Predicting metabolizable energy from digestible energy for growing and finishing beef cattle and relationships to the 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; 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.     

Predicting corn digestible and metabolizable energy content from its chemical composition in growing pigs

Background

The nutrient composition of corn is variable. To prevent unforeseen reductions in growth performance, grading and analytical methods are used to minimize nutrient variability between calculated and analyzed values. This experiment was carried out to define the sources of variation in the energy content of corn and to develop a practical method to accurately estimate the digestible energy (DE) and metabolisable energy (ME) content of individual corn samples for growing pigs. Twenty samples were taken from each of five provinces in China (Jilin, Hebei, Shandong, Liaoning, and Henan) to obtain a range of quality.

Results

The DE and ME contents of the 100 corn samples were measured in 35.3 ± 1.92 kg growing pigs (six pigs per corn sample). Sixty corn samples were used to build the prediction model; the remaining forty samples were used to test the suitability of these models. The chemical composition of each corn sample was determined, and the results were used to establish prediction equations for DE or ME content from chemical characteristics. The mean DE and ME content of the 100 samples were 4,053 and 3,923 kcal/kg (dry matter basis), respectively. The physical characteristics were determined, as well, and the results indicated that the bulk weight and 1,000-kernel weight were not associated with energy content. The DE and ME values could be accurately predicted from chemical characteristics. The best fit equations were as follows: DE, kcal/kg of DM = 1062.68 + (49.72 × EE) + (0.54 × GE) + (9.11 × starch), with R² = 0.62, residual standard deviation (RSD) = 48 kcal/kg, and P < 0.01; ME, kcal/kg of dry matter basis (DM) = 671.54 + (0.89 × DE) – (5.57 × NDF) – (191.39 × ash), with R² = 0.87, RSD = 18 kcal/kg, and P < 0.01.

Conclusion

This experiment confirms the large variation in the energy content of corn, describes the factors that influence this variation, and presents equations based on chemical measurements that may be used to predict the DE and ME content of individual corn samples.     

Effect of oat particle size on energy and nutrient utilization in growing pigs

An experiment was conducted to determine the energy content of oats and to investigate the effects of oat particle size on nutrient and energy balance in growing pigs. Eighteen barrows (23.56 ± 0.94 kg initial body weight) were randomly assigned to one of the three dietary treatments with six replicates per treatment. Whole oats were ground with a hammermill fitted with 4.8- and 3.2-mm screens to make coarse and medium particle size oats, respectively. Medium oats were further ground with a rotary steel cutting grinder fitted with a 2.0-mm screen, and the further ground oats were mixed with medium oats in a 1:3 ratio to make fine oats. Three experimental diets consisted of 96.3% of the coarse, medium, or fine oats as a sole source of energy were used. Pigs were fed diets for 16 d, including 10 d for adaptation and 6 d for total fecal and urine collection. Pigs were then moved into indirect calorimetry chambers to determine 24-h heat production and 12-h fasting heat production. All data were analyzed using the MIXED procedure of SAS with the individual pig as the experimental unit. The geometric mean particle sizes for coarse, medium, and fine oats were 765, 619, and 569 μm, respectively. Pigs fed the medium oats diet tended to have (P < 0.10) greater apparent total tract digestibility (ATTD) of starch, neutral detergent fiber, and gross energy than those fed coarse oats diet. The medium oats diet contained greater (P < 0.05) digestible energy (DE), metabolizable energy (ME), and net energy (NE) than the coarse oats diet. Pigs fed the fine oats diet had lower (P < 0.05) ATTD of Ca and P than those fed the coarse oats diet. The DE, ME, and NE contents of fine oats were comparable with those of coarse oats. The determined NE contents for coarse, medium, and fine oats were 2,335, 2,615, and 2,521 kcal/kg on a dry matter basis, respectively. The NE content in medium oats was greater (P < 0.05) than the NE values predicted using published equations. In conclusion, it was suggested to grind whole oats for 619 μm concerning energy utilization. Further grinding to 569 μm reduces Ca and P digestibility.     

