Browsing by Author "McDaniel, Zach S. (TTU)"
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Item Infrared thermography or rectal temperature as qualification for targeted metaphylaxis in newly received beef steers and the effects on growth performance, complete blood count, and serum haptoglobin during a 42-day feedlot receiving period*(2023) Smock, Taylor M. (TTU); Broadway, P. Rand; Burdick Sanchez, Nicole C.; Carroll, Jeffery A.; Hoffman, Ashley A. (TTU); Long, Nathan S. (TTU); Manahan, Jeff L. (TTU); McDaniel, Zach S. (TTU); Theurer, Miles E.; Wells, Jim E.; Hales, Kristin E. (TTU)Objective: The objective was to evaluate rectal tem- perature and infrared thermography as qualification for targeted metaphylaxis, and effects on clinical health, growth performance, complete blood count, and serum haptoglobin in newly received beef steers during a 42-d feedlot receiving period. Materials and Methods: Crossbred beef steers (n = 240; arrival BW = 258 ± 22.5 kg) were used. Experimental treatments were arranged as a generalized complete block design: sterile saline (NCON); conventional metaphylaxis administered to all steers (CONV); targeted metaphylaxis administered to steers with rectal temperature ≥39.7°C (RECT); or targeted metaphylaxis administered to steers with ocular infrared temperature ≥39.7°C (EYE). Body weight and blood samples for quantification of complete blood count and serum haptoglobin were collected on d 0, 14, and 42 relative to metaphylaxis. Results and Discussion: Metaphylaxis was adminis- tered to 0% of NCON, 100% of CONV, 48.9% of RECT, and 48.6% of EYE steers (P < 0.01). Therapeutic bovine respiratory disease (BRD) treatment rate did not differ (P = 0.16), although overall BRD treatment rate was minimal. Metaphylaxis was 62.5% of total active antimicrobial compound administered to RECT and 32.1% of total ac- tive antimicrobial compound administered to EYE. Both methods of targeted metaphylaxis decreased percentage of animals administered antimicrobials relative to CONV (P < 0.01), but total milligrams of active drug compound administered was not different (P = 0.65). Body weight, DMI, DMI as percentage of BW, and G:F did not differ at any time point (P ≥ 0.07). A tendency (P = 0.06) was observed for ADG from d 0 to 14, where CONV was greatest, RECT and EYE were intermediate, and NCON was least. Day 0 to 42 ADG was greatest in CONV and RECT, least in NCON, and intermediate in EYE (P < 0.01). Platelet count tended (P = 0.10) to be greatest in NCON and RECT, followed by EYE and CONV. No further hematologic treatment differences were observed (P ≥ 0.22). Implications and Applications: Overall BRD morbidity was unexpectedly low in the present study. Both methods of targeted metaphylaxis decreased the propor- tion of animals administered antimicrobials relative to conventional metaphylaxis; however, total milligrams of active drug compound administered was not different. The ADG of steers administered targeted metaphylaxis based on rectal temperature did not differ from those ad- ministered conventional metaphylaxis. Use of targeted metaphylaxis with measures of body temperature may decrease the proportion of animals administered metaphylaxis while maintaining optimal health and growth perfor- mance outcomes.Item Predicting metabolizable energy from digestible energy for growing and finishing beef cattle and relationships to the prediction of methane(2022) Hales, Kristin E. (TTU); Coppin, Carley A. (TTU); Smith, Zachary K.; McDaniel, Zach S. (TTU); Tedeschi, Luis O.; Cole, N. Andy; Galyean, Michael L. (TTU)Reliable predictions of metabolizable energy (ME) from digestible energy (DE) are necessary to prescribe nutrient requirements of beef cattle accurately. A previously developed database that included 87 treatment means from 23 respiration calorimetry studies has been updated to evaluate the efficiency of converting DE to ME by adding 47 treatment means from 11 additional studies. Diets were fed to growing-finishing cattle under individual feeding conditions. A citation-adjusted linear regression equation was developed where dietary ME