Feed Efficiency and Animal Robustness

Rauw, W. M.

doi:10.1002/9781118392331.ch8

Cited by 18 publications

(14 citation statements)

References 96 publications

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“…Although mass of the spleen is variable within species and affected by many factors, spleen mass is often assumed to be related to immune competence in avian species (Smith and Hunt, 2004). It has been hypothesized that immune function and stress response affect RFI (Rauw, 2012), and data in sheep support this hypothesis (Rincon-Delgado et al, 2011). If more efficient sheep have a more robust immune system, then spleen mass may contribute to this mechanism.…”

Section: Discussionmentioning

confidence: 92%

The relationship of residual feed intake and visceral organ size in growing lambs fed a concentrate- or forage-based diet

et al. 2015

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Section: Discussionmentioning

confidence: 92%

The relationship of residual feed intake and visceral organ size in growing lambs fed a concentrate- or forage-based diet

et al. 2015

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“…This reduction in metabolic space may reduce an animal's resilience to stressors and its ability to adapt to a wide variety of environmental conditions. Therefore, breeding goals that include robustness traits are required in the implementation of more sustainable agricultural production systems (Knap, 2009; Rauw, 2012). They combine robustness traits with production traits, balancing production potential with environmental sensitivity; this will increase or restore the animals' ability to interact successfully with the environment and improve welfare and productivity (Knap, 2009).…”

Section: Conclusion: Selection For Resistance or Tolerance?mentioning

confidence: 99%

Immune response from a resource allocation perspective

Rauw¹

2012

Front. Gene.

Self Cite

234

203

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The immune system is a life history trait that can be expected to trade off against other life history traits. Whether or not a trait is considered to be a life history trait has consequences for the expectation on how it responds to natural selection and evolution; in addition, it may have consequences for the outcome of artificial selection when it is included in the breeding objective. The immune system involved in pathogen resistance comprises multiple mechanisms that define a host's defensive capacity. Immune resistance involves employing mechanisms that either prevent pathogens from invading or eliminate the pathogens when they do invade. On the other hand, tolerance involves limiting the damage that is caused by the infection. Both tolerance and resistance traits require (re)allocation of resources and carry physiological costs. Examples of trade-offs between immune function and growth, reproduction and stress response are provided in this review, in addition to consequences of selection for increased production on immune function and vice versa. Reaction norms are used to deal with questions of immune resistance vs. tolerance to pathogens that relate host health to infection intensity. In essence, selection for immune tolerance in livestock is a particular case of selection for animal robustness. Since breeding goals that include robustness traits are required in the implementation of more sustainable agricultural production systems, it is of interest to investigate whether immune tolerance is a robustness trait that is positively correlated with overall animal robustness. Considerably more research is needed to estimate the shapes of the cost functions of different immune strategies, and investigate trade-offs and cross-over benefits of selection for disease resistance and/or disease tolerance in livestock production.

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“…In a recent review on feed efficiency and animal robustness, Rauw (2012) hypothesized that because efficient animals have decreased feeding event duration and frequency, they are less able to adapt to changes in environment conditions. However, observation of beef cows reared under extensive Canadian winter conditions has shown that cows that produced –RFI calves actually had higher backfat thickness with no differences in lifetime productivity compared with their herd mates that produced +RFI calves (Basarab et al ., 2007).…”

Section: Introductionmentioning

confidence: 99%

Reducing GHG emissions through genetic improvement for feed efficiency: effects on economically important traits and enteric methane production

Basarab

Beauchemin

Baron

et al. 2013

Animal

161

103

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Genetic selection for residual feed intake (RFI) is an indirect approach for reducing enteric methane (CH4) emissions in beef and dairy cattle. RFI is moderately heritable (0.26 to 0.43), moderately repeatable across diets (0.33 to 0.67) and independent of body size and production, and when adjusted for off-test ultrasound backfat thickness (RFIfat) is also independent of body fatness in growing animals. It is highly dependent on accurate measurement of individual animal feed intake. Within-animal repeatability of feed intake is moderate (0.29 to 0.49) with distinctive diurnal patterns associated with cattle type, diet and genotype, necessitating the recording of feed intake for at least 35 days. In addition, direct measurement of enteric CH4 production will likely be more variable and expensive than measuring feed intake and if conducted should be expressed as CH4 production (g/animal per day) adjusted for body size, growth, body composition and dry matter intake (DMI) or as residual CH4 production. A further disadvantage of a direct CH4 phenotype is that the relationships of enteric CH4 production on other economically important traits are largely unknown. Selection for low RFIfat (efficient, −RFIfat) will result in cattle that consume less dry matter (DMI) and have an improved feed conversion ratio (FCR) compared with high RFIfat cattle (inefficient; +RFIfat). Few antagonistic effects have been reported for the relationships of RFIfat on carcass and meat quality, fertility, cow lifetime productivity and adaptability to stress or extensive grazing conditions. Low RFIfat cattle also produce 15% to 25% less enteric CH4 than +RFIfat cattle, since DMI is positively related to enteric methane (CH4) production. In addition, lower DMI and feeding duration and frequency, and a different rumen bacterial profile that improves rumen fermentation in −RFIfat cattle may favor a 1% to 2% improvement in dry matter and CP digestibility compared with +RFIfat cattle. Rate of genetic change using this approach is expected to improve feed efficiency and reduce enteric CH4 emissions from cattle by 0.75% to 1.0% per year at equal levels of body size, growth and body fatness compared with cattle not selected for RFIfat.

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Feed Efficiency and Animal Robustness

Cited by 18 publications

References 96 publications

The relationship of residual feed intake and visceral organ size in growing lambs fed a concentrate- or forage-based diet

The relationship of residual feed intake and visceral organ size in growing lambs fed a concentrate- or forage-based diet

Immune response from a resource allocation perspective

Reducing GHG emissions through genetic improvement for feed efficiency: effects on economically important traits and enteric methane production

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