Gnotobiotic calves: derivation, maintenance, Thiry-Vella loop preparation, and ethylene oxide gas sterilization.

Twenty-four pregnant Holstein cows were used to develop techniques and procedures to obtain calves by hysterotomy and to maintain them in a closed gnotobiotic environment (sterile plastic-film isolators) for as long as 10 days for infectious disease research. Thiry-Vella loop preparation for obtaining intestinal loop secretions was done in a surgical isolator and was successful in 12 of 14 gnotobiotic calves. Ethylene oxide gas was effective in sterilizing heat-labile and moisture-sensitive instruments and equipment.