Serological studies on bovine besnoitiosis in Israel

Sera from 1,700 beef and dairy cattle in Israel were tested for besnoitiosis by indirect immunofluorescence. Over 90% of dairy animals were negative whereas about 50% of beef cattle were positive. Among beef bulls the percentage of positive reactors increased with age but in beef cows the pattern was less clear; 36% of young imported bulls negative upon arrival developed antibody titres after one season on the range. Cross-tests with Toxoplasma gondii antiserum and antigen indicated that the results of the survey for besnoitiosis were unlikely to have been influenced by Toxoplasma antibodies.