Prediction of the Growth and Composition of Beef Cattle

1984 ◽  
Vol 1984 ◽  
pp. 49-49
Author(s):  
B.L. Baldwin ◽  
J.W. Oltjen ◽  
A.C. Bywater ◽  
D.J. Thomson
Keyword(s):  
Body Weight ◽  
Beef Cattle ◽  
Body Fat ◽  
Feed Intake ◽  
Feed Additives ◽  
Metabolizable Energy ◽  
Synthesis Rate ◽  
Protein Synthesis Rate ◽  
Net Energy ◽  
Data Set

A dynamic model of beef cattle growth and composition was developed based upon concepts validated in detailed modelling analyses of the growth of individual organs. Concepts that cell number (DNA) and cell size are primary determinants of organ (animal) size are included. Initial body weight (BW) and composition (percentage body fat), mature body weight, feed intake and feed net energy values for maintenance (NEM) and growth (NEG) are inputs to the model. Alternative inputs descriptive of feed can be metabolizable energy (ME) concentration and efficiencies of ME use for maintenance and fattening. Current body DNA and protein content and ME intake are primary determinants of rates of protein accretion. Net synthesis of body fat is calculated after accounting costs of maintenance and protein synthesis. Rate constants defining DNA synthesis, and protein degradation and synthesis, and effects of feed additives and implants upon these were deduced using data from comparative slaughter (energy balance) trials with over 1,000 cattle (mainly Hereford) fed mixed diets. No systematic errors in prediction of body weight or composition due to mature body weight, ration or feed intake (FI) were evident within this data set.

scholarly journals Metabolizable energy levels in diets with a fixed nutrient: calorie ratio for free-range broilers

2021 ◽  
Vol 42 (6supl2) ◽  
pp. 4009-4022
Author(s):  
Thiago Rodrigues da Silva ◽  
◽  
Karina Márcia Ribeiro de Souza Nascimento ◽  
Charles Kiefer ◽  
Luanna Lopes Paiva Copat ◽  
...  
Keyword(s):  
Body Weight ◽  
Weight Gain ◽  
Energy Level ◽  
Body Fat ◽  
Feed Intake ◽  
Carcass Characteristics ◽  
Metabolizable Energy ◽  
Production Performance ◽  
Feed Conversion ◽  
Protein Deposition

The present study proposes to examine the effect of dietary levels of metabolizable energy, under a fixed nutrient:calorie ratio, on the production performance; body fat and protein deposition; and carcass characteristics of free-range broilers from 1 to 84 days of age. Nine hundred unsexed chicks were allocated to six treatments in a completely randomized design with six replicates of 25 birds each. Treatments consisted of diets with varying levels of metabolizable energy (2700, 2800, 2900, 3000, 3100 and 3200 Kcal ME/kg of diet) and a fixed proportion of nutrients relative to the energy level according to the nutritional requirements for each rearing phase. Body weight, weight gain, feed intake, feed conversion, production viability, metabolizable energy intake, protein intake, lysine intake, body fat deposition, body protein deposition and carcass characteristics were evaluated. Data were subjected to analysis of variance and, later, to regression analysis. Increasing levels of metabolizable energy, coupled with a fixed nutrient:calorie ratio, reduced feed intake, increased body weight and weight gain, improved feed conversion and did not affect carcass characteristics. In conclusion, adjusting the nutrient supply according to the dietary energy level improves production performance by improving feed conversion, ensuring adequate nutrient intake and preserving fat and protein deposition in the carcass when the metabolizable energy level is raised up to 3200 Kcal/kg in all rearing stages.

scholarly journals Feeding behavior, water intake, and energy and protein requirements of young Nellore bulls with different residual feed intakes

2020 ◽  
Vol 98 (9) ◽  
Author(s):  
Ana Clara B Menezes ◽  
Sebastião C Valadares Filho ◽  
Pedro D B Benedeti ◽  
Diego Zanetti ◽  
Mário F Paulino ◽  
...  
Keyword(s):  
Body Weight ◽  
Feeding Behavior ◽  
Water Intake ◽  
Feed Intake ◽  
Carcass Traits ◽  
Metabolizable Energy ◽  
Production Costs ◽  
Energy Requirements ◽  
Feed Ratio ◽  
Net Energy

