Detection of early pregnancy on osini sheep by rosette inhibition test [RIT]

Serum samples were collected from 30 Ossimi ewes 6 to 25 days after artificially inseminated. The rosette inhibition test [RIT] was tried for detection of pregnancy in these ewes. Aliquots of serum samples was incubated with sheep anti-lymphocyte serum prepared in rabbits, absorbed guinea pig serum and absorbed human RBCs. Early pregnancy was detected in sera of 11 out of the 30 samples examined. In all positive samples, more than 25% reduction in the numbers of rosettes were formed compared with negative controls. A dilution of the anti- lymphocyte serum [1 in 256 x 10 3] was selected and proved to give satisfactory results through the experiment. Using this dilution of antisera the time of performing the test was reduced to 2.5 hours in 12 serum samples. The present work supported the possible use of the RIT as a field test for the early pregnancy diagnosis in sheep