Browsing by Author "Miller, Mark F. (TTU)"
Now showing 1 - 7 of 7
- Results Per Page
- Sort Options
Item Comparison of Three Preharvest Sampling Strategies to Monitor Pathogens in Cattle Lairage Areas(2024) Flach, Makenzie G. (TTU); Dogan, Onay B. (TTU); Miller, Mark F. (TTU); Sanchez, Marcos X. (TTU); Brashears, Mindy M. (TTU)The objective of this study was to compare preharvest monitoring strategies by evaluating three different sampling methods in the lairage area to determine pathogen recovery for each sampling method and incoming pathogen prevalence from the cattle to inform in-plant decision making. Samples were gathered over a 5-month period, from February to June 2022, at a harvesting and processing facility located in Eastern Nebraska. Sampling methods included (i) fecal pats, (ii) boot swabs, and (iii) MicroTally swab. A total of 329 samples were collected over the study period (fecal pats: n = 105, boot swabs: n = 104, and MicroTally swabs: n = 120). Specific media combinations, an incubation temperature of 42°C, and incubation timepoints (18–24 h) were utilized for each matrix and the prevalence of Salmonella, Escherichia coli O157:H7, and six non-O157 Shiga-toxin producing E. coli (STEC) was evaluated using the BAX system Real-Time PCR assay. Overall, results from the study concluded that boot swabs were an effective sampling method for pathogen detection in the cattle lairage area. Boot swabs (97.1%) were statistically more likely to detect for Salmonella (p < 0.05) when compared to fecal pats (67.6%) and MicroTally swab (77.5%) methods. For E. coli O157:H7 and STEC – O26, O121, O45, and O103 prevalence, boot swabs were significantly better at detecting for these pathogens (p < 0.05) than MicroTally swabs (OR = 3.16 – 11.95) and a comparable sampling method to fecal pats (OR = 0.93 – 2.01, p > 0.05). Lastly, all three sampling methods detected a very low prevalence for E. coli O111 and O145; therefore, no further analysis was conducted. The boot swab sampling method was strongly favored because they require little training to implement, are inexpensive, and they do not require much sampling labor; therefore, would be a simple and effective sampling method to implement within the industry to evaluate pathogen prevalence preharvest.Item Evaluation of the contribution of tenderness, juiciness, and flavor to the overall consumer beef eating experience(2018) O'Quinn, Travis G.; Legako, Jerrad F. (TTU); Brooks, J. C. (TTU); Miller, Mark F. (TTU)The objectives of this study were to evaluate the contribution of tenderness, juiciness, and flavor to the overall consumer beef eating experience and to evaluate the risk of overall palatability failure due to the unacceptable level of one or more of these traits. Data from 11 previously conducted studies representing a wide range of treatments and levels of eating quality that included more than 1,500 beef samples and 1,800 consumers were compiled and analyzed for this study. Results of a multivariate regression indicated that tenderness, flavor, and juiciness accounted for 43.4%, 49.4%, and 7.4%, respectively, of overall palatability (P < 0.05; R2 > 0.99). Additionally, the odds of a steak being rated unacceptable overall when tenderness, juiciness, or flavor were rated unacceptable were 2.2 to 1 (69%), 1.9 to 1 (66%), and 3.3 to 1 (77%), respectively. This indicated overall palatability was 7.2, 6.5, and 12.3 times more likely to be rated unacceptable if tenderness, juiciness, or flavor, respectively, was also rated unacceptable. Additionally, the percentage of samples rated acceptable for each palatability trait increased (P < 0.05) as quality grade increased. More than 88% of USDA Prime samples were rated acceptable for each palatability trait, whereas only 74.8-77.3% of USDA Select samples were rated acceptable for each palatability trait. Marbling score accounted for 14-16% of the variation (P < 0.01) in consumer palatability scores for each trait and intramuscular fat percentage accounted for 17-21% of the variation in each trait (P < 0.01). Logistic equation models for the predicted probability of an acceptable rating for each palatability trait based on intramuscular fat percentage accounted for only a minimal amount of variation (P < 0.01; R2 ≤ 0.09). Results of this study indicate the relative contribution of tenderness, juiciness, and flavor to overall beef palatability. They provide evidence that