Biological basis for variation in residual feed intake in beef cattle. 1. Review of potential mechanisms

2004 ◽  
Vol 44 (5) ◽  
pp. 423 ◽  
Author(s):  
R. M. Herd ◽  
V. H. Oddy ◽  
E. C. Richardson

There is a growing body of evidence that there is genetic variation in beef cattle feed intake relative to their liveweight and weight gain. Difference in feed intake, above and below that expected or predicted on the basis of size and growth, is measured as residual feed intake. Variation in residual feed intake must be underpinned by measurable differences in biological processes. This paper summarises some plausible mechanisms by which variation in efficiency of nutrient use may occur and presents several testable hypotheses for such variation. A� companion paper [Richardson and Herd (2004) Aust. J. Exp. Ag. 44, 431–441] presents results from experiments on cattle following divergent selection for residual feed intake. There were at least 5 major processes identified by which variation in efficiency can arise. These are associated with variation in intake of feed, digestion of feed, metabolism (anabolism and catabolism associated with and including variation in body composition), activity and thermoregulation. The percentage contribution of different mechanisms, to variation in residual feed intake, was: 9% for differences in heat increment of feeding; 14% for differences in digestion; 5% for differences in body composition; and 5% for differences in activity. Together, these mechanisms may be responsible for about one-third of the variation in residual feed intake. The remaining two-thirds were likely to be associated with heat loss due to variation in other processes, such as protein turnover and ion transport. There is no shortage of candidate mechanisms that, singularly or in combination, might contribute to genetic variation in energy utilisation in ruminants. Further research in beef cattle, to better define these mechanisms and enable their incorporation into breeding programmes, may lead not only to cattle which eat less for the same performance, but are superior in other traits as well.

2004 ◽  
Vol 84 (2) ◽  
pp. 211-219 ◽  
Author(s):  
J. D. Nkrumah ◽  
C. Li ◽  
J. B. Basarab ◽  
S. Guercio ◽  
Y. Meng ◽  
...  

Leptin is a 16-kDa-hormone product of the obese gene synthesized and expressed predominantly by adipose tissues, which has been shown to play major roles in the regulation of body weight, feed intake, energy balance, fertility, and immune system functions. We report an investigation into the association of a previously identified cytosine to thymine missense mutation in exon 2 of the bovine leptin gene with feed intake, feed efficiency, growth, feeding behaviour, carcass quality and body composition in five genetic selection lines of a commercial population of beef cattle. Differences among genotypes in growth, feed intake and feed efficiency were not significant (P > 0.10) though steers homozygous for the thymine allele had positive residual feed intake (i.e., consumed more feed than expected) (+ 0.19 kg d-1) whilst steers homozygous for the cytosine allele had negative residual feed intake (-0.18 kg d-1). Steers carrying the thymine allele had a higher rate of gain in ultrasound backfat (P = 0.02), ultrasound backfat thickness (P = 0. 06), higher carcass grade fat (backfat) (P = 0.005), lower yield grade (P = 0.01) and lower lean meat yield (P = 0.007). The thymine allele also tended to be associated with higher loin subcutaneous fat (P = 0.07) and was associated with higher brisket subcutaneous fat (P = 0.01), and brisket body cavity fat (P = 0.0001). No associations were found among the different genotypes and real-time ultrasound marbling, ultrasound longissimus thoracis area, carcass marbling and carcass longissimus thoracis area (P > 0.10). Our results show that animals carrying the thymine allele versus the cytosine allele may produce carcasses with poorer grades and lower lean meat yields but do not differ in carcass marbling or other fat depots. Key words: Beef cattle, leptin, feed intake, carcass merit


2019 ◽  
Vol 97 (5) ◽  
pp. 2181-2187
Author(s):  
Ahmed A Elolimy ◽  
Emad Abdel-Hamied ◽  
Liangyu Hu ◽  
Joshua C McCann ◽  
Daniel W Shike ◽  
...  

Abstract Residual feed intake (RFI) is a widely used measure of feed efficiency in cattle. Although the precise biologic mechanisms associated with improved feed efficiency are not well-known, most-efficient steers (i.e., with low RFI coefficient) downregulate abundance of proteins controlling protein degradation in skeletal muscle. Whether cellular mechanisms controlling protein turnover in ruminal tissue differ by RFI classification is unknown. The aim was to investigate associations between RFI and signaling through the mechanistic target of rapamycin (MTOR) and ubiquitin-proteasome pathways in ruminal epithelium. One hundred and forty-nine Red Angus cattle were allocated to 3 contemporary groups according to sex and herd origin. Animals were offered a finishing diet for 70 d to calculate the RFI coefficient for each. Within each group, the 2 most-efficient (n = 6) and least-efficient animals (n = 6) were selected. Compared with least-efficient animals, the most-efficient animals consumed less feed (P < 0.05; 18.36 vs. 23.39 kg/d DMI). At day 70, plasma samples were collected for insulin concentration analysis. Ruminal epithelium was collected immediately after slaughter to determine abundance and phosphorylation status of 29 proteins associated with MTOR, ubiquitin-proteasome, insulin signaling, and glucose and amino acid transport. Among the proteins involved in cellular protein synthesis, most-efficient animals had lower (P ≤ 0.05) abundance of MTOR, p-MTOR, RPS6KB1, EIF2A, EEF2K, AKT1, and RPS6KB1, whereas MAPK3 tended (P = 0.07) to be lower. In contrast, abundance of p-EEF2K, p-EEF2K:EEF2K, and p-EIF2A:EIF2A in most-efficient animals was greater (P ≤ 0.05). Among proteins catalyzing steps required for protein degradation, the abundance of UBA1, NEDD4, and STUB1 was lower (P ≤ 0.05) and MDM2 tended (P = 0.06) to be lower in most-efficient cattle. Plasma insulin and ruminal epithelium insulin signaling proteins did not differ (P > 0.05) between RFI groups. However, abundance of the insulin-responsive glucose transporter SLC2A4 and the amino acid transporters SLC1A3 and SLC1A5 also was lower (P ≤ 0.05) in most-efficient cattle. Overall, the data indicate that differences in signaling mechanisms controlling protein turnover and nutrient transport in ruminal epithelium are components of feed efficiency in beef cattle.


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


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.


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