The Nebraska Beef Reports contain a summary of research conducted by scientists and graduate students in the Animal Science Department. The target audience for these reports are livestock producers, extension educators, and people in agri-business. The articles are written in a format and style with our Nebraska clientele in mind that is easy to read and understand.

2017

Corn Residue Quality throughout the Grazing Season, Shelby E. Gardine, Gavin L. Harsh, Robert G. Bondurant Bondurant, Jana L. Gramkow, Andrea K. Watson, and Terry J. Klopfenstein

Effects of Wintering System on Cow and Calf Performance in a Summer- Calving Intensive Production System, Shelby E. Gardine, Jason M. Warner, Curtis J. Bittner Bittner, Robert G. Bondurant, Karla Jenkins, Richard J. Rasby, Matt K. Luebbe, Galen E. Erickson, and Terry J. Klopfenstein

Effects of Field Pea Supplementation on Digestibility and Rumen Volatile Fatty Acid Concentration of Diets Containing High and Low Quality Forages, Hannah L. Greenwell, Jana L. Gramkow, Melissa L. Jolly-Breithaupt Breithaupt, Jim C. MacDonald, and Karla Jenkins

Evaluating the Impacts of Field Peas in Growing and Finishing Diets on Performance and Carcass Characteristics, Hannah L. Greenwell, Karla Jenkins, Jim C. MacDonald Donald, and Matt K. Luebbe

Relationship between Dietary Total Digestible Nutrients and Digestible Organic Matter in Beef Cattle Finishing and Growing Diets With or Without Distillers Grains, Hannah C. Hamilton, Jana L. Gramkow, Jim C. MacDonald Donald, Galen E. Erickson, Andrea K. Watson, and Terry J. Klopfenstein

Impact of Inoculum Source for in vitro and in situ Digestion Procedures Performed on Corn Residue and Grass Samples, Hannah C. Hamilton, Jana L. Harding, Jim C. MacDonald Donald, and Terry J. Klopfenstein

Evaluation of Plant- waxes to Estimate Forage Intake in Grazing Cattle, Hannah C. Hamilton, Jerry D. Volesky, and Robert M. Lewis Lewis

Summer Cocktail Forage Research in the Panhandle of Nebraska, Karla H. Jenkins, Cody Creech, Robert Higgins Higgins, and Josh Buttle

Comparison of diets collected from esophageally fistulated cows to forage quality estimated from fecal analysis, Bethany M. Johnston, Jay D. Jenkins, Jacqueline A. Musgrave Musgrave, L. A. Stalker, and Mitchell B. Stephenson

Evaluation of 0 or 300 mg of Optaflexx® on Growth Performance and Carcass Characteristics of Steers Fed to Different Degrees of Finish, Robert M. Jones, Curtis J. Bittner, F. Henry Hilscher Hilscher, Mallorie F. Wilken, and Galen E. Erickson

Comparison of Titanium® 5 PH- M versus Titanium® 5 plus NUPLURA® PH with the Presence or Absence of Monensin on Health and Performance of Newly Received Feedlot Calves Fed RAMP®, Robert M. Jones, Curtis J. Bittner, F. Henry Hilscher Hilscher, Mallorie F. Wilken, Rick Stock, and Galen E. Erickson

Effect of Harvest Method on Digestibility of Corn Residue, Tasha M. King, Melissa L. Jolly-Breithaupt, Jana L. Gramkow Gramkow, Terry J. Klopfenstein, and Jim C. MacDonald

The Influence of Diet and Oxidation on Calcium Retention of the Mitochondria in Fresh Beef, Emery K. Kunze, Nicolas J. Herrera, Katherine I. Domenech-Perez Perez, Michael D. Chao, and Chris R. Calkins

Organic Acids and Applications used for Reduction of E. coli on Beef Shoulder Clods used for Ground Beef, Kelly A. McCarty, Gary A. Sullivan, and Dennis E. Burson Burson

Development of Terminal and Maternal Economic Selection Indices in Beefmaster Cattle, Kathleen P. Ochsner, Michael D. MacNeil, Ronald M. Lewis, and Matthew L. Spangler

Effect of Three Initial Implant Programs with a Common Terminal Revalor®- 200 on Feedlot Performance and Carcass Traits of Weaned Steers, Colton R. Oney, Galen E. Erickson, Andrea K. Watson Watson, Marshall N. Streeter, Robert J. Cooper, Bill D. Dicke, D. J. Jordon, and Tony L. Scott