直接法和回归法测定玉米青贮对肉牛有效能值的研究

旨在应用直接法和回归法测定肉牛玉米青贮的消化能、代谢能和净能值,并探讨精料回归法用于估测肉牛单一粗饲料原料能值的可行性。试验选取12头体况良好、体重相近[(259±14.08)kg]的生长期公牛,随机分为3组,每组4头牛。分两期试验进行,试验一按试验牛自由采食量的95%、80%和60%3个水平饲喂全玉米青贮日粮;试验二在固定玉米青贮投喂量的基础上,各组分别按青贮饲喂量的15%、25%和50%(干物质基础)添加精料补充料。试验每期14d,其中前10d为预饲期,后4d为正试期。正试期消化代谢和呼吸代谢试验同期进行,测定玉米青贮对肉牛能量代谢规律。结果表明:1)肉牛对全玉米青贮日粮的各种营养物质消化率和能量消化率及代谢率随饲喂水平的提高总体逐渐降低;肉牛能量采食量(总能、消化能、代谢能和净能)随饲喂水平的提高逐渐升高,组间差异显著(P0.05)。2)玉米青贮对肉牛的消化能、代谢能和净能值随着饲喂水平的提高呈下降趋势,各有效能值变化范围分别为10.58~11.48 MJ/kg,8.33~9.44 MJ/kg和5.20~6.21 MJ/kg。3)添加精料补充料显著提高了肉牛对日粮的干物质采食量和粗蛋白消化率(P0.05),而洗涤纤维消化率精料添加比例组间差异不明显(P0.05);随着精料添加比例的增加,肉牛对日粮的能量采食量(总能、消化能、代谢能和净能)和能量消化率及代谢率逐渐上升,消化能代谢率各组之间无显著差异(P0.05)。4)根据试验日粮有效能值与精料添加量之间的关系建立线性回归方程后,外推估测得玉米青贮的消化能、代谢能和净能值分别为10.53 MJ/kg、8.29 MJ/kg和5.35MJ/kg,与95%饲喂水平组直接测定结果(10.58 MJ/kg、8.33 MJ/kg和5.20 MJ/kg)差异不显著(P0.05)。综上所述,回归法测定玉米青贮对肉牛的有效能值与直接法测定结果差异不明显,精料回归法可以用于估测肉牛单一粗饲料的有效能值。     

Effects of dietary energy on growth performance,carcass characteristics,serum biochemical index,and meat quality of female Hu lambs

This study evaluated the effects of dietary energy levels on growth performance, carcass traits, meat quality, and serum biochemical of female Hu lambs. Seventy female Hu lambs (aged 4 months) were randomly allotted to 5 dietary treatments. Lambs were fed diets with 5 levels of metabolizable energy (ME): 9.17 (E1), 9.59 (E2), 10.00 (E3), 10.41 (E4), and 10.82 MJ/kg (E5). The lambs were adapted to the experimental diets for 10 d and the experiment period lasted for 60 d. Dry matter intake and feed conversion ratio linearly (P < 0.001) increased and decreased (P < 0.001), respectively, with increasing dietary ME levels. Average daily gain (ADG) linearly (P < 0.001) increased with increasing dietary ME levels, with the highest final body weight (P = 0.041) observed in E4 group. Moreover, dietary energy level was associated with linear increases in serum total protein (TP) (P < 0.001), albumin (ALB) (P = 0.017), glucose (GLU) (P = 0.004), and low-density lipoprotein cholesterol (LDLC) (P = 0.006) concentrations, and it was associated with a quadratic decrease in serum triglyceride (TG) concentration (P = 0.002). Serum ammonia concentration, which was firstly decreased and then increased, was quadratically affected by dietary ME levels (P = 0.013). Compared with E1 group, lambs in E4 group had higher (P < 0.05) live weights, carcass weights, mesenteric fat ratio, non-carcass fat ratio, and larger loin muscle area, but lower (P < 0.05) meat colour a∗ and b∗ values, and lesser (P < 0.05) C17:0, C20:0, C18:1n-9t, C18:3n-3, and n-3 polyunsaturated fatty acids (PUFA), but greater (P < 0.05) C18:3n-6 and n-6:n-3 ratios in longissimus dorsi (LD) muscle tissue, and lesser (P < 0.05) C17:0, C18:3n-3, C22:6n-3, and n-3 PUFA in the biceps femoris (BF) muscle tissue. The results demonstrated that increasing dietary energy level improved the growth performance and affected carcass traits, serum biochemical indexes, and fatty acid profiles in different muscles of female Hu lambs. For 4-month-old female Hu lambs, the recommended fattening energy level is 10.41 MJ/kg.     

Energy content of intact and heat-treated dry extruded-expelled soybean meal fed to growing pigs

An experiment was performed to evaluate the energy content of extruded-expelled soybean meal (EESBM) and the effects of heat treatment on energy utilization in growing pigs. Eighteen growing barrows (18.03 ± 0.61 kg initial body weight) were individually housed in metabolism crates and randomly allotted to one of three dietary treatments (six replicates per treatment). The three experimental diets were the following: a corn-soybean meal-based basal diet and two test diets with simple substitution of a basal diet with intact EESBM or heat-treated EESBM (heat-EESBM) at a 7:3 ratio. Intact EESBM was autoclaved at 121 °C for 60 min to make heat-treated EESBM. Pigs were fed the experimental diets for 16 d, including 10 d for adaptation and 6 d for total collection of feces and urine. Pigs were then moved into indirect calorimetry chambers to determine 24-h heat production and 12-h fasting heat production. The energy content of EESBM was calculated using the difference method. Data were analyzed using the Mixed procedure of SAS with the individual pig as the experimental unit. Pigs fed heat-EESBM diets showed lower (P < 0.05) apparent total tract digestibility of dry matter (DM), gross energy, and nitrogen than those fed intact EESBM. A trend (P ≤ 0.10) was observed for greater heat increments in pigs fed intact EESBM than those fed heat-EESBM. This resulted in intact EESBM having greater (P < 0.05) digestible energy (DE) and metabolizable energy (ME) contents than heat-EESBM. However, no difference was observed in net energy (NE) contents between intact EESBM and heat-EESBM, showing a tendency (P ≤ 0.10) toward an increase in NE/ME efficiency in heat-EESBM, but comparable NE contents between intact and heat-EESBM. In conclusion, respective values of DE, ME, and NE are 4,591 kcal/kg, 4,099 kcal/kg, and 3,189 kcal/kg in intact EESBM on a DM basis. It is recommended to use NE values of feedstuffs that are exposed to heat for accurate diet formulation.     

