This research aims to evaluate urea plasma responses under different lipid sources and supplementation frequencies. The experiment was conducted throughout a 4-mo period during the dry season. The experiment was completely random, using a 3 × 2 factorial arrangement (3 supplements and 2 supplementation frequencies). The supplements were derived from 3 different sources, soybean grains, soybean oil and protected fat (Megalac-E), the 2 supplement frequencies were (D) daily or 3 d of week (Monday, Wednesday and Friday) called “alternate” (A). In the 4-mo experimental period, August–November, blood samples were taken from the jugular vein 4 h after the morning feeding. In all treatments, no creatinine levels differences were observed during August, October and November (P > 0.05). However, on September were observed lower values of creatinine for Megalac-E daily and soybean oil alternately supplied. Therefore, the highest creatinine plama levels observed for all treatments were on September and the lower showed on November. Overall, these data indicated that the creatinine plama level can be influenced according to the feeding strategy during the dry season. Table 1. Plasma creatinine concentration of heifers supplemented with different lipid sources at two different frequencies (mg/dL) ¹

	D-SG	A-SG	D-SO	A-SO	D-ML	A-ML
August	1.2A,b	1.2A,b	1.0A,b	1.1A,bc	1.2A,b	1.3A,b
September	2.8A,a	2.8A,a	2.6A,a	2.2B,a	2.4AB,a	2.6A,a
October	1.1A,b	1.4A,b	1.2A,b	1.4A,b	1.1A,b	1.3A,b
November	0.7A,c	0.8A,c	1.0A,b	0.8A,c	0.8A,b	0.8A,b

^a–c,A,BMeans with lowercase superscripts in columns and uppercase superscripts in rows differ (P < 0.05). ¹D = daily; A = alternately; SG = soybean; SO = soy oil, and ML = Megalac-E.