Abstract This study aimed to determine feeding behavior, water intake (WI), and energy requirements of high- and low-residual feed intake (RFI) Nellore bulls. Data were collected from 42 weaned Nellore bulls (initial body weight [BW] 260 ± 8.1 kg; age 7 ± 1.0 mo) housed in a feedlot in group pens that contained electronic feeders, waterers, and a scale connected to the waterers. The individual dry matter intake (DMI), WI, and BW were recorded daily. The indexes of average daily gain (ADG), feed efficiency (gain to feed ratio), and RFI were calculated based on the data collected. The number of feeder and waterer visits and the time spent feeding or drinking water per animal per day were recorded as feeding behavior measures. Energy requirements for maintenance and gain were calculated according to the BR-CORTE system. Low-RFI bulls had lower DMI (P < 0.01) than high-RFI bulls, and no differences (P > 0.05) were observed between the two groups regarding WI, performance, and feeding behavior measurements. The net energy requirements for maintenance, metabolizable energy for maintenance, and efficiency of metabolizable energy utilization were 63.4, 98.6 kcal/metabolic empty body weight (EBW)0.75 daily, and 64.3%, respectively, for low-RFI bulls, and 78.1, 123.9 kcal/EBW0.75 daily, and 63.0%, respectively, for high-RFI bulls. The equations obtained for net energy for gain (NEg) were: NEg (Mcal/EBW0.75) daily = 0.0528 × EBW0.75 × EBG0.5459 for low-RFI and 0.054 × EBW0.75 × EBG0.8618 for high-RFI bulls, where EBG is the empty body gain. We did not observe any difference (P > 0.05) regarding the composition of gain in terms of protein or fat deposition between the two groups. Both groups also presented similar (P > 0.05) carcass and non-carcass traits. Therefore, our study shows that low-RFI Nellore bulls eat less, grow at a similar rate, and have lower maintenance energy requirements than high-RFI bulls. We also suggest that the lower feed intake did not compromise the carcass traits of more efficient animals, which would reduce production costs and increase the competitiveness of the Brazilian beef sector on the world market.

scholarly journals 127 Predicting Dry Matter Intake of Gestating and Lactating Beef Cows

2020 ◽  
Vol 98 (Supplement_2) ◽  
pp. 58-58
Author(s):  
Megan A Gross ◽  
Claire Andresen ◽  
Amanda Holder ◽  
Alexi Moehlenpah ◽  
Carla Goad ◽  
...  
Keyword(s):  
Beef Cattle ◽  
Milk Yield ◽  
Feed Intake ◽  
Beef Cows ◽  
Multiple Regression Equation ◽  
Validation Data ◽  
Data Set ◽  
Lactating Cows ◽  
Downward Bias ◽  
Protein Supply

Abstract In 1996, the NASEM beef cattle committee developed and published an equation to estimate cow feed intake using results from studies conducted or published between 1979 and 1993 (Nutrient Requirements of Beef Cattle). The same equation was recommended for use in the most recent version of this publication (2016). The equation is sensitive to cow weight, diet digestibility and milk yield. Our objective was to validate the accuracy of this equation using more recent published and unpublished data. Criteria for inclusion in the validation data set included projects conducted or published within the last ten years, direct measurement of forage intake, adequate protein supply, and pen feeding (no tie stall or metabolism crate data). The validation data set included 29 treatment means for gestating cows and 26 treatment means for lactating cows. Means for the gestating cow data set was 11.4 ± 1.9 kg DMI, 599 ± 77 kg BW, 1.24 ± 0.14 Mcal/kg NEm per kg of feed and lactating cow data set was 14.5 ± 2.0 kg DMI, 532 ± 116.3 kg BW, and 1.26 ± 0.24 Mcal NEm per kg feed, respectively. Non intercept models were used to determine equation accuracy in predicting validation data set DMI. The slope for linear bias in the NASEM gestation equation did not differ from 1 (P = 0.07) with a 3.5% positive bias. However, when the NASEM equation was used to predict DMI in lactating cows, the slope for linear bias significantly differed from 1 (P < 0.001) with a downward bias of 13.7%. Therefore, a new multiple regression equation was developed from the validation data set: DMI= (-4.336 + (0.086427 (BW^.75) + 0.3 (Milk yield)+6.005785(NEm)), (R-squared=0.84). The NASEM equation for gestating beef cows was reasonably accurate while the lactation equation underestimated feed intake.

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.

Seasonal change in feed intake, body composition, and metabolic rate of white-tailed deer

1995 ◽  
Vol 73 (3) ◽  
pp. 452-457 ◽  
Author(s):  
Karol A. Worden ◽  
Peter J. Pekins
Keyword(s):  
Body Composition ◽  
Metabolic Rate ◽  
Body Fat ◽  
Feed Intake ◽  
Deuterium Oxide ◽  
Critical Time ◽  
Metabolizable Energy ◽  
Body Protein ◽  
Daily Energy ◽  
Time Of Year

