3550
None of the cows treated with vitamin D3 showed signs of milk fever during the peripartal period ; however , 22 % of the control cows developed clinical signs of milk fever during this period .
 vitamin D3, milk fever, milk fever
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Disease, Chemical 
Text: {0} 
Answer:
 vitamin D3, milk fever, milk fever