PSIII-16 - Effects of dietary corn origin (U.S., Argentina, and Brazil) on pig growth performance

Abstract: Corn is an important global commodity. Understanding its nutritional value and practically utilizing different corn sources and varieties in swine diets is important to U.S. corn and swine production. Globally, the U.S. “dent” corn variety is presumed to be of lesser quality when compared to “harder” flint-type corn (the preferred varieties in Argentina and Brazil) due to differences in whole kernel structure when shipped long distances. In fact, official work from the US Grains Council indicates that US corn produces more ethanol per bushel when compared to flint-type varieties of corn. This indicates a higher level of starch in US corn and increased starch content should mean a higher level of energy and nutrients. Therefore, swine producers globally benefit from understanding the feeding value of different varieties and origins of corn. The objective of this study was to assess the performance of pigs fed corn from three exporting countries: U.S., Argentina (ARG), and Brazil (BRZ). Two similar studies were conducted comparing the effect of 3 corn sources on late nursery pig growth performance. Study 1 used 96 nursery pigs (8.8 +/- 1.7 kg) split between 24 pens and study 2 used 114 nursery pigs (8.0 +/- 1.3 kg) split between 24 pens. Three experimental diets were formulated with corn sources from: 1) U.S.; 2) ARG; and, 3) BRZ. The U.S. corn diet was considered the control diet and was balanced to meet or exceed all nutrient requirements for the pigs. The U.S. corn was replaced with ARG corn and BRZ corn on a lb for lb basis in the diets. Pigs were assigned in a randomized block design based on initial body weights (BW) and sex. Feed and water were offered ad libitum over a 28-day period, pig BW and feed disappearance were measured each week. Average daily gain (ADG), average daily feed intake (ADFI), and feed efficiency (G:F) were determined after weeks 1, 2, and 4. Performance data was analyzed using PROC MIXED procedure in SAS considering dietary treatment as a main effect and pen as experimental unit. There were no significant differences (P > 0.05) in BW, ADFI, ADG, and feed efficiency between the three corn sources throughout all weeks and the overall 28 days. Overall performance values for the three treatments were: US corn ADG (0.66 kg), ADFI (0.91 kg), and G:F (0.72): Argentina corn, ADG (0.65 kg), ADFI (0.92), and G:F (0.70); and Brazil corn, ADG (0.65), ADFI (0.92), and G:F (0.71). In conclusion, the value of US corn is similar in nutrient content and nutritional quality as demonstrated by equivalent performance in nursery pigs. The aesthetics of whole kernels are not indicative of feeding value to swine.