Hypo-osmotic swelling test (HOST) and its response in fresh and freeze-thawed semen

Forty-eight ejaculates (24 each from FH and FJH crossbred bulls) were subje cted to freezing and hypo-osmotic swelling rest to record freezability in r elation to membrane integrity of the spematozoa. In fresh semen no signific ant difference between HOS-positive spematozoa of bath the crosses was foun d but hull variation was significant. HOS-positive sperm after freeze thawi ng also did not differ significantly between both the crosses, however, in FH crosses, a significant bull to bull variation was recorded. After freeze thawing the number of HOS-positive spermatozoa decreased to 30-50% and alm ost all the types of HOS-positive sperms were recorded. A significant posit ive correlation of BOS-positive sperm with mass motility, initial progressi ve motility, live count total intact acrosome and sperm concentration was a lso found.