the failure of even a single palatability trait dramatically increases the likelihood of overall palatability failure, indicating that no single palatability trait is most important, as beef palatability is dependent upon the acceptance of all three traits: tenderness, juiciness, and flavor.Item Influence of dietary roughage level and Megasphaera elsdenii on feedlot performance and carcass composition of thin cull beef cows fed for a lean market(2020) DeClerck, Jonathan C. (TTU); Reeves, Nathan R. (TTU); Miller, Mark F. (TTU); Johnson, Bradley J. (TTU); Ducharme, Gary A.; Rathmann, Ryan J. (TTU)One hundred forty-four cull cows (body condition score = 2.10 ± 0.61; BW = 456 ± 47 kg) were organized into a 2 × 2 factorial design (48 pens, 12 pens/treatment, and 3 cows/pen) to evaluate the effect of dietary roughage level and oral drenching of Megasphaera elsdenii NCIMB 41125 (M. elsdenii culture; Lactipro Advance; MS Biotec Inc., Wamego, KS) on performance and carcass characteristics. Cattle were finished over a 42-day realimentation period, and aggressively stepped up over a 10-day period to either a high roughage finisher (HRF; 25% roughage) or a low roughage finisher (LRF; 10% roughage). Within diet, cattle were administered no probiotic or 100 mL of M. elsdenii culture (M. elsdenii NCIMB 41125, 2 108 cfu/mL) on day 0. No diet × probiotic interactions were detected (P ≥ 0.15), suggesting that the magnitude of the response was not influenced by the concentrate level of the diet. The main effect of diet triggered several significant responses. Decreasing roughage level tended to improve average daily gain (ADG) by 9.7% (0.26 kg, P = 0.08), while decreasing dry matter intake (DMI) by 0.9 kg (P = 0.09), provoking a 19.7% enhancement of feed efficiency (0.036 units, P < 0.01). However, interim data revealed declines of performance parameters among both diets with a significant difference between treatments only documented during the final phase of the realimentation period. During the final 14 days, LRF posted a 0.68 kg increase in ADG (P = 0.05) and a 2.0 kg decrease in DMI (P = 0.01), translating to improved feed efficiency (0.054 units, P = 0.03). This suggests that increasing the caloric density of finishing diets may help offset the regression of performance typically observed following a compensatory gain. No carcass traits were impacted by either diet or M. elsdenii culture (P ≥ 0.08). Overall, oral drenching of M. elsdenii culture tended to augment ADG (0.26 kg, P = 0.08) and carcass ADG (0.20 kg, P = 0.10). Implying that M. elsdenii culture was effective at alleviating the acidosis risk prompted by the rapid step-up period employed in the trial and may help capitalize on the narrow timeline of compensatory gain in cull cow realimentation.Item Influence of megasphaera elsdenii and feeding strategies on feedlot performance, compositional growth, and carcass parameters of early weaned, beef calves(2020) DeClerck, Jonathan C. (TTU); Wade, Zain E. (TTU); Reeves, Nathan R. (TTU); Miller, Mark F. (TTU); Johnson, Brad J. (TTU); Ducharme, Gary A.; Rathmann, Ryan J. (TTU)Simmental-Angus calves [n = 135; 72 steers and 63 heifers; body weight (BW) = 212.4 kg ± 36.1] were early weaned (~5 mo) to evaluate multiple feeding regimens (conventional vs. aggressive energy diets ± Megasphaera elsdenii NCIMB 41125 (M. elsdenii culture (MEC); Lactipro Advance; MS Biotec Inc., Wamego, KS) in order to elucidate the optimal development strategy. Objectives were measured by tracking the effects of caloric density and oral drenching of growing phase performance and subsequent carcass traits. The 72-d experiment featured three groups: 1) control (CON), fed exclusively a 35% roughage diet; 2) aggressive (AGR), fed a blend of a 10% and 35% roughage diets; 3) MEC, fed the same diet as AGR and drenched with 50 mL of M. elsdenii NCIMB 41125 on day 1. A subset of calves (n = 45) was equipped with wireless rumination tags (Allflex Flex Tag; SCR Engineers, Ltd; Netanya, Israel), which logged daily rumination and general activity. Skeletal growth variables were assessed by measuring wither and hip height pretrial and post-trial. Ultrasonography provided additional resolution concerning growing phase compositional gain, which was later verified by carcass data collection. Data were analyzed as a nested analysis of variance with BW and gender serving as blocking factors. The increased caloric