Performing Department
Animal Science
Non Technical Summary
Efficiency enhancing technologies have been widely used in the beef industry since the early 1950's.Most recently, commercially available beta adrenergic agonists (BAA) were introduced. With the introduction of these technologies, management practices have been implemented to effectively use antimicrobials, direct-fed microbials, ionophores, growth implants and BAA for increasing beef cattle production.These technologies have played a pivotal role in improving beef production efficiency and helping to provide a safe, affordable protein source for feeding the world's growing population. Technology use has decreased the number of animals required by 69.9% and land use by 67.0% to produce the same amount of beef in 2007 as in 1977. In the same time period, average beef yield per animal has increased 77 kg from 274 to 351 kg.These technologies have also played a pivotal role in helping mediate beef prices due to lower production costs.Even with the improvement in animal performance and improved economic efficiency, the use of technology has been under scrutiny from various groups due to concerns over animal well-being, decreased retail meat quality and overall sustainability of beef production. Also, some producers have modified production practices to target niche markets that promote no technology use because they believe these products are superior or because of increased price premiums. Sustainability has been definced as"meeting society's present needs without compromising the ability of future generations to meet their own needs." This definition shows that beef production must be accomplished by providing a safe, wholesome, affordable product to consumers, but should also allow producers to meet their own needs by being economically efficient. Therefore, technology must play a pivotal role in the sustainability of beef production.The goals ofthis project are to: A) determine the effect of efficiency enhancing technologies on the efficiency and daily gains of beef cattle in the receiving/growing phase of production; and B) evaluate management practices for producing beef using various production systems during the feedlot phase.
Animal Health Component
10%
Research Effort Categories
Basic
20%
Applied
80%
Developmental
0%
Goals / Objectives
The goalof the first project is to determine the effect of supplementation with a direct-fed microbial [Bovamine Defender® (Lactobacillus acidophilus and Propionibacterium freudenreichii)] on the efficiency and daily gains of beef cattle in the receiving/growing phase of production.Goals of the second project are to1) evaluate management practices for producing beef using alternative production systems during the finishing phase; 2) determine the economic costs/values associated with alternative production systems compared to conventional beef systems; 3) provide data to the general public about the sensory and chemical attributes of beef produced by alternative production systems.
Project Methods
Goal 1. Six hundred calves (BW = 225 to 275 kg) will be procured and delivered to the Willard Sparks Beef Research Center (WSBRC). Routine processing will occur including: individual ear tag, body weight, treatment for internal and external parasites, vaccination against clostridial toxins, IBR, PI3, BRSV, and BVD type I and II, Mannheimia haemolytica and Pasteurella multocida, and a low-dose growth implant. After processing calves will be ranked by initial BW and randomly assigned to 24 feedlot pens that will have been previously assigned to a control treatment (negative control will be fed diet with no DFM) or an experimental treatment (control diet with addition of Bovamine Defender®; 24 pens, 25 animals/pen, n=12 pens/treatment). The control group will be fed a typical growing ration for beef cattle and the experimental treatments will consist of the same ration accompanied by Bovamine Defender® fed at 1 gram/animal/day over the course of the experiment. Bovamine Defender® will be mixed with 2.5 kg of ground corn in a Kitchen Aid mixer for 5 minutes before being applied directly into the Roto-Mix feed wagon as a portion of the total ration. All ration ingredients will be added to the aforementioned Roto-Mix feed wagon and allowed to mix for 4 minutes before delivering each treatment to their respective pens.Statistical Analyses. Data will be analyzed using SAS 9.3 (SAS Institute, Cary, N.C.). A randomized complete block design will be utilized for this experiment, blocking by initial BW within cattle source. Pen will serve as the experimental unit.Goal 2. Certified natural steers will be sourced and transported to the WSBRC, Stillwater, OK.Upon arrival, cattle will be weighed on a pen scale, placed in holding pens, and fed prairie hay and a receiving ration containing no monensin or tylosin.The morning after arrival, cattle will be weighed individually and identified with a visual numbered tag as well as an electronic identification (EID).This BW will be used to sort cattle into approximate weight groups.Cattle will be processed and sorted into approximate weight blocks. All steers will be vaccinated against clostridial toxins, IBR, PI3, BRSV, and BVD type I and II, Mannheimia haemolytica and Pasteurella multocida, and treated for internal parasites and external parasites. Cattle will be blocked by BW within source and randomly allocated to study pens. On d 