Steers fed the SmartLic NE-Mag 12 blocks consumed an average of 1.03 pounds of block per head daily. Hay consumption was not impacted by feeding either type of magnesium supplement, but dry matter digestibility was slightly higher with MAGOX compared to the CONTROL, and about 6% greater for steers fed the NE-Mag 12 block compared to CONTROL. (See figure 1.)
Total magnesium intake was tripled by feeding either type of supplement (19 grams/day for controls compared to 59 grams/day for supplemented groups). Availability of the magnesium from either supplement was above 50%. Urinary excretion of magnesium was substantially greater for cattle fed the MAGOX treatment than for the NE-Mag 12 block or the CONTROL treatment. Additionally, urinary excretion of magnesium was more erratic for cattle fed the MAGOX supplement compared to cattle consuming identical levels in the form of a block.
Blood plasma concentrations of magnesium were significantly higher for cattle fed the NE-Mag 12 block in comparison to CONTROL, and were intermediate when cattle were fed the MAGOX treatment. (See figure 2.)
Higher plasma concentrations of magnesium combined with lower urinary output and comparable fecal outputs of magnesium suggest that magnesium oxide is utilized more effectively when incorporated into SmartLic NE-Mag 12 blocks in comparison to feeding in a dry meal supplement. (See figure 3.) This is attributed to the fact that cattle consume blocks throughout the day, delivering small but uniform increments of essential nutrients. Alternatively, meal supplements tend to be consumed in a relatively short period of time, thereby causing nutrients to be excreted through the urine when they are present in excess.