Fig. 3

Decrease in weight gain of sheep by increasing infection level with mixed species of gastrointestinal nematodes. Mean difference in faecal egg counts between low parasite burden animals (LPAR) and high parasite burden animals (HPAR) is used as an indicator of level of infection and shown on the X-axis. Y-axis shows the ratio of weight gain of HPAR over LPAR. The continuous line shows the estimated effect of nematode infection with a 95 % confidence interval (dotted lines) computed with a Generalized Linear Model using the results of 73 trials (black dots with sizes proportional to sample size of the trials)