The importance of body composition in explaining variation in feed conversion efficiency and residual feed intake between meat sheep at two different ages

2006 ◽  
Vol 2006 ◽  
pp. 153-153
Author(s):  
S A Knott ◽  
L J Cummins ◽  
B J Leury ◽  
F R Dunshea

Residual feed intake (RFI) is a measure of feed efficiency calculated as the difference between an animal’s actual intake and its expected intake based on its liveweight and growth rate over a specified period of time (Richardson, Herd et al. 2002). The efficiency with which an animal utilises energy during growth, is dependent on a number of physiological factors including body composition and the relative proportions of lean tissue mass (LTM) and fat tissue mass (FTM), due to differences in the energy cost of depositing and maintaining these tissues. Protein or lean tissue is continually degraded and resynthesised and thus the rate at which this occurs may contribute to the variation in energy required by an animal for maintenance and growth (Archer, Richardson et al. 1999). The objective of this work was to determine the relationship between feed conversion ratio (FCR, kg feed:kg gain) and residual feed intake (RFI) with body composition in rams at six months of age (6mo), and then again in the same rams at thirteen months of age (13mo).

2004 ◽  
Vol 84 (2) ◽  
pp. 177-185 ◽  
Author(s):  
F. S. Schenkel ◽  
S. P. Miller ◽  
J. W. Wilton

Genetic associations between feed efficiency, growth, and live ultrasound measured body composition traits were studied in purebred beef bulls of six breeds in Ontario bull test stations from 1991 to 2000. Feed traits included average daily feed intake (FI), feed conversion ratio (FCR), and residual feed intake [feed intake adjusted for production alone (RFIp) or production and backfat thickness (RFIb)]. Growth traits were average daily weight gain (ADG), mid-test metabolic weight (MW), hip height (HH), and scrotal circumference (SC). Body composition traits included ultrasound backfat thickness (BF), longissimus muscle area (LMA), and predicted percentage of intramuscular fat (IFAT). Bulls were measured every 28 d for weight and individual feed intake, and at the end of test for ultrasound body composition traits. Number of records per trait ranged from 2284 (FI) to 13 319 (ADG). Fixed effects of test group, breed and end of test age (within breed), and random effects of animal and herd of origin were modeled using REML bivariate analyses for all traits. Heritability estimates were moderate for all traits (0.30 to 0.55), except for IFAT (0.14). The genetic correlation between RFIp and RFIb was high (0.99) within breeds, but breeds ranked differently with respect to RFIp and RFIb. Genetic correlations of RFIb with ADG and backfat thickness were essentially zero, which indicate that selection on residual feed intake could be implemented to reduce feed intake and improve feed conversion without compromising growth or changing levels of subcutaneous fat. Key words: Central test, genetic correlation, heritability, residual feed intake


2001 ◽  
Vol 41 (7) ◽  
pp. 1065 ◽  
Author(s):  
E. C. Richardson ◽  
R. M. Herd ◽  
V. H. Oddy ◽  
J. M. Thompson ◽  
J. A. Archer ◽  
...  

Yearling Angus steer progeny of parents selected for low residual feed intake (RFI; high efficiency) or high RFI (low efficiency) were evaluated for feed intake, growth and differences in body composition. RFI is the difference between actual feed intake and expected feed intake based on an animal’s size and growth over a test period. Individual intakes of a high grain content ration and growth rates were recorded for 140 days and then the steers were slaughtered for measurement of body composition. All internal organs and non-carcass fat depots were removed, weighed and ground for chemical analysis. Carcasses were kept overnight in the chiller and the left half of every carcass physically dissected into retail cuts, and then into total fat, lean and bone. Carcass fat and lean were then combined and ground for chemical analysis. Steers from low RFI parents ate less (P<0.05) than the steers from high RFI parents, for similar rates of growth. Improvement in RFI was accompanied by small changes in body composition towards greater lean and less fat in the progeny of low RFI parents. Correlations of sire estimated breeding values for RFI with end of test whole body chemical protein, chemical fat and a principal component that condensed information on fat and lean body composition at the end of the test, were statistically significant. These confirmed there was a genetic association between body composition and RFI, with fatness being associated with higher RFI (i.e. lower efficiency). However, the correlations were small and suggested that less than 5% of the variation in sire RFI was explained by variation in body composition of their steer progeny. There was no evidence that a difference in the chemical composition of gain over the test explained the greater intake of metabolisable energy (ME) by the high RFI steers. The results suggest that the difference in ME intake following a single generation of divergent selection for RFI was due to metabolic processes rather than to changes in body composition.


