scholarly journals Applying the California net energy system to growing goats1

2019 ◽  
Vol 3 (3) ◽  
pp. 999-1010
Author(s):  
Izabelle A M A Teixeira ◽  
Amélia K Almeida ◽  
Márcia H M R Fernandes ◽  
Kleber T Resende
Keyword(s):  
Energy Use ◽  
Energy System ◽  
Metabolizable Energy ◽  
Energy Requirements ◽  
Net Energy ◽  
Dairy Goats ◽  
Indigenous Goats ◽  
Metabolizable Energy Intake ◽  
Degree Of Maturity ◽  
Body Energy

Abstract The aim of this review is to describe the main findings of studies carried out during the last decades applying the California net energy system (CNES) in goats. This review also highlights the strengths and pitfalls while using CNES in studies with goats, as well as provides future perspectives on energy requirements of goats. The nonlinear relationship between heat production and metabolizable energy intake was used to estimate net energy requirements for maintenance (NEm). Our studies showed that NEm of intact and castrated male Saanen goats were approximately 15% greater than female Saanen goats. Similarly, NEm of meat goats (i.e., >50% Boer) was 8.5% greater than NEm of dairy and indigenous goats. The first partial derivative of allometric equations using empty body weight (EBW) as independent variable and body energy as dependent variable was used to estimate net energy requirements for gain (NEg). In this matter, female Saanen goats had greater NEg than males; also, castrated males had greater NEg than intact males. This means that females have more body fat than males when evaluated at a given EBW or that degree of maturity affects NEg. Our preliminary results showed that indigenous goats had NEg 14% and 27.5% greater than meat and dairy goats, respectively. Sex and genotype also affect the efficiency of energy use for growth. The present study suggests that losses in urine and methane in goats are lower than previously reported for bovine and sheep, resulting in greater metabolizable energy:digestible energy ratio (i.e., 0.87 to 0.90). It was demonstrated that the CNES successfully works for goats and that the use of comparative slaughter technique enhances the understanding of energy partition in this species, allowing the development of models applied specifically to goat. However, these models require their evaluation in real-world conditions, permitting continuous adjustments.

scholarly journals How did Lofgreen and Garrett do the math?

2019 ◽  
Vol 3 (3) ◽  
pp. 1011-1017
Author(s):  
James W Oltjen
Keyword(s):  
Body Weight ◽  
Energy Content ◽  
Energy System ◽  
Metabolizable Energy ◽  
Net Energy ◽  
Significant Difference ◽  
Linear Fit ◽  
Metabolizable Energy Intake ◽  
Logarithmic Equation ◽  
Finishing Beef Cattle

Abstract Lofgreen and Garrett introduced a new system for predicting growing and finishing beef cattle energy requirements and feed values using net energy concepts. Based on data from comparative slaughter experiments they mathematically derived the California Net Energy System. Scaling values to body weight to the ¾ power, they summarized metabolizable energy intake (ME), energy retained (energy balance [EB]), and heat production (HP) data. They regressed the logarithm of HP on ME and extended the line to zero intake, and estimated fasting HP at 0.077 Mcal/kg0.75, similar to previous estimates. They found no significant difference in fasting HP between steers and heifers. Above maintenance, however, a logarithmic fit of EB on ME does not allow for increased EB once ME is greater than 340 kcal/kg0.75, or about three times maintenance intake. So based on their previous work, they used a linear fit so that partial efficiency of gain above maintenance was constant for a given feed. They show that with increasing roughage level efficiency of gain (slope) decreases, consistent with increasing efficiency of gain and maintenance with greater metabolizable energy of the feed. Making the system useful required that gain in body weight be related to EB. They settled on a parabolic equation, with significant differences between steers and heifers. Lofgreen and Garrett also used data from a number of experiments to relate ME and EB to estimate the ME required for maintenance (ME = HP) and then related the amount of feed that provided that amount of ME to the metabolizable energy content of the feed (MEc), resulting in a logarithmic equation. Then they related that amount of feed to the net energy for gain calculated as the slope of the EB line when regressed against feed intake. Combining the two equations, they estimate the net energy for maintenance and gain per unit feed (Mcal/kg dry matter) as a function of MEc: 0.4258 × 1.663MEc and 2.544–5.670 × 0.6012MEc, respectively. Finally, they show how to calculate net energy for maintenance and gain from experiments where two levels of a ration are fed and EB measured, where one level is fed and a metabolism trial is conducted, or when just a metabolism trial is conducted—but results are not consistent between designs.

