332 Evaluating the Effects of Lactic Acid Adaptation in Beef Cattle Prior to an Acidosis Challenge

Abstract

Abstract The objective was to determine if a 7-day lactic acid adaptation in cannulated steers affected ruminal fermentation during an acidosis challenge. Steers (n=18; 790 ± 68 kg) were assigned to one of two treatments: control (CON) 500 mL of H2O or 1 mM DL-Lactic acid solution per kg steer BW (LAC). Steers were dosed with treatments via the cannula prior to feeding for seven days during the adaptation period. The adaptation diet consisted of 25% corn silage, 30% grass hay, 15% dry distillers grains, 25% dry rolled corn, 5% molasses and 10% supplement. To induce acidosis, steers were fasted for 24 hours and subsequently fed a high concentrate diet consisting of 15% corn silage, 15% dry distillers grains, 55% high moisture corn, 5% molasses, 10% supplement. Rumen fluid was collected throughout the acidosis challenge to measure fermentation characteristics including rumen pH, redox, ammonia, volatile fatty acids, and lactic acid. Data were analyzed using the MIXED procedure of SAS 9.4 with a repeated measures analysis. Dry matter intake was not affected (P ≥ 0.65) by treatment before or after the acidosis challenge. A treatment × time interaction was not observed (P = 0.83) for ruminal pH, but pH was affected (P < 0.01) by time and remained between 5.6 and 5.0 for about 14 hours during the challenge. A treatment × hour interaction tended (P = 0.08) to be observed for lactate; LAC had a greater concentration than CON at hour 14 during the challenge. However, a treatment × hour interaction was not detected (P ≥ 0.38) for ammonia, volatile fatty acids, fecal pH and redox potential. In conclusion, these results indicate that a 7-day lactic acid adaption at 1 mM per kg BW did not affect ruminal fermentation characteristics during an acidosis challenge.