Digestible and metabolizable energy concentrations and amino acid digestibility of dried yeast and soybean meal for growing pigs

Energy values and amino acid (AA) digestibility of dried yeast (DY) and soybean meal (SBM) were determined in 2 experiments with growing pigs. Experiment 1 was conducted to determine the digestible energy (DE) and metabolizable energy (ME) in DY and SBM. Thirty barrows with a mean initial body weight (BW) of 20.6 kg (SD = 1.04) were assigned to 5 dietary treatments in a randomized complete block design with period and BW as blocking factors. A reference diet was prepared with corn, canola meal, and soybean oil as energy-contributing ingredients. Four additional diets were prepared by adding 5% and 10% DY or SBM at the expense of energy-contributing ingredients in the reference diet. The ratio of corn, canola meal, and soybean oil was kept consistent across the experimental diets. Each experimental period consisted of 5-d adaptation and 5-d quantitative collection of feces and urine. Test ingredient-associated DE or ME intake (kcal/d) was regressed against test ingredient intake [kg dry matter (DM)/d] to estimate the DE or ME in test ingredients as the slope of linear regression model. The DE in DY was estimated at 3,933 kcal/kg DM, which was not different from the estimated DE in SBM at 4,020 kcal/kg DM. Similarly, there was no difference between DY and SBM in the estimated ME (3,431 and 3,756 kcal/kg DM, respectively). Experiment 2 was conducted to determine the standardized ileal digestibility (SID) of AA in DY and SBM. Twenty-one barrows with a mean initial BW of 20.0 kg (SD = 1.31) were surgically fitted with T-cannulas at the distal ileum and assigned to 3 dietary treatments in a randomized complete block design with BW as a blocking factor. Two semi-purified diets containing DY or SBM as the sole nitrogen source and one nitrogen-free diet (NFD) were prepared. The NFD was used to estimate the basal ileal endogenous losses of CP and AA. Pigs were fed the 3 diets for 5 d as adaptation, followed by 2 d of feeding with ileal digesta collection. The SID of AA, except Gly and Pro, in DY was less (P < 0.05) than in SBM. The SID of indispensable AA in DY ranged from 64.1% for Thr to 85.2% for Arg, and those in SBM ranged from 83.9% for Thr to 91.8% for Arg. In conclusion, energy values of DY are not different from those of SBM, whereas AA in DY is less digestible than in SBM. The estimated DE and ME as well as the SID of AA in DY and SBM can be used in diet formulation for growing pigs using these ingredients.     

Multi-carbohydrase enzymes improve feed energy in broiler diets containing standard or low crude protein

This study evaluated the effect of multi-carbohydrase (MC) on energy and nitrogen (N) balance and gene expression in broilers fed diets with different crude protein (CP) contents. The study employed a 2 × 2 factorial arrangement of treatments. The factors were presence or absence of MC, and standard (SCP) or low (LCP) dietary CP concentration. A 3-phase feeding program was used, including starter (0 to 7 d), grower (8 to 17 d) and finisher (18 to 28 d) phases. The study was undertaken in closed calorimetry chambers. Each of the 4 dietary treatments was replicated 8 times in total across 2 runs, with 2 birds per replicate (n = 64). Data for energy partitioning and N balance were collected from d 25 to 28. On d 28, birds were euthanized to collect muscle and intestinal tissue samples for gene expression. The results showed that the MC increased apparent metabolizable energy (AME, P < 0.01) and net energy (NE, P < 0.05), and reduced the feed conversion ratio (FCR, P < 0.01) in all diets. The proportion of energy retained as fat per total energy retention (REf/RE) was positively correlated with feed AME and NE (r = 0.541, P < 0.01 and r = 0.665, P < 0.001, respectively), suggesting that feed energy augmented with increased fat gain. Muscle ATP synthase subunit alpha (ATP5A1W) gene expression had a positive correlation with REf/RE and feed NE (r = 0.587, P < 0.001 and r = 0.430, P < 0.05, respectively). Similarly, muscle peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1A) expression was negatively correlated with weight gain and positively correlated with FCR (r = −0.451, P < 0.05 and r = 0.359, P < 0.05, respectively). These correlations show that over-expressions of muscle genes related to energy production reduce bird performance. This study demonstrated that MC increase dietary energy utilization, regardless of dietary CP concentration. However, the energy released by the enzymes increases feed energy-to-CP ratio, meaning there is excess energy that is then deposited as body fat. This suggests that supplemental MC in broiler feeds is beneficial if diets are formulated to contain marginal energy levels.     