Winter is a critical time of year for white-tailed deer (Odocoileus virginianus) in northern regions because their food consumption does not meet their daily energy demands. We measured feed intake, fasting metabolic rate (FMR), and body composition of five captive adult female white-tailed deer from September 1991 through March 1992 in New Hampshire to investigate the relationships between FMR and feed intake to fat deposition and mobilization. Deuterium oxide dilution was used to estimate monthly body composition, indirect respiration calorimetry was used to measure monthly FMR, and metabolizable energy intake (MEI) was calculated from daily feed intake. Mean percent body fat increased from 9.1 ± 1.5 to 24.9 ± 4.4% from September to December, and then declined through March. Mean percent body protein did not change during the study (range 20–21%). Mean MEI peaked during September and October (171.9 ± 8.1 and 168.7 ± 10.3 kcal∙kg body mass−0.75∙d−1, respectively), and declined 54% by February. Mean FMR ranged from 79 to 90 from October through March. Correlations between MEI or FMR and change in body fat were weak. It was estimated that intake rates of free-ranging deer were only 90–110% of winter FMR, and that deer with 20% body fat could balance their daily energy expenditure (1.7 × FMR) with fat stores for about 3 months, or the period of time during which MEI was depressed in captive deer.

The partition of nutrients in ewes maintained in a moderate compared with a lean body condition in late pregnancy

1997 ◽  
Vol 48 (6) ◽  
pp. 743 ◽  
Author(s):  
D. M. McNeill ◽  
R. W. Kelly ◽  
I. H. Williams
Keyword(s):  
Body Weight ◽  
Body Fat ◽  
Body Condition ◽  
Feed Intake ◽  
Late Pregnancy ◽  
Placental Weight ◽  
Fetal Weight ◽  
Fetal Size ◽  
Per Se ◽  
Free Body

The effect of ewe fatness on fetal weight at term was tested without the confounding effects of placental weight and feed intake. We hypothesised that fetal weights should be similar in fat or lean ewes with placentas of a similar size, and tested the hypothesis by manipulating nutrition so that, at mating, Merino ewes carrying a single fetus were in a medium (score 2·9, liveweight 46·6 kg) or lean (score 2·0, liveweight 40·6 kg) condition. They were maintained at this fatness difference until slaughter at Day 146 of pregnancy when fetal, placental, and maternal tissues were weighed and analysed for composition. Subgroups (n = 8 per fatness group) slaughtered at Day 110, a stage when most placental hypertrophy is complete but the majority of fetal hypertrophy is yet to occur, confirmed that the treatments differed in ewe fatness (3·82 v. 9·19 kg empty-body fat, s.e.m. = 0·960; P < 0·001) but not placental weight (487 v. 538 g, s.e.m. = 41·5, P > 0·05). By Day 146, fatness differences (4·77 v. 9·56 kg empty-body fat, s.e.m. = 0·960, P < 0·001) and placental similarities (434 v. 502 g, s.e.m. = 38·3, P > 0·05) were maintained, and both groups produced fetuses of similar size (4408 v. 4382 g, s.e.m. = 204·6, P > 0·05). However, the fetuses in the lean ewes had 20% less fat/kg fat-free body weight (24 v. 30 g/kg, s.e.m. = 1·3, P < 0·01). Fetal weight was correlated with placental weight (r = 0·70; P < 0·01) but not with ewe fatness. Fetal fatness, however, was correlated with ewe fatness (r = 0·69; P < 0·01). Ewe fatness per se did not influence fetal size but did influence the deposition of fat in the fetus, possibly via a greater ability of fatter ewes to partition more glucose toward their fetus.

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.

scholarly journals Metabolizable energy levels in diets with high lysine for growing and finishing pigs

2019 ◽  
Vol 40 (1) ◽  
pp. 365 ◽  
Author(s):  
Soraia Viana Ferreira ◽  
Lívia Maria dos Reis Barbosa ◽  
Camila Schultz Marcolla ◽  
Marcos Henrique Soares ◽  
Dante Teixeira Valente Júnior ◽  
...  
Keyword(s):  
Body Weight ◽  
Meat Quality ◽  
Feed Intake ◽  
Average Daily Gain ◽  
Metabolizable Energy ◽  
Feed Conversion ◽  
Water Losses ◽  
Final Body Weight ◽  
Metabolizable Energy Intake ◽  
Daily Gain

