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Browsing by Author "Stackhouse-Lawson, Kim, advisor"

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    2022 National Lamb Quality Audit: Phase I: Supply chain perceptions of the U.S. lamb industry. Phase II: In-plant survey of carcass characteristics related to quality and value of fed lambs and mutton
    (Colorado State University. Libraries, 2023) Newman, Lauren, author; Stackhouse-Lawson, Kim, advisor; Place, Sara, committee member; Nair, Mahesh Narayanan, committee member; Garry, Franklyn, committee member; Finck, Jessica, committee member
    The U.S. sheep and lamb population has slowly declined over the last eight decades, from 56 million head in 1942 to five million head in January of 2023. Sheep, often referred to as mutton in the meat industry, are mature animals that have at least two permanent incisors, spool joints, and are typically over 24 months of age. Lambs are considered young animals that lack permanent incisors, have at least one break joint, and are usually less than 14 months (USDA,1992). The U.S. lamb industry faces competition from imported lamb from Australia and New Zealand that is less expensive. This imported product increases the lamb supply within U.S. wholesale and retail stores, which, along with increased production costs, has raised concerns about the future viability of the U.S. lamb industry. In response to this pressure, the lamb supply chain can prioritize attributes that both reduce production costs and promote consumer demand. The first step in this process is to measure data from production through lamb carcass quality characteristics, especially data captured in the manufacturing settings. Benchmarking is necessary to identify needs to drive quality enhancements and to ultimately drive improvement and profitability of the lamb industry. The current National Lamb Quality Audit (NLQA) seeks to fill this gap by capturing baseline data from broad scope of the supply chain through perception surveys and in-plant audits. This baseline information will inform the lamb value chain on the current perceptions and lamb quality characteristics that may aid in identifying attributes to reduce costs and increase consumer demand. The NLQA, conducted three times since 1992, assesses the industry's progress on various quality characteristics that ultimately affect consumer demand for lamb. The most recent audit, conducted in 2015, primarily focused on the foodservice segment of the industry. As sheep genetics, management practices, available resources, and consumers' needs and expectations constantly evolve, more frequent audits that capture the entire supply-chain should be considered. The 2022 NLQA audit is designed to repeat successful portions of the 2015 audit, including a new supply chain survey to assess perceptions about the U.S. lamb industry and in-plant carcass characteristics. In phase I, 155 surveys were conducted from May 2022 through September 2022 to understand and quantify perceptions of the U.S. lamb industry. The survey was administered using a software package (Qualtrics®, Provo, Utah) customized to develop a structured order of questions for each industry segment. The survey was distributed via in-plant visits, social media, and email. Survey respondents remained anonymous, each taking approximately ten minutes to complete. Statistical analysis was conducted in Microsoft Excel and the Qualtrics® software. Thirty-two states were represented, with 88 percent of respondents identifying as the owner/operator of their respective business or operation and 86 percent representing commercial breeding operations. Respondents were asked to rank topics based on importance to their operation from 1 (least important) to 10 (most important). Animal welfare (8.9), lamb quality (8.4), and sustainability (7.6) were of most importance to producers. Respondents were also prompted to rank significant challenges in the industry (1=most important and 10=least important). The most significant challenges identified were operation costs (3.04), market volatility (3.70), and labor (4.08). Open-ended responses for defining sustainability were sorted and narrowed in terms of descriptions to find commonalities between respondents. Central themes from respondents included environmental stewardship, profitability, and producing high-quality lamb products. Results from the survey will provide valuable insight to discern gaps and opportunities between producers' viewpoints