ARS | Publication request: Effects of Implanting Growing Steers Grazing Short Grass Prairie Pastures on Subsequent Feedyard Excretion of P and N, Animal Performances, and Carcass Characteristics

Submitted to: Proceeding of Plains Nutrition Council Symposium
Publication Type: Proceedings
Publication Acceptance Date: April 15, 2000
Publication Date: N/A

Technical Abstract: Eighty crossbred steers (average BW 251 kg) were assigned to three implant treatment groups; no implant (control), Revalor G or Synovex S. Steers grazed a common pasture from November 23, 1998 to May 21, 1999. On d 179, steers were transported to the feedyard, weighed, and assigned to 9 pens. Three pens contained a clay base surface and 6 pens contained a fly-ash base surface. All steers were implanted with Synovex S at the beginning o the finishing period and reimplanted with Revalor S on d 91 of the finishing period. Steers were fed a finishing diet containing 80% rolled corn, 10% cottonseed hulls, and 10% protein/mineral supplement). After 137 d in the feedyard, the steers were harvested. Pen manure was collected with a skid loader and weighed. Feed and excreta N and P were determined colorimetrically. During the growing period, implanted steers had a greater final BW and ADG (P < 0.01) than control steers. Implanting steers sduring the growing period did not affect ADG in the feedyard (P > 0.10) compared with the control steers. Implanting steers during the growing phase did not affect the concentration of N and P in feedyard manure or the total quantity of manure excreted (P > 0.10). Feed intake during the finishing phase was similar (P > 0.10) in all treatment groups. Pre-feedyard implant treatment did not affect hot carcass weight, marbling score, fat thickness, or yield grade. Steers implanted with Revalor G during the grazing period had a greater (P = 0.01) rib eye area compared with the control and Synovex S steers. Under the conditions of this trial, implanting steers during the growing period did not affect performance, carcass characteristics, or nutrient excretion during the finishing period.