Effect of processing method on in sacco ruminal degradability of organic matter and nitrogen from canola seeds and in vitro intestinal nitrogen digestion of the in sacco residue

Authors: Gunter, Stacey; Springer, Timothy; LOEST, C. - New Mexico State University; Goldman, Jason

Submitted to: Animal Production Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/18/2013
Publication Date: 7/1/2014
Publication URL: http://handle.nal.usda.gov/10113/59327
Citation: Gunter, S.A., Springer, T.L., Loest, C.A., Goldman, J.J. 2014. Effect of processing method on in sacco ruminal degradability of organic matter and nitrogen from canola seeds and in vitro intestinal nitrogen digestion of the in sacco residue. Animal Production Science. 54:1030-1038.

Interpretive Summary: Canola is an emerging crop for the southern Great Plains of the United States. Production of this oil seed in Oklahoma has increased by 61% from 2007 to 2012 to an annual production of 80,318 tons. With canola production increasing on the southern Great Plains, interest has increased as to how this high-protein oil seed can be used as supplements for grazing ruminants. Farm production of whole raw soybeans have been considered by many cattle producers as an alternative source of supplemental protein compared to purchasing an oil-seed meal. Because of the increasing supply of canola on the southern Great Plains, this same question is being asked of whole canola seeds. There has been a significant amount of research in supplementing ruminants consuming forage-based diets with canola seed meal which have proven to be an acceptable supplement for protein deficient ruminants. However, supplementation research using whole canola seeds either as-harvested or processed is meager. In our experiment, we studied six feed processing methods (scarifying, grinding, rolling, roasting, and steam rolling) and compared them to canola seed meal in ruminal availability and intestinal digestion. The most limiting nutrient to augment energy intake and digestion in cattle grazing native tallgrass and midgrass prairies is ruminally degraded nitrogen and it seems that the most appropriate processing method tested was grinding to use whole canola seeds as a supplement. Other processing methods evaluated either increased processing cost or resulted in them being less available in the rumen.

Technical Abstract: An emerging crop on the Southern Plains of the United States is canola (Brassica napus L.), of which annual production has nearly doubled in the last 5 years. Although production has not exceeded the demand for oil, the question has arisen as to its supplemental value for cattle grazing the rangeland adjacent to production areas. In an experiment, six seed processing methods were evaluated by in sacco digestion of organic matter and nitrogen and in vitro intestinal in situ residue: 1) whole seeds with no processing; 2) seed coats scarified in a pneumatic seed scarifier; 3) ground in a four-knife mill; 4) unprocessed seed rolled to 0.5 mm thick; 5) seeds roasted then rolled to 0.5 mm thick; and 6) steamed then rolled to 0.5 mm thick. Processing methods were compared to a solvent extract canola seed meal. All processing methods increased in situ organic matter and nitrogen digestion in rumen with ground method being the greatest (P < 0.05). These results showed that the ground method produced the most (P < 0.05) ruminally degraded nitrogen/kilogram of organic matter digested in the rumen (67 g) of all methods evaluated. Further, extent of in vitro nitrogen digestion (intestinal) from in situ residue was reduced by increases in ruminal digestion and no processing method increased the total extent of nitrogen digestion over another (P > 0.05). The most limiting nutrient to augment energy intake and digestion in cattle grazing native tallgrass and midgrass prairies is ruminally degraded nitrogen and it seems that the most appropriate processing method is grinding to use whole canola seeds as a supplement. Other processing methods evaluated either increased processing cost or increased the ruminally undegraded nitrogen value.