The objective of this experiment was to evaluate the effects of metabolizable energy (ME) levels in diets with high digestible lysine concentration on performance, carcass traits, and meat quality of barrows from 95 to 158 days of age. Eighty commercial hybrid barrows (50 ± 1.82 kg) selected for lean meat deposition, were assigned to four dietary treatments (3,150, 3,235, 3,320, and 3,400 kcal EM kg-1) in a randomized design with 10 replicate pens per treatment and two pigs per pen. From 95 to 116 days of age, we observed no effects of ME on final body weight (FBW), average daily gain (ADG), metabolizable energy intake (MEI), and feed conversion (F: G). Average daily feed intake (ADFI) decreased linearly with increasing ME levels (? = 5.79961 - 0.00096790X - r2 = 0.89). From 95 to 137 days of age, no effects of ME were observed on final body weight (FBW), average daily gain (ADG), metabolizable energy intake (MEI), and feed conversion (F: G). Average daily feed intake (ADFI) decreased linearly with increasing ME (?= 6.1176 - 0.001X - r2= 0.97). From 95 to 158 days, of age no effects of ME were observed on FBW and ADG. Dietary ME influenced the ADFI and F: G, which decreased linearly with increasing ME concentrations (?= 8.12951 - 0.00149X - r2= 0.99; ?= 6.0914 - 0.001X - r² = 0.75, respectively). There was a linear increase in loin eye area (LEA) with increasing ME (? = - 29.851 + 0.0207 X - r² = 0.87). Backfat thickness, pH, and temperature, measured at different times after slaughter (0 min, 45 min, 3 h, and 24 h), were not affected by dietary ME. The level of ME also did not affect the meat quality parameters Color L*, Color a*, Color b*, Warner-Bratzler shear force, thaw water losses, cooking water losses, sum of water losses, intramuscular fat content, and TBARS. Diets with 3,400 kcal kg-1 ME, corresponding to 2.75, 2.57, and 2.31 g digestible lysine/Mcal of ME for pigs from 95 to 116, 116 to 137, and 95 to 158 days of age, respectively, resulted in best performance and carcass traits, without negative effects on meat quality.

Evaluation of the National Research Council (NRC) nutrient requirements for beef cattle: Predicting feedlot performance

2003 ◽  
Vol 83 (4) ◽  
pp. 787-792
Author(s):  
E. K. Okine ◽  
D. H. McCartney ◽  
J. B. Basarab
Keyword(s):  
Beef Cattle ◽  
Dry Matter ◽  
Research Council ◽  
Average Daily Gain ◽  
National Research Council ◽  
Metabolizable Energy ◽  
Dry Matter Intake ◽  
Net Energy ◽  
Feeder Cattle

The accuracy of predicted CowBytes® versus actual dry matter intake (DMI) and average daily gain (ADG) of 407 Hereford × Angus and Charolais × Maine Anjou (445.6 ± 36 kg) feeder cattle using digestable enery acid detergent fiber (DE) estimated from the (ADF) content [Laboratory analysis method (LAB)] and from values determined in vivo (INVIVO method) was examined. The diet consisted of a 73.3% concentrate diet, 22.0% barley silage, 1.6% molasses, and 3.1% feedlot supplement fed ad libitum (as-fed basis). The calculated DE values of the feed were used to predict the metabolizable energy (ME), net energy of maintenance (NEm), and net energy of gain (NEg) of the diet. These energy values were then used in CowBytes® to predict dry matter intake (DMI), ADG, and days on feed (DOF) necessary to meet targeted quality grade of AA and weights of 522 and 568 kg for the heifers and steers, respectively. There was no effect of gender and prediction method interaction (P > 0.10) on any of the variables measured. There were no (P > 0.05) differences in predicted DMI by either the INVIVO or LAB method but both methods underestimated DMI actually consumed by the cattle by 6.8 and 4.9% (P = 0.007), respectively. Indeed, regression values from these predictive methods and actual DMI were (P < 0.05) different from the one-to-one relationship expected by definition. In spite of the higher actual DMI, the actual ADG of the cattle was 14 and 11% (P = 0.0004) lower than was predicted by either the INVIVO or LAB methods. A possible reason for the lower ADG could be an overestimation of DE of the diet. Thus, if available, users of CowBytes® should use actual DMI from their experience in ration formulation. In addition, the effects of environmental temperature on digestibility of diets should be taken into consideration when using the DE of the diet as determined from in vivo digestibility trials or calculated from chemical analyses in determining the DMI of feedlot cattle. Key words: Beef cattle, performance, CowBytes®, National Research Council

Net energy value of timothy and bromegrass silages for beef cattle

1998 ◽  
Vol 78 (1) ◽  
pp. 107-114 ◽  
Author(s):  
D. R. Ouellet ◽  
J. R. Seoane ◽  
H. Lapierre ◽  
P. Flipot ◽  
J. F. Bernier
Keyword(s):  
Beef Cattle ◽  
Heat Production ◽  
Stem Elongation ◽  
Prediction Equation ◽  
Metabolizable Energy ◽  
Net Energy ◽  
Beef Steers ◽  
Boot Stage ◽  
Ad Libitum ◽  
Net Energy Value

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

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