Performing Department
(N/A)
Non Technical Summary
A potential strategy to reduce the environmental footprint of beef production is precision feeding, which is defined as a feeding method that utilizes net energy equations to calculate the quantity of feed required to fulfill maintenance and desired performance levels (Galyean, 1990). Generally, as animals increase energy consumption feed efficiency is improved; however, previous research indicates that maximum feed intake does not equal maximum feed efficiency (Gill et al., 1986). Additionally, precision feeding for different strategies have been shown to reduce nutrient loss, both in minimizing manure output and reductions in volatile nitrogen excretion (Driedger and Loerch, 1999). This strategy is well designed for small- and medium-sized feedlot producers as they typically have smaller pen sizes, which can help limit the amount of within pen variability that is observed in larger feedlot operations. This is aligned with the priority areas K, L, and N from the small- and medium sized farm program RFA. The objectives of this proposal is to examine increasing feeding levels using common feedlot rations for South Dakota and Kansas to determine:Animal performance and feed efficiencyEnteric methane production and nutrient excretionExamine how precision feeding impacts the economic returns to producersThe key outcome of this proposal is the development of specific dietary strategies using feed ingredients common to each region for small- and medium-sized producers that improve their economic and environmental sustainability and positions them to take advantage of future carbon credit programs through an easy and producer friendly management strategy.
Animal Health Component
100%
Research Effort Categories
Basic
0%
Applied
100%
Developmental
0%
Goals / Objectives
The goal of this proposal is to examine how an established, but not widely adopted, management strategy of precision feeding impacts animal efficiency and the environmental impact of feedlot production systems.The concept of restricting feed intake is a long-established management strategy in the literature and comes in various forms including restricted feeding (where intake is restricted based on level of anticipated intake), programmed feeding (based on net energy equations to calculate intake levels), and also limit feeding (Plegge, 1986; Galyean et al., 1999; Pritchard and Bruns, 2003). Although generally, as animals increase energy consumption feed efficiency is improved, previous research indicates that maximum feed intake does not equal maximum feed efficiency (Gill et al., 1986; Meissner et al., 1995). When fed at 5 to 10% below ad libitum intake levels, efficiency of gain has been observed in numerous studies to be improved over that of cattle fed ad libitum, although the mechanism of action behind this is still unclear (Zinn et al., 1995). When considering the definition of sustainable intensification is the maximization of outputs relative to inputs, overconsumption of feedstuffs represents a critical inefficiency in the cattle feeding process (Tedeschi et al., 2015). Therefore, the primary objective of this proposal is to examine increasing feeding levels using common feedlot rations for South Dakota and Kansas to determine:Objective 1.1 Animal performance and feed efficiencyObjective 1.2 Enteric methane production and nutrient excretionObjective 2.1 Examine how precision feeding impacts economic returns to producers
Project Methods
Treatmentswill be a grain-based finishing diet fed 1) Ad-libitum, 2) 92% of Ad-libitum intake, or 3) 96% of Ad-libitum.Objective 1.1Objective 1.1 will be completed at South Dakota State University at the Ruminant Nutrition Center and the Southeast Research Farm Feedlot. These locations will utilize backgrounded (~14 months old at harvest) and yearling steers (~22 months old at harvest), respectively. At these two locations, treatments will be replicated across 8 pens (total = 24 pens per location; 10" of bunk space per animal) to examine potential impacts of precision feeding on feed efficiency, animal performance, pen level dry matter intake, carcass trait responses and liver abscess prevalence and severity. Crossbred beef steers (n = 384; estimated initial BW = 454 kg) will be used in a 120-d feeding trial at the RNC near Brookings, SD (n = 24 pens) and the SERF (n = 24 pens). Steers will be sourced from SD auction facilities.Steers will be allotted to 1 of 24 pens (n = 8 hd/pen) with 8 replicate pens for each treatment at each SD location.Steers will be transitioned from a 60% to 93% concentrate diet over the course of 18 to 21 d. All steers will be fed a similar finishing diet. Growth performance will be used to calculate performance-based dietary NE to determine efficiency of dietary NE utilization. Steers will be marketed and harvested at a commercial abattoir when treatment blinded personnel determine that 60% of the population has sufficient fat cover to grade USDA Choice. Steers will be followed through the abattoir to determine harvest sequence by trained personnel. Carcass data will be obtained from plant camera records. Individual liver health will be evaluated by trained personnel and tied to individual animal identification tag.Statistical AnalysesPen will serve as the experimental unit for animal performance, feed intake and feed efficiency. Data will be analyzed using the MIXED procedure in SAS with the fixed effect of treatment and the random effect of pen and year. The data will be analyzed using the MIXED procedure in SAS with the fixed effects of treatment and location. Means will be separated using orthogonal