2017 ◽  
Vol 57 (4) ◽  
pp. 627 ◽  
Author(s):  
J. I. Velazco ◽  
R. M. Herd ◽  
D. J. Cottle ◽  
R. S. Hegarty

As daily methane production (DMP; g CH4/day) is strongly correlated with dry matter intake (DMI), the breeding of cattle that require less feed to achieve a desired rate of average daily gain (ADG) by selection for a low residual feed intake (RFI) can be expected to reduce DMP and also emission intensity (EI; g CH4/kg ADG). An experiment was conducted to compare DMP and EI of Angus cattle genetically divergent for RFI and 400-day weight (400dWT). In a 6-week grazing study, 64 yearling-age cattle (30 steers, 34 heifers) were grazed on temperate pastures, with heifers and steers grazing separate paddocks. Liveweight (LW) was monitored weekly and DMP of individual cattle was measured by a GreenFeed emission monitoring unit in each paddock. Thirty-nine of the possible 64 animals had emission data recorded for 15 or more days, and only data for these animals were analysed. For these cattle, regression against their mid-parent estimated breeding value (EBV) for post-weaning RFI (RFI-EBV) showed that a lower RFI-EBV was associated with higher LW at the start of experiment. Predicted dry matter intake (pDMI), predicted DMP (pDMP) and measured DMP (mDMP) were all negatively correlated with RFI-EBV (P < 0.05), whereas ADG, EI, predicted CH4 yield (pMY; g CH4/kg DMI) were not correlated with RFI-EBV (P > 0.1). Daily CH4 production was positively correlated with animal LW and ADG (P < 0.05). The associations between ADG and its dependent traits EI and pMY and predicted feed conversion ratio (kg pDMI/kg ADG) were strongly negative (r = –0.82, –0.57 and –0.85, P < 0.001) implying that faster daily growth by cattle was accompanied by lower EI, MY and feed conversion ratio. These results show that cattle genetically divergent for RFI do not necessarily differ in ADG, EI or pMY on pasture and that, if heavier, cattle with lower RFI-EBV can actually have higher DMP while grazing moderate quality pastures.


2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
Lucia Cordero ◽  
Marta Rivero Martínez ◽  
Paula Jara Caro Espada ◽  
Elena Gutiérrez ◽  
Evangelina Mérida ◽  
...  

Abstract Background and Aims Overhydration (OH) is an independent predictor of mortality on hemodialysis (HD). The gold standard to assess OH is BCM monitor from Fresenius®, however BCM is a hospital hold device limiting its use. New smart scales have emerged as household devices reporting daily body composition data. Objective To determine if Renpho ES-CS20M® could be useful on a 52 HD patient to estimate body composition data. Method 72 body composition assessments (BCA) during mid-week HD session were performed. Each BCA included: (1) Predialysis Renpho measurement, (2) Predialysis BCM monitor measurement, (3) Postdialysis Renpho measurement. To track the fluid balance during the HD session: (1) we recorded ultrafiltration, (2) food or fluid intake was not allowed, and (3) none of the HD patients urinated during the HD session. If any intravenous fluids were needed during the HD session, we subtracted them off from UF. Results Data from 52 HD patients were studied (age 58.8 ± 16.8 years, 56.9 % males, 14.7% diabetics), with a mean pre-HD weight of 70.0 ± 13. 4 Kg, overhydration of 1.7 ± 1.5 L and urea distribution volume of 31.7 ± 5.7 L. The mean ultrafiltration during HD session was -1.8 ± 0.9 L. Renpho estimated a Pre – HD hydration of 34.25 ± 6.02 Kg vs 33.4 ± 5.7 Kg by BCM, showing a good concordance between methods (ICC 0.788 [0.67-0.86], B -0.58, p &lt;0.01). Renpho poorly estimated pre – HD lean tissue mass at 45.4 ± 6.9 Kg compared with 33.8 ± 8.0 Kg by BCM. Although Renpho was able to provide a moderate concordant estimation of fat tissue mass (33.8 ± 8.0 % with Renpho vs 34.7 ± 9.6%), the bias proportion was unacceptable. Post- HD hydration by Renpho was not able to reproduce the ultrafiltracion achieved during the HD session (pre-HD 34.25 ± 6.02 Kg vs post-HD 34.08 ± 6.00 Kg). Conclusion Renpho has a proportional bias estimating predialysis hydration compared with BCM monitor, but is not able to assess changes produced with ultrafiltration or other parameters of body composition (as lean or fat tissue mass). Although smart scales are unacurate to assess body composition on HD patients, they could be useful on the follow up of them changing the accuracy for frequency.


