Utilization Of Metabolizable Energy For Growth Research Articles

Feed intake, digestibility and energy partitioning in beef cattle fed diets with cassava pulp instead of rice straw.

ObjectiveThis study was conducted to assess the effects of replacing rice straw with different proportions of cassava pulp on growth performance, feed intake, digestibility, rumen microbial population, energy partitioning and efficiency of metabolizable energy utilization in beef cattle.MethodsEighteen yearling Thai native beef cattle (Bos indicus) with an average initial body weight (BW) of 98.3±12.8 kg were allocated to one of three dietary treatments and fed ad libitum for 149 days in a randomized complete block design. Three dietary treatments using different proportions of cassava pulp (100, 300, and 500 g/kg dry matter basis) instead of rice straw as a base in a fermented total mixed ration were applied. Animals were placed in a metabolic pen equipped with a ventilated head box respiration system to determine total digestibility and energy balance.ResultsThe average daily weight gain, digestible intake and apparent digestibility of dry matter, organic matter and non-fiber carbohydrate, total protozoa, energy intake, energy retention and energy efficiency increased linearly (p<0.05) with an increasing proportion of cassava pulp in the diet, whereas the three main types of fibrolytic bacteria and energy excretion in the urine (p<0.05) decreased. The metabolizable energy requirement for the maintenance of yearling Thai native cattle, determined by a linear regression analysis, was 399 kJ/kg BW0.75, with an efficiency of metabolizable energy utilization for growth of 0.86.ConclusionOur results demonstrated that increasing the proportion of cassava pulp up to 500 g/kg of dry matter as a base in a fermented total mixed ration is an effective strategy for improving productivity in zebu cattle.

Energy requirements for maintenance and growth of Dorper crossbred ram lambs

This study aimed to determine the energy requirements of Dorper crossbred sheep that have been used for meat production in China. Thirty-five 1/2 Dorper×1/2 thin-tailed Han crossbred noncastrated ram lambs [34.1±0.6kg body weight (BW)] were used in a comparative slaughter trial. Seven ram lambs were randomly selected as the baseline group and slaughtered at 35kg BW. The remaining 28 lambs were randomly divided into four groups of seven lambs each. Three of the four groups were fed a mixed diet either for ad libitum intake, 60% or 45% of the ad libitum intake. The three groups were slaughtered when the ram lambs that were fed ad libitum reached 50kg BW. The ram lambs from the fourth group were also fed ad libitum as an intermediate group and slaughtered at 43kg BW. Total body energy, nitrogen, fat, ash, and moisture content were measured. In a digestibility trial, another 15 ram lambs (41.3±0.8kg BW) were housed in metabolism cages to estimate the metabolizable energy (ME) value of the diet at the three levels of feed intake. The daily net energy (NE) requirement for maintenance was 263kJ/kg0.75 of BW or 278kJ/kg0.75 of shrunk BW (SBW), with a partial efficiency of ME utilization for maintenance of 0.69. The NE requirement for growth ranged from 1.12 to 5.31MJ/d for daily gains of 100–400g BW, or from 1.29 to 6.18MJ/d for daily gains of 100–400g SBW. The partial efficiency of ME utilization for growth was 0.46. The energy requirements of Dorper×thin-tailed Han crossbred ram lambs were lower than those recommended by the British or American nutritional systems.

Effects of feeding level and water temperature on growth, nutrient and energy utilization and waste outputs of rainbow trout ( Oncorhynchus mykiss)

A study was carried out to determine the effect of feeding level and water temperature on growth and feed efficiency, nutrient and energy utilization and waste outputs of rainbow trout. A practical diet was fed to near-satiation to groups of fish reared at 6, 9, 12 and 15 °C. At each temperature, the feed intake of other groups of fish was restricted to about 85 % or 70 % of the amount of feed consumed in the previous week by the fish fed to near-satiation. Total feed intakes over 12 weeks were, on average, 76 % and 65 % of total feed intake of the near-satiety group for R1 and R2, respectively. Reducing the feed allocation resulted in significantly ( P < 0.05) lower weight gains compared to feeding to near-satiation regardless of the rearing temperature. Feeding level and water temperature had no significant ( P > 0.05) effect on feed efficiency, carcass composition or efficiencies of digestible nitrogen and digestible energy retention. Increasing temperature resulted in an increase in the apparent digestibility of dietary dry matter, nitrogen and energy ( P < 0.05). The increase in digestibility of dry matter and nitrogen with increasing temperature resulted in higher estimated total solid and solid nitrogen waste outputs per kg fish produced ( P < 0.05) at lower water temperatures. Estimated dissolved nitrogen and phosphorus waste outputs (g/kg fish produced) were not affected by the feeding level or water temperature. A highly significant ( P < 0.01) linear relationship was observed between metabolizable energy (ME) intake above basal metabolism and recovered energy. The efficiency of ME utilization for growth (K pf) was 0.61 and this coefficient was not affected by feed intake or water temperature. Protein and lipid were deposited in a constant ratio (1 kJ protein gain: 1.4 kJ lipid gain) regardless of ME intake or water temperature.

