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Adaptation in Beef CattleT. G. Jenkins

Meat Animal Research CenterClay Center NE

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ADAPTABILITYADAPTABILITY

Frequently a focus of discussion Frequently a focus of discussion but are we all discussing the same but are we all discussing the same concept? concept?

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Objectives:Objectives:

1. What is meant by 1. What is meant by AAdaptabilitydaptability

2. Evidence of 2. Evidence of AAdaptability in beef cattledaptability in beef cattle

3. Potential for application3. Potential for application

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TerminologyTerminology

PhenotypePhenotype: the appearance of an : the appearance of an individual resulting from the individual resulting from the interaction of genotype and interaction of genotype and environment environment

Genotype:Genotype: total sum of all genetic total sum of all genetic factors of an individual factors of an individual

Environment:Environment: all factors that all factors that influence the expression influence the expression

of of genes genes

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Types of AdaptabilityTypes of Adaptability

Evolutionary: Trans-generationalEvolutionary: Trans-generational

Phenotypic: adjustments made by Phenotypic: adjustments made by individual within a lifetimeindividual within a lifetime

may be linked to biological may be linked to biological processes that are processes that are evolutionaryevolutionary

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Evolutionary - Evolutionary -

Provides a species the ability for continued Provides a species the ability for continued existence (trans-generational)existence (trans-generational)

adaptability could be adaptability could be considered an optimization of a considered an optimization of a phenotype to express fecundity phenotype to express fecundity potential potential

ADAPTABILITY-ADAPTABILITY-

What creates a need for the organism to change?What creates a need for the organism to change?

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Changes in conditions in which affects the Changes in conditions in which affects the expression of the fecundity potential of species expression of the fecundity potential of species

EnvironmentEnvironment

geographic locationgeographic location

food resourcesfood resources

climatic conditionsclimatic conditions

pathogenspathogens

etcetc

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What allows the species to change:What allows the species to change:

Genetic variability Genetic variability

Individuals exist within a population whose Individuals exist within a population whose genotype provides a selective advantage in the genotype provides a selective advantage in the altered altered environment allowing environment allowing these individuals these individuals to leave greater number of offspringto leave greater number of offspring

existing allelesexisting alleles

mutationsmutations

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EExisting alleles xisting alleles (Mayr, 1970)(Mayr, 1970)

In manufacturing districts of England moth In manufacturing districts of England moth change color from white to black because of change color from white to black because of pollution. Predators were able to see white pollution. Predators were able to see white moths moths so black had selective advantageso black had selective advantage

MMutation utation (Nature Biotech, Feb, 1999)(Nature Biotech, Feb, 1999)

Specific strains of Salmonella have Specific strains of Salmonella have become resistant to antibiotics become resistant to antibiotics (Amoxicillin, Flofenicol, Streptomycin, (Amoxicillin, Flofenicol, Streptomycin, Tetracycline) Tetracycline)

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Phenotypes vary because Phenotypes vary because genetic variation exists in genetic variation exists in population that enable forces population that enable forces of change (environment) to of change (environment) to alter genotypic frequenciesalter genotypic frequencies

SSelectionelection

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Evidence for adaptation in beef cattleEvidence for adaptation in beef cattle

GGeographic locationeographic location

Ngunni in Africa tsetse flyNgunni in Africa tsetse fly

Bonsmara Bonsmara Animals that suffer from hyperthermie Animals that suffer from hyperthermie have an increased respiratory and pulse rate have an increased respiratory and pulse rate

with with concomitant metabolic, physiological and concomitant metabolic, physiological and endocrinological disturbances. Head shapeendocrinological disturbances. Head shape

BreedsBreeds – foundation phase frequently – foundation phase frequently associated with geographic location, associated with geographic location, enhance enhance

frequency of alleles of favored phenotypesfrequency of alleles of favored phenotypes

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Effecting genetic change may or may not lead Effecting genetic change may or may not lead to alleviation of environmental constraint.to alleviation of environmental constraint.Effecting genetic change may or may not lead Effecting genetic change may or may not lead to alleviation of environmental constraint.to alleviation of environmental constraint.

