Presentation on theme: "1 Adaptation in Beef Cattle T. G. Jenkins Meat Animal Research Center Clay Center NE."— Presentation transcript:
1 Adaptation in Beef Cattle T. G. Jenkins Meat Animal Research Center Clay Center NE
2 ADAPTABILITY Frequently a focus of discussion but are we all discussing the same concept?
3 Objectives: 1. What is meant by A daptability 2. Evidence of A daptability in beef cattle 3. Potential for application
4 Terminology Phenotype : the appearance of an individual resulting from the interaction of genotype and environment Genotype: total sum of all genetic factors of an individual Environment: all factors that influence the expression of genes Environment: all factors that influence the expression of genes
5 Types of Adaptability Evolutionary: Trans-generational Phenotypic: adjustments made by individual within a lifetime may be linked to biological processes that are evolutionary
6 Evolutionary - Provides a species the ability for continued existence (trans-generational) adaptability could be considered an optimization of a phenotype to express fecundity potential ADAPTABILITY- What creates a need for the organism to change?
7 Changes in conditions in which affects the expression of the fecundity potential of species Environment Environment geographic location food resources climatic conditions pathogensetc
8 What allows the species to change: Genetic variability Genetic variability Individuals exist within a population whose genotype provides a selective advantage in the altered environment allowing these individuals to leave greater number of offspring existing alleles mutations
9 E xisting alleles (Mayr, 1970) In manufacturing districts of England moth change color from white to black because of pollution. Predators were able to see white moths so black had selective advantage M utation (Nature Biotech, Feb, 1999) Specific strains of Salmonella have become resistant to antibiotics (Amoxicillin, Flofenicol, Streptomycin, Tetracycline)
10 Phenotypes vary because genetic variation exists in population that enable forces of change (environment) to alter genotypic frequencies S election
11 Evidence for adaptation in beef cattle G eographic location Ngunni in Africa tsetse fly Bonsmara Animals that suffer from hyperthermie have an increased respiratory and pulse rate with concomitant metabolic, physiological and endocrinological disturbances. Head shape Breeds – foundation phase frequently associated with geographic location, enhance frequency of alleles of favored phenotypes
12 Effecting genetic change may or may not lead to alleviation of environmental constraint. Failure C omposite population in Venezuela (all made using 50% Zebu and 50% unadapted Bos taurus breeds) appeared to have failed to produce productive cattle in spite of strong selection. C omposite population in Venezuela (all made using 50% Zebu and 50% unadapted Bos taurus breeds) appeared to have failed to produce productive cattle in spite of strong selection. S uccess S uccess Australian milking zebu (AMZ) : Pakistani Sahiwal and Red Sindhi dairy cattle were mated initially to high- producing Jersey cattle. Later, some infusion of Illawarra, Guernsey and Holstein-Friesian bloodlines occurred. Adaptation for heat tolerance and tick resistance in “bred for milk production. Australian milking zebu (AMZ) : Pakistani Sahiwal and Red Sindhi dairy cattle were mated initially to high- producing Jersey cattle. Later, some infusion of Illawarra, Guernsey and Holstein-Friesian bloodlines occurred. Adaptation for heat tolerance and tick resistance in “bred for milk production.
13 Texas Longhorn Why did this particular Creole type flourish in hostile nutritionally sparse environment? Resistant to tick fever
14 Brisket Disease is caused primarily by an oxygen shortage; oxygen availability is 17% less at 5,000 feet than it is at sea level; 20% less at 6,000 feet, 26% less at 8,000 feet, and 31% less at 10,000 feet. Cause excessive heart activity, eventually, the heart wears out and stops beating. The losses from the disease can vary depending on the origin of the cattle. In cattle born and raised at high elevations, the losses tend to run from.5% to 5%. In imported or lowland cattle the losses can range from 30% to 40%. There is test to identify animals that are resistant, moderately heritable, selection practiced to resolve
15 Breeds reproduction at low Levels of Dry Matter
16 Potential applications of Adaptability in Beef Cattle Production
17 Forage selectivity Parasite resistance Endophyte resistance Heat resistance Water needs Nutrient use
18 Recognition of novel phenotypes associated with economically important traits Determination if phenotype can be measured accurately Assessment of variation associated with phenotype Proportion of variation attributable to genetics Programs to implement change What is required to implement “Adaptability” to improve beef production