Fermentation characteristics and feeding value of ensiled wet corn distillers grains in combination with wet beet pulp for lactating dairy cows

Two experiments were conducted to evaluate (1) fermentation characteristics of ensiled wet corn distillers grains with solubles (WDG) and wet beet pulp (WBP) and (2) feeding value of ensiled blends of WDG and WBP in lactating dairy cow diets. On an as-fed basis, the ratio of ensiling for WDG:WBP was (1) 100:0 (DG100), (2) 67:33 (DG67), (3) 33:67 (DG33), and (4) 0:100 (DG0), respectively. Feedstuffs were ensiled and sampled at d 0, 4, 8, 21, and 112. Initial pH was lowest for DG100 and increased as the WBP was included. Low initial pH and increased acetic acid concentration with decreasing lactic acid concentration may have helped preserve both feedstuffs and their blends. Lactic acid was the predominant organic acid for DG100, and acetic acid was predominant at d 112 for the other 3 treatments. A feeding study followed the ensiling study. Nine cows (92 ± 4 DIM; mean ± SD) were used in a replicated 3 × 3 Latin square design. They were fed the (1) control diet; (2) low WDG diet with 21.7% DG33 blend (DM basis); and (3) high WDG diet with 24.6% DG67 blend (DM basis). There was no effect of diet on DMI. Milk yield was greater for cows fed WDG diets compared with cows fed the control diet; however, there was no effect of diet on energy-corrected milk. Milk fat concentration decreased for cows fed WDG diets compared with control diet; however, milk fat yield was not affected by diet. Cows fed WDG diets tended to produce milk with greater milk protein concentration and yield compared with cows fed the control diet, but there was no difference between WDG diets. Results provide evidence that ensiling WDG and WBP to preserve each wet by-product was possible and that ensiled blends could be incorporated in diets of lactating dairy cows to increase milk production and milk protein yield.