EVALUATION OF ALPHA AMYLASE CONTAINING CORN ON FINISHING CATTLE PERFORMANCE AND DIGESTIBILTY

One digestion and four finishing trials were conducted to evaluate the effect of a new corn hybrid containing an α-amylase trait, Syngenta Enogen Feed Corn (SYT-EFC) on site and extent of digestion, ruminal fermentation parameters, and feedlot performance. Experiments utilized corn containing the enzymatic gene compared to controls, the near isoline parental corn (NEG) or commercially available corn grain (CON), processed as dry-rolled corn (DRC) or high moisture corn (HMC) in diets with dry [distillers grains plus solubles (DGS)] or wet (Sweet Bran) milling byproducts. The corn grain of the experimental diets were fed as the sole grain source, comprising 100% of the concentrate in the diet. Cattle fed SYT-EFC, processed as DRC with Sweet Bran had increased G:F resulting in feeding values ranging from 103 to 116% of CON or NEG. Steers fed SYT-EFC, processed as DRC with DGS had increased G:F resulting in feeding values ranging from 101 to 107% of CON or 105% of NEG. However, when processed as HMC, feeding SYT-EFC resulted in 96 and 102% that of NEG when fed with Sweet Bran or DGS, respectively. Marbling and 12th rib fat thickness data were mixed among trials with being increased in cattle fed SYT-EFC or observing no detectable difference among treatments. Cattle fed SYT-EFC had greater postruminal starch digestibility compared to NEG resulting in a 2.2 and 6.3% increase in total tract starch digestibility in DGS and Sweet Bran diets, respectively. Overall, feeding corn containing an α-amylase trait as DRC would suggest a slight improvement in feed efficiency. Advisors: James C. MacDonald and Galen E. Erickso

Effects of Field Pea Supplementation on Digestibility and Rumen Volatile Fatty Acid Concentration of Diets Containing High and Low Quality Forages

Five ruminally cannulated steers were used to evaluate the effects of supplementation (no supplement, field peas, or dry rolled corn; 0.43% BW) with high and low quality forages on diet digestibility and rumen volatile fatty acid concentrations. Th e inclusion of field peas increased dry matter intake and organic matter digestibility over dry rolled corn and unsupplemented steers. Propionate proportions were less for field peas and control treatments than dry rolled corn, while acetate proportions increased in field peas, and control treatments as compared to dry rolled corn. As a result, acetate to propionate ratio was reduced when dry rolled corn was supplemented. Inclusion of field peas alters the volatile fatty acid concentrations, increases dry matter intake, and improves organic matter digestibility when supplemented to forage fed steers

Effect of Corn Residue Harvest Method on In Vivo and In Vitro Digestibility

A digestion study was conducted using 18 crossbred wether lambs to evaluate the effects of corn residue harvesting method and ensiling on the digestibility of corn residue. Husks had the greatest digestibility compared to any of the harvesting methods. No differences were observed for the digestibility of husklage, ensiled husklage, or stalklage. None of the harvest methods resulted in residue digestibilities similar to husks

Effect of Harvest Method and Ammoniation on Digestibility and Intake of Corn Residue

The effects of three harvest methods, both with and without ammonia treatment, on the in vivo digestibility and intake of baled corn residue were assessed in a digestion trial with lambs. Treatments included three corn residue harvest methods (conventional rake and bale, New Holland Cornrower™ with eight rows or with two rows of corn stalks chopped into the windrow containing the tailings [leaf, husk and upper stalk] from eight harvested rows) and the effects of ammoniation at 5.5% of DM compared to no ammoniation of the residue. Th e 2- Row baled residue (51.7%) had greater dry matter digestibility than both 8- Row (47.3%) and CONV (44.7%). Ammoniation increased dry matter digestibility by 24% (10 percentage units) across all residue types. Additionally, ammoniation increased intake. Utilizing alternative harvesting technologies and ammoniation can improve the digestibility of baled residue. These effects are additive and combining the two technologies resulted in the greatest improvement in digestibility

Site and Extent of Digestion of Finishing Diets Containing Syngenta Enhanced Feed Corn

Four ruminally and duodenally fistulated steers were utilized to evaluate the effects of Syngenta Enhanced Feed Corn™ containing an alpha amylase enzyme trait (SYT- EFC) compared to the isoline parental control corn without the alpha amylase enzyme trait (Negative Isoline) on site and extent of digestion in finishing diets. Cattle fed SYT- EFC dry rolled corn had numerically greater postruminal starch digestibility, excreted lower fecal starch, and had greater total tract starch digestibility compared to cattle fed Negative Isoline corn. These data would suggest that cattle are able to utilize more starch from corn containing the SYT- EFC trait, which has resulted in greater gains and efficiencies

