Influence of isobutyric acid supplementation on nutrient intake, its utilization, blood metabolites and growth performance of crossbred calves fed wheat straw based low protein diets

The effects of dietary supplementation with the sodium salt of isobutyric acid in a low protein (10% CP) wheat straw based diet on nutrient utilization, blood metabolites and growth performance were studied with male crossbred calves. The calves were divided into two equal groups of 6 each. The animals of the control group were fed a basal diet consisting of wheal straw, concentrate mixture and green oat fodder in 40:40:20 proportion whereas BCFA supplemented group received the basal diet+isobutyric acid at 0.75 percent of basal diet. The duration of study was 120 days. The feed intake between experimental groups did not differ significantly and the average total DMI (ro BW) was 1.99 and 1.95 kg day(-1) in control and BCFA supplemented diets. The dietary supplementation of BCFA improved (p<0.01) the DM, OM, CP (p<0.05), NDF and cellulose digestibilities by 8.50, 9.01, 5.39, 17.78 and 18.44 per cent over those fed control diet. The total N retention on BCFA supplementation was improved (p<0.01) due to the decreased (p<0.05) faecal N excretion. The BCFA supplementation did not alter the blood circulatory levels of glucose, total protein, albumin, urea N and amino acids. However after 120 days of experimental feeding a significant (p<0.05) increase in the concentrations of non-esterified fatty acid was observed in control group. The DCP intake and the DCP content of experimental diets was similar in both groups. However, the TDN content of BCFA supplemented diet was significantly (p<0.01) higher (64.35%) than that of control (59.60%). The total live weight gain in BCFA supplemented diet increased by 15.94% over control. The average daily gain and efficiency of feed conversion were also improved in BCFA fed calves by 13.38 and 26.71% respectively, compared to control. It is concluded that dietary supplementation with isobutyric acid improved the digestibility of nutrients and growth performance of carves.