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.

Effects of dietary spray-dried plasma protein on nutrient digestibility and growth performance in nursery pigs

The objectives were to determine the digestible energy and standardized ileal digestibility of amino acids (AA; Exp. 1) and to determine growth performance (Exp. 2) of 2 sources of dietary spray-dried plasma protein (SDPP) in nursery pigs. In Exp. 1, twelve nursery barrows (9.8 ± 0.9 kg) were assigned to a quadruplicated 3 × 2 Latin square design with 3 diets and 2 periods. Each period consisted of 5 days of adaptation, 2 days of fecal sampling, and 2 days of ileal collection. A basal diet was composed of corn, soybean meal, whey, and sucrose as the sole energy and AA sources. Experimental diets were prepared by replacing 15% of the energy and AA sources in the basal diet with SDPP 1 (manufactured in the USA; 78.2% crude protein and 4,862 kcal gross energy/kg as-is) or SDPP 2 (manufactured in Korea; 74.3% crude protein and 4,636 kcal gross energy/kg as-is). Spray-dried plasma protein 1 had greater digestible energy (P < 0.05), but less (P < 0.05) standardized ileal digestibility of Lys, Met, Trp, and Thr compared with SDPP 2. In Exp. 2, eighty-four nursery pigs (7.9 ± 0.7 kg) were allotted to 3 dietary treatments in a randomized complete block design with 7 replicate pens and 4 pigs per pen. Three corn-soybean meal-whey-based diets contained fish meal (6% and 3.5% for d 0 to 14 and d 14 to 28, respectively), SDPP 1 (4.5% and 2.7%), or SDPP 2 (5.0% and 3.0%) to maintain same energy and nutrient concentrations. During d 0 to 14 and overall period, pigs fed the diets containing SDPP gained more weight (P < 0.05) than those fed the fish meal diet with no difference between 2 SDPP sources. In conclusion, SDPP 1 contains greater digestible energy but less AA digestibility compared with SDPP 2. Growth-promoting effects of both SDPP sources in nursery diets have been clearly demonstrated in this work.

Effects of corn processing and cattle size on total tract digestion and energy and nitrogen balance

This study used 18 calves (295 ± 29 kg) and 18 yearlings (521 ± 29 kg) fed whole, cracked or steam-flaked corn (SFC) to evaluate nutrient digestion and energy balance across different types of processed corn and sizes of cattle. Cattle were fed a diet comprised of 75% corn (DM-basis) from whole, cracked or SFC to 2.5-times maintenance energy requirements. Subsequently, cattle were placed in individual stanchions and urine and feces was collected together with measures of gas production via indirect calorimetry. Data were analyzed using the MIXED procedure of SAS. There was no interaction of corn processing and cattle size (P ≥ 0.40). Time spent ruminating (min/d) and rumination rate (min/kg DM intake; DMI) was not affected by corn processing or cattle size. Eating rate (min/kg DMI) was faster (P < 0.01) for yearlings compared to calves. Total tract starch digestion was greatest (P = 0.01) for cattle fed SFC (97.5%), intermediate in cattle fed cracked (92.4%) and least in cattle fed whole corn (89.5%). Dietary digestible energy and metabolizable energy (Mcal/kg DMI) were greater (P ≤ 0.05) for cattle fed SFC compared to cracked or whole. A greater proportion of digestible energy was lost to heat production (P = 0.01) in cattle fed whole corn compared to cracked and tended to be greater (P = 0.08) in cattle fed SFC than cracked. Conversion of digestible energy to metabolizable energy in this study was more closely related to a dynamic model used to estimate metabolizable energy of feeds to dairy cows than to a linear model used to predict metabolizable energy of feeds to beef cattle. If library estimates of net energy for maintenance are correct, then retained energy (Mcal/d) should have been similar between each type of processed corn; however, retained energy was greater (P < 0.01) for cattle fed cracked compared to whole corn and tended to be greater (P = 0.06) compared to SFC. Yet, observed amounts of net energy based on measures of retained energy were not different (P ≥ 0.60) between cracked and SFC. Nitrogen balance was not affected (P ≥ 0.30) by corn processing or cattle size, although cattle fed cracked had numerically greater (P ≤ 035) N retention. These data indicate that physical processing of corn provides greater net energy to cattle in comparison to whole corn.

