Boletim de Indústria Animal (Jul 2017)
Monensin sodium and functional oil as additive in protein-energy supplement for pasture-fed heifers
Abstract
The use of functional oil as an additive is a potential alternative to replace inorganic antimicrobial agents. The objective of this study was to evaluate the effect of adding functional oil consisting of cashew and castor oil or monensin sodium to protein-energy supplement on the performance of 14-month-old Nellore x Red Angus heifers (initial mean body weight [BW] of 246 kg) raised on Tifton 85 pasture. The animals were randomly assigned to four treatments: 1) control (no supplementation); 2) addition of 2 g functional oil/animal/day, composed of 70% cashew oil and 30% castor oil; 3) addition of 4 g functional oil/animal/day, composed of 70% cashew oil and 30% castor oil, and 4) addition of 0.2 g monensin sodium/animal/day. The biomass availability and forage on offer were 5,940 kg dry matter/ha and 7.0 kg dry matter/100 kg BW/day, respectively. The average proportion of leaf blade, sheath plus stem and senescent material was 17.6%, 55.0% and 27.4%, respectively. The mean whole-plant contents of crude protein, neutral detergent fiber and in vitro dry matter digestibility were 8.5%, 72.3% and 42.7%, respectively. A significant effect was observed for average daily gain of heifers receiving monensin (0.576 g/day) compared to those that did not receive the protein-energy supplement (0.290 g/day). In contrast, the supplement containing the functional oil composed of cashew and castor oil provided weight gains (0.426 g/day) similar (P>0.05) to that of the supplement with monensin (0.576 g/days). Under the conditions of this experiment, only the supplement with monensin resulted in a higher average daily gain than that observed for unsupplemented animals (control), while animals fed the supplement with functional oil composed of cashew and castor oil (2 or 4 g/animal/day) did not exhibit differences in daily gain when compared to the other supplements.
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