0, all cattle will be weighed and randomly sorted to study pens (8 blocks; 1 replication/block; 8 pens/treatment; 14 steers/pen; 112 steers/treatment). Treatments will consist of an all-natural treatment (NAT), a conventional treatment (CONV), or a conventional treatment with the addition of a beta-agonist at the end of the feeding period (CONV-BAA). The NAT cattle will receive no antimicrobials, growth implants, or beta-agonists, and if antimicrobial treatment is deemed necessary, steers will be removed from the experiment. The CONV and CONV-BAA cattle will be implanted with 40 mg of estradiol and 200 mg of trenbolone acetate (Revalor-XS, Merck Animal Health) on d 0. They will also be fed 33 and 9 mg/kg of monensin and tylosin (Rumensin and Tylan, Elanco Animal Health, Greenfield, IN) daily, respectively. The CONV and CONV-BAA cattle will be eligible for antimicrobial treatment if deemed necessary. The CONV-BAA cattle will be fed a BAA (at the labeled dose and days on feed, and any withdrawal periods will be strictly adhered to prior to harvest).All cattle will be fed the same base diet. Cattle will be housed in 24, 12.2 x 30.5 m soil-surfaced feedlot pens with 12.2 m fence-line concrete feed bunk with a 76 L concrete fence-line water tank (Model J 360-F, Johnson Concrete, Hastings, NE) shared between two pens.Cattle will be weighed on d 28, 56, and 84 of the finishing phase.All cattle will be weighed prior to shipment to a commercial harvest facility. Body weights obtained the morning ofharvest will be used for calculation of dressing percentage.Carcass data, including liver scores, will be collected by trained personnel.Carcass Evaluation and Strip Loin SelectionRetail Display Analysis. Each steak will be placed in a 23.5 x 18.4 x 1.6 cm white foam tray (No. 42, Cryovac Sealed Air) with Cryovac absorbent pads and over-wrapped with polyvinyl chloride (PVC) film. Steaks will be placed in the retail case equipped with Promolux low UV lights (Atlanta Light Bupound Co., Atlanta, GA) and monitored daily for muscle color, surface discoloration and overall acceptability. Temperature on the retail case will be set to 0°C, with the defrost cycle occurring every 7 h for 1 h. Steaks will be rotated throughout the case, top to bottom and left to right every 24 h. Steaks will be visually evaluated by a 6 to 9 member trained color panel every 24 h.The steaks will be evaluated for 7 d.Slice Shear Force (SSF) Analysis. Steaks designated for SSF will be removed from the freezer and placed in a cooler for 24 h and allowed to thaw to 2 to 5°C.Once thawed, the steaks will be cooked to an internal temperature of 69-71°C using an impingement oven at 180°C (Lincoln Impinger, Model 1132-00-A, Lincoln Foodservice Products, Fort Wayne, IN). Once cooked, SSF will be measured using an Instron Universal Testing Machine (Model 4502, Instron Corporation, Canton, MS).Trained Sensory Panel. Steaks will be thawed and cooked in the same manner as the SSF procedures. After cooking, steaks will be cut into individual servings and immediately served. The panelists will evaluate and score each sample for initial and sustained juiciness on an 8-point scale (1 = extremely dry, 4 = slightly dry, and 8 = extremely juicy), first and overall impression tenderness on a 8 point scale (1 = extremely tough, 4 = slightly tough, and 8 = extremely tender), overall connective tissue amount on an 8-point scale (1 = abundant, 4 = moderate, and 8 = none), cooked beef flavor on a 15-point scale (5 = beef broth, 7 = ground beef, and 11 = beef brisket), metallic flavor on a 15-point scale ( 4 = strip steak, and 6 = pineapple juice), rancidity on a 15-point scale (vegetable oil warmed for 3 minutes = 7, and vegetable oil warmed for 5 minutes = 9), and green haylike flavor on a 15-point scale (6 = parsley).Proximate Analysis and Fatty Acid Composition Analysis.For fatty acid, proximate analysis, cholesterol analysis and mineral analysis, frozen samples will be shipped to a commercial laboratory.Economic Analysis. Body weights, carcass characteristics and health records will be collected individually for all cattle. Dry matter intake records will be summarized and recorded on a pen basis; however, for economic analysis, all animals within each respective pen will be assigned an intake value to the average of the pen for feed cost calculations. Feeder calf value will be calculated based on individual animal BW at the initiation of the experiment and the price structure obtained from the report KO_LS795 (AMS.USDA.GOV). For the feedlot phase, feed cost will be based on actual feed cost. The CONV cattle will be assigned a feed technology cost of $36.51/steer to account for cost of Rumensin, Tylan, and the BAA, as well as an additional $3.60/steer for the implants (Implant). Base carcass price will be the actual price at the time of harvest.Statistical Analysis. All animal performance data will be analyzed as a randomized complete block design using PROC MIXED (SAS 9.3; SAS Inst. Cary, NC). Pen will be considered the experimental unit, and weight block will be included as a random effect. All carcass data will be analyzed with pen as experimental unit and weight block included as a random effect. The USDA Quality Grade, Yield Grade, and liver scores will be analyzed using PROC GLIMMIX (SAS 9.3; SAS Inst. Cary, NC). Differences will be considered significantly different when P < 0.05 and a trend when 0.05 ≥ P ≤ 0.10.