Predicting Metabolizable Energy from Digestible Energy for Growing and Finishing Beef Cattle and Relationships to Prediction of Methane

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; r 2 = 0.99, root mean square prediction error [RMSPE] = 0.04, 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 DMI (SE = 0.0134). This value was also adjusted for the effects of dry matter intake (DMI) above maintenance, yielding a citation-adjusted relationship: CH4, Mcal/kg = 0.3344 – 0.05639 × multiple of maintenance; r 2 = 0.536, RMSPE = 0.0245, 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.

Impact of Feeding Syngenta Enogen® Feed Corn Compared to Control Corn in Different Diet Scenarios to Finishing Beef Cattle

The objective of this pooled statistical analysis was to evaluate Syngenta Enogen® Feed Corn (EFC) versus conventional corn (CON) when fed as either dry-rolled corn (DRC) or high-moisture corn (HMC) for effects on finishing beef cattle performance and carcass characteristics. Corns were evaluated in diets with byproduct inclusion rates of 0, 15, 18, 20, and 30% distiller grains or 25 and 35% Sweet Bran® (a commercial corn gluten feed product). Seven trials (n = 1856) consisting of 200 pen means comparing 26 diet treatments were analyzed using regression in a pooled analysis. When EFC was processed as DRC, the gain efficiency (G:F) improved compared with CON, but the response to feeding EFC decreased from a 4.8% improvement to no improvement compared to CON as distiller grains increased from 0% to 30%, but was significantly improved due to feeding EFC in diets with 0 to 18% distiller grains. Feeding cattle EFC as DRC increased the average daily gain (ADG) and G:F by 4.5% compared with CON corn in diets containing Sweet Bran®. No improvements in animal performance were observed when cattle were fed EFC compared to CON when processed as HMC in any situation. Feeding Enogen® corn improved the gain efficiency of finishing cattle compared with conventional corn when processed as dry-rolled corn and fed in diets with less than 20% distillers or diets that include Sweet Bran®.

PSXIII-24 Is it possible to finish beef cattle in feedlot and be environmentally friendly?

To improve production without affecting the environment, the objective of this research was to evaluate a natural additive to replace the conventional growth promoters in finishing beef cattle diets. 160 Nellore bulls were assigned into two treatments, where the only difference was the additive used: natural additive (Fator P - 600 mg/kg DM) and conventional growth promoters (25 mg/kg DM of monensin + 20 mg/kg DM of virginiamycin). The Fator P® is an organic additive certificated by IBD, which is a blend of the compounds; amino acids (lysine, methionine, and tyrosine), choline, minerals, probiotics and essential fatty acids (omega 3 and omega 6). The diet contained 14% CP and 76% TDN. Nellore young bulls (n = 160), weighing 433 ± 7 kg, with an average age of 24 months, were used. The feedlot facilities contained 16 collective pens, in which 10 animals were allocated. The animal performance was evaluated for 84 days, with 21 days of adaptation. Means were compared with 5% of significance. The conventional growth promoters reduced the dry matter intake. Natural 11.33 kg/day and 10.9 kg/day for the conventional. The conventional growth promoters reduced in 0.43 kg of dry matter intake (P = 0.042) or 0.1% of body weight (P = 0.001; 2.26% to 2.16%). No difference in average daily gain (P = 0.58). 1.655 kg/day for natural and 1.625 for the conventional. The feed efficiency ratio wasn’t different (P = 0.71), natural 146 g / kgMSˉ¹ and 148 g / kgMSˉ¹ for conventional. There were no difference in carcass yield (P = 0.89), mean 56.3%. The natural additives can improve the dry matter intake and can be used as an alternative to antibiotics in high concentrate diets for beef cattle in feedlot system. Thus, finishing beef cattle in the feedlot can be environmentally friendly.

