52.以肌肉注射抗生素ceftiofur來預防乳牛產後胎衣滯留（retained fetal membrane）之子宮感染的臨 床正確使用劑量是多少mg/kg一天一次？
(A)2.2
(B)3.3
(C)4.4
(D)5.5

參考來源：Plumb’s Veterinary Drug Hand book Sixth Edition 

Administer to cattle by IM or SC injection at 1.1 to 2.2 mg/kg of body weight (1 – 2 mL reconstituted sterile solution per 100 lbs body weight). Treatment should be repeated at 24-hour intervals for a total of three consecutive days. Ad- ditional treatments may be given on days four and five foranimals which do not show a satisfactory response (not re- covered) after the initial three treatments. (Package Insert; Naxcel®—Pfizer)