Net energy value of timothy and bromegrass silages for beef cattle

Metabolizable energy (ME), net energy for maintenance and net energy for growth of grass silages were evaluated by the comparative slaughter technique using a 2 × 2 × 3 factorial design. Sixty medium frame beef steers (259 ± 29 kg BW) were divided in groups of five and fed during 3 months either Timothy (T) or Bromegrass (B) harvested at stem elongation (S) of the first cut or at boot stage of the aftermath (A). Forages were fed at one of three levels of intake: ad libitum (FF), 80% of FF, or 65% of FF. Silages averaged 26.9% DM, 16.0% CP and 37.7% ADF. Regression of logarithm of heat production (HE) against ME intake were similar for all silages (log HE = 0.00046*ME + 2.4923; r2 = 0.89). From this equation, fasting HE of 311 kJ kg−0.75 d−1, ME for maintenance of 559 kJ kg−0.75 d−1 and efficiency of utilization of energy for maintenance of 56% were determined. Regression of ME intake against retained energy (RE) were similar for all silages. Efficiency of ME utilization for growth was 33% using the regression of ME over RE with a ME requirement for maintenance fixed at 559 kJ kg−0.75 d−1. Net energy for maintenance and growth were similar for all silages, averaging 6.17 and 3.70 MJ kg−1, respectively. The use of a prediction equation based on ADF of forages underestimated ME values of silages by approximately 25%. Moreover, NRC (1984) equations that estimate NE from experimentally estimated ME values tended to overestimate the net energy of our grass silages. Key words: Net energy, grass silages, timothy, bromegrass, beef cattle

Intake and utilization of energy from ammonia-treated and untreated wheat straw by steers and wether sheep given a basal diet of grass pellets and hay

AbstractTwo experiments, experiment 1 with six steers in a 3 × 3 Latin-square design and experiment 2 with four wether sheep in a cross-over design, were conducted to study the effect of species and ammonia treatment on intake and utilization of the energy of untreated wheat straw. Treatments were: (1) untreated wheat straw offered ad libitum on top of a basal diet (B) consisting of hay (0·25) and grass pellets (0·75) (UWS), (2) ammoniated wheat straw offered ad libitum plus B (AWS) and (3) ammoniated wheat straw offered at a restricted level plus B (AWS-). B was offered as a maintenance diet for both species and AWS- was only studied in steers. Voluntary intake of AWS zvas higher than that of UWS. No significant differences emerged between whole rations UWS and AWS with regard to energy digestion (ED), energy metabolizability (ρ = metabolizable energy (ME) I gross energy (GE)) and losses of digestible energy (DE) in urine and methane (average 187 J/KJ DE), but the efficiency of utilization of ME for growth (kg) was significantly higher for AWS than for UWS. ED and ρ of the straw part of the ration was significantly higher for AWS than for UWS. AWS- and AWS did not differ significantly with regard to ED, ρ and DE losses in methane and urine. Steers had a higher intake per kg0·75 per day than wether sheep. Across species, digestible energy intake (DEI) of the whole ad libitum fed diets was related to live weight (M)0·946 (s.e. of exponent 0·0152). ED and ρ of the straw part of the rations did not differ significantly between species, but steers had a significantly higher ED and ρ of β than wether sheep. Steers excreted a significantly lower proportion of DE in urine and a significantly higher proportion of DE in methane than did wethers. Total energy losses in urine and methane, however, did not differ between species.