Nutritional value of a new source of fermented soybean meal fed to growing pigs

Three experiments were conducted to test the hypothesis that the standardized ileal digestibility (SID) of amino acids (AA), concentrations of digestible energy (DE) and metabolizable energy (ME), and the standardized total tract digestibility (STTD) of P in a new source of fermented soybean meal (Fermex 200) are greater than in conventional soybean meal (SBM-CV). In experiment 1, 9 barrows (initial body weight: 9.17 ± 1.03 kg) were surgically fitted with a T-cannula in the distal ileum and allotted to a triplicated 3 × 3 Latin square design. A nitrogen-free diet and 2 diets that contained cornstarch and SBM-CV or Fermex 200 as the sole source of crude protein (CP), and AA were formulated. Results indicated that there were no difference between SBM-CV and Fermex 200 for SID of CP and AA. In experiment 2, 24 growing pigs (initial body weight: 14.19 ± 1.18 kg) were housed individually in metabolism crates. Pigs were allotted to a corn-based diet or 2 diets that contained corn and SBM-CV or corn and Fermex 200. Feces and urine samples were collected using the marker-to-marker approach with 5-d adaptation and 4-d collection periods. Results indicated that the concentration of DE and ME in Fermex 200 were not different from DE and ME in SBM-CV. In experiment 3, 40 barrows (initial body weight: 11.01 ± 1.38 kg) were allotted to 1 of 4 diets with 10 replicate pigs per diet. Four diets were formulated to contain Fermex 200 or SBM-CV and either 0 or 1,000 units/kg of microbial phytase. Pigs were housed individually in metabolism crates. Fecal samples were collected as explained for experiment 2. Results indicated that the STTD of P in Fermex 200 was greater (P < 0.01) than in SBM-CV, but the addition of microbial phytase to the diets increased the ATTD and STTD of P in SBM-CV, but not in Fermex 200 (interaction; P < 0.01). In conclusion, the SID of AA and concentrations of DE and ME in Fermex 200 were not different from values determined for SBM-CV, but the STTD of P was greater in Fermex 200 than in SBM-CV if microbial phytase was not added to the diet.     

The correlationship between the metabolizable energy content,chemical composition and color score in different sources of corn DDGS

Background

This study was conducted to evaluate the apparent metabolizable energy (AME) and true metabolizable energy (TME) contents in 30 sources of corn distillers dried grains with solubles (DDGS) in adult roosters, and establish the prediction equations to estimate the AME and TME value based on its chemical composition and color score.

Methods

Twenty-eight sources of corn DDGS made from several processing plants in 11 provinces of China and others imported from the United States. DDGS were analyzed for their metabolizable energy (ME) contents, measured for color score and chemical composition (crude protein, crude fat, ash, neutral detergent fiber, acid detergent fiber), to predict the equation of ME in DDGS. A precision-fed rooster assay was used, each DDGS sample was tube fed (50 g) to adult roosters. The experiment was conducted as a randomized incomplete block design with 3 periods. Ninety-five adult roosters were used in each period, with 90 being fed the DDGS samples and 5 being fasted to estimate basal endogenous energy losses.

Results

Results showed that the AME ranged from 5.93 to 12.19 MJ/kg, TME ranged from 7.28 to 13.54 MJ/kg. Correlations were found between ME and ash content (-0.64, P < 0.01) and between ME and yellowness score (0.39, P < 0.05) of the DDGS samples. Furthermore, the best-fit regression equation for AME content of DDGS based on chemical composition and color score was AME = 6.57111 + 0.51475 GE - 0.10003 NDF + 0.13380 ADF + 0.07057 fat - 0.57029 ash - 0.02437 L (R² = 0.70). The best-fit regression equation for TME content of DDGS was TME = 7.92283 + 0.51475 GE - 0.10003 NDF + 0.13380 ADF + 0.07057 fat - 0.57029 ash - 0.02437 L (R² = 0.70).

Conclusions

This experiment suggested that measuring the chemical composition and color score of a corn DDGS sample may provide a quality parameter for identifying corn DDGS sources energy digestibility and metabolizable energy content.     