Effect of Increasing Supplemental Rumen Undegradable Protein (RUP) on Performance of Calves Fed a Silage Growing Diet, Colton R. Oney, F. Henry Hilscher, Robert G. Bondurant Bondurant, Andrea K. Watson, Galen E. Erickson, and Terry J. Klopfenstein

Effect of Long- Term Corn Residue Grazing on Soil Properties, Manbir K. Rakkar, Humberto Blanco, Mary E. Drewnoski Drewnoski, Jim C. MacDonald, and Terry J. Klopfenstein

Shelf Life of Ground Beef from Cattle Fed Distillers Grains Containing Different Amounts of Oil, Faith D. Rasmussen, Chad G. Bower, and Gary A. Sullivan Sullivan

Effects of Distillers Grains or Fiber on Enterohemorrhagic Escherichia coli in Steers, Liesel G. Schneider, Curtis J. Bittner, Jordan E. Burhoop Burhoop, F. Henry Hilscher, Galen E. Erickson, Terry J. Klopfenstein, Rodney A. Moxley, and David R. Smith

Effect of Heifer Development System on Reproduction and Subsequent Gain as a Pregnant Heifer, Shelby A. Springman, Hazy Rae Nielson, Tonya L. Meyer, Mike Kirby, Jim Teichert, and Richard N. Funston

Impact of Heifer Development System in Two Different Breeding Seasons, Shelby A. Springman, Hazy Rae Nielson, Jacqueline A. Musgrave Musgrave, John Nollette, Andy Applegarth, and Richard N. Funston

Timed Insemination vs. Modified Estrus Detection in Beef Heifers, Benjamin T. Tibbitts, Tonya L. Meyer, Dan J. Kelly Kelly, and Richard N. Funston

Growth and Reproductive Performance of Yearling Beef Heifers Implanted with Revalor G in the Nebraska Sandhills, Benjamin T. Tibbitts, Hazy Rae Nielson, K. H. Ramsay Ramsay, and Richard N. Funston

Nutrient Content of Summer-Planted Oats after Corn Harvest and Grazing Performance, Kristen M. Ulmer, Robert G. Bondurant, Jana L. Gramkow Gramkow, Mary E. Drewnoski, and James C. MacDonald

Effect of Corn Residue Grazing or Baling on Subsequent Crop Yield and Nutrient Removal, Kristen M. Ulmer, Jordan L. Cox, Manbir K. Rakkar Rakkar, Robert G. Bondurant, Humberto Blanco-Canqui, Mary Drewnoski, Karla H. Jenkins, James C. Macdonald, and Rick J. Rasby

Delineating Complex Forage Mixtures Using Plant-Wax Markers, Napoleón Vargas Jurado, Hannah C. Hamilton, and Ronald M. Lewis

Effect of Feeding Field Peas on Fresh Beef Quality, Hope R. Voegele, Katherine I. Domenech, Emery K. Kunze Kunze, Felipe A. Ribeiro, Karla H. Jenkins, Jim C. MacDonald, and Chris R. Calkins

Rumen Undegradable Protein and Bambermycins Supplementation of Calves Grazing Corn Residue, Cody A. Welchons, Robert G. Bondurant, F. Henry Hilscher Hilscher, Jim C. MacDonald, and Galen E. Erickson

Pooled Gain Analysis of Steers Grazing Corn Residue and Supplemented with Distillers Grains, Cody A. Welchons and Jim C. MacDonald

2016

2016 Nebraska Beef Cattle Report (complete)

Statistics Used in the Nebraska Beef Report and Their Purpose

Table of Contents 2016 Nebraska Beef Cattle Report

Effect of Crude Glycerin Concentration on Forage Digestion Parameters in Beef Calves, Robert G. Bondurant, Jana L. Harding, Melissa L. Jolly- Breithaupt Breithaupt, James C. MacDonald, Andrea R. McCain, and Samodha C. Fernando

Carcass Gain, Efficiency, and Profitability of Steers at Extended Days on Feed, Robert G. Bondurant, Jim C. MacDonald, Galen E. Erickson Erickson, Kate Brooks, Rick N. Funston, and Kelly Bruns