concentration (Mcal/kg of dry matter [DM]) was the dependent variable and dietary DE concentration (Mcal/kg) was the independent variable: ME = 1.0001 × DE - 0.3926; r2 = 0.99, root mean square prediction error [RMSPE] = 0.04, and P < 0.01 for the intercept and slope. The slope did not differ from unity (95% CI = 0.936 to 1.065); therefore, the intercept (95% CI = -0.567 to -0.218) defines the value of ME predicted from DE. For practical use, we recommend ME = DE - 0.39. Based on the relationship between DE and ME, we calculated the citation-adjusted loss of methane, which yielded a value of 0.2433 Mcal/kg of dry matter intake (DMI; SE = 0.0134). This value was also adjusted for the effects of DMI above maintenance, yielding a citation-adjusted relationship: CH4, Mcal/kg = 0.3344 - 0.05639 × multiple of maintenance; r2 = 0.536, RMSPE = 0.0245, and P < 0.01 for the intercept and slope. Both the 0.2433 value and the result of the intake-adjusted equation can be multiplied by DMI to yield an estimate of methane production. These two approaches were evaluated using a second, independent database comprising 129 data points from 29 published studies. Four equations in the literature that used DMI or intake energy to predict methane production also were evaluated with the second database. The mean bias was substantially greater for the two new equations, but slope bias was substantially less than noted for the other DMI-based equations. Our results suggest that ME for growing and finishing cattle can be predicted from DE across a wide range of diets, cattle types, and intake levels by simply subtracting a constant from DE. Mean bias associated with our two new methane emission equations suggests that further research is needed to determine whether coefficients to predict methane from DMI could be developed for specific diet types, levels of DMI relative to body weight, or other variables that affect the emission of methane.Item Validation of an experimental model to induce liver abscesses in Holstein steers using an acidotic diet challenge and intraruminal bacterial inoculation*†(2024) McDaniel, Zach S. (TTU); Hales, Kristin E. (TTU); Nagaraja, T. G.; Lawrence, Ty E.; Tennant, Travis C.; Amachawadi, Raghavendra G.; Carroll, Jeff A.; Burdick Sanchez, Nicole C.; Galyean, Michael L. (TTU); Davis, Emily (TTU); Kohl, Kesley (TTU); Line, Dalton J. (TTU); Dornbach, Colten W. (TTU); Abbasi, Mina; Deters, Alyssa; Shi, Xiaorong; Ballou, Michael A. (TTU); Machado, Vinicius S. (TTU); Smock, Taylor M. (TTU); Broadway, Paul R.Objective: Our objectives were to develop and evaluate a model to induce liver abscesses (LA) in cattle and assess roles of Fusobacterium and Salmonella on LA formation and severity. Materials and Methods: Holstein steers (n = 40; initial BW = 110 ± 12.0 kg) were assigned randomly to treatments (n = 10 per treatment): (1) control diet (CON); (2) acidotic diet (AD); (3) AD plus inoculation of Fusobacterium necrophorum ssp. necrophorum (8.81 × 1010 cfu/steer; ADFn); or (4) AD and intraruminal inoculation of F. necrophorum (8.81 × 1010 cfu/steer) and Salmonella enterica Lubbock (1.52 × 1011 cfu/steer; ADFS). On d 0, steers were subjected to 4 acidotic cycles where they were fed the acidotic diet for 3 d and then the control diet for 2 d. Intraruminal bacterial inoculation was on d 20. From d 21, AD, ADFn, and ADFS steers remained on the acidotic diet until d 38. Euthanasia occurred on d 38, and gross pathology of the lung, rumen, liver, and colon were recorded. Results and Discussion: Liver abscess prevalence was 40% in ADFn and 50% in ADFS versus 0% in CON and AD. No pathological differences were noted in lung nor colon among treatments; however, ruminal damage was more severe in ADFn and ADFS than in CON and AD steers. Implications and Applications: Acidotic diet alone caused mild ruminal acidosis but no LA. Acidotic diet with intraruminal bacterial inoculation increased rumenitis severity and resulted in LA, thus validating the nutritional model to induce LA. Therefore, acidotic diet with intraruminal bacterial inoculation is a viable model to study the formation of LA.