2011 ◽  
Vol 40 (4) ◽  
pp. 929-937 ◽  
Author(s):  
T. Lucila Sobrinho ◽  
R.H. Branco ◽  
S.F.M. Bonilha ◽  
A.M. Castilhos ◽  
L.A. Figueiredo ◽  
...  

The objective of this work was to evaluate performance, efficiency parameters and phenotypic correlations among measurements of energy efficiency of Nellore cattle selected for post weaning weight and classified according to residual feed intake, calculated by the difference between observed and predicted intake, based on average metabolic body weight and average daily gain. Thus, animals were classified within three groups: high (> mean + 0.5 standard deviation, less efficient); medium (±0.5 standard deviation of the mean); and low (< mean - 0.5 standard deviation, more efficient) residual feed intake. No differences were observed at initial and final body weights, average daily gain and dry matter intake among groups. Animals with low residual feed intake also had greater feed efficiency, feed conversion and partial efficiency of growth and did not differ from the other animals regarding to relative growth rate and Kleiber ratio. Residual feed intake was significantly correlated to feed efficiency (-0.25), feed conversion (0.25), partial efficiency of growth (-0.37) and dry matter intake (0.16) but it did not present significant correlation with body weight (0.04), average daily gain (-0.02), relative growth rate (-0.03) and Kleiber ratio (-0.05). Significant correlations were found between feed conversion and initial body weight (0.34) and average daily gain (-0.46). Partial efficiency of growth presented significant correlation with all other efficiency parameters analyzed. Residual feed intake has high potential in productive efficiency, when compared to the other energy efficiency measurements, being independent of growth and size of the animals.


2013 ◽  
Vol 14 (3) ◽  
pp. 527-537 ◽  
Author(s):  
Miguel Henrique de Almeida Santana ◽  
Paulo Rossi Junior ◽  
Rodrigo de Almeida ◽  
Amanda Massaneira de Souza Schuntzemberger

Due to the potential metabolic changes related to the residual feed intake (RFI), this study investigated the correlation of traditional RFI (RFI1), RFI adjusted for final rump fat thickness (RFI2) and feed conversion ratio (FCR) with the metabolic and blood profiles, as well as determined the possible different classes of RFI1 and RFI2. For this purpose, 46 Nellore bulls, 22 month-old and 411kg of weight at the beginning of the study were used. The animals were fed with the same diet for 84 days, and blood samples were collected every 21 days for evaluation of serum metabolites and blood cell profiles. No significant correlations were found between FCR and metabolic or blood traits, although there was a significant correlation between RFI1 and urea serum concentration. There were also differences between the RFI classes for creatinine, in which more efficient animals showed higher values. The RFI2 did not correlate with any metabolic and blood cell variable, but young bulls with smaller RFI2 had a smaller number of eosinophils when compared to animals with higher RFI2. These results suggest that animals with a high RFI can have greater energy expenditure due to protein synthesis and degradation process, resulting in a larger blood urea level.


