Abstract:
I. Trials are described in which six sheep and one goat were artificially infested
with O. circumcincta and their reactions studied in detail.
2. The main pathological findings were:
(i) Marked decrease in packed red cell volume, haemoglobin concentration
and circulating red blood cell volume.
(ii) A sharp drop in plasma inorganic phosphate which occurred in five of
the seven animals.
(iii) Anorexia, decreased apparent nitrogen absorption and weight loss or
retarded weight gain.
(iv) A decrease in plasma albumin, gamma globulin and total circulating
plasma proteins.
3. Egg counts were low even with large worm burdens.
4. On reinfestation two sheep cleared themselves of the original and challenging
infestation.
5. Large numbers of larvae were necessary to cause death.