and data collected in plants to develop educational material to improve lamb quality. For phase II, in-plant assessments were conducted in four of the largest U.S. commercial lamb processing facilities across six production days from June to September 2022. On each production day, 50 percent of carcasses harvested and chilled were surveyed. Both hide-on and hide-off carcasses (n=2,605) and chilled carcasses (n=2,464) were surveyed. On the harvest floor, trained auditors collected data on mud scores, breed type, presence of horns, sex, wool length, and physiological age indicator data. Additionally, hot carcass weight (HCW), measured fat thickness (MFT), and reported USDA yield and quality grades were collected in the cooler. The distribution and summary functions of JMP® Software were used to determine the frequency distributions, means, standard deviations, and minimum and maximum values. Data was analyzed using the Type III ANOVA procedure, and a pairwise comparison was analyzed for dependent variables by treatment using the least squared means procedure in the 'lsmeans' package, of R© with the Tukey HSD adjustment. Dependent variables were YG, calculated YG, HCW, and MFT. Significance was determined at P-value ≤ 0.05. Phase II used in-plant assessments to benchmark current carcass quality characteristics related value of the fed lamb and mutton industry in the U.S. Among the carcasses (n = 1,605) that were audited for sex, 63.2 percent were wethers, 31.5 percent ewes, and 5.3 percent rams. Two percent of the carcasses were presented with horns. Of the 2,604 carcasses evaluated, 40.2 percent were speckle-faced (white-face and black-face cross), 38.8 percent were white-faced, 18.3 percent were black-faced, 1.46 percent had natural characteristics, and 1.72 percent were hair sheep. The average mud score was 2.12, and the average wool length was 5.03 cm. Additionally, 87.1 percent of the 2,437 carcasses presented two break joints indicating lamb, 5.70 percent with one break joint indicating yearling mutton, and 7.18 percent with no break joints indicating mutton. The average HCW (n=2,464) was 39.9 kg, whereas the MFT was 0.97 cm. The USDA stamped yield grade was 2.71 and 68.5 percent graded choice (CH), 22.6 percent graded prime (PR), and 8.9 percent were not graded. The 2022 NLQA in-plant survey of carcass quality characteristics will provide a current benchmark for carcass characteristics of lamb processed in the U.S. The data from this study can help industry segments to understand and develop strategic initiatives to improve the quality of fed lamb and mutton.
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    Impact of growth implants and tannin supplementation on enteric methane emissions and estimated nitrogen excretion in grazing stocker steers
    (Colorado State University. Libraries, 2023) Kutz, Mesa, author; Stackhouse-Lawson, Kim, advisor; Garry, Franklyn, committee member; Finck, Jessica, committee member; Place, Sara, committee member
    The objective of this experiment is to evaluate the effects of a growth-hormone implant (Revlor-G, Merck Animal Health., Rahway, NJ; 40 mg of trenbolone acetate and 8 mg of estradiol) and tannin supplementation (Silvafeed BX, Silva Team, San Michele Mondovi CN, Italy) on enteric methane (CH4) emissions and estimated nitrogen (N) excretion in stocker cattle. Grazing stocker steers (n = 20; initial BW = 343 ± 14 kg) were trained for three weeks to use a portable automated head-chamber system (AHCS; C-Lock Inc., Rapid City, SD) and SmartFeed Pro automated feeder (C-Lock Inc., Rapid City, SD) for dietary supplementation. After the training period, steers were randomly assigned to one of four treatments: 1) no tannin and no implant (Control [CON]); 2) tannin supplement and no implant (Tannin [TAN]); 3) implant and no tannin (Implant [IMP]); and 4) tannin supplement and implant (Implant + Tannin [IMP + TAN]). The tannin was offered at 0.30% DM tannin intake through 0.5 kg/hd/d sweetfeed mix (Sweetfeed Mix, AgFinity., Eaton, CO). Treatment groups without tannin (Control and Implant) received the same sweetfeed mix ration at 0.5 kg/hd/d without the tannin supplementation. Daily forage intake was estimated using the NRC (1996) forage intake prediction equation. Total intake included the estimated forage, bait (alfalfa pellets from AHCS), and sweetfeed mix. Across the experiment, no animal consistently consumed all 0.5 kg/hd/d of the offered sweetfeed mix. On average, the CON cattle