Table 2.

Effect of milk replacer medication, breed, gender, week, and the interaction of milk replacer with these on selected antibiotic resistance genes in the feces of dairy calves.

	Gene copies/16S rRNA			SE4	P<
	Control1	Subtherapeutic2	Therapeutic3		Trt	Breed	Gender	Day	Interactions5
tetG	0.65	0.90	13.5	14.3	NS	NS	NS	NS	NS
tetO	2.27	2.13	5.35	1.53	0.02	NS	NS	NS	NS
tetW	10.3	4.00	1.84	9.13	NS	NS	0.07	NS	NS
tetX	0.50	0.69	0.88	0.68	NS	0.03	NS	NS	Trt*gender; breed*gender; breed*week
sul1	0.13	0.12	1.11	0.58	NS	NS	NS	NS	Gender*week
sul2	0.06	0.06	0.13	0.12	NS	NS	NS	NS	Breed*week
ermB	0.89	0.78	0.67	0.99	NS	NS	NS	NS	NS
ermF	0.66	0.09	0.16	0.75	NS	NS	NS	0.004	NS

¹Control milk replacer containing no antibiotics fed from day 2 to weaning (59 ± 2 day).

²Medicated milk replacer containing 10 mg/calf/day of tetracycline and neomycin fed from day 2 to weaning.

³Medicated milk replacer containing 1000 mg/calf/day of tetracycline and neomycin fed from day 36 to weaning.

⁴SE for treatment LS means.

⁵Other significant (P < 0.10) two and three way interactions of treatment, breed, gender, and week.