A response of nutrient utilization, digestibility and daily weight gain of crossbred cattle (Black Angus x Zebu) from 13-15 months of age to dietary concentrate supplemention
A Latin square design experiment of concentrate supplementation with 5 treatments and 5 cattle (Black Angus ´ Zebu) of 223±16.7 kg aiming to find the optimum nutrient utilization and daily weight gain (DWG) was conducted. The experiment was carried out at Sau Duc cattle farm, which was located at Vinh Gia commune, Tri Ton district of An Giang province and the laboratory E205 of Department of Animal Science, College of Argiculture of Can Tho University from December 2018 to April 2019. The treatments were 0, 0.5, 1.0, 1.5 and 2.0 kg concentrate supplemented per head per day corresponding to C0, C0.5, C1.0, C1.5 and C2.0 treatments. One experimental period lasted 14 days with 7 days for adaptation and 7 days for sampling. Fresh elephant grass was fed at the fixed level of 5 kg/head/day (in fresh), while rice straw was fed ad libitum for all treatments. The results showed that total DM intake was significantly different (P<0.05) among treatments with the higher values for the concentrated suppmentation treatments. The ME intake of C2.0 treatment (52.0 MJ/head/day) was slightly higher (P>0.05) than that of C1.5 treatment (49.2 MJ/head/day) but it was significantly higher (P<0.05) compare to C1.0, C0.5 and C0 treatments (43.4, 39.2 and 34.6 MJ/head/day, respectively). DM and OM digestibility (%) were significantly different (P<0.05) among the treatments with the highest values for the C2.0 treatment. It was also showed that when increasing the level of concentrate supplementation, it improved the CP digestibility from 54.1% to 71.9%. Daily weight gain of experimental cattle was significantly different (P<0.05) among treatments and it was 153, 292, 438, 536 and 557 g/day for the C0, C0.5, C1.0, C1.5 and C2.0 treatments. The feed cost (VND per day) for experimental cattle increased by increasing supplemental levels of concentrate, however the feed cost per kgDWG was lower for the C1.0 and C1.5 treatments (38.4 and 38.2 thousand VND/kg, respectively). The conclusion was that increasing concentrate levels in beef cattle diets from 0 to 2.0 kg was gradually improved nutrient intake, digestibility and daily weight gain. For the beef crossbred cattle (Black Angus ´ Zebu), concentrate supplementation level from 1.0 to 1.5 kg per day in diets could be properly recommended for farmers’ practice in term of feed utilization and economic return.
