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Mistakes made in the stud industry. F.W.C. Neser. What is animal breeding. Animal breeding may be seen as the optimal exploitation of the species biological variation Ollivier (2000). Yesterday, Today & Tomorrow?. Genetic Variation - Dogs. 10cm vs 2m. 159kg. vs. 1kg.
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Mistakes made in the stud industry F.W.C. Neser
What is animal breeding Animal breeding may be seen as the optimal exploitation of the species biological variation Ollivier (2000)
Genetic Variation - Dogs 10cm vs 2m 159kg vs 1kg
Genetic Variation - Horses Thumbeline (42cm) vs Clydesdale (2m+)
You usually get what you select for – but not always Sometimes the unexpected happens
Inbreeding The breeding of animals that are more closely related than the average of the population
Inbreeding • Increase homosigosity • Decrease variation • Decrease in performance, especially in fertility and survivability • Affects polygenic traits because of inbreeding depression • Genetic defects least of the problems • Linebreeding
Genetic diversity • Genetic diversity can be defined as the variation of genes and genotypes present in a population, and provide a basis of adaptive and evolutionary processes (Frankham et al., 2002) • Tankwa goats • Climate change
Genetic bottleneck • Most endangered species went through genetic bottleneck • Limited genetic variation within specie. • Any inbreeding or wrong mating practices will destroy the variation that is left
Solution • Create genetic lines within population • Lines should be manage as one population • Sires should be rotated between lines using as specific order • This way inbreeding will be limited and new diversity can be created • Recordkeeping
Indekse Blup – Teelwaardes Groter akkuraatheid Komplekse Modelle Seleksie vordering Fase 2 – Jaagnaprestasie
Blup - Probleme • Seleksiedoelwitte • Telersgeendoelwitte • Teveelproduksiete min fiksheid
Blup - Probleme • Inteling • VSA -3.7 milj Holsteins • Effektiewepopulasie grootte 60 diere • Jersey’s 38 diere
Holstein inbreeding Inbreeding USA average; - F = 5.85% (2012) 1910 1930 1950 1970 1990 2010
Fiksheid • Fiksheid = NATUURLIKE SELEKSIE: • Oorlewing • Vrugbaarheid
Fiksheid dui op die relatiewe vermoë van draers van ‘n spesifieke genotiepe om hulle gene na die genepoel van die volgende generasie oor te dra. Dit word die aanpassingswaarde of die fiksheid in die Darwin sin, van ‘n genotiepe genoem (Dobzhnsky, 1959)
The heritability of fitness traits are usually low and will be severly influence by inbreeding depression and heterosis (Bourdon, 1997)
+ GENES FOR FITNESS INTENSIVE SYSTEMS NATURAL PASTURES
Selection for growth under different conditions Environmental limit No limit on size Environment limit size Artificial conditions Natural conditions
What is a genotype x environment interaction This is where an animal excels in one environment but fail to perform in a second environment, while another animal may excels in the second but fail to perform in the first
Genotype for: High appetite Large Frame High heat production Productivity Genotype for: Low appetite Small Frame Low heat production Optimum Unfavourable
No genotype, no matter how versatile, is equally efficient in all environments - Dobzhansky (1951)
Persepsies oor vrugbaarheid • Allediere is ewe vrugbaar • Vrugbaarheidkanniegenetiesverbeter word nie • Voerjoudierevrugbaar
MINDER VRUGBAAR BOGEMIDDELD VRUGBAAR NIE GEKALF
Fase 4: Teelwaardes + Molekulêreinligting • Eers net kwaliteitseienskappe • Vleissagtheid • Marmering • Produksieeienskappe • Voeromsetting • Vrugbaarheid • Groei • Melkproduksie • Wolproduksie/Veseldikte • Skape – 753 QTL’s, 212 eienskappe • Beeste – 6 305 QTL’s, 416 eienskappe
Fase 4: Teelwaardes + Molekulêreinligting • Nie die “Magic bullet” nie • Hoofgeenverklaar tot 30% van σa2 • Meeste QTL’s verklaarbaie min – minder as 1% van die σa2 • Belangriksteeienskappe word deurbaie gene beinvloed • Omgewingskakel gene aan of af • Patentereg – grootmaatskappye
Application in the game industry • DNA Fingerprinting: • Parentage verification • Microsatellites & SNP: • Inbreeding • Heterozygosity and genetic variation • Specie verification • Whole genome sequencing • Genetic variation
Summary • Limit inbreeding • Maintain genetic diversity • Work with the environment • Recordkeeping