Economic evaluation of several commercial compounded concentrates as supplements for growing crossbred heifers in confinement

To evaluate three different supplements in terms of body growth and economic benefit, 21 crossbred heifers of initial body weight (BW) 198.4 ± 49.5 kg (yearlings) and 280.4 ± 19.3 kg (older animals) were assigned to three balanced groups for use in an 84-d experiment, conducted in a tropical dry forest climatic zone. The individually penned animals received water and fresh gramineous forage cut daily ad libitum; also, a daily supplement of 2 kg of one of the three commercial concentrates: (T0, T1, and T2) of respective percentage composition (CP 19.2, 14.5, and 16.2; Ca 1.83, 3.59, and 1.81; P 1.75, 1.52, and 1.77). Wither height was measured forthnightly and BW, supplement intake (SI) and forage intake (FI) were determined weekly. Data were analyzed according to a completely randomized experimental design, with repeated observations, and Tukey HSD test. Economic evaluation was based on the criteria partial budget and gross margin, in which three animal selling prices (7.1, 40, and 70 Bs/kg BW) were tested. Daily BW gain (mean 0.52 kg) did not differ (P > 0.05) among treatments. SI was complete in all three treatments. FI also showed no treatment effects with respective means of 11.22, 11.28, and 11.26 kg/d as fed. Economic evaluation revealed that the best biological performance does not always coincide with the greatest economic benefit and that selection of the most favorable supplement depends on the animal selling price. When the latter was six times the cost of the supplement (kg/kg) supplementation was profitable.