In vitro Cultivation of Ostertagia ostertagi, the Medium Stomach Worm of Cattle. I. Development from Infective Larvae to Egg-Laying Adults

Abstract
When a 70 min exsheathing process and 2-step roller culture system were used, infective larvae of O. ostertagi developed in large numbers to mature adult males and females in 28 and 29 days, respectively. Females laid fertile eggs in the 2 to 16-cell stages from day 34 on. Some of the expelled eggs developed to the morula stage, in the culture fluid, by day 52. Yields of mature adults and eggs were best when cultures were started with 100,000 larvae in 100 ml medium. The optimal culture system produced 20-35% mature adults, from days 28 through 52.