2009 ◽  
Vol 49 (6) ◽  
pp. 351 ◽  
Author(s):  
S. A. Barwick ◽  
M. L. Wolcott ◽  
D. J. Johnston ◽  
H. M. Burrow ◽  
M. T. Sullivan

Genetic parameters for Brahman (BRAH) and Tropical Composite (TCOMP) cattle were estimated for steer production traits recorded at weaning (WEAN), 80 days post-weaning (POSTW), feedlot entry (ENTRY) and after ∼120 days feedlot finishing (EXIT). The TCOMP was 50% Bos indicus, African Sanga or other tropically adapted Bos taurus, and 50% non-tropically adapted Bos taurus. Data involved 2216 steers, comprising 1007 BRAH by 53 sires and 1209 TCOMP by 50 sires. Individual daily feed intake (DFI) and residual feed intake (RFI) were assessed on 680 BRAH and 783 TCOMP steers over an ~70-day feedlot test. Other traits were liveweight (LWT), average daily gain (ADG), ultrasonically scanned rump (SP8) fat depth, rib (SRIB) fat depth, M. longissimus area (SEMA) and intra-muscular fat % (SIMF), body condition score (CS), hip height (HH), flight time (FT) and serum insulin-like growth factor-I concentration (IGF-I). BRAH were significantly (P < 0.05) lighter at ENTRY and EXIT, and had lower DFI (10.8 v. 13.2 kg/day) and RFI (–0.30 v. 0.17 kg/day), greater SP8 (5.8 v. 5.1 mm) but similar SRIB at ENTRY, lower SRIB (8.2 v. 8.9 mm) but similar SP8 at EXIT, and greater HH than TCOMP. Heritabilities for DFI, RFI, LWT, ADG, scanned body composition, HH and IGF-I measures, across measurement times, were generally in the 20 to 60% range for both genotypes. Genetic variance for RFI was 0.19 (kg/day)2 in BRAH and 0.41 (kg/day)2 in TCOMP, suggesting a clear potential to genetically change RFI in both genotypes. Trait variances and genetic correlations often differed between the genotypes, supporting the use of genotype-specific parameters in genetic evaluation. The genotype differences may be associated with evolutionary changes that have occurred in B. indicus as a part of their adaptation to tropical environments. Measures with potential to be used as genetic indicators of DFI were LWT measures in BRAH and TCOMP, ADG at ENTRY in TCOMP, and SP8 and SIMF at ENTRY in BRAH. Measures with potential to be genetic indicators of RFI were HH and ADG at ENTRY in BRAH, and IGF-I in both genotypes. Taller and faster-growing BRAH steers at ENTRY had genetically lower RFI. IGF-I was negatively genetically correlated with RFI whether IGF-I was measured at POSTW, ENTRY or EXIT. SRIB fatness at EXIT was strongly positively genetically correlated with RFI in TCOMP but only lowly correlated in BRAH. Fatness at ENTRY was lowly and negatively genetically correlated with RFI. The results emphasise the need for a population-specific understanding of trait relationships and of trait differences between measurement times if genetic indicator traits are to be utilised in genetic evaluation of RFI.


1971 ◽  
Vol 22 (5) ◽  
pp. 829 ◽  
Author(s):  
TF Leche

Sixty Jersey and 48 Friesian bull calves were reared from birth on either of two planes of nutrition. A milk replacer and a concentrate diet were given before and after weaning respectively. The Jerseys were weaned at 45 kg and the Friesians at 77 kg. At liveweights arranged in logarithmic progression between birth and 249 kg, three calves of each treatment group were killed for analysis of body composition. Before and after weaning, the Friesians grew more rapidly than the Jerseys on the same treatment. They were also more efficient in terms of feed intake per liveweight gain. Similarly, calves of both breeds on the high plane of nutrition grew faster and more efficiently than the corresponding calves on the low plane. The growth of the Friesians was affected less by the feed restriction than was that of the Jerseys. After weaning, the feed conversion efficiency of the Friesians did not change significantly with increasing liveweight. Feed efficiency was reduced in the Jerseys as they grew larger. These results are compared with others from the literature and are discussed in relation to the difference in mature size between these breeds.


2019 ◽  
Vol 97 (8) ◽  
pp. 3550-3561 ◽  
Author(s):  
Jocelyn R Johnson ◽  
Gordon E Carstens ◽  
Wimberly K Krueger ◽  
Phillip A Lancaster ◽  
Erin G Brown ◽  
...  

