38 

 (ig/ml) than ZnMet , ZnO or control treatments (.78 ± .27, .62 

 ± . 1, and .75 ± .26 (ig/ml, respectively), but not ZnS0 4 (.87 

 ± .17 |ig/ml) . During the depletion phase (d 21 to 49) mean 

 serum Zn levels did not differ (P > .05) from those levels 

 before the beginning of depletion (d 21) . Overall serum Cu 

 levels fell slightly with all treatments (Figure 4-2) . Most 

 serum concentrations were, however, above the minimum critical 

 level of .65 (ig/ml, suggested by McDowell et al . (1984) . 

 There were no treatment effects (P > .05) for any of the 

 sampling days. 



The ZnLys treatment had the highest (P < .05) Zn 

 accumulation (581, 389, and 340 mg/kg) for kidney, liver and 

 pancreas, respectively (Table 4-2). Both ZnS0 4 and ZnMet 

 treatments had higher (P < .05) liver Zn concentrations (195 

 and 198 mg/kg, respectively) than the control treatment (127 

 mg/kg) . Liver Zn concentrations for ZnO were not different (P 

 > .05) than control, ZnS0 4 or ZnMet. Kidney Zn concentrations 

 of both ZnS0 4 and ZnMet treatments tended (P < .15) to be 

 higher than controls. The remaining Zn levels for bone, bone 

 marrow, cornea, skin, hoof and muscle were not different (P > 

 .05) among treatments. Most of the Zn concentrations for 

 those tissues were relatively constant among treatments. 



Response to treatments in terms of tissue MT (Table 4-3) 

 were very similar to that of tissue Zn levels. The ZnLys 

 treatment had the highest (P < .05) MT levels of 79, 167, and 

 68 (ig MT/g for liver, kidney, and pancreas, respectively. 