307 Effect of Feeding Distilllers Grain from Wheat on Growth Performance of Growing and Finishing Beef Cattle

The uniqueness of wheat-based distiller grain (wDG) with high protein and digestible fibre gives great feeding opportunities for cattle as energy, protein or fiber source. This abstract summarizes recent research findings on the use of wDG in beef cattle diets. For growing beef cattle, steers fed diets (forage:concentrate, 55:45) with increasing replacement of barley grain with wDG from 0, 8, 16, 24 to 32% (DM basis) linearly (P < 0.01) increased average daily gain (ADG) from 1.09 to 1.28 kg/d and DM intake (DMI) from 7.26 to 7.94 kg/d without affecting gain:feed (0.158). By comparing protein source of canola meal and corn DG in diets containing 60% of silage and 40% of barley grain, steers fed wDG diet had similar ADG (1.46 kg/d) with corn DG (1.51 kg/d), and had no differences in gain:feed (0.178) with canola meal (0.183). For finishing beef cattle, with increasing wDG from 10, 20 to 40% in the place of barley grain of finishing diets, the DMI linearly (P < 0.01) increased from 10.2 to 10.9 kg/d, whereas, the gain:feed linearly (P < 0.01) decreased from 0.172 to 0.159 without altering the ADG (1.74 kg/d). The wDG was also suggested to be fed as fiber source to replace roughage in finishing diet. Entirely substitution of wDG for roughage of finishing diet decreased (P < 0.01) ruminal pH from 5.95 to 5.75 of beef heifers; however, the ADG and gain:feed of steers were not affected. The results suggested that although substitution of wDG for roughage in finishing diets may increase the incidence of ruminal acidosis, this outcome does not appear to adversely impact the performance of the cattle. The wDG can be successfully incorporated to substitute a portion of grain or roughage within growing and finishing diets with minimal or no adverse impact on cattle growth performance.

93 Equivalent Effects of Growing Phase ADG and DOF at Various Placement Weights on Finishing Beef Cattle Performance Using Meta-analysis Approach

A meta-analysis approach was used to interpret effects of growing phase days and rate of gain on finishing performance at theoretically similar maturity using a dataset derived from 53 manuscripts. Growing phase feeding strategies included dry-lot feeding a high-energy finishing diet post-weaning (HG; n = 16), silage (DL-forg; n = 32) or a moderate energy diet (DL; n = 78), stocking cattle on winter wheat (WW; n = 16) or range (GR; n = 43). Independent variables of interest were initial growing phase body weight (initial BW), growing phase average daily gain (ADG), days-on-feed in growing phase (DOF), and final growing phase body weight. Data were analyzed using the PROC MIXED procedure of SAS, with treatment means weighted by experimental units (EU) per treatment. Optimal combinations of growing phase DOF and initial BW differed between models. Yet, for dressing percent (R2 = 0.39), LMA (R2 = 0.55), final finishing BW (R2 = 0.58), and HCW (R2 = 0.54) models, an 80-d growing phase for cattle starting at 240 kg resulted in greatest responses by these variables. Simulations evaluating effects of growing phase ADG on finishing performance (dressing percent; LMA; final body weight; HCW) were set equivalent to simulations evaluating the sensitivity of growing phase DOF in response to initial BW. Solving these simulations generated the initial BW at which cattle were more responsive to growing phase length (DOF) than ADG (LMAcritical point = 255 kg; DPcritical point = 242 kg; Final finishing BWcritical point = 231 kg; HCWcritical point = 233 kg). For finishing performance traits listed, each critical point represents the inflexion at which growing phase ADG exerts greatest influence on each trait modeled. Thus, for example, for cattle starting a growing phase at under 233 kg, faster growing phase ADG results in greater hot carcass weight response.

Proteomic Analysis of Liver from Finishing Beef Cattle Supplemented with a Rumen-Protected B-Vitamin Blend and Hydroxy Trace Minerals

Vitamin B and trace minerals are crucial molecular signals involved in many biological pathways; however, their bioavailability is compromised in high-producing ruminant animals. So far, studies have mainly focused on the effects of these micronutrients on animal performance, but their use in a rumen-protected form and their impact on liver metabolism in finishing beef cattle is poorly known. We used a shotgun proteomic approach combined with biological network analyses to assess the effects of a rumen-protected B-vitamin blend, as well as those of hydroxy trace minerals, on the hepatic proteome. A total of 20 non-castrated Nellore males with 353 ± 43 kg of initial body weight were randomly assigned to one of the following treatments: CTRL—inorganic trace minerals without supplementation of a protected vitamin B blend, or SUP—supplementation of hydroxy trace minerals and a protected vitamin B blend. All animals were fed the same amount of the experimental diet for 106 days, and liver biopsies were performed at the end of the experimental period. Supplemented animals showed 37 up-regulated proteins (p < 0.10), and the enrichment analysis revealed that these proteins were involved in protein folding (p = 0.04), mitochondrial respiratory chain complex I (p = 0.01) and IV (p = 0.01), chaperonin-containing T-complex 2 (p = 0.01), glutathione metabolism (p < 0.01), and other aspects linked to oxidative-stress responses. These results indicate that rumen-protected vitamin B and hydroxy trace mineral supplementation during the finishing phase alters the abundance of proteins associated with the electron transport chain and other oxidation–reduction pathways, boosting the production of reactive oxygen species, which appear to modulate proteins linked to oxidative-damage responses to maintain cellular homeostasis.

