Abstract
1. Proteinuria was found in most sucking lambs and calves examined but was less prevalent in bottle-fed kids or bucket-fed calves. 2. This incidence of proteinuria corresponded to the presence of immune lactoglobulin in the serum. 3. The extent of proteinuria in lambs and calves rose to 20 g./l. or more, whereas in kids values of only 4 g./l. were obtained. 4. The proteins present in the urine of lambs and kids have been compared with those in the urine of calves by using boundary electrophoresis and paper electrophoresis. 5. Sedimentation analyses have been made on the proteins of lamb, kid and calf urine. Components with sedimentation coefficients 3s and less were present. The separated slow electrophoretic components were found to have sedimentation coefficients 3.3, 3.6 and 3.3s respectively. 6. The sedimentation analyses, and for calf urine the electrophoretic data, support the view that the slow-moving electrophoretic components of calf and lamb urine are degraded immune lactoglobulins. 7. There was electrophoretic evidence for other degraded proteins in some lamb urine which showed multiple zones that could not be related to serum or colostral proteins.