Abstract The objectives of this study were to examine the relationship between residual feed intake (RFI) and DM and nutrient digestibility, in vitro methane production, and volatile fatty acid (VFA) concentrations in growing beef cattle. Residual feed intake was measured in growing Santa Gertrudis steers (Study 1; n = 57; initial BW = 291.1 ± 33.8 kg) and Brangus heifers (Study 2; n = 468; initial BW = 271.4 ± 26.1 kg) fed a high-roughage-based diet (ME = 2.1 Mcal/kg DM) for 70 d in a Calan-gate feeding barn. Animals were ranked by RFI based on performance and feed intake measured from day 0 to 70 (Study 1) or day 56 (Study 2) of the trial, and 20 animals with the lowest and highest RFI were identified for subsequent collections of fecal and feed refusal samples for DM and nutrient digestibility analysis. In Study 2, rumen fluid and feces were collected for in vitro methane-producing activity (MPA) and VFA analysis in trials 2, 3, and 4. Residual feed intake classification did not affect BW or BW gain (P &gt; 0.05), but low-RFI steers and heifers both consumed 19% less (P &lt; 0.01) DMI compared with high-RFI animals. Steers with low RFI tended (P &lt; 0.1) to have higher DM digestibility (DMD) compared with high-RFI steers (70.3 vs. 66.5 ± 1.6% DM). Heifers with low RFI had 4% higher DMD (76.3 vs. 73.3 ± 1.0% DM) and 4 to 5% higher (P &lt; 0.01) CP, NDF, and ADF digestibility compared with heifers with high RFI. Low-RFI heifers emitted 14% less (P &lt; 0.01) methane (% GE intake; GEI) calculated according to Blaxter and Clapperton (1965) as modified by Wilkerson et al. (1995), and tended (P = 0.09) to have a higher rumen acetate:propionate ratio than heifers with high RFI (GEI = 5.58 vs. 6.51 ± 0.08%; A:P ratio = 5.02 vs. 4.82 ± 0.14%). Stepwise regression analysis revealed that apparent nutrient digestibilities (DMD and NDF digestibility) for Study 1 and Study 2 accounted for an additional 8 and 6%, respectively, of the variation in intake unaccounted for by ADG and mid-test BW0.75. When DMD, NDF digestibility, and total ruminal VFA were added to the base model for Study 2, trials 2, 3, and 4, the R2 increased from 0.33 to 0.47, explaining an additional 15% of the variation in DMI unrelated to growth and body size. On the basis of the results of these studies, differences in observed phenotypic RFI in growing beef animals may be a result of inter-animal variation in apparent nutrient digestibility and ruminal VFA concentrations.


2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Rodolfo Valtuille ◽  
Maria Elisa Casos ◽  
Elmer Andres Fernandez ◽  
Adrian Guinsburg ◽  
Cristina Marelli

The aims of this study were to analyse body composition, to detect the presence of undernutrition, and to establish a relationship between undernutrition and the biological markers routinely used as indicators of nutritional status in hemodialysis (HD) patients (pts). We used a body composition monitor (BCM) that expresses body weight in terms of lean tissue mass (LTM) and fat tissue mass (FTM) independent of hydration status. From nine HD units, 934 pts were included. Undernutrition was defined as having a lean tissue index (LTI = LTM/height2) below the 10th percentile of a reference population. Biochemical markers and parameters delivered by BCM were used to compare low LTI and normal LTI groups. Undernutrition prevalence was 58.8% of the population studied. Low LTI pts were older, were significantly more frequently overhydrated, and had been on HD for a longer period of time than the normal LTI group. FTI (FTI = FTM/ height2) was significantly higher in low LTI pts and increased according to BMI. LTI was not influenced by different BMI levels. Albumin and C-reactive protein correlated inversely (r=-0.28). However neither of them was statistically different when considering undernourished and normal LTI pts. Our BCM study was able to show a high prevalence of undernutrition, as expressed by low LTI. In our study, BMI and other common markers, such as albumin, failed to predict malnutrition as determined by BCM.


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