scholarly journals Mapping quantitative trait loci controlling milk production in dairy cattle by exploiting progeny testing.

Genetics ◽  
1995 ◽  
Vol 139 (2) ◽  
pp. 907-920 ◽  
Author(s):  
M Georges ◽  
D Nielsen ◽  
M Mackinnon ◽  
A Mishra ◽  
R Okimoto ◽  
...  
Keyword(s):  
Quantitative Trait Loci ◽  
Dairy Cattle ◽  
Milk Production ◽  
Quantitative Trait ◽  
Bovine Genome ◽  
Progeny Testing ◽  
Cattle Breeding ◽  
Trait Loci ◽  
Dairy Cattle Breeding ◽  
Autosomal Microsatellites

Abstract We have exploited "progeny testing" to map quantitative trait loci (QTL) underlying the genetic variation of milk production in a selected dairy cattle population. A total of 1,518 sires, with progeny tests based on the milking performances of > 150,000 daughters jointly, was genotyped for 159 autosomal microsatellites bracketing 1645 centimorgan or approximately two thirds of the bovine genome. Using a maximum likelihood multilocus linkage analysis accounting for variance heterogeneity of the phenotypes, we identified five chromosomes giving very strong evidence (LOD score > or = 3) for the presence of a QTL controlling milk production: chromosomes 1, 6, 9, 10 and 20. These findings demonstrate that loci with considerable effects on milk production are still segregating in highly selected populations and pave the way toward marker-assisted selection in dairy cattle breeding.

scholarly journals A Genome Scan for Quantitative Trait Loci Affecting Milk Production in Norwegian Dairy Cattle

2002 ◽  
Vol 85 (11) ◽  
pp. 3124-3130 ◽  
Author(s):  
H.G. Olsen ◽  
L. Gomez-Raya ◽  
D.I. Våge ◽  
I. Olsaker ◽  
H. Klungland ◽  
...  
Keyword(s):  
Quantitative Trait Loci ◽  
Dairy Cattle ◽  
Milk Production ◽  
Quantitative Trait ◽  
Genome Scan ◽  
A Genome ◽  
Trait Loci ◽  
Norwegian Dairy

scholarly journals Mapping Quantitative Trait Loci for Milk Production and Health of Dairy Cattle in a Large Outbred Pedigree

Genetics ◽  
1998 ◽  
Vol 149 (4) ◽  
pp. 1959-1973 ◽  
Author(s):  
Qin Zhang ◽  
Didier Boichard ◽  
Ina Hoeschele ◽  
Cynthia Ernst ◽  
Andre Eggen ◽  
...  
Keyword(s):  
Quantitative Trait Loci ◽  
Dairy Cattle ◽  
Milk Production ◽  
Quantitative Trait ◽  
Genetic Correlations ◽  
Mapping Function ◽  
Chromosome 17 ◽  
Chi Square ◽  
Repulsion Phase ◽  
Trait Loci

Abstract Quantitative trait loci (QTL) affecting milk production and health of dairy cattle were mapped in a very large Holstein granddaughter design. The analysis included 1794 sons of 14 sires and 206 genetic markers distributed across all 29 autosomes and flanking an estimated 2497 autosomal cM using Kosambi's mapping function. All families were analyzed jointly with least-squares (LS) and variance components (VC) methods. A total of 6 QTL exceeding approximate experiment-wise significance thresholds, 24 QTL exceeding suggestive thresholds, and 34 QTL exceeding chromosome-wise thresholds were identified. Significance thresholds were determined via data permutation (for LS analysis) and chi-square distribution (for VC analysis). The average bootstrap confidence interval for the experiment-wise significant QTL was 48 cM. Some chromosomes harbored QTL affecting several traits, and these were always in coupling phase, defined by consistency with genetic correlations among traits. Chromosome 17 likely harbors 2 QTL affecting milk yield, and some other chromosomes showed some evidence for 2 linked QTL affecting the same trait. In each of these cases, the 2 QTL were in repulsion phase in those families appearing to be heterozygous for both QTL, a finding which supports the build-up of linkage disequilibrium due to selection.

scholarly journals Quantitative Trait Loci Affecting Milk Production Traits in Finnish Ayrshire Dairy Cattle

2003 ◽  
Vol 86 (5) ◽  
pp. 1828-1836 ◽  
Author(s):  
S.M. Viitala ◽  
N.F. Schulman ◽  
D.J. de Koning ◽  
K. Elo ◽  
R. Kinos ◽  
...  
Keyword(s):  
Quantitative Trait Loci ◽  
Dairy Cattle ◽  
Milk Production ◽  
Quantitative Trait ◽  
Production Traits ◽  
Milk Production Traits ◽  
Trait Loci

scholarly journals Quantitative Trait Loci Mapping for Lameness Associated Phenotypes in Holstein–Friesian Dairy Cattle

2019 ◽  
Vol 10 ◽  
Author(s):  
Enrique Sánchez-Molano ◽  
Veysel Bay ◽  
Robert F. Smith ◽  
Georgios Oikonomou ◽  
Georgios Banos
Keyword(s):  
Quantitative Trait Loci ◽  
Dairy Cattle ◽  
Quantitative Trait ◽  
Quantitative Trait Loci Mapping ◽  
Holstein Friesian ◽  
Trait Loci

Policy of selecting bulls to breed bulls

1987 ◽  
Vol 44 (1) ◽  
pp. 29-38 ◽  
Author(s):  
M. E. Goddard
Keyword(s):  
Dairy Cattle ◽  
Genetic Variance ◽  
Selection Response ◽  
Progeny Testing ◽  
Cattle Breeding ◽  
Sire Evaluation ◽  
Dairy Cattle Breeding ◽  
Breeding Programmes ◽  
Computer Simulation Program ◽  
Selection Of

ABSTRACTIn the breeding of dairy cattle the selection of bulls to breed young bulls for progeny testing is a crucial process. This paper compares several policies for making this selection based on the criteria-selection response, inbreeding depression, loss of genetic variance and variability of response. A number called the ‘effective number of new bulls to breed bulls selected each year’ (NBBe) is defined which is closely related to the last three of these criteria. Past studies of the design of dairy cattle breeding programmes have assumed that selection is within a group of bulls progeny tested in the same year (policy I). However, modern sire evaluation methods allow comparison of sires tested in different years. To evaluate the effect of selecting bulls to breed bulls from all available bulls (policy II) a computer simulation program was used. Policy II results in an increase in the response to selection but a substantial decrease in NBBe. When compared at the same NBBe, policy II results in a smaller selection response than policy I. A policy which allows the best bulls to be used for more than 1 year but which limits the maximum number of years for which they can be used, results in the best compromise. If bulls are to be used for several years there is little advantage to be gained from making more matings within each year to more high-rated bulls or to older, more reliably evaluated bulls.

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