PSXII-15 - Impacts of Forage Maturity and Apple Cider Vinegar Supplementation on Fermentation Parameters Using Ruminal Batch Culture

Abstract: Grassfed dairy production systems often rely on alternative diet supplements such as apple cider vinegar (ACV) to improve productivity. The objectives of this study were to 1) compare rumen fermentative patterns resulting from diets consisting of forages harvested at mature and vegetative stages, and 2) evaluate the effects of ACV supplementation on fermentation metrics of vegetative forage mixtures using ruminal batch culture, performed as two different experiments. In each experiment, treatments were arranged as a randomized design with three periods per experiment. In experiment 1, 15 mL tubes were supplemented with 1.0 g DM of either vegetative 50% red clover + 50% orchardgrass (VEG) or mature 50% red clover + 50% orchardgrass (MAT). Tubes were inoculated with a 3:1 buffer: rumen fluid mixture (12 mL) and incubated at 39ºC under anerobic conditions for 48 h. In experiment 2, tubes received either 1.0 g DM VEG substrate only or 1.0 g DM VEG substrate + 0.125 mL ACV. Samples were collected at 0, 1, 2, 4, 6, 8, 12, 18, 24, and 48 h, pooled, and analyzed for carbohydrates (WSC), pH, in vitro DM disappearance (IVDMD), methane (CH₄), and ammonia N (NH₃-N). Data were analyzed using PROC GLIMMIX of SAS at P ≤ 0.05. The VEG treatment produced more CH₄ than the MAT treatment (4.98 mg/ dL v. 2.87 mg/ dL; P</em> < 0.0001); however, CH₄ from the VEG treatment was not affected by ACV. Tubes receiving VEG had greater WSC (2.39 mg/mL v. 1.56 mg/mL; P ≤ 0.05), IVDMD (81.7% v. 77.3%; P ≤ 0.05), and mean pH compared with those receiving MAT. Tubes receiving MAT had greater concentrations of NH₃-N (P < 0.01) compared with tubes receiving VEG. Fermentation metrics of VEG tubes were not affected by ACV; however, considerations need to be made for forage maturity.