Meeting the energy requirements for lactation in a macropodid marsupial: current nutrition versus stored body reserves

Food intake and digestion were investigated at four stages in the first 218 days of lactation in tammar wallabies (Macropus eugenii) carrying litters of one, and in non‐lactating females as a control. This period of lactation in tammars, which includes the phase of exponential growth of the young, is comparable to gestation plus early lactation in ruminant placentals. Food and energy intakes by mothers remained at the non‐lactating level while rate of growth of young was slow (up to Day 105 of lactation) but then rose as the growth rate of young increased, keeping pace with the predicted requirements for milk synthesis and export. There was no indication of the energy deficit seen in late gestation and early lactation in many herbivorous placental mammals. The gross efficiency of utilization of ME for growth of offspring was estimated as 13–15%, which is at least as high as values for placentals during gestation. The mean intake of metabolizable energy (ME) at 218 days was 603 kJ.kg‐0.75.d‐1, which represented 136% of ME intake by nonlactating females, or an increment of 159 kJ.kg‐0.75.d‐1. It was estimated that ME intake may rise to 773 kJ.kg‐0.75.d‐1 at peak lactation, which would be 174% of the non‐lactating level or an increment of 329 kJ.kg‐0.75. d‐1. This allometrically‐scaled increment is similar to values for some ruminants that use body reserves extensively to offset peak lactational food requirements. These and previously‐reported trends suggest that ecologically comparable herbivorous marsupials and placentals utilize different physiological strategies to minimize demands on food resources during reproduction, but that both daily and overall demands can be similar.

Energetics of Animal Production

Abstract Principles and results concerning Danish research during the last 10 years on energetics of animal production are reviewed. All presented results have been obtained by means of the respiration plant in Copenhagen working according to the indirect calorimetry technique. In the first part of the paper, the concepts of maintenance requirement and efficiency of metabolizable energy utilization for growth, egg and milk production are examined. Subsequently, different methods for estimation of maintenance and energy utilization are described and illustrated with 30 equations. The specific problems concerning the methodology and interpretation of the results are deliberated. Finally, the general issues concerning animal energetics are discussed and a new procedure for estimation of energy utilization is proposed.

Metabolizable energy requirements for maintenance of Kenyan goats

Twenty goats, aged 7 months and weighing between 13 and 18 kg, were given diets containing 0, 20, 40 and 60% coffee pulp and hay ad libitum for 20 weeks. Metabolizable energy (ME) intake of the goats was estimated in vitro during 12- and 8-week periods and related to liveweight gain in a regression involving 40 sets of data. A maintenance requirement of 556 kJ ME kg −0.75 day −1 was calculated, which was similar to some reports in the literature but exceeded others by 20%. Less variable was energy cost of gain which was estimated at 27.9 kJ ME per g. Efficiency of utilization of ME for growth was 35.8%. Values reported here are useful for feeding Kenyan goats under confinement.

Effect of age on energy utilization of early-weaned growing calves weighing less than 100 kg

ABSTRACTTo study, after weaning at 6 weeks of age, the effect of age on energy utilization of growing calves and to estimate the requirements of metabolizable energy (ME) for calves weighing less than 100 kg, 243 energy balance trials were conducted using 68 Holstein-Friesian castrated male calves at 7, 9 and 13 weeks of age. Regression analyses of energy retention (ER, kj/kg M0·75) on intakes of ME (kJ/kg M0·75) gave the following equations at the respective age: ER = 0·479 (s.e. 0·070) ME — 197, for 7 weeks, ER = 0·521 (s.e. 0·052) ME - 216 for 9 weeks and ER = 0·523 (s.e. 0·043) ME - 236, for 13 weeks. Amounts of ME for maintenance (MEm) calculatedas ER = 0 were 413, 415 and 451 kJ/kg M0·75 for calves at 7, 9 and 13 weeks of age, respectively. The efficiency of utilization of ME for growth was not significantly different among the ages and was 0·500 (s.e. 0023). ME required for growth was estimated to be 510 kJ/kg M0·75 for each kg gain in weight, irrespective of age. The requirements of ME of calves weighing less than 100 kg were lower than those estimated by extrapolation of British and American standards.

Energy metabolism in lambs fed silage diets with sucrose or a growth promoter

The effect of feeding silage with sucrose or Avotan added was examined. A first cut, ryegrass silage was fed at maintenance and 1.5 times maintenance either alone, with sucrose added to make the total water soluble carbohydrate content of the diet up to 150 g kg −1 DM or with Avotan added at 45 mg kg −1 mean DM intake to wether lambs of initial mean weight 42.2 kg. Digestibility, nitrogen (N) and energy balance and efficiency of utilization of metabolizable energy (ME) for growth ( kf) were determined by open circuit calorimetry. Digestibilities of N and energy were, respectively, 0.720 and 0.754 for silage plus sucrose, 0.734 and 0.732 for silage plus Avotan and 0.743 and 0.742 for silage fed alone. Faecal N losses were significantly higher ( P < 0.001) for the sucrose diet, but there were no significant differences in urine N or in N retention among the diets. Significantly lower ( P < 0.01) faecal, urinary and methane energy losses and significantly higher metabolic heat losses for the sucrose diet were found when compared to silage alone. Avotan had no significant effect on energy metabolism. Efficiencies of utilization of ME for growth ( kf) were 0.54 for silage plus sucrose, 0.30 for silage plus Avotan and 0.43 for silage alone. Adding Avotan did not affect methane production or kf significantly, but the addition of sucrose reduced methane energy losses significantly ( P < 0.01) and increased the efficiency of utilization of dietary ME.

