Calcium, Phosphorus, and Micro Minerals Supplementation Does Not Affect Nutrient Intake and Digestibility, and Performance of Nellore Cattle Fed Different Diets

Phosphorus supplementation is commonly reported as unnecessary for beef cattle in feedlots. However, the impact of absence of other macro and microminerals for beef cattle is not frequently reported in literature. The objectives of this study were measure the effects of mineral supplementation on nutrient intake and digestibility, and performance of Nellore beef cattle fed with and without calcium (Ca), phosphorus (P) and micromineral (MM) supplemental sources during the growing and finishing phases. Forty-two Nellore beef cattle (initial BW = 270.4 ± 36.6 kg, age = 8 months) were assigned to one of 6 treatments, aimed to have different Ca:P ratios: Sugarcane (400 g/kg DM) and a soybean meal and soybean hull-based concentrate with (SH100) and without (SH0) Ca, P and MM supplementation; Sugarcane (400 g/kg DM) and a soybean meal and ground corn based concentrate with (SC100) and without (SC0) Ca, P and MM supplementation; and corn silage (600 g/kg DM) with a soybean meal and corn-based concentrate with (CS100) and without (CS0) Ca, P and MM supplementation. The experiment was conducted as a completely randomized design with a 3 × 2 factorial arrangement of treatments. Nutrient intake, digestibility and performance were not affected by mineral factor (P > 0.10). Dietary effects were observed (P < 0.01) for DM, OM, CP and NDF digestibilities. Sugarcane based diets presented a greater DM and OM digestibility coefficients. It could be related to greater amounts of concentrate in these diets. Neutral detergent fiber presented a reduced digestibility in diets where sugarcane was forage source and the concentrate was ground corn-soybean hulls based. This smaller coefficient may be a consequence of the proportion of indigestible NDF in relationship to dietary NDF. Regarding CP digestibility coefficient, corn silage based diets presented a smaller coefficient than sugarcane based diets. It could be explained by smaller amount of urea in CS diets, and consequently smaller amounts of RDP. Among sugarcane based treatments, SH diets presented greater CP digestibility coefficients than SC diets. With regard to productive performance and efficiency parameters measured, average daily gain, and empty body weight gain, hot and cold carcass yield, carcass length, rib eye area, and subcutaneous fat thickness were not affected (P > 0.10) by treatments. The absence of inorganic supplemental sources of Ca, P, Cu, Mn, Zn and Co in diets for Nellore beef cattle during both the growing and finishing phases does not affect nutrient intake, digestibility and performance.