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Agricultural and Biosystems Engineering, Animal Science

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Journal of Animal Science





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Historically high temperatures and low rainfall during the 2012 growing season resulted in drought-stressed conditions in much of the U.S. corn belt. The objective of this experiment was to investigate the impact of these conditions on the composition and energy content in corn and determine if relationships exist among corn quality measurements, chemical composition, and digestibility of energy. Twenty-eight samples of corn from the 2012 drought-stressed crop (DS), plus 2 samples from the 2011 crop to serve as controls (CNTRL), were collected in Iowa and Illinois using yield as an initial screen for drought impact. Yields ranged from 2.5 to 14.8 t/ha. Each sample was graded by an official of the U.S. grain inspection agency and analyzed for 1,000 kernel weight, kernel density, ether extract, starch, GE, NDF, and CP content. Diets were formulated using each of the 30 corn samples and were fed at 2.6 times the estimated maintenance energy requirement according to the NRC (2012). Sixty individually-housed barrows (PIC 359 X C29; initial BW = 34.2 ± 0.2 kg) were randomly allotted in an incomplete crossover design to 30 diets across 4 periods. Diet and fecal samples were analyzed in order to determine DE values. Both ME and NE values were then calculated from DE values using methods developed by Le Goff and Noblet (2001) and Noblet et al. (1994) respectively. Mean DE, ME, and NE values between the CNTRL and DS samples were not different (3.72 vs. 3.68 Mcal/kg respectively; 3.66 vs. 3.62 Mcal/kg respectively; and 2.92 vs 2.87 Mcal/kg respectively; P> 0.10). Comparing CNTRL with DS, there were no differences (P > 0.10) in ether extract (EE) (4.07% vs 3.96%), CP (8.56 vs 9.18%), or starch (70.5 vs 69.5%). However, ADF and NDF were higher in the DS samples (2.23 and 8.19%) when compared to CNTRL (1.89 and 6.92%); P < 0.001 and P = 0.015, respectively. Small but significant correlations were observed between DE and NDF (r = -0.51; P = 0.008), kernel density (r = 0.51; P = 0.007) and % damaged kernels (r = 0.41; P = 0.031). No statistically significant correlations were observed between DE and starch, or ADF content, nor between DE and test weight. We can conclude that corn grown in droughtstressed conditions has similar energy content to corn grown under more favorable conditions, and therefore can be successfully utilized in swine diets. Furthermore, NDF proved to be superior to fat, starch, and ADF content in explaining the variation in corn energy content.


This is a manuscript of an article published as Newman, M. A., C. R. Hurburgh, and J. F. Patience. "Defining the physical properties of corn grown under drought-stressed conditions and the associated energy and nutrient content for swine." Journal of animal science 94, no. 7 (2016): 2843-2850. doi:10.2527/jas.2015-0158. Posted with permission.

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American Society of Animal Science



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