32 

 of a difference among sources in the present study is also in 

 agreement with a sheep experiment to determine if Zn from 

 ZnMet would influence muscle (longissimus or biceps femoris) 

 Zn concentrations (Medeiros et al . , 1989) . A genetic 

 difference might also exist between the species used by other 

 researchers in terms of their Zn metabolism especially between 

 ruminants and monogastrics . It is suggested that this trial 

 be conducted using similar levels of supplemental Zn in 

 combination with lower levels of basal dietary Zn . This kind 

 of study would be more expensive because it would necessitate 

 the use of purified or semipurified diet. 



Implications 



These results suggest that at adequate levels of dietary 

 Zn, bioavailability of supplemental Zn sources may be less 

 important than under conditions of limited dietary Zn or 

 increased supplemental Zn . 



Summary and Conclusions 



A 12 wk experiment was conducted to compare supplemental 

 ZnMet, ZnS0 4 , and ZnO on Zn, Cu and MT concentrations in 

 various fluids and tissues of 32 yearling cattle. 

 Supplemental Zn (3 60 mg/d) was fed for 4 wks, withdrawn for 4 

 wks and then resumed for another 4 wks. Mineral ( Zn and Cu) 

 concentrations were determined in serum, liver, pancreas, 

 kidney, bone, bone marrow, hair, hoof and neck muscle, and Zn 