contrasts for linear and quadratic components and significance declared a P ≤ 0.05 and tendency between 0.05 < P ≤ 0.10.Objective 1.2:?Before the experiment, 60 steers will be shipped from South Dakota to the Kansas State University Beef Cattle Research Center.Processing will include deworming, implanting (120 mg of trenbolone acetate and 24 mg of estradiol or similar), collection of receiving weights, and vaccination for viral respiratory pathogens and clostridial organisms. Animals will then be moved into 2 feedlot pens containing 4 Insentech feed intake nodes for initial acclimation to the feed intake system. Approximately 7 d after arrival, one greenfeed emission measurment system (AHCS) will be placed in each system for a 21-d acclimation to the system. After the total 28-d acclimation period, steers will be weighed and those animals that adequately adapted to both the Insentech and AHSC will be blocked by weight into treatment groups. Each treatment will have a total of 18 animals per treatment, with 8 animals per pen (n = 48).Weights will be collected once monthly for the duration of the experiment to determine animal performance via linear regression.On d 1, the middle of the trial, and at the end, fecal and urine samples will be collected from a subset of 4 steers per treatment for fecal N, urine N, and urine creatinine analysis.To calculate N balance, we will utilize calculatedfecal outputto determine fecal N excretion and urine output determined by urine creatinine concentration. This will be estimated as described by Valadares et al. 1999, using a creatinine coefficient of 29 mg/kg of BW. The results of these analyses will then be used to calculate N balance.Enteric CH4 and CO2 production will be determined utilizing 2 AHCS, equipment deployment for the duration of the experimental period with one unit placed in each pen. Treatments will be comingled in each pen, so that each treatment is equally represented in each pen (n = 8 per treatment per pen). Visits will be set up for a maximum of 6 drops per visit with 30 second intervals between each drop and a minimum of 4 h between each visit to encourage animals to space visits out across the day. The gas analyzers will be calibrated weekly, and CO2 recoveries will be conducted monthly to ensure accuracy. Enteric CH4 results will be analyzed as grams CH4/d, grams of CH4/kg of BW gain, grams of CH4/kg of DMI, and as a percentage of gross energy lost as CH4.Statistical AnalysesIndividual animal will serve as the experimental unit for performance and enteric CH4 emissions. Data will be analyzed using the MIXED procedure in SAS with the fixed effect of treatment and the random effect of pen and year. The data will be analyzed using the MIXED procedure in SAS with the fixed effect of treatment and random effect of pen. Means will be separated using orthogonal contrasts for linear and quadratic components and significance declared a P ≤ 0.05 and tendency between 0.05 < P ≤ 0.10.Objective 2.1While it is hypothesized that precision feeding will decrease feed result in decrease feed costs for small and medium sized producers, there is much uncertainty regarding the overall financial impact of implementing this strategy. We will track the differences between precision feeding and the status quo to determine the overall impact of implementation of this practice. Cost and return estimates will initially be reported as enterprise budgets by working with local producers to generate consensus around 'typical' practices (including estimated costs and returns), with results from Objective 1.1 informing anticipated costs and returns for precision feeding. We will also consult local producers to ensure our assumptions regarding the costs of practice implementation are realistic. We will elicit this information via focus groups held in the study region, with a minimum of two at each study site. Given the inherit market risk associated with variable prices, we will also conduct a Monte Carlo simulation using a partial budget comparing precision feeding to the status quo. Using historical price distributions and correlations to inform our stochastic variables, we will simulate the differences in profit across the systems over a suite of potential market outcomes. Results of the Monte Carlo simulation will prove insightful to help 1) determine which strategy is more likely to be most profitable, and 2) which variables impact the difference in profitability the most. These results will be important in to show the relative impact of implementing a precision feeding strategy for small and medium size producers and help determine which economic variables need to be monitored when considering a switch in management.Finally, results from Objective 1.2 will be used to determine the reduction in GHG associated with precision feeding, which we assume will generate credits that can be sold either through traditional offset markets or the rapidly developing inset markets.EvaluationThe regions selected for this project contain large populations of our nations beef cattle herd, including many small- and medium-sized producers, multi-enterprise producers, and underserved producers. The advisory committee will assist in guiding the project across each objective including identification of producer partners for focus group activity in objective 2, and extension and outreach activities. Upon project start in April of 2023, advisory committee members will be identified for the project from local stakeholders, with PI's targeting producers and companies that serve small- and medium-sized producers and professionals with experience in precision feeding of cattle.