consumed 0.32 kg/hd/d, the TAN group consumed 0.41 kg/hd/d, the IMP cattle consumed 0.44 kg/hd/d, and the IMP + TAN group consumed 0.36 kg/hd/d. Moreover, the lack of a tannin x implant interaction (two-way ANOVA; P=0.24) also suggested sweetfeed mix intake did not depend on either treatment level. In response, we evaluated the effect of tannin supplementation and a growth-promoting implant in a separate analysis and data were analyzed with treatment levels as follows: I1) NO-IMP: All animals that did not receive growth implant; I2) IMP: All animals that did receive growth implant; T1) NO-TAN: All animals that did not receive tannin supplement; T2) TAN: All animals that did receive tannin supplement. The sample size for the evaluation of the tannin effect included: NO-TAN (n = 9; 5 animals were implanted with growth promotant) and TAN (n = 9; 5 animals were implanted with growth promotant), while the growth implant effect included: NO-IMP (n = 8; 4 animals were supplemented tannin) and IMP (n = 10; 5 animals were supplemented tannin). Supplementation with tannin did not impact, animal performance metrics (initial body weight, final body weight, and ADG) across the entire study or within early or late study periods (P ≥ 0.33). Steers supplemented with the NO-TAN supplement tended (P ≥ 0.10) to have greater dry matter intake (DMI) and less CH4 yield (MY) compared to cattle supplemented with TAN. There was no effect of tannin supplementation on enteric CH4 production (g/d; P = 0.24) and EI (P = 0.23). N utilization as measured through blood urea nitrogen (BUN), urine N, fecal N, or fecal P was not different among TAN and NO-TAN animals (P ≥ 0.12). Growth-promoting implants did not affect initial body weight (P = 0.86) or final body weight (P = 0.51). There was no effect of growth hormone implant on average daily gain (ADG) during the 90-d of the study (P = 0.80). However, IMP steers tended (P = 0.10) to have greater ADG during the first half of the study (d 0 to 45). Implanted steers also had greater forage (P = 0.05) and bait intake (P = 0.02), and numerically greater total DMI (P = 0.13) over the 90-d study. For IMP steers, there was no effect (P > 0.19) of growth implant on methane (CH4) production or emission intensity (EI; g CH4/kg gain) during the 90-d study. However, IMP steers had decreased (P = 0.03) EI during the first period. Additionally, the IMP steers tended to have less CH4 yield (MY; g CH4/g DMI, P = 0.09) and BUN (P = 0.08) than NO-IMP steers. There was no growth-promoting implant effect (P > 0.30) on cattle urine and fecal N, creatinine, or fecal P. In summary, supplementing tannin in the diet of grazing stocker steers tended to reduce total estimated DMI but did not affect enteric CH4 emissions compared to steers that received no tannin supplement. Implanting steers with Revalor-G tended to 1) increase total DMI in the 90 d study, 2) increase ADG in the early period (d 0 to 45) and 3) decrease CH4 EI in the first 45 d post-implantation.
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    Impact of low-level tannin supplementation on enteric methane emissions, estimated nitrogen excretion, oxidative stress, and animal performance in organic dairy heifers
    (Colorado State University. Libraries, 2023) Schilling, Ashley, author; Stackhouse-Lawson, Kim, advisor; Place, Sara, committee member; Pinedo, Pablo, committee member; Velez, Juan, committee member; Moore-Foster, Rhyannon, committee member
    Heightened attention and concern regarding the role of anthropogenic greenhouse gas (GHG) emissions in climate change has challenged every industry to reduce their environmental impact. In cattle production systems, the importance of feeding the growing human population while minimizing environmental impacts has been given significant attention throughout the 21st century (Steinfeld et al. 2006; Golub et al., 2012; Eisler et al. 2014). In 2020, the United States dairy industry was responsible for approximately 1.4% of total anthropogenic GHG emissions (EPA, 2021). The GHGs with the largest global warming potential (GWP) equivalents in dairy cattle production systems are nitrous oxide (N2O) and methane (CH4) (Rotz et al., 2021). The use of tannins as a feed additive in cattle production systems has been explored as a GHG mitigation strategy given their potential to reduce enteric CH4 and reactive-nitrogen (N) emissions, while also benefiting animal health. Tannins are secondary components of plants comprised of phenolic compounds