Mapping QTL influencing gastrointestinal nematode burden in Dutch Holstein-Friesian dairy cattle.
BACKGROUND
Parasitic gastroenteritis caused by nematodes is only second to mastitis in terms of health costs to dairy farmers in developed countries. Sustainable control strategies complementing anthelmintics are desired, including selective breeding for enhanced resistance.


CONCLUSIONS
To quantify and characterize the genetic contribution to variation in resistance to gastro-intestinal parasites, we measured the heritability of faecal egg and larval counts in the Dutch Holstein-Friesian dairy cattle population. The heritability of faecal egg counts ranged from 7 to 21% and was generally higher than for larval counts. We performed a whole genome scan in 12 paternal half-daughter groups for a total of 768 cows, corresponding to the approximately 10% most and least infected daughters within each family (selective genotyping). Two genome-wide significant QTL were identified in an across-family analysis, respectively on chromosomes 9 and 19, coinciding with previous findings in orthologous chromosomal regions in sheep. We identified six more suggestive QTL by within-family analysis. An additional 73 informative SNPs were genotyped on chromosome 19 and the ensuing high density map used in a variance component approach to simultaneously exploit linkage and linkage disequilibrium in an initial inconclusive attempt to refine the QTL map position.
Coppieters
Wouter
W
Unit of Animal Genomics, Faculty of Veterinary Medicine and Centre for Biomedical Integrative Genoproteomics, University of Liège (B43), Liège, Belgium. wouter.coppieters@ulg.ac.be
Mes
Ted H M
TH
Druet
Tom
T
Farnir
Frédéric
F
Tamma
Nico
N
Schrooten
Chris
C
Cornelissen
Albert W C A
AW
Georges
Michel
M
Ploeger
Harm W
HW
D000818:Animals; D002417:Cattle / Q000235:genetics* / Q000469:parasitology*; D002418:Cattle Diseases / Q000235:genetics / Q000469:parasitology; D002874:Chromosome Mapping / Q000662:veterinary*; D003612:Dairying; D005243:Feces / Q000469:parasitology; D005260:Female; D016678:Genome; D005838:Genotype; D007411:Intestinal Diseases, Parasitic / Q000235:genetics / Q000469:parasitology; D015810:Linkage Disequilibrium; D008297:Male; D009348:Nematoda / Q000502:physiology; D009349:Nematode Infections / Q000235:genetics / Q000469:parasitology; D010063:Ovum / Q000469:parasitology; D020641:Polymorphism, Single Nucleotide; D040641:Quantitative Trait Loci