The aim of this study was to evaluate the effects on dry matter intake (DMI), daily gain (DG), feed efficiency (FE) and rumen fermentation of including fresh alfalfa (FA) on a restricted TMR diet of finishing steers. Twenty steers (8 with 8-mm ruminal catheters), fed a TMR diet (ground corn grain, soybean meal, pasture hay, mineral-vitamin concentrate and Anavrin; 65% DM, 12.8% CP, 23% NDF) were blocked by BW and distributed in 2 feeding treatments (n=10/treatment): 1) TMR offered at a level of 2.8% of BW (DM basis): ‘TMR’ or 2) TMR offered at a level of 1.7% of BW (DM basis) plus FA (22.1% DM, 14.5% CP, 50.3% NDF) offered in an unlimited quantity: ‘PMR+FF’. The experiment lasted 60 d, and steers were weighed every 12 d, for 2 consecutive days each time. DMI was individually measured 3 times for 5 consecutive days, beginning days 20, 34 and 48 days, by difference offered-refused for each feedstuff. Ruminal pH, N-NH3 and volatile fatty acids (VFA) were measured on days 19, 33 and 47, at 0930, 1300, 1500, 1700, 1900, 2100, 0300 and 0930 h. The inclusion of fresh forage resulted in 40% of the total DMI, with no differences on intake (Table 1). However, in the PMR+FF treatment DG and FE tended to be reduced, possibly due to a reduced energy ingestion, considering the fiber content of FA and TMR. As expected, the inclusion of FA in the diet increased pH and acetate, and reduced propionate ruminal percentage, resulting in triplicated acetic/propionate rate. Overall, the inclusion of fresh alfalfa in the diet increased ruminal pH and acetic/propionate rate without affecting DMI. Including fresh alfalfa in finishing steers’ diet could have positive implications on feed costs and meat composition without negatively affecting productivity, but more studies are needed.

The objective of this was to evaluate the effects on dry matter consumption (DMI), daily gain (DG), feed efficiency (FE) and rumen fermentation of including monensin or an additive composed of essential oils, flavonoids and tannins. (Anavrin) in the diet of fattening steers, studying possible associative effects between them. Thirty steers (12 with 8 mm rumen probes), feeders with TMR diet (ground corn, soybean meal, grass hay, mineral-vitamin concentrate; 65% MS, 12.8% PB, 23% FDN), offer 2.8% of your PC (MS base), were blocked by PC and distributed in 3 treatments (n=10/treatment), adding to the basal diet: 1) 0.033 g of monesin/kg TMR offered: MON', 2) 0.35 g of Anavrin/100 kg BW: 'Anavrin' or 3) both included each at the same dose of 1 and 2 treatments: 'Anavrin® +MON'. The experiment lasted 60 d, and the steers were weighed every 12 d, for 2 consecutive days each time. The DMI was measured individually 3 times over 5 consecutive days, starting on days 20, 34 and 48, by difference offered-rejected for each food. Rumen pH, N-NH 3 and volatile fatty acids (VFA) were measured on days 19, 33 and 47, at 9:30; 13:00; 15:00; 17:00; 19:00; 21;00; 3:00 and 9:30h. Productive behavior (GR and FE) was similar for all treatments, and rumen fermentation was similar for Anavrin and MON. Adding a combination of both additives (Anavrin+MON) leads to a lower DI with respect to Anavrin alone, a lower butyrate concentration than monensin alone, showing associative effects. The percentage of propionic tended to be higher when the combination was added, which should lead to lower methane emissions. Overall, the use of Anavrin led to results similar to those of monensin.