Transmission of salmonellae among calves penned individually.

An analysis of the spatial and temporal patterns of excretion of salmonellae by calves penned individually showed that non-contagious routes were more important than contagious routes in disease spread. The avoidance of aerosol production, and the effective cleaning and disinfection of utensils between feeds and of buildings between batches, are likely to be more important than pen design in the control and prevention of calf salmonellosis.     

The detection of Salmonella infection in calves by the fluorescent antibody test

The fluorescent antibody test (FAT) was used for the direct detection of salmonellas in 182 lymph nodes from adult cattle and from calves submitted for autopsy or used for experimental purposes. Salmonellas were detected in 22 samples by the FAT and in 18 by culture examination. The predictive value of the FAT was 68% and it was concluded that the test could be used for the rapid presumptive diagnosis of bovine salmonellosis.     

Nine DNA probes for detection of toxin and adhesin genes in Escherichia coli isolated from diarrhoeal disease in animals

DNA gene probes specific for genes encoding heat labile enterotoxin (LTI), heat stable enterotoxins (STIa, STII), vero cytotoxins (VT1, VT2), and adhesins K88 (F4), K99(F5), F41 and 987P(F6) were used to examine 873 isolates of E. coli from cases of diarrhoea (680 from pigs, 187 from cattle and six from sheep). A total of 188 were toxin gene positive and of these 84 belonged to the classical ETEC serogroups. Of the other 104 toxin gene positive strains, 80 hybridized with the VT2 probe of which 34 were from cases of porcine post-weaning diarrhoea belonging to serogroup 0138:K81 and 22 were untypable strains from cattle.     

Effect of monensin on the performance of cattle on pasture or fed harvested forages in confinement

Three series of trials were conducted to evaluate the effect of monensin on the growth performance of cattle. Twenty-four trials were conducted to evaluate the addition of monensin at 200 mg/d to limited quantities of supplemental concentrate for growing cattle grazing pastures. The pastures ranged from dormant end-of-the-season grasses and crop residues to lush green pastures, and were located in several different states. Pasture plus supplement supported gains of control cattle (without monensin) of .24 to .96 kg, with an average of .56 kg/d. The addition of 200 mg monensin to the supplement increased daily gain in all 24 trials by an average of .09 kg daily (+16.3%). Eleven trials were conducted with monensin and energy supplements fed at .907 kg.- head-1 X d-1 to growing cattle grazing growing, nondormant pastures for an average period of 117 d. Each trial was designed to compare the performance of unsupplemented cattle, cattle fed a supplement and cattle fed a supplement with monensin. Cattle on pasture gained .50 kg daily. Supplement feeding increased average daily gain by .09 kg and the addition of monensin to the supplement further increased gain by .09 kg, for a total increase of .18 kg (34.2%). The efficiencies with which supplemental feed was converted to extra gain (kg supplement/kg gain) for the supplement-only and the monensin treatment groups were 10.1:1 and 5.0:1, respectively. In a series of 12 trials, monensin was added at a level of 33 mg/kg air-dry diet to limited quantities of supplemental feed for cattle fed harvested forages in confinement. All trials compared monensin feeding with a nonmedicated control treatment. Hay was fed in 8 of the 12 trials, fresh-cut green-chop in two trials and ensiled corn stover and ensiled milo stover in one trial each. Monensin reduced feed intake by -3.1%, improved average daily gain by .09 kg (+14.4%) and improved feed efficiency by 15.3%.     

Methaemoglobinaemia caused by hydroxycarbamide (hydroxyurea) ingestion in a dog

A three-year-old female neutered greyhound was presented after ingestion of its owner's hydroxycarbamide (hydroxyurea) tablets. The dog was found to be cyanosed, and methaemoglobinaemia was demonstrated by co-oximetry. Therapy included methylene blue, oxygen, packed red blood cell transfusion, N-acetylcysteine and crystalloid fluids. Methaemoglobinaemia resolved within 16 hours. Granulocyte colony-stimulating factor was administered for five days in an attempt to prevent severe neutropenia. Mild delayed transient myelotoxicity was suspected. The dog made a full recovery.