of diverse molecular weights and of variable complexity (Place et al., 2011). They are classified into two major classes: 1) hydrolysable and 2) condensed tannins and exhibit variable affects depending on their class, concentration/purity, dose, type, and other factors such as animal species, animal physiological state, and diet composition (Makkar 2003; Aboagye and Beauchemin, 2019). When fed to ruminants, such as dairy cattle (Bos taurus), tannins act as rumen modifiers by altering protein and carbohydrate degradation in the rumen. Moreover, tannins have demonstrated anti-microbial, anti-parasitic, antioxidant, anti-inflammatory, and anti-viral effects in animals and the ability to serve as a bloat control mechanism (Mangan, 1988; Jones et al., 1971, Min et al., 2005). Since tannins target rumen microbial populations that assist in fiber degradation, unintended consequences can include reductions in feed intake, digestibility, and rate of BW gain when tannins are supplemented at concentrations greater than 55 g condensed tannins/kg dry matter (DM) (Min et al., 2003). Therefore, the objective of this study was to determine the impact of low-level tannin (< 0.30 g/kg DMI) supplementation on enteric CH4 emissions, estimated N excretion, oxidative stress, and performance in organic Holstein heifers. Heifers (n=20) were supplemented with Silvafeed® ByPro, a Schinopsis lorentzii condensed tannin product, at increasing levels as recommended by the manufacturer: 0% (CON), 0.075% (LOW), 0.15% (MED), and 0.30% (HIG) of dry matter intake (DMI). Based on animal success to a 28 d acclimation period, 20 certified organic Holstein heifers (BW = 219 ± 17 kg) were randomly assigned into one of the four treatment groups and stratified based on initial body weight (i.e., a completely randomized design). A 7 d pretrial gas analysis was performed prior to study initiation to account for individual animal emission differences. Daily, heifers were supplemented with one kg of sweet feed and tannin in accordance with the assigned treatment in individual feeding stanchions for 45 d and fed a basal total mixed ration (TMR) diet through four SmartFeed Pro intake measurement bunk systems (C-Lock Inc., Rapid City, SD) which allowed for measurement of individual animal feed intake. Additionally, CH4 and carbon dioxide (CO2) production was measured using one GreenFeed automated head chamber system (AHCS, C-Lock Inc., Rapid City, SD) for the entirety of the study. Statistical analysis was conducted in R© (R Core Team, 2021, v. 4.1.2). Data were analyzed as a completely randomized design with animal (n=20) as the experimental unit, using the Type III ANOVA procedure. Post-hoc pairwise comparisons for dependent variables by treatment were performed using the least squared means procedure with the Tukey HSD adjustment applied. Daily CH4 production ranged from 136.5 to 140.1 g CH4/hd/d between treatments. No significant difference was observed between treatments for daily CH4 production (P=0.95), CO2 production (P=0.95), CH4 as a percent of gross energy (GE) intake (Ym; P=0.87), CH4 yield (MY; g CH4/kg DMI; P=0.80), and CH4 emission intensity (EI; g CH4/kg of BW gain; P=0.70). Similarly, a treatment effect was not observed for DMI (kg/d; P=0.92), average daily gain (ADG; kg BW gain/d; P=0.53), or feed efficiency (G:F; kg of BW gain/kg of DMI; P=0.42). Nitrogen intake ranged from 195 to 214 g/d among treatments (P=0.93). No significant difference was observed among treatments for fecal output (P=0.98), fecal N (FN; P=0.98), fecal neutral detergent fiber (NDF; P=0.33), or fecal acid detergent fiber (ADF; P=0.30). Estimated urine nitrogen (UN) (P=0.77), FN:UN (P=0.93), and N excretion (P=0.86) did not differ among treatments when estimated using methodologies described by Kohn (2005) (Table 5). Similarly, estimated UN (P=0.66), FN:UN (P=0.94), and N excretion (P=0.72) did not differ among treatments when estimated using methodologies described by Reed (2015). Moreover, no significant difference was observed among treatments for serum parameters, blood urea nitrogen (BUN; P=0.99) or creatinine (P=0.20), the common oxidative stress biomarker malondialdehyde (MDA; P=0.63), or antioxidant enzyme biomarkers superoxide dismutase (SOD; P=0.26) and reduced glutathione (GSH; P=0.19). Ultimately, the results of this study would not indicate that low-level tannin supplementation alters CH4 emissions, estimated N excretion, oxidative stress, or animal performance in organic dairy heifers.