The utilization by lambs of the energy and protein in dried pelleted grass treated with formaldehyde

1979 ◽  
Vol 29 (2) ◽  
pp. 245-255 ◽  
Author(s):  
D. J. Thomson ◽  
S. B. Cammell
Keyword(s):  
Energy Intake ◽  
Crude Protein ◽  
Dry Matter ◽  
Metabolizable Energy ◽  
Net Energy ◽  
Digestible Energy ◽  
Energy Retention ◽  
Metabolizable Energy Intake ◽  
Total Body ◽  
Body Energy

ABSTRACTA primary growth crop of perennial ryegrass (cv. S24), containing 17% crude protein and 9·9 MJ metabolizable energy/kg dry matter, was artificially dried, ground through a 3·0 mm screen and pelleted either without further treatment (C), or after the application of formaldehyde (T) at a rate of 1 g/100 g crude protein. The C and T diets were each fed to 20 lambs for 77 days. Diets C and T were given ad libitum and at three lower planes of nutrition. Similar amounts of dry matter, nitrogen and digestible energy were consumed at each of the four planes of nutrition by lambs fed diets C and T. Carcass energy, fat and protein retention, and total body energy retention were measured by the comparative slaughter technique and did not differ between the diets (P> 0·05). Metabolizable energy intake was calculated from digestible energy intake using the factor 0·81. The efficiency of utilization of the metabolizable energy for growth and fattening (kf) and the net energy value were calculated by linear regression analysis from the total body energy retention, the calculated metabolizable energy intake and dry-matter intake data scaled to M0·75. They did not differ between the diets (P > 0·05), and were 0·370 (C) and 0·431 (T) for kf, and 2·09 (C) and 1·97 MJ/kg dry matter (T) for net energy.

scholarly journals 222 Partitioning of retained energy between protein and fat gain, and heat of product formation and support metabolism in growing beef cattle

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 158-158
Author(s):  
Phillip A Lancaster
Keyword(s):  
Linear Regression ◽  
Mixed Models ◽  
Multivariate Regression ◽  
Literature Search ◽  
Energy Use ◽  
Random Variable ◽  
Product Formation ◽  
Metabolizable Energy ◽  
Overall Efficiency ◽  
Metabolizable Energy Intake

Abstract Multiple linear regression inaccurately computes the efficiency of energy use for protein and fat gain. The objective was to quantify efficiency of metabolizable energy use for protein and fat gain along with heats of product formation and support metabolism. A literature search was performed to compile data (31 studies, 214 treatment means) on metabolizable energy intake (MEI) and composition of empty body gain in growing steers and heifers. Data analyses were performed using R statistical package for mixed models with study as random variable. Linear regression of MEI on energy gain (EG; P < 0.001; R2 = 0.627) resulted in an estimate of metabolizable energy for maintenance (MEm) of 156 kcal/kg.75 and efficiency of ME use for gain of 0.518. Linear regression of MEI on EG as protein and fat (P < 0.001; R2 = 0.623) resulted in an estimate of MEm of 149 kcal/kg.75, and efficiency of protein (kp) and fat (kf) gain of 0.274 and 0.585, respectively, resulting in an overall efficiency of EG of 0.520. Nonlinear regression model (EG = kg*(MEI-MEm)) resulted in an estimate of MEm of 103 kcal/kg.75 and efficiency of EG of 0.342. The heat of product formation was assumed to be 0.48 (1 – 0.52) and the heat of support metabolism (HiEv) 0.18 (0.52 – 0.34). Multivariate regression was used to fit simultaneous models for EG as protein (EGp = (kp+HiEvp)*k*MEA) and fat (EGf = (kf+(0.18-HiEvp))*(1-k)*MEA). Estimates (P < 0.001) of kp and kf were 0.12 ± 0.01 and 0.63 ± 0.02, and HiEvp and proportion of ME available for protein gain (k) were 0.11 ± 0.01 and 0.75 ± 0.01, respectively. The heat of product formation and support metabolism for protein were 0.77 and 0.11, and fat were 0.30 and 0.07, respectively. In conclusion, efficiency of ME use for protein was lesser than for fat gain, and heat of support metabolism was greater for protein than fat gain.

