Submitted to: Kentucky Beef Report
Publication Type: Other
Publication Acceptance Date: 6/9/2006
Publication Date: N/A
Interpretive Summary: Stocker cattle grazing endophyte-infected tall fescue during the late spring and summer exhibit symptoms of toxicosis (e.g., high body temperature, labored breathing, retainment of winter haircoat, and poor weight gain). The malady is caused by consumption of ergot alkaloids that are produced by the endophyte. Weight gains are improved on tall fescue by either interseeding pastures with clovers or by feeding concentrates. Although weight gain on fescue can be improved through management, it is uncertain if these management approaches can influence the prolonged adjustment to feedyard rations often observed by feedyard managers. Furthermore, effect of steroid hormone implants on feedyard performance of cattle background on tall fescue has not been fully elucidated. An experiment was conducted with steers grazed on endnophyte-infected tall fescue to determine the additive effects of feeding of soybean hulls on pasture and post-graze steroid hormone implants on BW increases and DM after being placed on corn silage-concentrate diets. Dry matter consumption was not affected by pasture and pen treatments, and increased and stabilized by 14 d in 2004 and between 14 and 28 d in 2005. Overall, body weight changes following grazing of toxic fescue and placement on the corn silage-concentrate diet indicated that feeding soybean hulls to stocker cattle grazing toxic fescue and post-graze implantation with steroidal hormones can enhance the efficiency of weight gain and likely allow cattle to reach a finish body weight in an acceptable period of time. Feeding low cost concentrate feeds is an effective management for increasing weight gain on toxic tall fescue, which would be of benefit to cattle producers that are background calves on toxic fescue and retaining ownership in the feedyard.
Technical Abstract: Stocker cattle grazed on toxic tall fescue during the spring and summer can exhibit symptoms of toxicosis resulting in poor weight gains and extended times of adjustment to feedyard rations. A 2-yr experiment (2004 and 2005) monitored body weight (BW) change and dry matter (DM) consumption for 36 beef steers during a pen phase that followed spring and summer grazing of toxic tall fescue. The objective was to determine effects of feeding soybean hulls (SBH) during fescue grazing and post-graze implanting with steroid hormones on BW change and DM consumption following grazing of toxic tall fescue. Treatments for a pasture phase were either group fed pelleted soybean hulls (SBH) or a pasture-only control. For a pen phase, a corn silage-concentrate ration was fed and steers on the SBH pasture treatment were ear implanted with progesterone (200 mg) and estradiol benzoate (20 mg), and steers on the pasture control treatment were split into implant and no implant treatment groups. Feeding SBH in 2004 resulted in greater BW at the initiation of the pen phase and this effect was consistent through the entire pen phase. Implanted steers on the pasture control treatment had greater BW than non-implanted steers at approximately 28 d during the pen phase. Low rainfall and heavier steers in 2005 resulted in no effect of SBH feeding or ear implantation. Dry matter consumption was not affected by pasture and pen treatments, and increased and stabilized by 14 d in 2004 and between 14 and 28 d in 2005. Results of the experiment showed that stocker cattle background on toxic tall fescue can be fed SBH to enter the feedyard at a heavier weight and implanted with steroid hormones to reach a finished BW in an acceptable amount of time.