Comparison of digestible and metabolizable energy and digestible phosphorus and amino acid content of corn ethanol coproducts from Brazil and the United States produced using fiber separation technology for swine

Three experiments (exp.) were conducted to determine and compare the digestibility of nutrients and energy of corn distillers dried grains with solubles (DDGS) from the United States (USDDGS), a dried mixture of corn bran with solubles (CBS) from Brazil (BRCBS), and high protein corn distillers dried grains (HP-DDG) from the United States (USHPDG) and Brazil (BRHPDG) in growing pigs. The feed ingredients were evaluated for apparent total tract digestibility (ATTD) of gross energy (GE), dry matter (DM), crude protein (CP), ether extract, neutral and acid detergent fiber (NDF and ADF, respectively), and digestible and metabolizable energy (DE and ME, respectively) using the total collection and index methods in exp. 1; ATTD and standardized total tract digestibility (STTD) of phosphorus (P) in exp. 2; and apparent (AID) and standardized (SID) ileal digestibilities of CP and amino acids (AA) in exp. 3. Fifty crossbred barrows (32.4 ± 6.9, 38.3 ± 5.2, and 46.2 ± 5.3 kg body weight [BW], in exp. 1, 2, and 3, respectively) were fed a corn basal diet in exp. 1, a P-free diet in exp. 2, and an N-free diet in exp. 3 or diets with 40% inclusion of test ingredients to provide 10 replications per treatment. Pigs were housed individually in metabolism cages (exp. 1) or in pens (exp. 2 and 3) and fed at 2.8 times the maintenance DE requirement (110 kcal/kg BW^0.75) based on their BW at the beginning of each experiment. Except for ATTD of NDF, which tended (P = 0.058) to be greater by the index method compared with the total collection method, no difference between the total collection and index methods was observed for ATTD of remaining nutrients and DE. The ATTD of DM, GE, NDF, and DE content of BRHPDG were greater (P < 0.001) than USHPDG, BRCBS, and USDDGS. The AID of CP, Arg, His, Ile, Leu, Lys, Thr, and Val and the SID of His, Leu, Lys, and Val of BRHPDG were 8% to 36% greater (P < 0.05) than those from USHPDG. Except for Trp, all AID and SID AA values were greater (P < 0.05) in BRHPDG than in USHPDG. The ATTD of DM, GE, NDF, and ADF; DE and ME content; AID of CP, Arg, Ile, Leu, Phe, Thr, and Trp; and SID of CP, Arg, Phe, and Thr of USDDGS were 9% to 45% greater (P < 0.05) than those in BRCBS. The ATTD and the STTD of P in USHPDG and USDDGS were 26% to 42% greater (P < 0.05) compared with BRHPDG and BRCBS. In conclusion, BRHPDG had a greater digestibility of energy and most of the AA than USHPDG, while the BRCBS evaluated had lower nutritional value than the USDDGS source.     

Characterization of energy and performance of swine fed a novel corn-soybean extruded product

Background

A novel extruded product was characterized with a metabolism and lactation trial to establish the product’s energy content, and its effects on lactating sow performance. The product was composed of a 60:40 corn-soybean blend, which was then extruded. This product containing the co-extruded 60:40 corn-soybean blend was commercially developed and is used extensively in swine diets in southwest Minnesota. GE of dietary treatments were determined by isoperibol bomb calorimetry. Twelve barrows (59.9 ± 1.4 kg), were used to determine the digestible and metabolizable energy of the extruded product. DE of treatments was determined by subtracting fecal energy from GE provided to barrows by each respective treatment. ME was determined by subtracting urinary energy from calculated digestible energy. Sixty-three sows were used for the lactation trial. Three dietary treatments were utilized: CONTROL (an industry standard diet); PRODUCT (contained the product, vitamins and minerals); OIL (matched the lysine:ME ratio of PRODUCT by addition of soy oil). Sow weight, backfat thickness at the right and left last ribs, body condition score, number of piglets, and litter weights were recorded on the date of farrowing (d 0), (d 9), and at weaning. Blood and milk samples were obtained at weaning, and blood was analyzed for plasma urea nitrogen (PUN), milk was analyzed for total protein and fat content.

Results

On a dry-matter basis, the test diet provided 3,908 kcal/kg DE and 3,833 kcal/kg ME, which was significantly greater than the basal diet, which provided 3,633 kcal/kg DE and 3,567 kcal/kg ME (P < 0.0001). These data were used to establish the DE and ME of the product, which were 3,882 kcal/kg and 3,798 kcal/kg, respectively, on an as-fed basis. No effect of diet was observed for changes in sow backfat (RBF P = 0.24; LBF P = 0.07) or body condition score (P = 0.12) during lactation. Milk total protein (P = 0.69), fat (P = 0.66), PUN, average piglet gain (P = 0.55) and piglet mortality (P = 0.70) did not differ between treatments.

Conclusions

While the novel extruded product was higher in energy content than traditional feedstuffs, it resulted in the same lactational sow performance. Thus, the co-extruded corn-soybean product is a reasonable inclusion in sow lactation diets.     

Digestible and metabolizable energy in corn grains from different origins for growing pigs

An experiment was conducted to determine the digestible energy (DE) and metabolizable energy (ME) concentrations in nine sources of corn grains fed to growing pigs and to compare the energy values among their countries of origin. A total of nine sources of corn grains including five sources of yellow corn from the United States (USY), two sources of yellow corn from South Africa (SAY), and two sources of white corn from South Africa (SAW) were used. Nine barrows with an initial body weight of 37.1 ± 8.6 kg were allotted to a 9 × 9 Latin square design with nine diets and nine periods. The DE concentration in SAY (3347 kcal/kg) was greater (P < 0.001) than in USY (3269 kcal/kg), but was less (P < 0.001) than in SAW (3436 kcal/kg) on an as‐fed basis. Similarly, the ME concentration in SAY (3291 kcal/kg) was greater (P < 0.001) than in USY (3209 kcal/kg), but was less (P < 0.001) than in SAW (3386 kcal/kg). In conclusion, the DE and ME concentrations in nine sources of corn grains are different among their countries of origin.     