Effect of fish meal on the mobilization of body energy in dairy cows

1987 ◽  
Vol 45 (3) ◽  
pp. 345-348 ◽  
Author(s):  
E. R. Ørskov ◽  
G. W. Reid ◽  
C. A. G. Tait
Keyword(s):  
Fish Meal ◽  
Energy Requirement ◽  
Metabolizable Energy ◽  
Early Lactation ◽  
Protein Supplements ◽  
Treatment Groups ◽  
Fat Mobilization ◽  
Four Levels ◽  
Metabolizable Energy Intake ◽  
Body Energy

ABSTRACTThirty-two Friesian cows in early lactation were divided into four treatment groups to receive ad libitum a mixed diet consisting of silage (0·70) and grain-based concentrate (0·30). Fish meal was subsequently mixed into the diet at levels of 0, 40, 80 and 120 g/kg to provide crude protein concentration (g/kg dry matter) in the complete diets of 156, 181, 200 and 212 respectively. In the 2nd week after calving the yields of fat-corrected milk (FCM) were 28·5, 29·2, 32·0 and 34·9 kg/day for the four levels respectively; at this time, food intake was sufficient only to meet the calculated energy requirement for 15 kg FCM per day. Due to recurring problems with ketosis on the diet containing 120 g fish meal per kg, this treatment was terminated and the experiment continued for 15 weeks with the groups receiving 0, 40 and 80 g/kg fish meal supplements. During this time average yields of FCM were 23·5, 25·6 and 28-0 kg FCM per day respectively and energy intakes were calculated to be sufficient to meet the requirement for 18 kg FCM per day.It appeared possible to increase milk yield by stimulating fat mobilization through giving undegraded protein supplements to underfed cows in early lactation. However, when an excessive mobilization occurred with a high supplement, and when the animals were yielding 15 to 20 kg FCM more than their metabolizable energy intake was calculated to sustain, some cows became ketotic.

scholarly journals Relationships of retained energy and retained protein that influence the determination of cattle requirements of energy and protein using the California Net Energy System

2018 ◽  
Vol 3 (3) ◽  
pp. 1029-1039 ◽  
Author(s):  
Luis O Tedeschi
Keyword(s):  
Body Fat ◽  
Energy System ◽  
The Body ◽  
Metabolizable Energy ◽  
Net Energy ◽  
Body Protein ◽  
Protein Requirements ◽  
Growing Cattle ◽  
Lower Correlation

Abstract Interrelationships between retained energy (RE) and retained protein (RP) that are essential in determining the efficiency of use of feeds and the assessment of energy and protein requirements of growing cattle were analyzed. Two concerns were identified. The first concern was the conundrum of a satisfactory correlation between observed and predicted RE (r = 0.93) or between observed and predicted RP when using predicted RE to estimate RP (r = 0.939), but a much lower correlation between observed and predicted RP when using observed RE to estimate RP (r = 0.679). The higher correlation when using predicted vs. observed RE is a concern because it indicates an interdependency between predicted RP and predicted RE that is needed to predict RP with a higher precision. These internal offsetting errors create an apparent overall adequacy of nutrition modeling that is elusive, thus potentially destabilizing the predictability of nutrition models when submodels are changed independently. In part, the unsatisfactory prediction of RP from observed RE might be related to the fact that body fat has a caloric value that is 1.65 times greater than body protein and the body deposition of fat increases exponentially as an animal matures, whereas body deposition of protein tends to plateau. Thus, body fat is more influential than body protein in determining RE, and inaccuracies in measuring body protein will be reflected in the RP comparison but suppressed in the RE calculation. The second concern is related to the disconnection when predicting partial efficiency of use of metabolizable energy for growth (kG) using the proportion of RE deposited as protein—carcass approach—vs. using the concentration of metabolizable energy of the diet—diet approach. The culprit of this disconnection might be related to how energy losses that are associated with supporting energy-expending processes (HiEv) are allocated between these approaches. When computing kG, the diet approach likely assigns the HiEv to the RE pool, whereas the carcass approach ignores the HiEV, assigning it to the overall heat production that is used to support the tissue metabolism. Opportunities exist for improving the California Net Energy System regarding the relationships of RE and RP in computing the requirements for energy and protein by growing cattle, but procedural changes might be needed such as increased accuracy in the determination of body composition and better partitioning of energy.

