In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: Large parenteral doses of vitamin D3 ( 15 to 17 . 5 x 10 ( 6 ) IU vitamin D3 ) were associated with prolonged hypercalcemia , hyperphosphatemia , and large increases of vitamin D3 and its metabolites in the blood plasma of nonlactating nonpregnant and pregnant Jersey cows .
### Output Text:
Large parenteral doses of <span class="chemical">vitamin D3</span> ( 15 to 17 . 5 x 10 ( 6 ) IU <span class="chemical">vitamin D3</span> ) were associated with prolonged hypercalcemia , hyperphosphatemia , and large increases of <span class="chemical">vitamin D3</span> and its metabolites in the blood plasma of nonlactating nonpregnant and pregnant Jersey cows . 