title: Genome-wide association study for cheese yield and curd nutrient recovery in dairy cows.
abstract: Cheese production and consumption are increasing in many countries worldwide. As a result, interest has increased in strategies for genetic selection of individuals for technological traits of milk related to cheese yield (CY) in dairy cattle breeding. However, little is known about the genetic background of a cow's ability to produce cheese. Recently, a relatively large panel (1,264 cows) of different measures of individual cow CY and milk nutrient and energy recoveries in the cheese (REC) became available. Genetic analyses showed considerable variation for CY and for aptitude to retain high proportions of fat, protein, and water in the coagulum. For the dairy industry, these characteristics are of major economic importance. Nevertheless, use of this knowledge in dairy breeding is hampered by high costs, intense labor requirement, and lack of appropriate technology. However, in the era of genomics, new possibilities are available for animal breeding and genetic improvement. For example, identification of genomic regions involved in cow CY might provide potential for marker-assisted selection. The objective of this study was to perform genome-wide association studies on different CY and REC measures. Milk and DNA samples from 1,152 Italian Brown Swiss cows were used. Three CY traits expressing the weight (wt) of fresh curd (%CYCURD), curd solids (%CYSOLIDS), and curd moisture (%CYWATER) as a percentage of weight of milk processed, and 4 REC (RECFAT, RECPROTEIN, RECSOLIDS, and RECENERGY, calculated as the % ratio between the nutrient in curd and the corresponding nutrient in processed milk) were analyzed. Animals were genotyped with the Illumina BovineSNP50 Bead Chip v.2. Single marker regressions were fitted using the GenABEL R package (genome-wide association using mixed model and regression-genomic control). In total, 103 significant associations (88 single nucleotide polymorphisms) were identified in 10 chromosomes (2, 6, 9, 11, 12, 14, 18, 19, 27, 28). For RECFATand RECPROTEIN, high significance peaks were identified in Bos taurus autosome (BTA) 6 and BTA11, respectively. Marker ARS-BFGL-NGS-104610 (∼104.3 Mbp) was highly associated with RECPROTEINand Hapmap52348-rs29024684 (∼87.4 Mbp), closely located to the casein genes on BTA6, with RECFAT. Genomic regions identified may enhance marker-assisted selection in bovine cheese breeding beyond the use of protein (casein) and fat contents, whereas new knowledge will help to unravel the genomic background of a cow's ability for cheese production.
authors.affiliation: Department of Agronomy, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padova, Viale dell'Università 16, 35020 Legnaro, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Dadousis
authors.affiliation: Istituto di Biologia e Biotecnologia Agraria (IBBA), Consiglio Nazionale delle Ricerche (CNR), Via Einstein-Loc. Cascina Codazza, 26900 Lodi, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Biffani
authors.affiliation: Department of Agronomy, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padova, Viale dell'Università 16, 35020 Legnaro, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Cipolat-Gotet
authors.affiliation: Bioinformatics Core, Parco Tecnologico Padano, Via Einstein-Loc. Cascina Codazza, 26900 Lodi, Italy.
authors.forename: E L
authors.initials: EL
authors.lastname: Nicolazzi
authors.affiliation: Department of Animal Sciences, University of Wisconsin, Madison 53706.
authors.forename: G J M
authors.initials: GJM
authors.lastname: Rosa
authors.affiliation: Department of Animal Sciences, University of Wisconsin, Madison 53706; Department of Biostatistics and Medical Informatics, University of Wisconsin, Madison 53706.
authors.forename: D
authors.initials: D
authors.lastname: Gianola
authors.affiliation: Italian Brown Breeders Association, Loc. Ferlina 204, Bussolengo 37012, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Rossoni
authors.affiliation: Italian Brown Breeders Association, Loc. Ferlina 204, Bussolengo 37012, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Santus
authors.affiliation: Department of Agronomy, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padova, Viale dell'Università 16, 35020 Legnaro, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Bittante
authors.affiliation: Department of Agronomy, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padova, Viale dell'Università 16, 35020 Legnaro, Italy. Electronic address: alessio.cecchinato@unipd.it.
authors.forename: A
authors.initials: A
authors.lastname: Cecchinato
mesh_terms: D000818:Animals; D001947:Breeding; D002364:Caseins; D002417:Cattle; D002611:Cheese; D005260:Female; D055106:Genome-Wide Association Study; D008892:Milk / Q000737:chemistry
chemical_list: D002364:Caseins
keywords: cheese yield; curd recovery; dairy cattle; genome-wide association study; whey loss