肉用绵羊饲粮营养物质消化率和代谢能预测模型的研究

本试验旨在建立肉用绵羊饲粮营养物质消化率和代谢能(ME)的预测模型。选用66只体重为(45.0±2.0)kg的体况良好的杜泊×小尾寒羊F1代杂交肉用羯羊,随机分为11个处理,每个处理6个重复,每个重复1只羊。采用随机区组设计,分别测定11种不同粗饲料组成的饲粮的营养物质含量,通过物质代谢试验和气体代谢试验测定这11种饲粮的营养物质消化率、消化能(DE)及ME,在分析饲粮营养物质含量、可消化营养物质、DE和ME的基础上,筛选出最佳估测因子并建立估测方程。结果表明:饲粮干物质(DM)、有机物(OM)、粗蛋白质(CP)、总能(GE)消化率与饲粮中CP、GE和OM含量呈显著或极显著正相关(P0.05或P0.01),与中性洗涤纤维(NDF)含量呈显著负相关(P0.05);饲粮NDF消化率与饲粮中DM、OM、CP、GE含量达到显著或极显著负相关(P0.05或P0.01),与NDF含量达到极显著正相关(P0.01)。利用饲粮中营养物质含量对ME进行估测的最佳方程为ME=-49.593+0.594OM-0.107NDF(R2=0.949,P0.01)。由此得出,饲粮营养物质消化率、ME与营养物质含量均有较强的相关性,可通过营养物质含量对饲粮的营养物质消化率、ME进行合理估测。     

Concentration and heritability of immunoglobulin G and natural antibody immunoglobulin M in dairy and beef colostrum along with serum total protein in their calves

Immunoglobulin (Ig) G and natural antibody (NAb) IgM are passively transferred to the neonatal calf through bovine colostrum. Maternal IgG provides pathogen- or vaccine-specific protection and comprises about 85% of colostral Ig. NAb-IgM is less abundant but provides broad and nonspecific reactivity, potentially contributing to protection against the dissemination of pathogens in the blood (septicemia) in a calf’s first days of life. In the dairy and beef industries, failure of passive transfer (FPT) of colostral Ig (serum total protein [STP] <5.2 g/dL) is still a common concern. The objectives of this study were to: (1) compare colostral IgG concentrations and NAb-IgM titers between dairy and beef cows; (2) assess the effect of beef breed on colostral IgG; (3) compare passive transfer of colostral Ig in dairy and beef calves; and (4) estimate the heritability of colostral IgG and NAb-IgM. Colostrum was collected from Holstein dairy (n = 282) and crossbred beef (n = 168) cows at the University of Guelph dairy and beef research centers. Colostral IgG was quantified by radial immunodiffusion and NAb-IgM was quantified by an enzyme-linked immunosorbent assay. In dairy (n = 308) and beef (n = 169) calves, STP was estimated by digital refractometry. Beef cows had significantly greater colostral IgG (146.5 ± 9.5 standard error of the mean [SEM] g/L) than dairy cows (92.4 ± 5.2 g/L, P <0.01). Beef cows with a higher proportion of Angus ancestry had significantly lower colostral IgG (125.5 ± 5.8 g/L) than cows grouped as “Other” (142.5 ± 4.9 g/L, P = 0.02). Using the FPT cutoff, 13% of dairy and 16% of beef calves had FPT; still, beef calves had a significantly larger proportion with excellent passive transfer (STP ≥6.2 g/dL, P <0.01). The heritability of colostral IgG was 0.04 (±0.14) in dairy and 0.14 (±0.32) in beef. Colostral NAb-IgM titers in dairy (12.12 ± 0.22, log₂ [reciprocal of titer]) and beef cows (12.03 ± 0.19) did not differ significantly (P = 0.71). The range of NAb-IgM titers was 9.18–14.60, equivalent to a 42-fold range in antibody concentration. The heritability of colostral NAb was 0.24 (±0.16) in dairy and 0.11 (±0.19) in beef cows. This study is the first to compare colostral NAb-IgM between dairy and beef cows. Based on the range in NAb-IgM titers and the heritability, selective breeding may improve colostrum quality and protection for neonatal calves in the early days of life.     