Effects of dietary levels of calcium, phosphorus, and 1-alpha-hydroxycholecalciferol on digestibility, retention of calcium and phosphorus, and concentration of metabolizable energy in diets fed to sows in late-gestation

The apparent total tract digestibility and retention of calcium (Ca) and phosphorus (P) and concentrations of digestible energy and metabolizable energy in diets fed to late-gestating sows were not affected by Ca and P levels, but they were increased by dietary supplementation with 1-alpha-hydroxycholecalciferol. There was no interaction between dietary Ca and P and supplementation with 1-alpha-hydroxycholecalciferol.

Metabolizable energy in corn is greater than in hybrid rye when fed to gestating sows, but exogenous enzymes did not increase energy digestibility

The metabolizable energy (ME) in corn was greater (P < 0.05) than in hybrid rye when fed to sows in mid-gestation, although the difference between the two grains was less than the difference previously observed in growing pigs. An exogenous enzyme mixture did not increase apparent total tract digestibility of dry matter or gross energy in corn or hybrid rye fed to gestating sows. Likewise, digestible energy and ME in corn and hybrid rye were not increased by the enzymes.

Feeding Sows Lucerne, or Diets with Similar Energy and Nutritional Profiles to Lucerne, Improves the Pre-Weaning Performance of Piglets

Feeding fibre and branched-chain amino acids (BCAA) to sows during late gestation and lactation, respectively, have been shown to improve litter weights at weaning. Therefore, supplementing primiparous sow diets with lucerne chaff, a feedstuff high in fibre, BCAA and tryptophan, may improve the performance of their progeny. Experiment 1 investigated the effects of feeding primiparous sows (n = 118) either (i) a control diet (CON); (ii) CON with 1 kg of lucerne chaff (LUC); or (iii) a diet formulated to have a similar digestible energy and BCAA content as CON + LUC (SIMLUC 1) until farrowing. The LUC and SIMLUC 1 diets improved day 21 litter weight (p = 0.055). In Experiment 2 primiparous (n = 111) and multiparous sows (parities 2–5, n = 112) were fed either the CON or SIMLUC diet (SIMLUC 2) from day 110 of gestation to farrowing (PreF), or to day 10 post-farrowing (PreF + PostF). The SIMLUC 2 diet tended to be more beneficial to primiparous compared to multiparous sows when fed PreF, as indicated by an interaction between diet and parity on day 21 average piglet weights (p = 0.078). Overall, SIMLUC is most effective in improving primiparous progeny performance as evidenced by their D21 weights.

PSVI-10 Effects of dietary spray-dried plasma protein on nutrient digestibility and growth performance in nursery pig

The objectives were to determine the digestible energy, standardized ileal digestibility of AA, and growth performance of dietary spray-dried plasma protein (SDPP) in nursery pigs. In Exp. 1, twelve nursery barrows (9.8 ± 0.9 kg) were assigned to a quadruplicated 3 × 2 Latin square design with 3 diets and 2 periods. Each period consisted of 5 days of adaptation, 2 days of fecal sampling, and 2 days of ileal collection. A basal diet was composed of corn, soybean meal, dried whey, and sucrose as the sole energy and AA sources. Experimental diets were prepared by replacing 15% of the energy and AA sources in the basal diet with SDPP 1 (manufactured in the US; 78.2% CP and 4,862 kcal GE/kg as-is) or SDPP 2 (manufactured in Korea; 74.3% CP and 4,636 kcal GE/kg as-is). Spray-dried plasma protein 1 had greater digestible energy (4,799 vs. 4,469 kcal/kg as-is; P &lt; 0.05), but less (P &lt; 0.05) standardized ileal digestibility of lysine, methionine, tryptophan, and threonine compared with SDPP 2. In Exp. 2, eighty-four nursery pigs (7.9 ± 0.7 kg) were allotted to 3 dietary treatments in a randomized complete block design with 7 replicate pens and 4 pigs per pen. Three corn-soybean meal-whey-based diets contained fish meal (6% and 3.5% for d 0 to 14 and d 14 to 28, respectively), SDPP 1 (4.5% and 2.7%), or SDPP 2 (5% and 3%) to maintain same energy and nutrient concentrations. During d 0 to 14 and overall period, pigs fed the diets containing SDPP gained more weight (P &lt; 0.05) than those fed the fish meal diet with no difference between 2 sources of SDPP. Overall, 2 sources of SDPP have different energy concentrations and AA digestibility, but similar growth promoting effects in nursery pigs.