Effect of Winter Distillers Grains Supplementation Level on Spayed Heifer Performance, Robert G. Bondurant, Brandon L. Nuttelman, Curtis J. Bittner Bittner, James C. MacDonald, and Terry J. Klopfenstein

Producer Concerns and Perceptions Regarding the Effect of Methane on Cattle Production and the Environment, Bradley M. Boyd, Amanda Burken, Lisa Franzen- Castle Castle, Karla Jenkins, Richard J. Rasby, Matt K. Luebbe, Rick Stowell, Samodha C. Fernando, and Galen E. Erickson

Metabolic and Body Temperature Responses to Environmental Conditions across Seasons in Finishing Steers, Bradley M. Boyd, Terry L. Mader, Curtis J. Bittner Bittner, Dirk Burken, Henry Hilscher, Gene Wijffels, John B. Gaughan, Megan Sullivan, Judy Cawdell- Smith, and Galen E. Erickson

Effects of Shade and Feeding Zilpaterol Hydrochloride to Finishing Steers on Performance, Carcass Quality, Heat Stress, Mobility, and Body Temperature, Bradley M. Boyd, Steven D. Shackelford, Kristin E. Hales Hales, Tami M. Brown- Brandl, Meredith L. Bremer, Matthew L. Spangler, Tommy L. Wheeler, David A. King, and Galen E. Erickson

Effects of Feeding OmniGen- AF® on Immune Function, Performance, and Carcass Characteristics during the Feeding Period, Joe O. Buntyn, Sara E. Sieren, Curtis J. Bittner Bittner, Dirk Burken, Galen E. Erickson, Nicole C. Burdick Sanchez, Jeff A. Carroll, Steven J. Jones, Ty B. Schmidt, Keven C. Dehann, and Troy J. Wistuba

Modifying Different Components of Distillers Grains and the Impact on Feedlot Performance, Zachary E. Carlson, Curtis J. Bittner, Dirk Burken Burken, Galen E. Erickson, and James C. MacDonald

Evaluation of the Relative Contribution of Protein in Distillers Grains in Finishing Diets on Animal Performance, Zachary E. Carlson, Galen E. Erickson, James C. MacDonald Donald, and Matt K. Luebbe

Feeding Vitamin E May Reverse Sarcoplasmic Reticulum Membrane Instability Caused by Feeding Wet Distillers Grains Plus Solubles to Cattle, Michael D. Chao, Katherine I. Domenech, and Chris R. Calkins Calkins

Effects of Dietary Antioxidant Supplementation on Cattle Finished with 30% Wet Distillers Grains Plus Solubles on Fatty Acid Profiles and Display Life, Michael D. Chao, Katherine I. Domenech, Hope R. Voegele Voegele, Emery K. Kunze, and Chris R. Calkins

Effect of Feeding Distillers Grains and Supplementing with Dietary Antioxidants on Ground Beef Shelf Life and Fatty Acid Profile, Brandy D. Cleveland and Gary Sullivan

Effects of Feeding Isolated Nutrient Components in MDGS on Growing Cattle Performance, Brianna B. Conroy, Curtis J. Bittner, Jim C. MacDonald Donald, Matt K. Luebbe, and Galen E. Erickson

Impact of Feeding Distillers Grains or Isolated Components in Distillers Grains on Feedlot Performance and Carcass Traits, Brianna B. Conroy, Matt K. Luebbe, Galen E. Erickson Erickson, Jim C. MacDonald, and Jacob A. Hansen

Utilizing Corn Residue or Fall Double Cropped Forages for Winter Backgrounding of Calves, Jordan L. Cox, Kristin E. Hales, Kristen M. Ulmer Ulmer, Richard J. Rasby, Steven D. Shackleford, Chad Engle, John Rieckman, Harvey C. Freetly, and Mary E. Drewnoski

Granulosa Cell Exposure to Excess Androgens Inhibits Their Ability to Proliferate in the Cow Which May Cause or Perpetuate Androgen Excess, Andrea S. Cupp, Sarah Romereim, Adam F. Summers Summers, William E. Pohlmeier, Renee M. McFee, Renata Spuri- Gomes, Scott G. Kurz, Anthony K. McNeel, Robert A. Cushman, John S. Davis, and Jennifer R. Wood

