Icterus condemnations compose a substantial proportion (41%) of total condemnations of bob veal, the class of veal composed of calves < 3 weeks old and weighing up to 68 kg. At postmortem examination, bob veal condemned because of icterus have generalized yellow discoloration of tissues, which is commonly associated with large, yellow liver (fatty liver), and a paucity of other gross pathologic changes. To establish that the generalized yellow discoloration was attributable to high tissue bilirubin concentrations and to examine the underlying mechanism(s) that might be responsible, blood samples and tissue specimens were obtained from clinically normal and icteric bob veal calves at slaughter. For comparison, blood samples were collected from clinically normal, 1- to 5-day-old Holstein calves being raised on local dairy farms. Hematologic and serum biochemical analyses were obtained for the 3 groups of calves (normal local, normal slaughter, and icteric slaughter), and tissues of slaughter calves were examined for histologic evidence of inflammatory or degenerative changes. Mean +/- SD total bilirubin concentration and creatine kinase (CK) activity in icteric bob veal (3.3 +/- 0.8 mg/dl; 869 +/- 788 U/L), normal bob veal (1.4 +/- 0.7 mg/dl; 486 +/- 890 U/L), and normal local calves (0.5 +/- 0.2 mg/dl; 156 +/- 158 U/L) were significantly different. When data for both normal and icteric bob veal calf groups were combined for analysis, total bilirubin concentration regressed significantly on hepatic lipid scores (P = 0.00003) and CK activity (P = 0.00049). Colostrum consumption was determined by measuring serum total protein concentration and serum gamma-glutamyltransferase activity. Bob veal calves that had not consumed colostrum had significantly higher total bilirubin (P = 0.00005) and CK (P = 0.0008) values. It was concluded that normal and icteric bob veal calves have significant increase in total bilirubin concentration, and icterus of bob veal calves is secondary to unconjugated hyperbilirubinemia. Lack of colostrum consumption was strongly correlated with icterus in bob veal calves.

Casein has been used as a protein source in diets designed to dissolve canine ammonium urate uroliths and to prevent their recurrence, because it contains fewer purine precursors than do many other sources of protein. However, an important question is whether reduced quantities of dietary casein have any benefit in modifying saturation of urine with urates. To answer this question, activity product ratios of uric acid, sodium urate, and ammonium urate were determined in 24-hour urine samples produced by 6 healthy Beagles during periods of consumption of a 10.4% protein, casein-based (10.4% casein) diet and a 20.8% protein, casein-based (20.8% casein) diet. Significantly lower activity product ratios of uric acid, sodium urate, and ammonium urate were observed when dogs consumed the 10.4% casein diet. Significantly lower 24-hour urinary excretions of ammonia and phosphorus were observed when dogs consumed the 10.4% casein diet. Twenty-four-hour urinary excretions of magnesium and 24-hour urine pH values were significantly higher when dogs were fed the 10.4% casein diet. These results suggest that use of the 10.4% casein diet in protocols designed for dissolution and prevention of uric acid, sodium urate, and ammonium urate uroliths in dogs may be beneficial.