Protein and energy concentrations of meat meal and meat and bone meal fed to pigs based on in vitro assays

The objective of this study was to develop equations for estimating ileal digestible crude protein (CP) and metabolizable energy (ME) contents of meat meal (MM) and meat and bone meal (MBM) as feed ingredients for pigs based on in vitro assays. Test ingredients were 4 sources of MM and 3 sources of MBM. Ash and CP contents of the ingredients ranged from 3.8% to 33.1% and 46.8% to 82.9% (as-is basis), respectively. In vitro ileal disappearance (IVID) of CP was determined and ileal digestible CP content was calculated by multiplying CP content by IVID of CP. In vitro total tract disappearance (IVTTD) of dry matter (DM) was determined and ME was calculated using gross energy, CP contents, and IVTTD of DM. The IVID of CP and IVTTD of DM ranged from 77.2% to 88.7% and from 82.7% to 92.4%, respectively. Calculated ileal digestible CP and ME contents ranged from 37.8% to 73.5% DM and 2,405 to 3,905 kcal/kg DM, respectively. Ash contents were negatively correlated (P < 0.001) with CP (r = −0.99), in vitro ileal digestible CP (r = −0.97), gross energy (r = −1.00), in vitro digestible energy (r = −0.97), and adjusted ME (r = −0.97). The most fitting equations for ileal digestible CP and adjusted ME were: ileal digestible CP (% DM) = 11.91 − 0.90 × Ash (% DM) + 0.74 × IVID of CP (%) (R² = 0.99) and adjusted ME (kcal/kg DM) = 130.85 − 50.90 × ash (% DM) + 47.06 × IVTTD of DM (%) (R² = 0.99). To validate the accuracy of the prediction equations for ME, mean bias and linear bias were determined using a regression analysis. Calculated ME values of MM and MBM were in a good agreement with data obtained from animal experiments based on a statistically insignificant bias in the models. In conclusion, ME concentrations of MM and MBM as swine feed ingredients can be calculated using ash concentration and in vitro disappearance of dry matter.     

Corn protein has greater concentrations of digestible amino acids and energy than low-oil corn distillers dried grains with solubles when fed to pigs but does not affect the growth performance of weanling pigs

Three experiments were conducted to test the hypothesis that standardized ileal digestibility (SID) of amino acids (AA) and digestible energy (DE) and metabolizable energy (ME) in a new source of corn protein are greater than in corn distillers dried grains with solubles (DDGS) and that corn protein may be included in diets for weanling pigs. In experiment 1, the SID of AA was determined in two sources of DDGS (DDGS-1 and DDGS-2) and in corn protein. Results indicated that SID of most AA was greater (P < 0.05) in DDGS-2 and corn protein than in DDGS-1, but corn protein contained more digestible AA than both sources of DDGS. In experiment 2, the DE and ME in corn, the two sources of DDGS, and corn protein were determined. Results demonstrated that DE (dry matter basis) in corn protein was greater (P < 0.05) than in corn, but ME (dry matter basis) was not different between corn and corn protein. However, DE and ME in corn (dry matter basis) were greater (P < 0.05) than in DDGS-1 and DDGS-2. In experiment 3, 160 weanling pigs were allotted to four treatments in phases 1 and 2 and a common diet in phase 3. Corn protein was included at 5% to 10% in phases 1 and 2 at the expense of plasma protein and enzyme-treated soybean meal. Results indicated that although differences in average daily gain and gain to feed ratio were observed in phase 1, no differences among treatments were observed for the overall experimental period. In conclusion, the concentration of digestible AA is greater in corn protein than in DDGS; DE and ME in corn protein are also greater than in DDGS; and up to 10% corn protein may be included in phase 1 and phase 2 diets for weanling pigs.     

Chemical composition,energy and amino acid digestibility in double-low rapeseed meal fed to growing pigs

Background

The nutritional value of rapeseed meal may be variable due to the variation of its chemical composition. And a precise understanding of the nutritional value of an ingredient is beneficial for the accurate diet formulation and reduction of feed costs. This study was conducted to determine the chemical composition, digestible energy (DE) and metabolizable energy (ME) content, and apparent ileal digestibility (AID) and standardized ileal digestibility (SID) of amino acids (AA) for growing pigs. Thirteen solvent-extracted double-low rapeseed meal (DLRSM) samples were obtained from the main double-low rapeseed producing areas in China.

Methods

The DE and ME contents of the 13 DLRSM samples were measured in growing pigs (six pigs per DLRSM sample, average initial body weight (BW) = 48.3 kg). The AID and SID of AA of 10 DLRSM samples were determined in 12 crossbred barrows (average initial BW = 35.3 kg) by using two 6 × 6 Latin square designs. Each Latin square comprised one N-free diet and 5 DLRSM test diets.

Results

The chemical composition of DLRSM varied among samples, and the coefficient of variation was greater than 10 % for ether extract (EE), neutral detergent fiber (NDF), acid detergent fiber (ADF), calcium (Ca), and total glucosinolates. The AA content of DLRSM varied among samples especially for lysine (Lys) and methionine (Met). On a dry matter (DM) basis, the apparent total tract digestibility (ATTD) of gross energy (GE), the DE and ME and the ME:DE ratio of DLRSM averaged 62.39 %, 2862 kcal/kg and 2723 kcal/kg, and 94.95 %, respectively. The mean value of SID of Lys was 70.52 % which varied from 66.54–76.54 %. The SID of crude protein (CP), Met, and threonine (Thr) averaged 72.81 %, 82.41 %, and 69.76 %, respectively.