density of the diets administered to MEC and AGR calves resulted in greater average daily gain and gain:feed values compared with CON even during the first 21 d of diet acclimation (P ≤ 0.05). Additional fiber concentration of CON diets led to increased rumination times in 9 of the 10 wk of trial (P ≤ 0.10). No differences amongst treatments were detected for skeletal variables or ultrasound 12th rib fat. Cattle fed CON diets posted 3.4% inferior BW at the end of the growing period trial and a 3.8% reduction in hot carcass weight (HCW), reinforcing the theory that intensifying caloric intake during the growing phase does not compromise future feedlot performance. Ultrasound marbling scores for MEC-treated cattle were 19° greater than AGR treated cattle (P ≤ 0.05) at the end of the growing phase trial. Nearly the exact same advantage (22°) was observed in the cooler 5 mo later (P = 0.42). Implying MEC metabolically imprinted cattle to favor marbling development. It appears that maximizing dietary caloric density in light-weight calves does not adversely affect the growth curve, while oral dosing of MEC during the growing period may be a precursor for enhanced quality grade.Item Influence of ractopamine hydrochloride and days on feed on feedlot performance and red meat yield in thin cull beef cows targeted for a lean market(2020) DeClerck, Jonathan C. (TTU); Lucherk, Loni W. (TTU); Reeves, Nathan R. (TTU); Miller, Mark F. (TTU); Bernhard, Bryan C. (TTU); Rathmann, Ryan J. (TTU)Thin, beef, cull cows [n = 144; initial body weight (BW) = 465.8 ± 56.9 kg, initial body condition score (BCS) = 2.13 ± 0.68] were serially slaughtered to evaluate the relationship between ractopamine hydrochloride (RH) administration and days on feed (DOF) on feedlot performance and carcass cutout value in a lean cow market. Cows were organized into a 3 × 2 factorial arrangement of treatments (48 pens, 8 pens per treatment, 3 cows per pen) and blocked by BW nested within pregnancy status. Treatment pens were top-dressed 400 mg per cow per day of RH (Actogain 45; Zoetis, Parsippany, NJ) for the final 28 d prior to slaughter to cows spending 28, 42, or 56 DOF. Pen served as the experimental unit, for all calculations. No RH × DOF interactions were detected (P ≥ 0.11), indicating that despite a majority of compensatory gain occurring during the first 28 d of the trial, the magnitude of the RH response was not affected by DOF. Compared to controls, RH incited improvements in feedlot performance, but had a greater extent on carcass weight gain and efficiency. Specifically, RH improved average daily gain (ADG) by 13.7% (P = 0.04) and carcass ADG by 16.9% (P = 0.02) Cattle fed RH displayed a 15.5% improved gain to feed ratio (P = 0.02) and a 20% improved carcass gain to feed ratio (P = 0.05). Inclusion of RH in the finishing diet increased hot carcass weight by 4.5% (P = 0.05; 12.9 kg). However, supplementation of RH did not alter red meat yield (P ≥ 0.16), but provoked a 11.1% improvement in lean maturity (P < 0.01). Evaluation of the main effect of DOF provided insight into the compensatory state of beef cull cows on a high-concentrate diet. Serial slaughter offal weights presented confounding results. With additional DOF, a numerical increase in liver weights (P = 0.20) suggested that organ tissue replenishment occurred throughout the trial, and cattle experienced compensatory gain during the entire feeding phase. In contrast, lung and heart weights were not altered, while kidney tended to decrease linearly (P = 0.08) despite additional DOF. Furthermore, extending DOF generated a linear increase in dry matter intake (P < 0.01) yet a tendency for a decline in ADG (P = 0.10), reinforcing the premise that most of compensatory gain occurred during the first 28 d of the trial. If thin (BCS ≤ 4), healthy candidates can be finished, feeders can reap the benefits of an additive relationship between compensatory gain and RH.Item The influence of Megasphaera elsdenii on rumen morphometrics of cull cows immediately stepped up to a high-energy finishing diet(2020) DeClerck, Jonathan C. (TTU); Reeves, Nathan R. (TTU); Miller, Mark F. (TTU); Johnson, Bradley J. (TTU); Ducharme, Gary A.; Rathmann, Ryan J. (TTU)Forty-five beef cull cows [body weight (BW) = 503 ± 58 kg; body condition score (BCS) = 2.1 ± 0.6] were randomized into two treatments to compare the effects of oral drenching of no probiotic vs. 100 