|RANATHUNGA, SANJEEWA - South Dakota State University|
|GARCIA, ALVARO - South Dakota State University|
|SCHINGOETHE, DAVID - South Dakota State University|
Submitted to: Professional Animal Scientist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/22/2018
Publication Date: 8/1/2018
Citation: Ranathunga, S.D., Kalscheur, K., Garcia, A.D., Schingoethe, D.J. 2018. Fermentation characteristics and feeding value of ensiled wet corn distillers grains in combination with wet beet pulp. Professional Animal Scientist. 34(4):346-355. https://doi.org/10.15232/pas.2018-01727.
Interpretive Summary: Non-forage fiber sources can partially replace conventional forages in dairy rations to lower feed costs or during times when forages are limiting. Both wet distillers grains and wet beet pulp are by-products of agricultural processing. Both can be effective non-forage fiber sources in cow diets, however storage of wet co-products can be challenging. This experiment evaluated the effectiveness of ensiling wet distillers grains with wet beet pulp in different ratios, and then it evaluated the ensiled blends as a substitute for forage in lactating dairy cow diets. Ensiling is an effective method of preserving wet distillers grains and wet beet pulp both alone or blended together. The low initial pH for all treatments and increased acetic acid over time suggested that preservation was enhanced by ensiling the two feeds together. Blends of wet distillers grains and wet beet pulp fed in dairy cow diets as a substitution for alfalfa haylage increased milk production and milk protein yield. Although milk fat percentage was reduced for the ensiled blends, milk fat production was the same. This research demonstrated that ensiled wet distillers grains and wet beet pulp as a source of nonforage fiber is an effective alternative feedstuff for lactating dairy cow diets when forages are limiting.
Technical Abstract: Two experiments were conducted to evaluate the fermentation characteristics of ensiled wet corn distillers grains (WDG) alone or with wet beet pulp (WBP). The feeding value of the ensiled blends as a non-forage fiber source in substitution for forage fiber in lactating dairy cow diets was also evaluated. Combination of WDG and WBP were ensiled during the first experiment as follows: 1) 100:0 of WDG:WBP (DG100), 2) 67:33 of WDG:WBP (DG67), 3) 33:67 of WDG:WBP (DG33), and 4) 0:100 of WDG:WBP (DG0). Samples were collected at days 0, 4, 8, 21 and 112 for analysis. The initial pH was lowest for DG100 and increased (P<0.05) as concentration of WDG decreased. Dry matter of the feedstuffs prior to ensiling was 330, 302, 265, and 231 g/kg for 100DG, DG67, DG33, and DG0, respectively. Lactic acid prior to ensiling was greatest for DG100 and decreased as WBP was included in the treatments. Acetic acid prior to ensiling was highest for DG0 and decreased with progressive inclusion of WDG in the treatments. Acetic acid increased over time in all treatments, and was highest for the DG0. The low initial pH for all treatments and the increased acetic acid over time, suggested preservation of both feeds was enhanced by ensiling them together. In the second experiment, nine cows with 92 ± 4 DIM were used in a 3×3 Latin square with 3-wk feeding periods. Experimental diets were: 1) control diet which contained 99 and 255 g/kg of DM of corn silage and alfalfa hay with 172 g/kg DM alfalfa haylage; 2) treatment 1 (HWDG) which contained 106 and 273 g/kg of DM of corn silage and alfalfa hay with 246 g/kg DM of a DG67 blend substituted alfalfa haylage and 3) treatment 2 (LWDG) which contained 99 and 255 g/kg of DM of corn silage and alfalfa hay with 217 g/kg DM of a DG33 blend substituted alfalfa haylage. Dry matter intake (24.7 kg/d) was similar for all diets. Cows fed HWDG and LWDG produced more milk (39.2 and 38.0 vs 35.7 kg/d) when compared to control. Milk fat percentage decreased for cows fed HWDG and LWDG compared to control (31.0 and 31.1 vs. 36.0 g/kg), however milk fat yield did not differ among treatments. Cows fed HWDG and LWDG tended to have higher milk protein concentration compared to control (32.4 and 32.8 vs. 31.8 g/kg). Also, milk protein yields were higher (1.2 and 1.3 vs. 1.1 kg/d) for cows fed HWDG and LWDG. These results suggest that blends of WDG and WBP can substitute for alfalfa haylage in dairy cow diets while increasing total milk production and milk protein yield.