FailureFailure

CComposite populationomposite population in Venezuela (all made using in Venezuela (all made using 50% Zebu and 50% unadapted Bos taurus breeds) 50% Zebu and 50% unadapted Bos taurus breeds)

appeared to have failed to produce productive appeared to have failed to produce productive cattle in spite of strong selection.  cattle in spite of strong selection. 

SSuccess uccess Australian milking zebu (AMZ)Australian milking zebu (AMZ): Pakistani Sahiwal and : Pakistani Sahiwal and

Red Sindhi dairy cattle were mated initially to high-Red Sindhi dairy cattle were mated initially to high-producing Jersey cattle. Later, some infusion of Illawarra, producing Jersey cattle. Later, some infusion of Illawarra, Guernsey and Guernsey and Holstein-Friesian bloodlines occurred. Holstein-Friesian bloodlines occurred.

Adaptation for heat tolerance and tick resistance in “bred Adaptation for heat tolerance and tick resistance in “bred for milk production. for milk production.

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Texas LonghornTexas Longhorn

Why did this particular Creole type flourish in Why did this particular Creole type flourish in hostile nutritionally sparse environment? hostile nutritionally sparse environment?

Resistant to tick feverResistant to tick fever

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Brisket DiseaseBrisket Disease is caused is caused primarily by an oxygen shortage; primarily by an oxygen shortage; oxygen availability is 17% less at 5,000 oxygen availability is 17% less at 5,000 feet than it is at sea level; 20% less at feet than it is at sea level; 20% less at 6,000 feet, 26% less at 8,000 feet, and 6,000 feet, 26% less at 8,000 feet, and 31% less at 10,000 feet. Cause 31% less at 10,000 feet. Cause excessive heart activity, eventually, the excessive heart activity, eventually, the heart wears out and stops beating.heart wears out and stops beating.The losses from the disease can vary The losses from the disease can vary depending on the origin of the cattle. In depending on the origin of the cattle. In cattle born and raised at high cattle born and raised at high elevations, the losses tend to run elevations, the losses tend to run from .5% to 5%. In imported or lowland from .5% to 5%. In imported or lowland cattle the losses can range from 30% cattle the losses can range from 30% to 40%.to 40%.There is test to identify animals that There is test to identify animals that are resistant, moderately heritable, are resistant, moderately heritable, selection practiced to resolveselection practiced to resolve

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0

10

20

30

40

50

3000 4000 5000 6000 7000

Dry Matter Intake (kg/yr)

Eff

icie

ncy

(g

/kg

DM

)

Red Poll Pinzgauer Charolais

Angus Gelbvieh Limousin

Hereford Braunvieh Simmental

Charolais

Pinzgauer

Limousin

Simmental

Braunvieh

Gelbvieh

Red Poll

Angus

Hereford

Red Poll

Angus

Pinzgauer

Jenkins and Ferrell.

1994. JAS 72:2787

Breeds reproduction at low Levels of Dry Matter Breeds reproduction at low Levels of Dry Matter

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Potential applications of Adaptability in Beef Cattle ProductionPotential applications of Adaptability in Beef Cattle Production

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Forage selectivityForage selectivity

Parasite resistance Parasite resistance

Endophyte resistanceEndophyte resistance

Heat resistanceHeat resistance

Water needsWater needs

Nutrient useNutrient use

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Recognition of novel phenotypes associated with economically Recognition of novel phenotypes associated with economically important traitsimportant traits

Determination if phenotype can be measured accuratelyDetermination if phenotype can be measured accurately

Assessment of variation associated with phenotypeAssessment of variation associated with phenotype

Proportion of variation attributable to geneticsProportion of variation attributable to genetics

Programs to implement changePrograms to implement change

What is required to implement “Adaptability” to What is required to implement “Adaptability” to improve beef productionimprove beef production