Date Full Report Received


Date Abstract Report Received



Primary Investigator:
Co-Investigators: Michael Tokach, S.S. Dritz, R.D. Goodband, Joel DeRouchey, Chad Hastad

The objectives of this research were to evaluate a broad range of moderate to severe feed processing of both nursery and finishing pig diets on growth performance, caloric efficiency, economics and carcass characteristics. The research focused on the effects of ingredient particle size, diet type, and pelleting. In order to establish economics of the different processing methods, commercial rates were applied for grinding, mixing, pelleting and delivery.

Reducing corn particle size improved feed efficiency (every 100-µ reduction in particle size improved F/G by approximately 1%) and economic return in finishing pigs but not in nursery pigs. In finishing, the response is particularly significant because the diets used in the study included only 30 to 39% corn due to the inclusion of DDGS and midds. The nursery results were unexpected due to previous research reporting improvements during the nursery phase with reductions in corn particle size. Our research indicates that reducing corn particle size below 600 microns does not benefit nursery pigs.

When grinding all major ingredients or the entire diet post mixing, a consistent lack of response in feed efficiency was found when diets were fed in meal form. In fact, ADFI was actually poorer for pigs fed this type of diet, which may be due to reduced palatability. Feeders were checked frequently to ensure pigs had ad libitum access to feed and that the ADFI response was not due to feed bridging in feeders. Disappointingly, feed efficiency and caloric efficiency were identical in pelleted high by-product diets regardless of whether only the corn was finely ground or if the complete diet was finely ground. Since these did not change, this indicates that fine-grinding DDGS, wheat middlings, and soybean meal did not significantly improve their energy value for nursery or finishing pigs.
As expected, pelleting diets in both experiments improved growth rate, feed efficiency, and caloric efficiency. This improvement could be due to improvements in diet digestibility, because feed intake was not changed. Pelleting increased total revenue and income over feed cost in both experiments when using a pelleting charge of $6/ton.
Producer bottom line:
• Reducing corn particle size improved fed efficiency and economics in finishing pigs.
• Fine grinding other major ingredients or the whole diet after mixing was not advantageous because feed intake was reduced when the diet was fed in meal form and feed efficiency was unchanged compared to just fine grinding the corn portion.
• Pelleting improved feed efficiency, caloric efficiency, and income over feed cost and should be further explored by producers and feed manufacturers as a means to improve net return in light of current high feed costs.
Dr. Joel DeRouchey
Kansas State University
Department of Animal Sciences and Industry
222 Weber Hall
Manhattan, KS 66506