mL of Megasphaera elsdenii NCIMB 41125 (M. elsdenii culture; Lactipro Advance; 2 × 108 cfu/mL; MS Biotec, Inc., Wamego, KS) on the realimentation of cull cows. The study featured a rapid 0-d step-up of concentrate-naïve cull cows to a 90% concentrate diet (1.43 Mcal/kg of NEg). The cows were finished for 35 d and were fitted with a wireless rumination tag (Allflex Flex Tag; SCR Engineers, Ltd, Netanya, Israel), which tracked head movement to record eating and chewing activity. Rumen morphometrics was recorded on the harvest floor, with each carcass assigned a rumenitis score, and a fragment of the cranial sac removed for further papillae analysis. An additional 23, thin, non-fed cull cows were harvested at the same abattoir to compare the effects of concentrate realimentation on ruminal morphometrics. Megasphaera elsdenii culture-drenched cattle registered a 13.3% increase in rumination time (39.27 min/d, P = 0.03) during the first week of the trial compared to controls. A numerical rumination advantage for M. elsdenii culture-administered cattle was observed during week 2 of trial (P = 0.17), with no differences between treatments from weeks 3 to 5 (P ≥ 0.40). Subjective rumenitis evaluations approached a tendency (P = 0.12), with non-M. elsdenii culture-drenched concentrate-fed cattle logging twice the score of their day 0 cohorts (2.52 vs. 1.17) suggesting considerable lactic insults occurred to the ruminal epithelium in the short 35-d trial. Despite the short feeding duration, concentrate realimentation prompted a significant improvement in mean papillae area (P < 0.01). Among concentrate-fed treatments, M. elsdenii culture-drenched cattle posted superior absorptive surface area (P = 0.01) and a greater ratio of papillae area of absorptive surface area (P = 0.05), suggesting that M. elsdenii culture is favorably altering the ecology of the rumen and promoting papillae growth perhaps by mitigating lactate-driven pH drops. In conclusion, M. elsdenii culture application in a 0-d step-up protocol to finishing diets can help mitigate the effects of ruminal acidosis.Item Validation of a Bacteriophage Hide Application to Reduce STEC in the Lairage Area of Commercial Beef Cattle Operations(2023) Flach, Makenzie G. (TTU); Dogan, Onay B. (TTU); Miller, Mark F. (TTU); Sanchez-Plata, Marcos X. (TTU); Brashears, Mindy M. (TTU)Finalyse, a T4 bacteriophage, is a pre-harvest intervention that utilizes a combination of bacteriophages to reduce incoming Escherichia coli O157:H7 prevalence by destroying the bacteria on the hides of harvest-ready cattle entering commercial abattoirs. The objective of this study was to evaluate the efficacy of Finalyse, as a pre-harvest intervention, on the reduction in pathogens, specifically E. coli O157:H7, on the cattle hides and lairage environment to overall reduce incoming pathogen loads. Over 5 sampling events, a total of 300 composite hide samples were taken using 25 mL pre-hydrated Buffered Peptone Water (BPW) swabs, collected before and after the hide wash intervention, throughout the beginning, middle, and end of the production day (n = 10 swabs/sampling point/timepoint). A total of 171 boot swab samples were also simultaneously taken at the end of the production day by walking from the front to the back of the pen in a pre-determined ‘Z’ pattern to monitor the pen floor environment from 3 different locations in the lairage area. The prevalence of pathogens was analyzed using the BAX® System Real-Time PCR Assay. There were no significant reductions observed for Salmonella and/or any Shiga toxin-producing E. coli (STEC) on the hides after the bacteriophage application (p > 0.05). Escherichia coli O157:H7 and O111 hide prevalence was very low throughout the study; therefore, no further analysis was conducted. However, boot swab monitoring showed a significant reduction in E. coli O157:H7, O26, and O45 in the pen floor environment (p < 0.05). While using Finalyse as a pre-harvest intervention in the lairage areas of commercial beef processing facilities, this bacteriophage failed to reduce E. coli O157:H7 on the hides of beef cattle, as prevalence was low; however, some STECs were reduced in the lairage environment, where the bacteriophage was applied. Overall, an absolute conclusion was not formed on the effectiveness of Finalyse and its ability to reduce E. coli O157:H7 on the hides of beef cattle, as prevalence on the hides was low.