251 Effects of Roughage Source on Rumination Time and Ruminal Ph in Steers Fed a Steam-flaked Corn Finishing Diet

Research is limited on how physically effective fiber from various roughage sources aids in rumination time and ruminal pH of finishing beef cattle. This experiment’s objective was to evaluate rumination time and ruminal pH of beef steers consuming finishing diets with varying roughage sources (corn stalks, cotton burrs, or wheat silage). We hypothesized that roughage type would not impact rumination time and ruminal pH if different sources provide similar dietary neutral detergent fiber (NDF). Ruminally cannulated steers (n = 6; average BW = 644.56 + 13.15 kg) were used in a 3 × 3 replicated Latin square with 3 dietary treatments and 3, 21-d periods (20-d diet adaptation, 1-d sampling). Steers consumed a steam-flaked corn-based finishing diet containing corn stalks (CS), cotton burrs (CB), or wheat silage (WS) included at 7% (DM basis) of the diet. Dietary NDF was similar across treatments. Steers were fitted with a sensory collar to record daily rumination (Allflex Livestock Intelligence). Ruminal pH was measured using a handheld pH probe on d-21 at 0, 3, 6, 12, 24 hr postprandial. The NDF and dry matter intake (DMI) were greatest for steers consuming the WS diet (P &lt; 0.01) while CS and CB diets did not differ (P = 0.81). While dietary NDF and estimated physically effective NDF (peNDF) were similar among roughage sources, CB had the lowest actual peNDF, consistent with lower rumination time (P &lt; 0.01) and lower ruminal pH (P = 0.29). This experiment’s results indicate that roughage source impacted rumination time despite feeding steers a steam-flaked corn-based finishing diet with similar roughage and NDF levels. Using rumination time (min/d) to determine peNDF was a better indicator of rumen function parameters than particle size measured via the Penn State Particle Separator equation.

PSIV-6 Effect of a Direct Fed Microbial Feed Additive on Finishing Beef Cattle Performance and Liver Abscess Rate

A feedlot study was conducted comparing the effects of a direct-fed microbial feed additive (DFM) to no feed additive (CON) on performance and liver abscess rates in finishing beef cattle. The study utilized 60 crossbred steers (initial BW 274 kg ± 2.23) individually fed using a Calan gate system. Steers were housed in separate pens by treatment to avoid DFM cross-contamination, with pen (barn of 30 steers) assigned randomly to each treatment. Cattle were fed a diet consisting of 15% corn silage, 36.5% high moisture corn, 24.5% dry rolled corn, 20% modified distillers grains, and 4% supplement for 189 days. The DFM counts were estimated using cell cytometry and was top dressed at a concentration of approximately 81 billion bacterial cells/head/day. The DFM additive used in this study was developed to reduce the abundance of Fusobacterium necrophorum and Streptococcus bovis in the rumen. No effect of treatment on hot carcass weight (HCW), average daily gain (ADG), dry matter intake (DMI), feed efficiency (G:F), or carcass traits (Table 1) were observed. No significant difference in the occurrence of liver abscesses between treatment groups were observed with 4 steers having abscessed livers in the CON group and 3 steers in the DFM group. Additionally, there were no differences in the severity of liver abscesses; all observed liver abscesses received the score of A. The DFM utilized in this study did not significantly affect performance, liver abscess rate, or the severity of liver abscesses in finishing beef cattle.

The Effect of Different Sources of Selenium Supplementation on the Meat Quality Traits of Young Charolaise Bulls during the Finishing Phase

The aim of the study was to compare the effects of sodium selenite (SS), selenium yeast (SY), and hydroxy-selenomethionine (OH-SeMet) on the meat quality and selenium (Se) deposition of finishing beef cattle. Sixty-three bulls were distributed over 3 treatments and fed SS, SY, or OH-SeMet at 0.2 mg kg−1 dry matter (DM) for 60 d. None of the Se sources affected the growth performance or carcass characteristics. OH-SeMet showed a higher Se transfer to the meat than SS or SY (p < 0.01). SY and OH-SeMet reduced the shear force of the meat (p < 0.0001), improved pH (p < 0.001), and reduced the drip losses (p < 0.001) and the lipid oxidation of the meat (p < 0.001). During 8 d of storage, OH-SeMet showed higher levels of meat lightness (L*) and yellowness (b*) than SS (p < 0.001), while the SY meat showed a higher L* than SS, albeit only on d 6. OH-SeMet improved b*, compared to SS, and also compared to SY on days 4, 7, and 8 (p < 0.001). Supplementing beef with SY and OH-SeMet improved several meat quality parameters. OH-SeMet appears to be the most effective strategy to improve the Se content and color stability of beef cattle meat.