Energy and protein utilization in growing cattle.

Limited data are available to describe the different phases of dietary protein and energy utilization in growing cattle as compared with those in adult cattle or in growing nonruminants. The European data on this topic are summarized to indicate application in appropriate feeding standards. Net protein requirements are widely variable with breed and sex. They are lower in steers than in bulls and lower in early maturing than in late maturing breeds. They are clearly defined for growing and fattening bulls where they are influenced by breed, live weight and live weight gain. New systems have been proposed to express the protein allowances. They provide a great step towards a concept explaining N supply to ruminants. However, protein degradability in the rumen, efficiency of microbial protein synthesis, intestinal digestibility and metabolic efficiency of amino acid absorption in the intestine need to be described more accurately. Even if body energy retention measured by the slaughter technique is systematically lower than when measured by calorimetric balance, both techniques can correctly describe the effect of breed sex, weight, or daily gain on energy retained, in relative value, and its distribution between protein and fat deposition. But further research is needed to confirm the distribution of metabolizable energy between maintenance and growth and the efficiency of metabolizable energy utilization for growth. Thus, different authors have preferred to calculate the energy allowances, not by a factorial method, but by regression between energy intake and the corresponding weight and daily gain of animals measured during feeding trials.

The utilization of the dietary energy of pangola and setaria by young growing beef cattle

SUMMARYThe net energy values for growth and fattening of two artificially dried tropical grasses-, pangola (Digitaria decumbens) and setaria (S. sphacelata var. sericea cv. Nandi), of similar estimated metabolizable energy content (8·07 and 7·96 MJ/kg D.M.) were determined with cattle using a slaughter technique. Growing cattle with a mean initial weight of 175 kg were given equal quantities of dry matter of the two grasses at each of three planes of nutrition above maintenance for a period of 152 days.The initial energy, fat and protein content of the total body of the 24 test animals was estimated from regressions relating fasted live weight to theśe components, derived from 12 similar cattle slaughtered at the beginning of the feeding period. The final energy, fat and protein content of the test animals was determined directly by chemical analysis. The metabolizable energy (ME) content of the grasses was estimated from the level of digestible energy (DE) determined with eight cattle, assuming that ME = 0·815 DE.The cattle fed pangola gained more live weight, empty-body weight, fat, protein and energy than animals fed similar quantities of setaria. The net energy value for growth and fattening (NEf) was determined using regressions relating energy retention to the quantity of dry matter eaten. NEf in MJ/kg dry matter was 2·27 for pangola and 1·31 for setaria.Efficiency of utilization of ME for growth and fattening (kf) was.27·7% for pangola and 16·9% for setaria. These values for tropical grasses are lower than any values reported for temperate pasture species. Thus the lower efficiency of utilization of ME may cause the lower production of cattle which graze tropical grasses.It was concluded that as the kf values of different tropical grasses are not constant, kf values should be measured on a wider range of tropical grasses so that this factor can be taken into account when evaluating grasses in animal production systems.

Protein metabolism in growing lambs fed on fresh ryegrass (Lolium perenne) -clover (Trifolium repens) pasture ad lib. 1. Protein and energy deposition in response to abomasal infusion of casein and methionine.