Effect of Harvest Method on Digestibility of Corn Residue

Corn residues can be an economical forage source for producers and advanced harvest methods have increased the quality of baled residue. A digestion study was conducted to evaluate the effects of harvest method of corn residues (low- stem, highstem, and conventional) on digestibility in lambs. Samples from total fecal collection were dried 1 of 3 ways to determine effects on digestibility estimates. Corn residue containing low- stem had greatest overall digestibility with high- stem residue being intermediate and conventional harvesting having the lowest digestibility. Drying method had no effect on digestibility estimates

Impact of Corn Silage Inclusion on Nutrient Digestion and Rumen Fermentation in Finishing Cattle

A digestion study was conducted comparing different inclusions of corn silage used as a roughage source on digestibility, feeding behavior and rumen environment. Treatments consisted of 3 inclusions of corn silage at 0, 7.5 and 15% of the diet DM, and a control treatment with 7.5% alfalfa. As expected, increasing available energy and decreasing roughage (either silage or alfalfa) showed an increase in diet digestibility and ruminal propionate concentrations. However, average ruminal pH was least, with more time spent in subacute acidosis (pH \u3c 5.3) when cattle were fed no roughage. These data suggest that feeding cattle increasing silage inclusions as a roughage source prevented ruminal conditions from entering and remaining in subacute acidosis. Feeding corn silage at 15% gave similar digestibility responses compared to 7.5% alfalfa. Including silage as a roughage source at 15% could help prevent acidosis and digestive upset in feedlot cattle

Effects of Brown Midrib Corn Silage Hybrids with or without Kernel Processing at Harvest on Nutrient Metabolism in Beef Steers

A 2 × 3 factorial digestion study evaluated three corn silage hybrids and kernel processing for finishing steers. The three hybrids included a control corn silage, a brown midrib, and a brown midrib with a softer endosperm. Both brown midrib hybrids had greater fiber digestibility than the traditional control corn silage hybrid. No differences were observed between brown midrib hybrids for all other nutrients. Cattle fed brown midrib hybrids had a lower average ruminal pH compared to the control suggesting more fermentation, but no differences in volatile fatty acid concentration or proportions. Kernel processing had no effect on apparent total tract nutrient digestibility for any nutrients measured in this study. Kernel processing did not impact any ruminal characteristics or metabolism by beef steers. In finishing diets including elevated levels of corn silage, brown midrib corn silage hybrids allow for improved fiber digestibility and more energy available to the animal for improved growth performance over cattle fed control corn silages. Kernel processing did not appear to affect any ruminal fermentation and digestibility parameters, despite an observed improvement in feed efficiency in a similar finishing trial

Effects of Isolated Nutrients in Distillers Grains on Total Tract Digestibility and Digestible Energy in Forage Diets

A digestion study was conducted to evaluate the contribution of individual nutrient components of distillers grains on nutrient digestibility and digestible energy. All diets contained 56% brome hay with a control diet containing either 40% corn; or 40% modified distillers grains. Four additional diets compared the contribution of fat, protein, fiber, and solubles components of distillers grains. No differences were observed for digestibility of DM, OM, and NDF among treatments. Feeding the isolated protein resulted in similar digestible energy to modified distillers grains, suggesting the bypass protein component contributes heavily to energy in distillers

Impact of Feeding Distillers Grains With or Without Oil Removal As Well As Supplemental Corn Oil on Nutrient Digestibility by Finishing Cattle

A digestion trial was conducted to determine the effects of the removal of corn oil from modified distillers grains plus solubles (MDGS) and the impact of supplemental corn oil on finishing cattle nutrient digestion. Four treatments were evaluated: a corn control diet (CON), 40% de-oiled MDGS (DO MDGS), or 38% de-oiled MDGS plus 2% corn oil (MDGS + Oil) formulated to equal the fat content of FF MDGS, or 40% full fat MDGS (FF MDGS). Treatment differences were observed for digestibility of dry matter, organic matter, and fiber, but not for fat. When oil was added to de-oiled MDGS, digestibility was decreased for dry matter, organic matter, and fiber when compared to de-oiled or full fat MDGS. Digestibility values from feeding DGS relative to corn control diets do not follow the same trend, digestible energy increases with DGS feeding, but OM digestibility decreases with DGS feeding