Adhesion of Staphylococcus aureus and Escherichia coli to bovine udder epithelial cells

An assay for the adhesion of tritiated thymidine-labelled Staphylococcus aureus and Escherichia coli to bovine mammary ductular epithelial cell lines was developed. The relative adhesion of 15 strains of S. aureus to these cell lines was examined. Four strains did not adhere and the remaining 11 adhered at variable levels. Adhesion to different cell lines was generally similar. Adhesion to freshly collected bovine mammary epithelial cells was significantly greater than that to cells maintained in tissue culture. The system described was demonstrated to be a suitable model for studying adhesion of mastitis-causing organisms to bovine mammary epithelial cells.     

Influence of dietary protein on the pathophysiology of haemonchosis in lambs given continuous infections

Mixed-sex groups of three-month-old Finn Dorset and Dorset Horn lambs were given complete diets containing either high or low protein. A trickle infection with Haemonchus contortus of 200 larvae, given three times a week, began one month later for a 17 week period. Erythrokinetic, metabolic, digestibility and balance studies were conducted with the male lambs during weeks 12 to 14 of the infection. Clinical signs of haemonchosis became evident only in the low protein diet group. The infection was characterised by severe macrocytic anaemia, hypoproteinaemia, hypoalbuminaemia, reduced survival, high egg counts and a significantly greater worm burden. In the high protein diet group many lambs developed resistance to further infection in contrast to the low protein group in which no resistance developed. Live-weight gain was not affected by infection in the high protein diet group but decreased in the lambs given the low protein diet compared with uninfected controls. However, infection did not appear adversely to affect the digestive efficiency, nitrogen retention or iron absorption in either dietary group although loss of appetite occurred in the low protein group. Examination of a sample joint from the carcases showed infection was associated with a marked reduction in muscle mass in lambs given the low protein diet relative to the control animals.     

Cardiomyopathy and woolly haircoat syndrome of Poll Hereford cattle: electrocardiographic findings in affected and unaffected calves

Electrocardiograms were recorded from 4 calves with cardiomyopathy and woolly haircoat syndrome (CWH), a lethal autosomal recessive trait of Poll Hereford cattle and from 9 unaffected calves. Electrocardiograms of calves with CWH were characterised by multifocal ventricular premature contractions which occurred singly, in pairs, in runs and as episodes of ventricular tachycardia. Bigeminal rhythms were recorded occasionally. The frequency of ventricular premature contractions ranged from 5 to 120.min-1. Ventricular premature contractions in calves with CWH were attributed to myocardial degeneration and fibrosis which were observed grossly and microscopically. Electrocardiograms in unaffected calves were characterised by normal sinus rhythm and by variation in the morphology of wave forms between animals. The durations of the various wave forms were less than those previously recorded from adult cattle.     

Otopharmacology

Therapy for diseases of the ear canal is, in most respects, similar to therapy for other diseases of dogs and cats. As a target for drug therapy, however, the unique anatomy of the external ear canal presents differences that are both advantageous and disadvantageous. This article will describe principles of therapy and pharmacologic properties from the perspective of topical therapy directed at the surface of the ear canal, the epidermis, and the dermis.     

Quantitative correlation of parasitological and serological techniques for the diagnosis of Trypanosoma congolense infection in cattle

A comparison was made between serological and parasitological techniques for the diagnosis of bovine trypanosomiasis in Zambia. Overall sero-prevalence rates as determined by IFAT and ELISA were respectively 2.7-fold and 2.9-fold greater then the percentage of samples found positive with the dark ground/phase contrast buffy coat technique (DG). The results obtained by the two serological techniques were found to be closely correlated (94.2%) agreement) and titres obtained by ELISA tended to be slightly higher than those obtained by IFAT. Linear regression analysis of the results obtained by the IFAT and DG techniques revealed a highly significant correlation. This finding would permit the use of only one of the techniques in an epidemiological survey and to extrapolate the results from the regression line.     

Inbreeding and immunoglobulin G1 concentrations in cattle

Immunoglobulin G1 concentration (IgG1) was measured in presuckle colostrum and calf serum obtained at 36 h and at weaning from inbred and straightbred Angus, Brangus, Hereford, Red Angus and Simmental cattle. Sources of variation considered as dam traits examined for IgG1 in colostrum and 36-h calf serum included line of sire, sire within line, age, and linear regression of IgG1 on inbreeding of dam. Only line of sire and inbreeding of dam were significant in the analysis of 36-h calf serum. Sources of variation considered as calf traits examined for IgG1 in calf serum at 36 h and at weaning included line of sire, sire within line, sex of calf, age of dam, and regressions of calf serum IgG1 on inbreeding of the calf and on dam's colostral IgG1. Only sire within line and the regression on dam's colostral IgG1 were significant for calf serum IgG1 at 36 h. Large differences existed in 36-h calf serum IgG1 between sires both within lines and when lines were ignored. Calves with 36-h serum IgG1 of less than 10 mg/ml were two to four times more likely to die before weaning than calves with higher IgG1 levels. The heritability estimates of IgG1 by paternal half-sib analysis were .41 +/- .30 for colostrum measured as a trait of the dam and .56 +/- .25 for 36-h. calf serum and .05 +/- .17 for calf serum at weaning considered as a trait of the calf. These estimates indicate that IgG1 in colostrum and 36-h calf serum could be increased by selection.(ABSTRACT TRUNCATED AT 250 WORDS)