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United States Department of Agriculture

Agricultural Research Service

Research Project: RANGELAND AND LIVESTOCK RESOURCE MANAGEMENT Title: Effects of Supplemental Ground Flaxseed Fed to Beef Cattle Grazing Summer Native Range on the Northern Great Plains

Authors
item Scholljegerdes, Eric
item Kronberg, Scott

Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 10, 2010
Publication Date: June 1, 2010
Citation: Scholljegerdes, E.J., Kronberg, S.L. 2010. Effects of Supplemental Ground Flaxseed Fed to Beef Cattle Grazing Summer Native Range on the Northern Great Plains. Journal of Animal Science. 88:2108-2121.

Interpretive Summary: Supplementing cattle during the summer grazing period can be desirable for livestock producers wishing to increase livestock growth performance. Use of fats in supplements for grazing animals has improved feed efficiency with various fat sources, such as soybean oil, corn oil, or whole soybeans. Two experiments were conducted simultaneously to evaluate the effects of supplemental ground flaxseed on site and extent of digestion and growth performance in beef cattle grazing summer native range. Six Angus heifers fitted with ruminal and duodenal cannulas were used in Exp. 1 and eighteen Angus cross steers were used in Exp. 2. Cattle from both experiments were allotted to one of three individually fed treatments: grazing only with no supplement (CON); grazing plus a cracked corn-soybean meal supplement fed at 0.32% of BW once daily (CRN); or grazing plus a ground flaxseed supplement fed at 0.18% of BW once daily (FLX). Feeding flaxseed at 0.18% of BW to grazing cattle can be as effective as feeding a conventional corn-soybean meal based supplement in improving the energy density of the diet without negatively impacting forage intake or diet digestibility. In addition, supplemental flaxseed will provide an improvement in feed efficiency when forage quality is higher than will corn. In addition, the supply of linolenic acid, an omega-3 fatty acid, to the small intestine will ultimately provide tissues with more of this essential fatty acid. Therefore, ground flaxseed, appears to be a viable option for use as an energy supplement to steers grazing native range by improving growth performance without reducing forage utilization.

Technical Abstract: Two experiments were conducted simultaneously to evaluate the effects of supplemental ground flaxseed on site and extent of digestion and growth performance in beef cattle grazing summer native range. Six Angus heifers (avg initial BW 367 ± 8.0 kg) fitted with ruminal and duodenal cannulas were used in Exp. 1 and eighteen Angus cross steers (avg initial BW 368 ± 4.6 kg) were used in Exp. 2. Cattle from both experiments were allotted to one of three individually fed treatments: grazing only with no supplement (CON); grazing plus a cracked corn-soybean meal supplement fed at 0.32% of BW once daily (CRN); or grazing plus a ground flaxseed supplement fed at 0.18% of BW once daily (FLX). In Exp. 1, supplement did not affect (P = 0.22) masticate in vitro organic matter digestibility, however, between supplemented treatments, cattle fed FLX tended (P = 0.08) to select a lower quality masticate than Corn-fed cattle. Forage OM intake was not affected (P = 0.12) by supplementation nor was there a difference (P = 0.49) between CRN and FLX. A quadratic (P = 0.001) response was observed for forage OM intake as the grazing season advanced. Duodenal and fecal OM flow was not different (P > 0.39) across treatments. Therefore, true ruminal and total tract OM digestibility did not differ (P > 0.37) between CON and supplemented treatments and total tract digestibility was greater (P = 0.01) for CRN than FLX. Likewise, ruminal NDF digestibility also did not differ (P = 0.26) with supplementation and CRN was not different (P = 0.22) from FLX. Total duodenal N flow did not differ (P = 0.16) across treatments but responded quadratically (P = 0.03) with advancing season. True ruminal N digestibility was not affected by supplementation (P > 0.16). In Exp. 2, there was a treatment × period interaction for forage intake (P < 0.001), ADG (P = 0.001) and feed efficiency (P < 0.001). Additional supplement did not change (P = 0.34) forage intake compared with CON but CRN was greater than FLX (P < 0.001). Nevertheless, ADG was greatest for supplemented steers (P < 0.001) compared with CON but did not differ (P = 0.41) between CRN and FLX. Feed efficiency was greater (P < 0.001) for supplemented steers and was greater (P = 0.01) for Flax than Corn. Although supplemental ground flaxseed reduced diet digestibility compared with the corn-based supplement, this reduction in diet digestibility did not negatively impact the growth performance of grazing steers.

Last Modified: 12/20/2014
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