1. Male lambs that had been born in autumn and wintered on forage diets were cannulated in the abomasum, confined indoors in individual pens, and fed on fresh primary growth ryegrass (Lolium perenne) – clover (Trifolium repens) pasture ad lib, for a 12-week period during spring. Mean diet organic matter digestibility (OMD) was 0/76, nitrogen content 29 g/kg dry matter (DM) and metabolizable energy (ME) content 11.1 MJ/kg DM. Thirteen lambs were infused into the abomasum with 44 g sodium caseinate +0/5 g L-methionine/d and 12 lambs were similarly infused with equivalent amounts of inorganic sodium and phosphorus. Initial live weight was 16/5 kg.2. The twenty-five treatment lambs were slaughtered at the end of the experiment, and thirteen similar lambs were slaughtered when the experiment commenced. Body composition was determined and rates of protein, fat and energy deposition were calculated using comparative slaughter procedures.3. Voluntary herbage DOM intakes tended to be slightly greater for control than protein-infused lambs, but calculated ME intakes including that infused as amino acids were similar for the two groups. Live-weight gains were 79 and 99 g/d for control and protein-infused lambs respectively (P &lt; 0/05) and corresponding values for carcass gain: live-weight gain were 0/44 and 0/50 (P &lt; 0/01), Wool growth was markedly increased by the amino acid infusion.4. Carcass and whole body protein content was increased 10 g/kg by the protein infusion (P &lt; 0/01) and fat content depressed approximately 25 g/kg (P &lt; 0/05). Rates of protein deposition in both carcass and wool-free whole body were markedly increased by protein infusion, and total deposition including wool was 12.6 and 21.0 g/d for control and protein-infused lambs (P &lt; 0/001). Energy deposited in protein as a proportion of total energy deposition was 0/27 and 0/41 for control and protein-infused lambs (P &lt; 0/001), but total energy retention and the efficiency of utilization of ME for growth did not differ between the two groups of lambs.5. It was estimated that 60 and 100 g total amino acids/d were absorbed from the small intestine in the control and protein-infused lambs respectively, corresponding to 0.16 and 0/25 of total ME intake. It was concluded that absorption of protein from the small intestine was limiting protein deposition in the growing lambs fed on fresh ryegrass-based spring pasture in this study. Absorption of cystine+methionine was specifically shown to be limiting. However, the protein deficiency was not a major factor in the low value for the efficiency of utilization of ME for growth for this diet (0/30).

Estimates of maintenance requirement of growing lambs

1. Total body energy retention (ER) and metabolizable energy intake (MEI) values from experiments with 231 lambs (Suffolk male x (Border Leicester male x Cheviot female) female) housed indoors and given thirteen forage diets were used to estimate the metabolizable energy (ME) required for maintenance. 2. ER was measured using the comparative slaughter technique, and the lambs were fed at several planes of nutrition above maintenance between 2 and 5 months of age. 3. The daily ER and MEI results were scaled to live weight (kg0.75) and linear regression lines fitted to the values for individual diets. Extrapolation of the fitted lines to zero ER gave estimates of maintenance requirement ranging from 141 to 466 kJ ME/kg0.75 per d and values for the efficiency of utilization of ME for growth and fattening (Kf) of 0.25-0.53 (mean 0.39). 4. An alternative analysis constrained the estimated maintenance requirement to be the same for all diets. An iterative search procedure indicated minimal residual variation at 339 kJ/kg0.75 per d. This common value of ME for maintenance gave Kf values ranging from 0.30 to 0.54 (mean 0.39). 5. The implications of the technique were considered together with some discussion of the variability of the estimate. Allowing the minimum RSD to vary by 10% gave a maintenance requirement of between 231 and 408 kJ/kg0.75 per d.

Prediction of the energy requirements for growth in beef cattle. 2. Hereford × British Friesian steers given dried grass or barley

SUMMARY1. Hereford × British Friesian castrate male cattle, growing from about 80 to 500 kg, were given equal amounts of metabolizable energy (ME) from dried grass pellets or from a pelleted diet of barley and a protein supplement. Two animals on each diet were fed close to appetite (High) and two at a level mid-way between maintenance and appetite (Medium). The rations for all animals were reduced to approximately maintenance for 4 weeks on three occasions equally spaced throughout the experiment. Measurements of energy and nitrogen balance were made for each animal at intervals of 6 to 8 weeks. Total body-water content was estimated from D20 dilution at intervals of 110 kg live weight.2. Values for the metabolizability of the gross energy of the dried grass and barley/protein diets were 0·55 and 0·67.3. Metabolic heat production during growth was closely related to body weight to the power 0·75. Predicted basal metabolism was 395 kJ/kg 0·75 per 24 hr.4. Estimates of the net efficiency of utilization of ME for growth were unaffected by small variations in the exponent of W used to describe the effect of body size on heat production. Both diets were utilized above maintenance with a net efficiency close to 0·62.5. Nitrogen balance trials seriously overestimated nitrogen retention. Gains in fat-free body mass estimated from D2O dilution were combined with calorimetric measurements of energy retention to predict the relationship between energy retention and weight gain. The agreement between observed and predicted live-weight gain was good at the lower body weights and on the lower ration. For fatter animals eating the high ration at higher body weights, live-weight gains were less than predicted.