title: Genotype by environment interaction for the interval from calving to first insemination with regard to calving month and geographic location in Holstein cows in Denmark and Sweden.
abstract: The objectives of this study were to investigate genotype by environment interaction effects, with environments defined as calving month and geographic location, on the interval from calving to first insemination (CFI) of Holstein cows in Denmark and Sweden. The data set included 811,285 records on CFI for first-parity cows from January 2010 to January 2014 housed in 7,458 herds. The longest mean CFI was 84.7 d for cows calving in April and the shortest was 76.3 d for cows calving in September. The longest mean CFI of 87.1 d was recorded at the northernmost location (LOC-8), whereas the shortest mean CFI of 73.5 d was recorded at the southernmost location (LOC-1). The multiple trait approach, in which CFI values in different calving months and different geographic locations were treated as different traits, was used to estimate the variance components and genetic correlations for CFI by using the average information (AI)-REML procedure in a bivariate sire model. Estimates of genetic variance and heritability were highest for January calvings and 3 times smaller for June calvings. Location 2 had the highest heritability and LOC-8 the lowest, with heritability estimates decreasing from LOC-2 to LOC-8. Genetic correlations of CFI between calving months were weakest between cold months (December and January) and warm months (June, August, and September); the lowest estimate was found between January and September calvings. Genetic correlations of CFI between the different geographic locations were generally strong, and the weakest correlation was between LOC-3 and LOC-8. These results indicate a genotype by environment interaction for CFI primarily regarding seasons described by calving months. The effect of geographic location was less important, mostly producing a scaling effect of CFI in different locations. We concluded that CFI is more sensitive to seasonal effects than geographic locations in Denmark and Sweden.
authors.affiliation: Center for Quantitative Genetics and Genomics, Department of Molecular Biology and Genetics, Aarhus University, PO Box 50, DK-8830 Tjele, Denmark; Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, PO Box 7023, SE-750 07 Uppsala, Sweden. Electronic address: ahmed.ismael@mbg.au.dk.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Ismael
authors.affiliation: Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, PO Box 7023, SE-750 07 Uppsala, Sweden.
authors.forename: Erling
authors.initials: E
authors.lastname: Strandberg
authors.affiliation: Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, PO Box 7023, SE-750 07 Uppsala, Sweden.
authors.forename: Britt
authors.initials: B
authors.lastname: Berglund
authors.affiliation: Center for Quantitative Genetics and Genomics, Department of Molecular Biology and Genetics, Aarhus University, PO Box 50, DK-8830 Tjele, Denmark; Knowledge Center for Agriculture (SEGES), DK-8200 Aarhus N, Skejby, Denmark.
authors.forename: Morten
authors.initials: M
authors.lastname: Kargo
authors.affiliation: Knowledge Center for Agriculture (SEGES), DK-8200 Aarhus N, Skejby, Denmark.
authors.forename: Anders
authors.initials: A
authors.lastname: Fogh
authors.affiliation: Center for Quantitative Genetics and Genomics, Department of Molecular Biology and Genetics, Aarhus University, PO Box 50, DK-8830 Tjele, Denmark.
authors.forename: Peter
authors.initials: P
authors.lastname: Løvendahl
mesh_terms: D000818:Animals; D002417:Cattle / Q000235:genetics* / Q000502:physiology; D003718:Denmark; D004777:Environment; D005260:Female; D005298:Fertility / Q000235:genetics; D059647:Gene-Environment Interaction; D014644:Genetic Variation; D005838:Genotype; D007314:Insemination; D010298:Parity; D036801:Parturition; D010641:Phenotype; D011247:Pregnancy; D012621:Seasons; D013548:Sweden; D013997:Time Factors
keywords: calving month; female fertility; genotype by environment interaction; geographic location; interval from calving to first insemination