|May, J - UNIV OF ARKANSAS|
|Rosenkrans Jr, Charles - UNIV OF ARKANSAS|
Submitted to: American Society of Animal Science Southern Section Meeting
Publication Type: Abstract Only
Publication Acceptance Date: October 15, 2002
Publication Date: February 3, 2003
Citation: LOOPER, M.L., AIKEN, G.E., MAY, J.A., ROSENKRANS JR, C.F. 2003. INFLUENCE OF STEROID IMPLANTATION AND SUPPLEMENTATION ON PERFORMANCE AND LACTATE DEHYDROGENASE ACTIVITY IN STEERS GRAZING BERMUDAGRASS. AMERICAN SOCIETY OF ANIMAL SCIENCE SOUTHERN SECTION MEETING. 81(Suppl. 2):22. Technical Abstract: Forty-five steers (BW = 246 ± 5.4 kg) were randomly allocated to one of three paddocks of bermudagrass [Cynodon dactylon (L.) Pers] to determine the effects of timing of steroid implantation and supplementation on average daily gain and lactate dehydrogenase (LDH) activity. Steers received either no supplementation or 1.4 kg/d per steer of a corn-soybean meal supplement. Steers were assigned to either no implant, one implant at d 0 and one implant at d 56 (EI), or one implant at d 56 (LI). Steers were weighed at the initiation and termination of the trial to determine weight gain and average daily gain (ADG). Blood samples were collected on d 0, 62, and 108 and LDH activity was quantified. Ultrasonography of steers was performed to determine rump fat (RF) and backfat (BF). Supplementation of steers increased (P < 0.0001) ADG during 108 d of grazing (0.57 0.04 vs 0.93 0.05 kg/d for non-supplemented and supplemented steers). Steroid implants tended (P = 0.13) to increase overall weight gain and ADG. Backfat was increased (P < 0.05) in LI steers compared with EI and control steers. Both BF and RF was greatest (P < 0.05) in supplemented steers. Supplementation increased (P < 0.0001) serum protein (99.5 2.6 and 117.5 3.8 mg/mL for non-supplemented and supplemented steers,). There was an implant x supplementation interaction (P < 0.05) for LDHR (lactate as the substrate) and LDHF (pyruvate as the substrate). Altered LDH activity may be one mechanism by which supplementation and steroid implantation improve steer performance.