Economics of Rebreeding Non- pregnant Females, Aline G. da Silva, Jacqueline A. Musgrave, Don C. Adams Adams, John Nollette, Andy Applegarth, and Rick N. Funston

Effect of Dam Age on Offspring Productivity, Aline G. da Silva, Jacqueline A. Musgrave, John Nollette Nollette, Andy Applegarth, and Rick N. Funston

Impact of Supplementing Cattle with OmniGen- AF at the Receiving or Finishing Phase on Beef Shelf- Life, Katherine I. Domenech, Michael D. Chao, Joe Buntyn Buntyn, Ty B. Schmidt, and Chris R. Calkins

Beef Fatty Acid Profiles from Steers Finished with De-oiled Dry Distillers Grains Plus Solubles vs. a Corn- Based Diet, Katherine I. Domenech, Keni E.Z. Nubito, Galen E. Erickson Erickson, and Chris R. Calkins

Accurate Amounts and Nutritive Values of Corn Residues, Shelby E. Gardine, Andrea K. Watson, Jana L. Harding Harding, and Terry J. Klopfenstein

Effects of Different Inoculum Used for In Vitro and In Situ Digestion Procedures Performed on Corn Residue Samples, Hannah C. Hamilton, Jana Harding, Jim C. MacDonald Donald, and Terry J. Klopfenstein

Effects of Replacing a Traditional Growing Diet with a Complete Pelleted Feed on Total Tract Digestibility of Growing Diets, Jana L. Harding, Melissa L. Jolly, Galen E. Erickson Erickson, and Jim C. MacDonald

Evaluating Syngenta Enhanced Feed Corn on Finishing Cattle Performance and Carcass Characteristics, Marie E. Harris, Melissa L. Jolly- Breithaupt, Brandon L. Nuttelman Nuttelman, Dirk Burken, Galen E. Erickson, Ivan G. Rush, and Matt K. Luebbe

Effects of Protein Supplementation in Corn Silage Growing Diets Harvested at 37 or 43% DM on Cattle Growth, F. Henry Hilscher, Robert G. Bondurant, Jana L. Harding Harding, Terry J. Klopfenstein, and Galen E. Erickson

The Effect of Delayed Corn Silage Harvest on Corn Silage Yield and Finishing Performance in Yearling Steers, F. Henry Hilscher, Dirk Burken, Curtis J. Bittner Bittner, Jana L. Harding, Terry J. Klopfenstein, and Galen E. Erickson

Annual Forages following Irrigated Winter Wheat, Karla H. Jenkins, Aaron Berger, and Gary Hergert Hergert

Evaluating Syngenta Enhanced Feed Corn Processed as Dry- Rolled or High- Moisture Corn on Cattle Performance and Carcass Characteristics, Melissa L. Jolly- Breithaupt, Curtis J. Bittner, Dirk Burken Burken, Galen E. Erickson, Jim C. MacDonald, and Matt K. Luebbe

Site and Extent of Digestion of Finishing Diets Containing Syngenta Enhanced Feed Corn, Melissa L. Jolly- Breithaupt, Jana L. Harding, Jim C. MacDonald Donald, Galen E. Erickson, and Matt K. Luebbe

Effect of Harvest Method on Residue Quality, Tasha M. King, Robert G. Bondurant, Jana L. Harding Harding, Jim C. MacDonald, and Terry J. Klopfenstein

Effect of Diet on the Rumen Microbial Community Composition of Finishing Cattle and the Role it Plays in Methane Emissions, Allison L. Knoell, Christopher L. Anderson, Anna C. Pesta Pesta, Galen E. Erickson, and Terry J. Klopfenstein

Effect of Feeding Dried De-oiled Distillers Grains and Addition of Postmortem Antioxidants on Ground Beef Shelf Life, Jenae C. Martin, Brandy D. Cleveland, Tommi F. Jones Jones, Jim C. MacDonald, and Gary Sullivan

Impact of Crude Glycerin Supplementation on Rumen and Duodenal Microbial Populations in Forage Diets, Andrea R. McCain, Robert G. Bondurant, Melissa Jolly Jolly, Jana L. Harding, Samodha C. Fernando, and Jim C. MacDonald

Effect of Corn Residue Composition on Digestibility by Lambs, Levi J. McPhillips, Janessa J. Updike, Jim C. MacDonald Donald, Terry J. Klopfenstein, Jana L. Harding, and Melissa L. Jolly- Breithaupt

