Journal ArticleDOI
Metabolic differences in Angus steers divergently selected for residual feed intake
TLDR
It is hypothesised that high-RFI (low-efficiency) steers have higher tissue energy requirements, are more susceptible to stress and utilise different tissue substrates to generate energy required in response to exposure to a stressful stimulus.Abstract:
Residual feed intake measures variation in feed intake independent of liveweight and liveweight gain First generation steer progeny (n = 33) of parents previously selected for low or high post-weaning residual feed intake were examined to determine metabolic processes contributing to variation in residual feed intake Blood samples were taken from the steers from weaning through to slaughter These samples were analysed for key metabolites and hormones Total urine and total faecal collections were taken from the steers in an animal-house experiment to estimate dry matter digestibility, microbial protein production and protein turnover At weaning, there were phenotypic correlations between concentrations in plasma of β-hydroxy butyrate (r = 055, P 005) Neither the ratio of 3-methyl histidine : creatinine in urine, as a measure of rate of muscle breakdown, nor the dry matter digestibility measured in the animal house were correlated with residual feed intake in the animal house (r = 004, P>005), or residual feed intake over the whole experiment (r = –022, P>005), and neither were associated with genetic variation in residual feed intake It is hypothesised that high-RFI (low-efficiency) steers have higher tissue energy requirements, are more susceptible to stress and utilise different tissue substrates (partly as a consequence of differences in body composition) to generate energy required in response to exposure to a stressful stimulusread more
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Journal ArticleDOI
Adaptation to hot climate and strategies to alleviate heat stress in livestock production.
TL;DR: The objective of this paper was to review the effective strategies to alleviate heat stress in the context of tropical livestock production systems and those involving genetic selection for heat tolerance.
Journal ArticleDOI
Relationships of feedlot feed efficiency, performance, and feeding behavior with metabolic rate, methane production, and energy partitioning in beef cattle
J. D. Nkrumah,Erasmus Okine,G. W. Mathison,K. Schmid,Changxi Li,John A. Basarab,M. A. Price,Zhiquan Wang,Stephen S. Moore +8 more
TL;DR: The relationship of feedlot feed efficiency, performance, and feeding behavior with digestion and energy partitioning of 27 steers is determined and has practical implications for the selection of animals that eat less at a similar BW and growth rate and for the environmental sustainability of beef production.
Journal ArticleDOI
Physiological basis for residual feed intake.
R. M. Herd,P. F. Arthur +1 more
TL;DR: Residual feed intake is a measure of feed efficiency that is independent of level of production, such as size and growth rate in beef cattle, and thus is a useful new trait for studying the physiological mechanisms underlying variation in feed efficiency.
Journal ArticleDOI
Exploring a possible link between the intestinal microbiota and feed efficiency in pigs
Ursula M. McCormack,Ursula M. McCormack,Tânia Curiao,Stefan G. Buzoianu,Maria Luz Prieto,Tomas Ryan,Patrick Varley,Fiona Crispie,Elizabeth Magowan,Barbara U. Metzler-Zebeli,Donagh P. Berry,Orla O'Sullivan,Paul D. Cotter,Gillian E. Gardiner,Peadar G. Lawlor +14 more
TL;DR: This study is one of the first to show that differences in intestinal microbiota composition, albeit subtle, may partly explain improved feed efficiency (FE) in low residual feed intake (RFI) pigs.
Journal ArticleDOI
Effect of divergence in residual feed intake on feeding behavior, blood metabolic variables, and body composition traits in growing beef heifers.
TL;DR: The feeding behavior traits of eating rate, daily feeding events, and nonfeeding events were positively correlated (P < 0.05) with RFI and RFI(c).
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