Ebook Influence Of Diet, Production Traits, Blood Hormones And Metabolites, And Mitochondrial Complex Protein Concentrations On Residual Feed Intake In Beef Cattle
The United States Department of Agriculture reported (2002) that feed accounted for approximately 60% of the total production cost for cattle (Elstien, 2002). Animal selection for decreased feed intake (FI) without adversely effecting performance would improve efficiency and profitability of the beef production system.
Historically selection for feed to gain ratio (F:G) has been used by beef producers to improve feed efficiency . This method of selection will produce more output with less input required. Feed to gain ratio is linked to frame size because large framed steers will be have a lower feed to gain than small framed steers when fed to a specific weight endpoint (Thonney et al., 1981). Large framed animals will have a greater average daily gain (ADG) and relative growth rate (RGR) than small framed animals because these parameters are correlated with metabolic mid-weight (Nkrumah et al., 2004). Therefore it would be inferred that as F:G improves, frame size and mature weight would increase. Cattle raised on pasture showed an increase in live weight production and net income with a decrease in frame size (Long et al., 1975). Cows with larger mature weight were associated with lower cow calf pair efficiency (Albertini et al., 2008). Therefore to improve production efficiency, a selection parameter is needed that will decrease FI independent of growth.
Beef cattle have genetic variation in efficiency that is independent of size and growth rate (Arthur et al., 1997). This is measured as residual feed intake (RFI) and was proposed by Koch et al. (1963). Residual feed intake is the difference between the animal’s actual FI and expected FI calculated by regressing actual FI against ADG and metabolic mid-weight during a 70 d test period (Archer et al., 1997). Postweaning tests for RFI determined it was a moderately heritable trait with substantial genetic variation within the population (Arthur et al., 1997). Residual feed intake was genetically and phenotypically correlated with FI and F:G ratio but not ADG in Angus bulls and heifers during a 70 d test period postweaning (Arthur et al., 2001). Progeny of parents selected for reduced RFI consumed less feed during the test period without influencing growth (Herd et al., 1997). Research was also reported that females with lower RFI at weaning required less FI as cows with same level of performance (Arthur et al., 1999). Therefore RFI could be used to improve feed efficiency without influencing growth and mature size of beef cattle.
Presently an RFI measurement requires the determination of animal FI over a 70 d period, which is expensive and time consuming (Herd et al., 2003). Developing an easier, less expensive method would increase the use of RFI as a selection criterion to improve feed efficiency (Herd et al., 2003). Previous research reported RFI was genetically correlated to serum concentrations of insulin-like growth factor-I (IGF-I) in Angus cattle at weaning (Moore et al., 2003) and selection for lower weaning serum IGF-I concentrations improved feed efficiency in beef cattle (Moore et al., 2005). Also previous research reported that FI influenced insulin and glucose concentrations in beef heifers (Yelich et al., 1996). Yambayamba et al. (1996) reported that serum concentrations of glucose, insulin, and IGF-I in beef heifers were elevated due to increased FI. Richardson et al. (2004) reported that RFI is correlated with blood concentrations of insulin, glucose, urea, leptin and creatinine.
Differential expression and activity of mitochondrial proteins have been linked to differences in feed efficiency of beef cattle. Longissmus dorsi muscle mitochondrial protein content of NAD4, CORE I, COX II, and ANT I was increased in steers with improved efficiency (Sandelin et al., 2004). Also activity of muscle mitochondria complex I and II differed between high and low F:G steers (Sandelin et al., 2004).
The dissertation will review the effects of RFI on postweaning weight measurements, growth, and carcass composition. These physiological changes can influence blood hormone and metabolite levels, so the relationship of selected blood metabolites and hormones with RFI will be investigated. Finally the review investigates the relationship between feed efficiency and mitochondrial function and complex protein concentrations in poultry and cattle.
CONTENTS
ACKNOWLEDGEMENTS
LIST OF TABLES
ABSTRACT
Chapter
1. LITERATURE REVIEW
- Introduction
Effect of residual feed intake on production traits
Effect of residual feed intake on carcass measurements
Effect of residual feed intake on concentrations of blood metabolites and
hormones
Effect of efficiency on mitochondrial function
Conclusion
2. RELATIONSHIP BETWEEN RESIDUAL FEED INTAKE, DIET, PRODUCTION TRAITS, AND SERUM CONCENTRATIONS OF GLUCOSE, INSULIN AND INSULIN-LIKE GROWTH FACTOR I IN BEEF STEERS
- Abstract
Introduction
Materials and Methods
- Experimental Design
Production Trait Collection and Calculation
Blood Metabolite and Hormone Collection and Analysis
Statistical Analysis
Results and Discussion
- Dietary Effects on Production Traits and Serum Metabolites
Relationship between Residual Feed Intake, Diet, and Production Traits
Relationship between Residual Feed Intake, Serum Metabolites and Hormones
Conclusion
3. MITOCHONDRIAL PROTEIN COMPLEX RATIOS DIFFER BETWEEN RESIDUAL FEED INTAKE PHENOTYPES IN CATTLE
- Abstract
Introduction
Materials and Methods
- Animal Management
Production Trait Collection and Calculation
Lymphocyte Isolation and Preparation of Homogenate
Immunocapture and Measurement of Mitochondrial Protein Complexes
Statistical Analysis
Results and Discussion
- Production Traits
Mitochondrial Complex Protein Concentrations and Ratios
Conclusion
4. EFFECTS OF POSTRUMINAL AMINO ACID SUPPLY DURING THE GROWING PHASE ON RESIDUAL FEED INTAKE, GROWTH PERFORMANCE AND ULTRASOUND CARCASS MEASUREMENTS
- Abstract
Introduction
Materials and Methods
- Experimental design, management, and growth of feedlot steers
Efficiency Status
Statistical Analysis
Results and Discussion
- Dietary effects on production and carcass characteristics
Relationship between residual feed intake measurements,
performance, and carcass measurements
Conclusion
LITERATURE CITED
VITA
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