RELATIONSHIPS BETWEEN OESOPHAGOSTOMUM COLUMBIANUM INFECTION AND NUTRITIONAL STATUS OF SHEEP .I. EFFECTS ON GROWTH AND FEED UTILIZATION

The infection of young sheep with 1500 infective larvae of the parasitic nematode Oesophagostomum columbianum was associated with loss of weight of degree and duration varying with the plane of nutrition. Greater losses of weight were observed in sheep maintained on a low protein ration of chaffed wheaten straw and molasses than in those on a high protein ration of chaffed lucerne. A similar situation was observed with all the other parameters which were measured. Furthermore, within the low plane group those animals which were infected with five consecutive daily doses of 300 larvae were more severely affected in terms of all the parameters than were those infected with a single dose of 1500 larvae. Loss of weight was associated with marked reductions in the feed intake of the animals following infection. The utilization of feed expressed as kilograms of body weight gained or lost per unit of either total feed or crude protein consumed was more severely depressed in all infected sheep compared with their “pair-fed” controls. The water, sodium, and potassium contents of the faeces increased in association with the infection. © 1969 CSIRO. All rights reserved.