6Pitts WJ, Millers WJ, Fosgate OT. Effect of zinc defi- ciencies and restricted feeding from two to five months of age on reproduction in Holstein bulls [ J ]. J Dairy Sci,1966, 49:995 - 1000. 被引量:1
7Aliha, Ezzooh, Ekhnawy K E. Effect of zinc supple- mentation on reproductive performance of Bar kiewes un- der practical field condition [ J ]. Vet Med J Giza, 1998, 46 : 77 - 87. 被引量:1