Recovery from ketamine alone was rapid and smooth with cats rolling into sternal recumbency and then cautiously walking with ataxia. Recovery to walking without incoordination was also rapid (< 2 h) and no abnormal behavioural patterns were observed during recovery. Administration of midazolam after ketamine, had beneficial effects and the therapeutic window for midazolam was found to lie between 0.05 mg/kg and 0.5 mg/kg. Administration of any dose of midazolam after ketamine caused a greater proportion of cats to assume a laterally recumbent position with head down compared with ketamine alone, however, the time period of recumbency was only significantly longer with a midazolam dose of 2.0 mg/kg or above. Doses of midazolam of 0.5 mg/kg or above decreased muscle rigidity but did not affect salivation or respiratory pattern observed in cats which received ketamine alone. A significantly greater proportion of cats which received ketamine and midazolam 0.5 mg/kg or above did not swallow in response to a finger or a laryngoscope placed in the mouth compared with that which received ketamine alone. The length of time in which cats did not swallow was only significantly longer at midazolam doses of 1.0 mg/kg and above. At midazolam doses of 0.5 mg/kg or above, the proportion of cats without a nociceptive response to a tail or paw clamp was significantly greater than cats which received ketamine alone. The time period without nociceptive response, however, was not influenced by midazolam administration. The time taken for cats which received ketamine and midazolam 0.05 mg/kg or 0.5 mg/kg to assume sternal position, walk with ataxia, walk without ataxia, behave normally when approached or restrained and recover normal arousal state was not significantly different from cats which received ketamine alone. Ketamine and midazolam 5.0 mg/kg significantly prolonged all recovery times compared with ketamine alone. Unfortunately, a greater proportion of cats which received ketamine and midazolam 0.5 or 5.0 mg/kg exhibited detrimental behavioural effects. These were more likely to be adverse and included restlessness, vocalization and difficulty approaching and restraining cats. In this study, an     

Pathological changes of tracheal mucosa in chickens infected with infectious laryngotracheitis virus

Six-week-old chickens were inoculated via the posterior thoracic air sac with infectious laryngotracheitis virus. Chickens were sacrificed on various days through day 16 postinoculation (PI), and the trachea was examined by scanning electron microscopy (SEM) and light microscopy (LM). The pathological changes observed on day 1 PI were hypertrophy and hyperplasia of goblet cells. From day 3 PI, the epithelial cells protruded collectively and fused to form syncytia, which contained many intranuclear inclusion bodies. Subsequently, epithelial syncytia desquamated, one after another, and connective tissues were exposed in places. Serofibrinous exudate and detritus were abundant on the surface of the exposed connective tissues and seemed to form a pseudomembrane. On day 5 PI, the remaining epithelial cells began to repair the devastated mucosa just under the pseudomembrane. On day 6 PI, microvillus-rich regenerating epithelial cells were arranged like paving stones. On day 8 PI, the epithelial cells proliferated extensively and formed folds with cyst-like structures. By day 16 PI, the tracheal epithelium was covered with cilia and regained its normal histologic appearance.     

Reaction cements as materials for the sustained release of trace elements into the digestive tract of cattle and sheep. II. Release of cobalt and selenium

Acid-base reaction cements, containing salts of copper, cobalt and selenium, were placed in the reticulum of sheep and cattle, and the rate of release of cobalt and selenium from them was measured. The rate of release of cobalt decreased with time but was sufficient to provide adequate supplementation for at least 6 months. After an initial rate of release of 4 mg Se/day for 1-2 weeks, the mean subsequent rate of release of selenium over a period of 4 months was 0.1 mg Se/day (identical to 5 micrograms Se/day/cm2 surface area). Field trials in lambs and growing steers showed that the cement increased the selenium concentration of their blood throughout a summer grazing period.     

A comparative study on certain enzymes of the granulocyte from different ruminant species

In the present study the level of enzyme hydrolases (alkaline phosphatase, myeloperoxidase, elastase, arginase, lysozyme and β-galactosidase) of polymorphonuclear cell (PMN) granules in different ruminant species and their release in response to activation was studied. Buffalo PMN alkaline phosphatase activity was higher (P < 0.01) than in PMNs of cattle and goats. Interestingly, myeloperoxidase was higher in cattle PMNs and least in goat PMNs (P < 0.01), a similar pattern was observed in the distribution of enzyme arginase. As far as lysozyme is concerned, its activity was significantly higher (P < 0.01) in PMNs of buffaloes than in the case of cattle and goat PMNs. On activation, these cells released MPO and elastase, in all the species studied, while lysozyme was secreted only in buffalo PMN cells. Activity of certain enzymes related to oxidant defence systems such as glutathione peroxidase and glutathione reductase were higher in cattle and goats compared to that in buffaloes. These observations are likely to have bearing on immunodefense roles played by PMNs and reflected differences among the ruminant species studied.     

Les vaccins dans la prevention de la rhinotracheite infectieuse du chat adjuvant BCG gel d''alumine (preparation, controle, immunite)

Immunogenicity of different vaccines against the main viral diseases was compared: feline infectious rhinotracheitis, feline panleucopenia virus and calicivirus. These inactivated vaccines developed higher protective activity when adjuvants such as BCG or aluminium hydroxide were used. Animals vaccinated and boostered with an identical dose of these vaccines resisted the viral challenges. Neutralizing antibodies titers obtained with BCG adjuvated vaccines were twofold higher than those containing aluminium hydroxide.