PSIV-B-25 Digestible energy and metabolizable energy of high-fiber ingredients in growing pig diets

The objective of this study was to determine the digestible energy (DE) and metabolizable energy (ME) concentrations in high-fiber ingredients fed to growing pigs. Twelve barrows with an initial body weight of 57.5 kg (SD = 5.7) were individually housed in metabolism crates. A replicated 6 × 3 incomplete Latin square design with 12 animals, 6 experimental diets and 3 periods was employed. A basal diet was composed of 75.0% corn and 22.7% soybean meal (SBM) as the sole energy sources. Four experimental diets were prepared by replacing 40% of corn and SBM with soybean hulls (SH), corn gluten feed (CGF), wheat bran (WB), or rice bran (RB). An additional diet was prepared by replacing 10% of corn and SBM with cashew nut hulls (CNH). Each period consisted of a 4-d adaptation period and a 4-d collection period, and the marker-to-marker procedure was used for total collection of feces and urine. The DE and ME values in RB (3,969 and 3,936 kcal/kg DM) were greater (P &lt; 0.05) than those in CGF (2,654 and 2,520 kcal/kg DM) and SH (2,492 and 2,541 kcal/kg DM) and the energy values in WB (3,162 and 3,118 kcal/kg DM) were not different from those in RB, CGF, or SH. The DE and ME values in CNH (350 and 572 kcal/kg DM) were less (P &lt; 0.05) than those in all other test ingredients. In conclusion, energy concentrations in RB were greatest among the high-fiber test ingredients, whereas CNH had the lowest values.

543 Late-Breaking: Development of a Model to Predict Dietary Metabolizable Energy from Digestible Energy in Beef Cattle

We aimed to assess whether predicting the metabolizable energy (ME) to digestible energy (DE) ratio (MDR), rather than a prediction of ME with DE, is feasible and to develop a model equation to predict MDR in beef cattle. For this, we constructed a literature database based on published data. A meta-analysis was conducted with 306 means from 69 studies containing both dietary DE and ME concentrations measured by calorimetry to test whether the exclusion of the y-intercept is adequate in the linear relationship between DE and ME. A random coefficient model with study as the random variable was used to develop equations to predict MDR in growing and finishing beef cattle. The developed equations were evaluated with other published equations. The no-intercept linear equation represented the relationship between DE and ME more appropriately than the equation with a y-intercept. Within our growing and finishing cattle data, the animal’s physiological stage was not a significant variable affecting MDR after accounting for the study effect (P = 0.213). The mean (± SE) of MDR was 0.849 (± 0.0063). Two linear equations with the dry matter intake and content of several dietary nutrients were developed to predict MDR. When using these equations, the observed ME was predicted with high precision (R2 = 0.92). The model accuracy was also high, as shown by the high concordance correlation coefficient (&gt; 0.95) and small root mean square error of prediction (RMSEP), less than 5% of the observed mean. Moreover, a significant portion of the RMSEP was due to random bias (&gt; 93%), without mean or slope bias (P &gt; 0.05). We concluded that dietary ME in beef cattle could be accurately estimated from dietary DE and its conversion factor, MDR, using the two equations developed in this study.