Increased liquid diet (LD) volume or changing dilution rates of milk replacer fed to calves increases weight gain and may improve herd future productivity. Environmental enrichment (EE) may also improve gains by improving welfare. Twenty-four male Holstein colostrum-fed newborn calves were used in a randomized blocks experimental design during 8 weeks of liquid diet feeding. Calves were fed either whole milk or milk replacer (25% CP; 19% fat; 14% solids) according to a step up/step down feeding system (6L/d until 14d; 8L/d from 15 to 42d; 6L/d from 43 to 49d; and 4L/d from 50 to 56d), with or without environmental enrichment. Calves were individually housed with free access to water and concentrate. A stationary brush and a nipple to be used as a pacifier, both fixed in each hutch, were used as environmental enrichment. Data were analyzed as repeated measuremets using SAS, and the effects of LD, EE, age and their interactions were evaluated. Association of different liquid diets with environmental enrichment did not show differences in calves performance on average. However, environmental enrichment, mainly when associated with whole milk as liquid diet, decreased starter intake during the first 3 weeks of age and during the sixth week (P < 0.07), when volume fed was decreased. Calves fed whole milk associated with environmental enrichment were heavier than calves fed milk replacer from wk 5 until wk 8 (P < 0.06). Table 1. Performance of calves fed different liquid diets (LD) associated with environmental enrichment (EE)

	Milk			Milk replacer			P-value
	Control	EE		Control	EE		LD	EE	LD × EE	Age	LD × EE × Age
BW, kg	59.4±1.54	59.8±1.183		56.1±1.66	57.5±1.54		0.125	0.578	0.972	<0.0001	0.06
BW gain, g/d	712±33.5	787±38.7		683±35.6	695±38.8		0.121	0.252	0.417	<0.0008	0.19
Starter intake, g/d	280±35.8	203±42.5		327±38.5	254±42.6		0.236	0.082	0.971	<0.0001	0.07
Heart girth, cm	91.3±1.91	93.7±2.39		91.4±2.05	92.8±2.26		0.851	0.393	0.828	<0.0001	0.28
Hip width, cm	24.5±0.37	24.4±0.44		23.8±0.39	24.1±0.44		0.218	0.746	0.623	<0.0001	0.53
Withers height, cm	84.5±0.77	85.7±0.92		83.4±0.83	84.2±0.93		0.141	0.270	0.823	<0.0001	0.61