Plasma urea concentration of beef heifers fed with different lipid sources and frequency supplementation

Abstract Text: 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 days 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 four hour after the morning feeding. Subsequently, these samples were centrifuged and stored until the urea blood level was evaluated.  In all treatments, no urea levels differences were observed in August and September (P> 0.05). The Megalac–E that was supplied daily presented a higher urea plasma level in comparison to the alternate supplement of soybean oil in October (P< 0.05).The animals that were given soybean oil supplements daily showed lower urea plasma concentration values (P< 0.05) in November by treatments and periods. Overall, this data indicated that the urea blood level can be influenced according  to the feeding strategy during the dry season.

Keywords: soybean grains, soybean oil, protect fat.

Plasma urea concentration of heifers supplemented with different lipid sources at two different frequencies (mg/dL)

D-SG A-SG D-SO A-SO D-ML A-ML August 27,5 Aa 26.8 Aa 27.6Aa 26.7 Aa 27.8 Aa 26.2 Aa September 21,1 Aa 21.1 Aa 29.9 Aa 21.6 Aa 26.1  Aa 28.6 Aa October 24,8 ABa 23.0 ABa 28.9 ABa 17.9 Ba 32.3 Aa 25.0 ABa November 24.4 ABa 28.0 Aa 13.5 Bb 23.5  ABa 21.9  ABa 22.3 ABa

Lowercase in columns and capital letters in rows differ (P< 0.05).  

D=daily; A=alternately; SG=Soybean grain; SO=Soybean oil; ML=Megalac-E