Effects of feeding calcium hydroxide treated corn stover during backgrounding on carcass characteristics and beef quality

Abstract Text:

Sixty-seven purebred Angus steers (initial BW +/-197 kg.) were used to evaluate the effects of calcium hydroxide treated corn stover in backgrounding diets after a common finishing phase.  Steers were randomly assigned to 1 of 4 treatments 1) backgrounding a turnip cover crop (CC) for 29 days before adapted to ad libitum alfalfa haylage diet for remaining 20 d of study; 2) untreated corn stover as the control treatment (CON), 3) corn stover treated with 50% DM water (H₂O); 4) 50% DM water and calcium hydroxide (CaOH₂). Steers were fed individually using a Calan system.  All diets were formulated on a dry matter (DM) basis to contain 30% corn stover, 15% alfalfa haylage, 25% dried distillers grains with solubles, 25% dry rolled corn, and 5% supplement containing monensin.  Steers were slaughtered when average backfat of the group reached 0.4 inches.  Carcass characteristics were collected 48 hours postmortem and both boneless strip loins and shoulder clods (IMPS #180 and #114) from the right side of the carcass were collected.  Strip loin steaks were used to evaluate purge, cook loss, and Warner-Bratzler shear force (WBSF).  Shoulder clods were processed to ground beef for evaluation of retail shelf life.

Dietary treatment had no effect on carcass characteristics including HCW (P=0.6943), ribeye area (P=0.2590), backfat (P=0.7795), USDA Yield Grade (P=0.8904), USDA Quality Grade (P=0.8771), and marbling score (P=0.8496). Although purge loss (P=0.8839) and cook loss (P=0.1492) were not affected by treatment, WBSF was lower for CC than CON (1.6 vs 2.23kg respectively; P=0.001).  Objective b* values of fresh steaks on day 0 were higher for CON than CaOH₂ (18.7 vs 15.76; P=0.0019), and on day 5, CON was higher than CC (17.42 vs 14.71; P=0.0064) and CaOH₂ (17.42 vs 14.87; P=0.0231).  Ground beef subjective lean color was more bright cherry red and discoloration affected less of the samples on day 3 for CON than CC and CaOH₂ (5.45 vs 4.73 and 4.85; 8.95 vs 7.40 and 7.48; P<0.001).  The consumer panel found that CON was more desirable than CC on day 2 (6.42 vs 5.69; P=0.0007), than H₂O (5.45 vs 4.95; P=0.0413) and CC (4.55; P<0.001) on day 3, and than CC (3.55 vs 3.01; P=0.0146) on day 4. The use of calcium hydroxide treated corn stover in backgrounding diets of beef calves does not affect carcass characteristics, moisture loss, or WBSF, but does have minimal impact on ground beef shelf life.

Keywords: alkali-treatment, corn stover, beef