More details on so-called corn diet

Slow-growth diets prove effective in buying time for producers.


By Sharon Norton, Katie Betts, Jim Jolliff, Chad Pilcher and Matt Ritter, Provimi/Cargill Inc.; Jim Erickson, Brian Ramer and Cale Parson, TDM Midwest/Hog Slat Inc.; and Nicholas Gabler and John Patience, Iowa State University Department of Animal Science and Iowa Pork Industry Center

via National Hog Farmer - Oct 15, 2020


The question of holding diets came about when the flow of market-ready animals was disrupted by the novel coronavirus earlier this year. At that time, recommendations were made on what producers could do to slow the growth of their pigs until the opportunity arose to send them to harvest. Nick Gabler, an Iowa State University Animal Science professor, quickly initiated a study to evaluate various dietary options to reduce growth rates.


One of the more popular and cost-effective options adopted in one form or another by the industry from this work was the so-called "corn diet."


This diet was formulated to be easy and inexpensive to adopt. It was achieved by removing all soybean meal and synthetic amino acids, and by increasing corn to 97% inclusion rate with all necessary vitamins and minerals.


Initial recommendations were not to feed the corn diet for more than three to four weeks; this was a precautionary recommendation that was not supported by any experimental data.


Consequently, a collaborative study between Provimi NA, TDM Midwest/Hog Slat and ISU set out to answer a number of questions about the corn diet.


         How would pigs perform if you feed the corn diet for more than three weeks?

         How would pigs perform if you take pigs previously on the corn diet and return them to a regular, nutritionally balanced finishing diet?

         With further evaluation of the corn diet, how would the pigs perform if given the corn diets for only three weeks?


The experiment was initiated in May at the TDM/Hog Slat Research facility in Chili, Ind. A total of 955 pigs with an average initial weight of 203 pounds were allotted (approximately 6.9 square feet per pig per pen) to one of four treatments:


         a standard finishing diet fed for 42 days prior to harvest;

         the standard finishing diet above fed for three weeks, followed by the 97% corn diet for the final three weeks prior to harvest;

         the 97% corn diet fed for three weeks before being returned to the control diet for the final three weeks prior to harvest; or

         the 97% corn diet fed for the full 42-day experimental period.


At the time of the experiment, the ingredient cost of the control diet was $160.92 per ton, and that of the 97% corn diet was $127.16 per ton.


Goal accomplished ...


Excellent growth rates ...


Conclusion ...