Estrus traits derived from activity measurements are heritable and closely related to the time from calving to first insemination.
The aim of this study was to estimate genetic parameters for estrus-related traits that could improve selection for increased fertility due to improved ability of the cow to return to cycling and go into heat after calving. We compared the time from calving to first insemination (CFI) to 3 physical activity traits: the interval from calving to first high activity (CFHA), estrus duration (ED), and estrus strength (ES). We calculated CFI based on data from commercial Holstein herds that included the insemination dates for 11,363 cows. The CFHA, ED, and ES traits were derived from electronic activity tags for 3,533 Holstein cows. Estimates of heritability were 0.07 for CFI, 0.16 for CFHA, 0.02 for ED, and 0.05 for ES. We found a strong genetic correlation between CFI and CFHA (0.96). Genetic correlations between ED and CFI and CFHA were -0.37 and -0.68, respectively. Genetic correlations between ES and CFI and CFHA were -0.50 and -0.58, respectively. The heritability of CFHA and its strong genetic correlation with CFI suggest that including CFHA in the genetic evaluation of female cow fertility could improve the effectiveness of selection, because CFHA reflects the ability to return to cyclicity and go into heat after calving.
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.
Ahmed
A
Ismael
Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, PO Box 7023, SE-750 07 Uppsala, Sweden.
Erling
E
Strandberg
Department of Molecular Biology and Genetics, Aarhus University, PO Box 50, DK-8830 Tjele, Denmark; Knowledge Center for Agriculture, DK-8200 Aarhus N, Skejby, Denmark.
Morten
M
Kargo
Knowledge Center for Agriculture, DK-8200 Aarhus N, Skejby, Denmark.
Anders
A
Fogh
Department of Molecular Biology and Genetics, Aarhus University, PO Box 50, DK-8830 Tjele, Denmark.
Peter
P
Løvendahl
D000465:Algorithms; D000818:Animals; D002417:Cattle; D004971:Estrus / Q000235:genetics / Q000378:metabolism*; D005260:Female; D007314:Insemination / Q000235:genetics*; D009043:Motor Activity; D010641:Phenotype; D019655:Quantitative Trait, Heritable
activity tag; estrus; fertility; heritability