Anant Vichurungsai, Wanwisa Ngampongsai, Saowanit Kuprasert, and Surasuk Kochapakdee

pp. 1499 - 1509

Abstract

       The effect of levels of concentrate supplementation on nutrient utilization and nitrogen balance of Thai native cows in mid-pregnancy was studied. Four mid-pregnant (4-6 months) Thai native cows, 4-4.5 years old with average body weight (BW) of 238±23 kg were arranged in a 4 x 4 Latin square design. The cows were fed plicatulum hay ad libitum and supplemented with concentrate (13.74% crude protein, CP) at 0.25, 0.50, 0.75 and 1% of BW, respectively. The highest total dry matter (DM), organic matter (OM) and CP intake (80.28, 73.19 and 6.30 g/kgBW^0.75/d, respectively) was obtained for cows supplemented with concentrate at 1% of BW and these values were linearly increased (P<0.01) as the levels of concentrate increased. Neutral detergent fiber (NDF) and acid detergent fiber (ADF) intake for cows supplemented with concentrate at 1% of BW (44.10 and 25.83 g/kgBW^0.75/d, respectively) and 0.75% of BW (43.15 and 25.61 g/kg BW^0.75/d, respectively) were not significantly different (P>0.05) but these values were significantly different (P<0.05) from those for cows supplemented with concentrate at 0.25% of BW (31.90 and 19.39 g/kgBW^0.75/d, respectively) and 0.50% of BW (38.87 and 23.33 g/kgBW^0.75/d, respectively). Digestion coefficients of DM, OM, CP and total digestible nutrient (TDN) for cows supplemented with concentrate at 1% of BW (57.50, 60.13, 54.23 and 56.78%, respectively) were significantly higher (P<0.05) than those for cows supplemented with other levels of concentrate. However, effect of levels of concentrate supplementation were not significantly different (P>0.05) for digestion coefficients of crude fiber. Digestible CP and TDN intake for cows supplemented with concentrate at 0.75% of BW (62.34 g/%BW/d and 1.06 kg/%BW/d, respectively) and 1%
of BW (86.91 g/%BW/d and 1.19 kg/%BW/d, respectively) were optimal when compared with the digestible CP and TDN requirement of cows in mid pregnancy. Increasing levels of concentrate supplementation linearly (P<0.001) increased nitrogen balance of the cows and significant differences (P<0.05) were found among the levels of supplementation (0.00, 0.09, 0.22 and 0.33 g/kgBW^0.75/d at 0.25, 0.50, 0.75 and 1% of BW, respectively). The highest metabolizable energy (ME) intake was found for cows supplemented with concentrate at 1% of BW (3.74 Mcal/%BW/d) and this value was linearly increased (P<0.01) as the levels of concentrate increased.
         The findings of this study suggested that Thai native cows in mid-pregnancy fed plicatulum hay as basal roughage obtained the optimal CP and energy when they were supplemented with concentrate at 0.75%
of BW.