Effect of air temperature and energy intake on body mass, body composition and energy requirements in sheep

2002 ◽  
Vol 138 (2) ◽  
pp. 221-226 ◽  
Author(s):  
A. ALLAN DEGEN ◽  
B. A. YOUNG
Keyword(s):  
Energy Intake ◽  
Body Mass ◽  
Air Temperature ◽  
Total Body Water ◽  
Metabolizable Energy ◽  
Energy Requirements ◽  
Water Volume ◽  
Air Temperatures ◽  
Metabolizable Energy Intake ◽  
Total Body

Body mass was measured and body composition and energy requirements were estimated in sheep at four air temperatures (0 °C to 30 °C) and at four levels of energy offered (4715 to 11785 kJ/day) at a time when the sheep reached a constant body mass. Final body mass was affected mainly by metabolizable energy intake and, to a lesser extent, by air temperature, whereas maintenance requirements were affected mainly by air temperature. Mean energy requirements were similar and lowest at 20 °C and 30 °C (407·5 and 410·5 kJ/kg0·75, respectively) and increased with a decrease in air temperature (528·8 kJ/kg0·75 at 10 °C and 713·3 kJ/kg0·75 at 0 °C). Absolute total body water volume was related positively to metabolizable energy intake and to air temperature. Absolute fat, protein and ash contents were all affected positively by metabolizable energy intake and tended to be related positively to air temperature. In proportion to body mass, total body water volume decreased with an increase in metabolizable energy intake and with an increase in air temperature. Proportionate fat content increased with an increase in metabolizable energy intake and tended to increase with an increase in air temperature. In contrast, proportionate protein content decreased with an increase in metabolizable energy intake and tended to decrease with an increase in air temperature. In all cases, the multiple linear regression using both air temperature and metabolizable energy intake improved the fit over the simple linear regressions of either air temperature or metabolizable energy intake and lowered the standard error of the estimate. The fit was further improved and the standard error of the estimate was further lowered using a polynomial model with both independent variables to fit the data, since there was little change in the measurements between 20 °C and 30 °C, as both air temperatures were most likely within the thermal neutral zone of the sheep. It was concluded that total body energy content, total body water volume, fat and protein content of sheep of the same body mass differed or tended to differ when kept at different air temperatures.

Energy and protein utilization for maintenance and growth in Omani ram lambs in hot climates. I. Estimates of energy requirements and efficiency

2001 ◽  
Vol 136 (4) ◽  
pp. 451-459 ◽  
Author(s):  
R. J. EARLY ◽  
O. MAHGOUB ◽  
C. D. LU
Keyword(s):  
Research Council ◽  
Geometric Mean ◽  
National Research Council ◽  
Live Weight ◽  
Metabolizable Energy ◽  
Energy Requirements ◽  
Maximum Temperature ◽  
Net Energy ◽  
Linear Quadratic ◽  
Temperate Climates

Energy requirements for maintenance and growth were estimated by comparative slaughter in Omani male lambs during the hot summer months (July–October: maximum temperature, 48 °C). Weaned lambs (n = 10 per diet) were fed one of three totally mixed, 160 g CP/kg DM diets that contained 600, 400 or 200 g rhodesgrass hay/kg for low (9·98 MJ/kg, medium (10·3 MJ/kg) and high (11·4 MJ/kg) energy contents, respectively. All diets were balanced to meet the minimum nutritional needs for maximum growth. The trial lasted for 113–114 days. The purpose of having three diets was to induce a broad spectrum of growth rates that could be used in regression analysis (tested for linear, quadratic and exponential effects). Metabolizable energy (ME) intake was regressed on live weight (LW), empty body weight, tissue energy and tissue protein gain and vice versa. Coefficients of determinations were not significantly improved by quadratic or logarithmic regressions over linear relationships. Geometric mean regressions were used to control further biases due to major axis dependence when Y is regressed on X or vice versa. Based on tissue energy gain, the best estimates of ME required for maintenance (MEm) and gain (MEg) were 526 kJ/kg LW0·75/d and 42·1 kJ/kg LW0·75/g LW gain, respectively. Net energy values for maintenance (NEm) and gain (NEg) were 278 kJ/kg LW0·75/d and 20·6 kJ/kg LW0·75/g LW gain, respectively. These equations predicted MEm and NEm requirements that were similar to or slightly greater than those established by the US National Research Council (1985) and the UK Agricultural and Food Research Council (1993) for growing male lambs. The MEg and NEg requirements were substantially greater (by 43–89%) in this respect. Efficiency values were calculated as net energy available for maintenance or gain divided by the metabolizable energy available for maintenance or gain. The efficiency of metabolizable energy used for maintenance and gain was 0·50 and 0·52, respectively, and did not appear to be much different from values for other breeds of sheep in temperate climates. Dietary energy concentrations did not affect the efficiency of energy deposition. The data suggest that Omani sheep in hot climates have greater NEg requirements, and consequently MEg requirements, than other breeds of sheep in temperate climates.