Finishing Yearling Heifers Using Self- Fed Dried Distillers Grains on Pasture, Jared M. Mracek, Jason M. Warner, Bradley R. Wetovick Wetovick, Dennis E. Bauer, Twig T. Marston, Jim C. MacDonald, Jerry D. Volesky, and Richard J. Rasby

Effect of Safeguard® on Fecal Egg Count and Steer Performance in Newly Received Calves, Antonio J. Neto, Curtis J. Bittner, Brandon L. Nuttelman Nuttelman, and Galen E. Erickson

Effect of MGA vs CIDR Estrus Synchronization on Estrus Response and Pregnancy Rates in 311 d Old Beef Heifers, Hazy R. Nielson, Rosemary V. Anderson, and Rick N. Funston Funston

How Many Clean-up Bulls Are Needed aft er Estrus Synchronization and Artificial Insemination?, Hazy R. Nielson and Rick N. Funston

Comparison of TAI at GnRH Injection and Delayed Insemination of Non- estrus Beef Heifers, Hazy R. Nielson, Dan J. Kelly, T. L. Meyer, and Rick N. Funston

Effect of Feeding De-oiled Dry Distillers Grains Plus Solubles on Beef Oxidation, Color and Tenderness, Keni E.Z. Nubiato, Katherine I. Domenech, Galen E. Erickson Erickson, and Chris R. Calkins

Evaluation of Distillers Grains Components Singly or in Combination in a Calf Fed Feedlot Study, Rachel A. Oglesbee, Curtis J. Bittner, F. Henry Hilscher Hilscher, Galen E. Erickson, Jim C. MacDonald, and Matt K. Luebbe

Student Perceptions and Knowledge of the Feedlot Industry and the Feedyard Management Specialization Internship, Rachel A. Oglesbee, Meredith L. Bremer, Kari L. Lewis Lewis, Dennis R. Brink, Terry J. Klopfenstein, Jim C. MacDonald, and Galen E. Erickson

Rumen Protected Amino Acids in Finishing Cattle Diets, Colton Oney, Curtis J. Bittner, F. Henry Hilscher Hilscher, Andrea K. Watson, Terry J. Klopfenstein, Galen E. Erickson, and Whitney Rounds

Methane Production, Diet Digestibility, and VFA Profile of Growing Steers Fed High or Low Quality Forage, A. C. Pesta, M. L. Jolly- Breithaupt, Samodha C. Fernando Fernando, Paul J. Kononoff, and Galen E. Erickson

Use of Dietary Nitrate or Sulfate for Mitigation of Methane Production by Finishing Steers, Anna C. Pesta, Robert G. Bondurant, Samodha C. Fernando Fernando, and Galen E. Erickson

Effects of Direct- Fed Microbial Supplementation in Different Diets on Performance and Carcass Characteristics of Beef Feedlot Heifers, Laura F. Prados, Nirosh D. Aluthge, Curtis J. Bittner Bittner, F. Henry Hilscher, Samodha C. Fernando, and Galen E. Erickson

Impact of a Newly Developed Direct- Fed Microbial on Performance in Finishing Beef Steers, Laura F. Prados, Nirosh D. Aluthge, Robert G. Bondurant Bondurant, Samodha C. Fernando, and Galen E. Erickson

Impact of Inoculating Corn Silage with Buchnerii 500 on Feedlot Cattle Performance with or without Added Yeast Product at Time of Feeding, Cassandra A. Row, Curtis J. Bittner, Jana L. Harding Harding, James C. MacDonald, Terry J. Klopfenstein, Angel A. Aguilar, Renato J. Schmidt, and Galen E. Erickson

Effect of Corn Plant Maturity on Yield and Nutrient Quality of Corn Plants, 2- Year Summary, Cassandra A. Row, Robert G. Bondurant, Andrea K. Watson Watson, Jana Harding, Jim C. MacDonald, Terry J. Klopfenstein, and Galen E. Erickson

Cows with Excess Androgen are Anovulatory and Have Differing Patterns of Progesterone Secretion, Renata Spuri- Gomes, Sarah C. Tenley, Mohamed A. Abedal- Majed Majed, Scott G. Kurz, Jeff Bergman, Jennifer R. Wood, and Andrea S. Cupp

