Abstract
The development of a resistance by cattle to artificial infestations with Boophilus microplus ticks is reported and the sequence of development discussed. There was a regression of adult female ticks becoming replete with infestation (regression y = 2399.41 – 574x ± 54) up to the fourth infestation. The weight of replete female ticks dropped from resistant cattle increased with infestation but this effect is confounded with the effects of climate. The day of modal drop of replete females increased with infestation, which indicated an effect of resistance on modal drop. Egg-laying was not affected by a developing resistance, but the fertility of eggs from female egg-laying ticks was. There was an increase in fertility of eggs laid after the second infestation.