Worm burden of West African Dwarf goats separated into low and high FEC (strong and weak responder) groups/phenotypes on the basis of their FEC until day 52 after commencement of the escalating (immunising) infections with Haemonchus contortus and according to the treatment groups indicated on the y-axis of the figure. All the animals, except the naive and challenge infection controls received the same relatively heavy doses of the immunising infection, which was later truncated on day 56, as follows: 500 L3 on day 0 (d0), 1000 on d7, 2000 on d14, 3000 on d21 and 4000 on d28 (total number of L3 received, 10,500). The equally heavy challenge dose, 6000 L3, was given to the appropriate groups on d63. All immunised challenged and dewormed goats effectively controlled the subsequent heavy challenge infections which resulted in near total elimination/rejection of the challenge infection in the low FEC (haemonchotolerant) goats. For further details see Chiejina et al. [14].