Progress 07/01/10 to 12/31/12
Outputs
Target Audience: Target audients would be cow-calf producers, feedlot cattle producers and beef and dairy heifer development interests. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest?
Nothing Reported
What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Subunits comprising complex I of mitochondria were correlated to residual feed intake (efficiency) phenotypes in cattle. Heifer residual feed intake phenotype was more descriptive of progeny efficiency than phenotype determined as mature animals when lactating or nonlactating. Efficiency of feed use was improved when post ruminal amino acid flow was balanced with energy intake. Residual feed intake phenotype effects nutrient requirement of steers. Milk production by cattle increases as metabolic efficiency (residual feed intake) improves. Differences among animals in efficiency of feed use for maintenance and growth functions were explained in part due to mitochondrial function. This finding allows a biological explanation for why animals differ in metabolic efficiency. Research also affirmed benefit to phenotypic evaluation of animals for efficiency during prepubertal development. It was discovered that milk production was linked to metabolic efficiency. If this finding holds true, it will impact dairy heifer development protocols, and could improve milk production greater than 10% with no change in feed or management inputs. Also found was that diets typically fed to cattle oversupply energy/undersupply absorbable amino acids and that by balancing absorbable amino acid supply to energy consumed feed efficiency could be improved 10% or greater. Residual feed intake phenotype impacted nutrient requirements and subsequently diet formulation
Publications
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2010
Citation:
Kerley, M.S. 2010. Potential for nutritional imbalance in high quality forages. Proc. Grazing Conf. Sym. 4th Grazing Livestock Nutrition Conference. July 9-10, 2010. Estes Park, CO.
- Type:
Journal Articles
Status:
Published
Year Published:
2011
Citation:
Brooks, M.A., J.H. Porter and M.S. Kerley. 2011. Assessment of amino acid supplementation on rumen microbial efficiency and nitrogen metabolism using a continuous culture system. Professional Animal Scientist 27:152.
- Type:
Journal Articles
Status:
Published
Year Published:
2012
Citation:
Brooks, M.A., R.M. Harvey, N.F. Johnson and M.S. Kerley. 2012. Rumen degradable protein (RDP) supply effects microbial efficiency in continuous culture and steer growth. J. Aim. Sci. 90:4985.
- Type:
Journal Articles
Status:
Published
Year Published:
2014
Citation:
Brooks, M.A., R.M. Harvey, N.F. Johnson, E.A. Koutsar and M.S. Kerley. 2014. Effect of varying dietary starch and fiber levels and inoculum source on simulated rumen fermentation characteristics. Zoo Biology 33:110.
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Progress 07/01/10 to 06/30/12
Outputs
OUTPUTS: Residual feed intake (RFI) is used as an efficiency measure of beef cattle. Understanding what causes RFI differences among animals and understanding how RFI influences nutrient requirments is needed. This research measured subunit proteins of complex I in mitochondria of cattle. This was based upon previous research that measured increased oxygen uptake, increased complex I to complex III ratio and increased complex I concentration in mitochondria of negative RFI (efficient) cattle. Subunit 1 protein was predictive of negative RFI phenotype. This research is now being used to determine if subunit 1 protein can be employed as a marker for RFI. It was previously measured that intake varied by 1.4-fold among animals without differences in growth. The potential is to improve efficiency 40% among extremes, or 20% by the population. The question asked was if selection for intake reduction of 20% by the population occurred, how would nutrient requirement be altered for growth functions. We altered amino acid supply to range between 80 to 120% of the animal's requirement. The RFI phenotype of the animal responded in feed efficiency to post-ruminal amino acid supply provided by the diet. This research is now being used to formulate diets that take advantage of efficiency phenotype of cattle. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Mitochondrial research conducted in this grant has provided some explanation as to why animals differ in RFI. Efficient (netgative RFI) animals had greater concentrations of complex I proteins and subunit 1 protein of complex I. This subunit protein is responsible for shuttling electrons into the electron transfer chain. We hypothesize that this provides the animal with an energetic advantage. We have also demonstrated that RFI phenotype alters nutrient requirements of cattle, and presented a means to formulate diets to maximize efficiency potential of an animal's RFI phenotype.
Publications
- No publications reported this period
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