The acidification of milk is used as a way of maintain low bacteriological load. In the tropical climate, the high temperatures can make the use of this technique difficult, increasing diarrhea occurrence and reducing animal’s performance. During the summer (max. 29°C; min.17.4°C), 44 male and female Holstein newborn calves were used in a randomized blocks experimental design and fed different liquid feed: commercial milk replacer (20.7% CP; 15.5% fat; 12.5% solids); whole milk; and acidified milk. Milk was acidified to a pH of 4.2 with lactic acid, 12–24h before feeding, and kept in room temperature. Animals were individually housed with free access to water and concentrate. Calves were fed 6L/d of liquid diet (2 meals) until weaning at 56 d. Acidified milk resulted in performance and blood metabolites similar to that observed for whole milk, with higher weight gain and lower fecal scores as compared with milk replacer. Acidify whole milk to pH 4.2 is a good alternative to store the milk in high environmental temperatures for feeding dairy calves. Table 1.

	Treatment			SEM	P<1
	Milk replacer	Whole milk	Acidified milk		T	A	T × A
Intake
Concentrate, g/d	245.8	395.2	344,2	63.04	0.095	<0.0001	0.512
Liquid diet, L/d	5,424.8b	5,634.6a	5,624.5a	42.49	0.002	<0.0001	0.01
Fecal score	2.48c	1.79a	1.98b	0.069	<0.0001	<0.0001	0.122
Weight at birth, kg	33.2	32.1	32.0	1.81	0.412	—	—
Weight at weaning, kg	38.5b	48.4a	48.0a	1.67	<0.0001	<0.0001	<0.0001
Weight gain, kg/d	0.234b	0.631a	0.640a	0.0304	<0.0001	<0.0001	<0.0001
Hematocrit,%	19.25b	22.88a	23.59a	0.586	<0.0001	0.023	0.224
Glucose, mg/dL	113.2b	127.6a	119.2b	2.91	0.001	0.0115	0.083
Lactate, mg/dL	10.5	11.1	11.6	0.62	0.4829	<0.0001	0.0256
Protein, g/dL	6.09b	6.62a	6.63a	0.122	0.0017	<0.0001	0.335
BHB, mmol/L	0.112b	0.157a	0.155a	0.0074	0.0002	<0.0001	0.1647

^abcMeans with different letters within a row indicate statistical difference (P < 0.05). ¹T = treatment effect; A = age effect; T × A: Interaction treatment × age effect.