Conclusions

There was great variability in chemical composition especially in the concentration of EE, NDF and ADF, but no significant differences in energy content of the DLRSM samples were observed. In addition, the AID and SID of all AA were relatively similar among DLRSM samples except for that of Lys.     

Antibiotic resistance,antimicrobial residues,and bacterial community diversity in pasture-raised poultry,swine, and beef cattle manures

Animal manure can be a source of antibiotic-resistant genes (ARGs) and pharmaceutical residues; however, few studies have evaluated the presence of ARG in pasture-raised animal production systems. The objective of this study was to examine changes in microbiome diversity and the presence of antibiotic residues (ABRs) on three farms that contained a diverse range of animal species: pasture-raised poultry (broiler and layer), swine, and beef cattle. Total bacterial communities were determined using 16S rRNA microbiome analysis, while specific ARGs (sulfonamide [Sul; Sul1] and tetracycline [Tet; TetA]) were enumerated by qPCR (real-time PCR). Results indicated that the ARG abundances (Sul1 [P < 0.05] and TetA [P < 0.001]) were higher in layer hen manures (16.5 × 10⁻⁴ and 1.4 × 10⁻⁴ µg kg⁻¹, respectively) followed by broiler chickens (2.9 × 10⁻⁴ and 1.7 × 10⁻⁴ µg kg⁻¹, respectively), swine (0.22 × 10⁻⁴ and 0.20 × 10⁻⁴ µg kg⁻¹, respectively) and beef cattle (0.19 × 10⁻⁴ and 0.02 × 10⁻⁴ µg kg⁻¹, respectively). Average fecal TetA ABR tended to be greater (P = 0.09) for broiler chickens (11.4 µg kg⁻¹) than for other animal species (1.8 to 0.06 µg kg⁻¹), while chlortetracycline, lincomycin, and oxytetracycline ABRs were similar among animal species. Furthermore, fecal microbial richness and abundances differed significantly (P < 0.01) both among farms and specific species of animal. This study indicated that the microbial diversity, ABR, ARG concentrations, and types in feces varied from farm-to-farm and from animal species-to-animal species. Future studies are necessary to perform detailed investigations of the horizontal transfer mechanism of antibiotic-resistant microorganisms (ARMs) and ARG.     

Effect of divergence in residual methane emissions on feed intake and efficiency,growth and carcass performance,and indices of rumen fermentation and methane emissions in finishing beef cattle

Residual expressions of enteric emissions favor a more equitable identification of an animal’s methanogenic potential compared with traditional measures of enteric emissions. The objective of this study was to investigate the effect of divergently ranking beef cattle for residual methane emissions (RME) on animal productivity, enteric emissions, and rumen fermentation. Dry matter intake (DMI), growth, feed efficiency, carcass output, and enteric emissions (GreenFeed emissions monitoring system) were recorded on 294 crossbred beef cattle (steers = 135 and heifers = 159; mean age 441 d (SD = 49); initial body weight (BW) of 476 kg (SD = 67)) at the Irish national beef cattle performance test center. Animals were offered a total mixed ration (77% concentrate and 23% forage; 12.6 MJ ME/kg of DM and 12% CP) ad libitum with emissions estimated for 21 d over a mean feed intake measurement period of 91 d. Animals had a mean daily methane emissions (DME) of 229.18 g/d (SD = 45.96), methane yield (MY) of 22.07 g/kg of DMI (SD = 4.06), methane intensity (MI) 0.70 g/kg of carcass weight (SD = 0.15), and RME 0.00 g/d (SD = 0.34). RME was computed as the residuals from a multiple regression model regressing DME on DMI and BW (R² = 0.45). Animals were ranked into three groups namely high RME (>0.5 SD above the mean), medium RME (±0.5 SD above/below the mean), and low RME (>0.5 SD below the mean). Low RME animals produced 17.6% and 30.4% less (P < 0.05) DME compared with medium and high RME animals, respectively. A ~30% reduction in MY and MI was detected in low versus high RME animals. Positive correlations were apparent among all methane traits with RME most highly associated with (r = 0.86) DME. MY and MI were correlated (P < 0.05) with DMI, growth, feed efficiency, and carcass output. High RME had lower (P < 0.05) ruminal propionate compared with low RME animals and increased (P < 0.05) butyrate compared with medium and low RME animals. Propionate was negatively associated (P < 0.05) with all methane traits. Greater acetate:propionate ratio was associated with higher RME (r = 0.18; P < 0.05). Under the ad libitum feeding regime deployed here, RME was the best predictor of DME and only methane trait independent of animal productivity. Ranking animals on RME presents the opportunity to exploit interanimal variation in enteric emissions as well as providing a more equitable index of the methanogenic potential of an animal on which to investigate the underlying biological regulatory mechanisms.