Table 3.

Changes in the use of antimicrobial drugs in preweaned calves on California dairies following the implementation of the Veterinary Feed Directive (VFD) final rule on January 1, 2017 compared to practices during the year 2016.

Changes since Jan 1st 2017	Percent	SE	N	95% Confidence limits
				Lower	Upper
Antimicrobial drugs used in milk or milk replacer
No changes made	61.0	6.4	59	47.7	72.9
Increased amount or duration	1.7	1.7	59	0.2	11.7
Decreased amount or duration	10.1	4.	59	4.5	21.3
Discontinued 1 or more	18.6	5.1	59	10.5	31
Added 1 or more	1.7	1.7	59	0.2	11.7
Othera,b	8.4	3.7	59	3.5	19.2
Antimicrobial drugs used in solid feed
No changes made	81.7	5	60	69.4	89.7
Increased amount or duration	0		60
Decreased amount or duration	5	2.8	60	1.6	14.8
Discontinued 1 or more	5	2.8	60	1.6	14.8
Added 1 or more	1.7	1.7	60	0.2	11.5
Othera	5	2.8	60	1.6	14.8
Antimicrobial drugs used in water
No changes made	83.6	4.8	61	71.7	91.1
Increased amount or duration	0		61
Decreased amount or duration	1.6	1.6	61	0.2	11.3
Discontinued 1 or more	1.6	1.6	61	0.2	11.3
Added 1 or more	4.9	2.8	61	1.5	14.6
Othera	6.6	3.2	61	2.4	1.7

^aUsed antimicrobial drugs occasionally.

^bStopped using uniprim (trimethoprim and sulfadiazine oral antibiotic powder).