Effects of Supplementing OmniGen- AF® with or without Ractopamine Hydrochloride on Performance and Carcass Characteristics of Feedlot Steers, Kelby M. Sudbeck, Robert G. Bondurant, Troy J. Wistuba Wistuba, Kevin C. DeHaan, James C. MacDonald, Galen E. Erickson, and Matt K. Luebbe

Effects of Supplemental Energy and Protein Source on Performance of Steers Grazing Irrigated Corn Residue, Benjamin T. Tibbitts, Jim C. MacDonald, Rick N. Funston Funston, Cody A. Welchons, Robert G. Bondurant, and F. Henry Hilscher

Evaluation of Different Byproduct Combinations along with Treated Corn Stover on Growing Steer Performance, Kristen M. Ulmer, Curtis J. Bittner, F. Henry Hilscher Hilscher, Galen E. Erickson, and James C. MacDonald

Observations of Forage Quality and Calf Gain when Grazing Double Cropped Forage following Wheat Harvest, Kristen M. Ulmer, Robert G. Bondurant, Jana L. Harding Harding, Gary Lesoing, M. E. Drewnoski, and James C. MacDonald

Effect of Corn Residue Harvest Method on In Vivo and In Vitro Digestibility, Janessa J. Updike, Levi J. McPhillips, Melissa L. Jolly- Breithaupt Breithaupt, Jana L. Harding, Terry J. Klopfenstein, and Jim C. MacDonald

Effects of Wintering System on Cow and Calf Performance in a Summer-Calving Intensive Production System, Jason M. Warner, Curtis J. Bittner, Robert G. Bondurant Bondurant, Karla H. Jenkins, Richard J. Rasby, Matt K. Luebbe, Galen E. Erickson, and Terry J. Klopfenstein

Evaluation of Varying Corn Grain (and Byproduct) Inclusion in Beef Cattle Finishing Diets, Andrea K. Watson, Matt K. Luebbe, and Galen E. Erickson Erickson

Effect of Pelleted Byproducts on Performance When Fed to Growing Cattle, Cody A. Welchons, Curtis J. Bittner, Dirk Burken Burken, Jim C. MacDonald, and Galen E. Erickson

Effect of Pelleted Feed Products and Bambermycins on Performance When Fed to Cattle Grazing Residue, Cody A. Welchons, Robert G. Bondurant, F. Henry Hilscher Hilscher, Jim C. MacDonald, Galen E. Erickson, and Cody A. Nichols

Performance and Economics of Supplementing Yearlings on Smooth Bromegrass Pastures, Cody A. Welchons, Robert G. Bondurant, Terry J. Klopfenstein Klopfenstein, Jim C. MacDonald, and Andrea K. Watson

2015

2015 Beef Cattle Report (complete)

Statistics Used in the Nebraska Beef Report and Their Purpose

Comparison of Wet or Dry Distillers Grains Plus Solubles to Corn as an Energy Source in Forage-Based Diets, Nerissa A. Ahern, Brandon L. Nuttelman, Terry J. Klopfenstein Klopfenstein, James C. MacDonald, and Galen E. Erickson

Genetic Parameter Estimates for Calving Difficulty and Birth Weight in a Multibreed Population, Cashley M. Ahlberg, Larry A. Kuehn, R. Mark Thallman Thallman, Stephen D. Kachman, and Matthew L. Spangler

Effect of 300 or 400 mg Daily of Ractopamine Hydrochloride on Growth Performance and Carcass Characteristics of Finishing Steers During the Last 14, 28, or 42 Days, Curtis J. Bittner, Dirk B. Burken, Adam L. Shreck Shreck, James C. MacDonald, Galen E. Erickson, and Nathan A. Pyatt

Effects of Next Enhance® Concentrations in Finishing Diets on Performance and Carcass Characteristics of Yearling Feedlot Cattle, Curtis J. Bittner, Galen E. Erickson, Karla H. Jenkins Jenkins, Matt K. Luebbe, Martin A. Andersen, and Geoff I. Zanton

Response to Increasing Concentrations of De-oiled Modified Distillers Grains Plus Solubles in Beef Feedlot Diets, Meredith L. Bremer, Curtis J. Bittner, Dirk B. Burken Burken, Galen E. Erickson, and James C. MacDonald