Mary E. Drewnoski
Date of this Version
Conway, A. C. 2019. Selective harvest methods and chemical treatment of baled corn residue for utilization in growing calf and dry cow diets. Ph.D. Dissertation. University of Nebraska-Lincoln.
Three studies were conducted to evaluate baled corn residue using selective harvest method and anhydrous ammonia treatments to assess utility in growing calf and dry cow diets. Baled corn residue was harvested using conventional rake-and-bale (CONV) method, or harvested using the New Holland Cornrower in which either eight rows (8ROW), or two rows (2ROW) of corn stalks were chopped into the windrow with tailings. Bales were either not treated or ammoniated at 5.5% DM. When fed to wether lambs in a mixed ration (65% residue, 30% wet corn gluten feed) to determine digestibility, the 2ROW residue had greater apparent DM, NDF, ADF digestibility, as well as in vitro DM and OM digestibility than either CONV and 8ROW, which were not different. Ammoniation resulted in a 20 to 26% increase in apparent DM, OM, NDF, and ADF digestibility and digestible energy content of the residue. When corn residue was baled as CONV, 2ROW, or using the EZ-Bale system (EZB) with a disengaged combine spreader (treated or ammoniated at 3.7% DM) and fed to growing cattle (65% with 30% wet distillers grains), only the 2ROW method increased (P < 0.01) ADG (1.06 kg/d) compared to CONV (0.96 kg/d) and EZB (0.99 kg/d). Ammoniation increased (P < 0.01) ADG from 0.75 to 1.26 kg/d and increased (P < 0.01) G:F from 0.158 to 0.179. Selective harvest methods altered (P ≤ 0.01) plant part proportions, and ammoniation differentially increased the digestibility among the various plant parts. A third study used the same treatments fed as whole bales to dry cows and measured intake, waste, and refusals. Ammoniation increased (P < 0.01) DM intake by 18% and waste including refusals ranged between 29.3 and 42.3% of offered DM. Ammoniated residues had sufficient CP to meet cow protein requirements throughout gestation, but only the ammoniated 2ROW and EZB residue had enough DOM to meet gestation energy requirements. Ammoniated corn residue increases digestibility and improves animal performance, and these effects can be enhanced when combined with some selective harvest methods due to changes in plant part proportion and increased susceptibility of cob to ammoniation.
Advisor: Mary E. Drewnoski