scholarly journals Estimates of maintenance requirement of growing lambs

1979 ◽  
Vol 41 (1) ◽  
pp. 223-229 ◽  
Author(s):  
D. J. Thomson ◽  
J. S. Fenlon ◽  
S. B. Cammell
Keyword(s):  
Live Weight ◽  
Metabolizable Energy ◽  
Alternative Analysis ◽  
Maintenance Requirement ◽  
Common Value ◽  
Residual Variation ◽  
Energy Retention ◽  
Metabolizable Energy Intake ◽  
Total Body ◽  
Body Energy

1. Total body energy retention (ER) and metabolizable energy intake (MEI) values from experiments with 231 lambs (Suffolk ♂× (Border Leicester ♂× Cheviot ♀) ♀) 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 togethe 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.

scholarly journals California net energy system for Bos taurus indicus

2019 ◽  
Vol 3 (3) ◽  
pp. 991-998
Author(s):  
Mario Luiz Chizzotti ◽  
Sebastião de Campos Valadares Filho ◽  
Pedro Del Bianco Benedeti ◽  
Flávia Adriane de Sales Silva
Keyword(s):  
Body Weight ◽  
Beef Cattle ◽  
Bos Taurus ◽  
Energy Requirement ◽  
Energy System ◽  
Energy Requirements ◽  
Net Energy ◽  
Nutrient Requirements ◽  
Crossbred Cattle ◽  
Bos Taurus Indicus

Abstract The California net energy system (CNES) was the reference for the development of most energy requirement systems worldwide, such as Nutrient Requirements of Beef Cattle (NASEM, Nutrient requirements of beef cattle, 8th Revised ed, 2016) and Brazilian Nutrient Requirements of Zebu and Crossbred Cattle (Valadares Filho, S. C., L. F. C. Silva, M. P. Gionbelli, P. P. Rotta, M. I. Marcondes, M. L. Chizzotti, and L. F. Prados, BR-CORTE: nutrient requirements of zebu and crossbred cattle, 3rd ed, 2016). This review aimed to compare methods used by NASEM and BR-CORTE to estimate the energy requirements for beef cattle. The net energy requirements for maintenance (NEm) of BR-CORTE is based on empty body weight (EBW), whereas NASEM uses shrunk body weight (SBW), but the Bos taurus indicus presents 10% to 8% lower NEm than Bos taurus taurus. We have compared animals with different EBW and SBW but with same equivalent empty body weight/standard reference weight ratio (0.75), as both systems have suggested different mature weights. Both systems predicted similar net energy requirements for gain (NEg) for animals with 1.8 kg of daily gain. However, estimated empty body gain was lower for NASEM estimations when the same metabolizable energy for gain is available. For pregnancy and lactation of beef cows, the NEm and net energy requirements for pregnancy (NEp) of a Zebu cow estimated by BR-CORTE were lower than the values estimated by NASEM. Furthermore, the magnitude of differences between these systems regarding NEp increased as pregnancy days increase. The NASEM and BR-CORTE systems have presented similar values for energy requirement for lactation (0.72 and 0.75 Mcal/kg milk, respectively).

Undernutrition in grazing sheep. I. Changes in the composition of the body, blood, and rumen contents

1972 ◽  
Vol 23 (3) ◽  
pp. 483 ◽  
Author(s):  
DJ Farrell ◽  
RA Leng ◽  
JL Corbett
Keyword(s):  
Volatile Fatty Acids ◽  
Energy Content ◽  
Tritiated Water ◽  
The Body ◽  
Metabolizable Energy ◽  
Energy Requirements ◽  
Plasma Urea ◽  
Merino Sheep ◽  
Group A ◽  
Body Energy

Studies were made on three initially similar groups of adult Merino sheep at pasture; each group comprised eight animals of which four each had a rumen cannula. Group A was kept at about the initial mean liveweight of 35 kg; groups B and C were reduced in weight over 14 weeks by restriction of grazing and then held at about 26 and 23 kg respectively for 9 months. Measurements were made at intervals of 4-6 weeks of ruminal concentrations of volatile fatty acids (VFA) and ammonia, rumen volume and flow rate of digesta, tritiated water (TOH) space, and blood composition. Haemoglobin concentrations and haematocrit values decreased in the undernourished sheep, but there were no marked changes in blood β-hydroxybutyrate, or lactate, or plasma urea nitrogen. Estimates of body composition from TOH space indicated that sheep in groups B and C lost 51 and 58 Mcal respectively during the first 14 weeks; estimated fat contents were thereafter about 9 and 7% of liveweight. Metabolizable energy requirements for maintenance were calculated from estimated VFA production rates and changes in body energy content. During a 9 month period commencing shortly after shearing and extending into winter, requirements per unit liveweight were about 45% greater for the undernourished groups B and C than for group A.

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