Genome-Wide Associations for Coagulation Traits, Individual Cheese Yield and Curd Nutrient Recoveries in Bovine Milk

The cow’s ability to produce cheese was decomposed into eleven milk coagulation curd-firming and syneresis properties (MCP), three cheese yield (CY) and 4 milk component recoveries into the curd (REC) traits, and genome-wide association analyses were conducted. The MCP traits were: 3 traditional single point lacto-dynamographic properties (RCT: rennet coagulation time, min; k : time to a curd firmness (CF) of 20 mm, min; a : CF 30 min after rennet addition), 6 parameters modeling 360 CF data for each milk sample (CF : potential asymptotic CF at infinite time, mm; k : curd firming instant rate constant, %×min ; k : syneresis instant rate constant, %×min ; RCT : RCT from modeling; CFMAX : maximum CF, mm; tMAX : time at CFMAX, min), milk- protein (%) and pH. The 3 CY traits were the weight (wt) of fresh curd (%CYCURD), curd solids (%CYSOLIDS), and curd moisture (%CYWATER) as % of wt of milk processed. The 4 REC (RECFAT, RECPROTEIN, RECSOLIDS, and RECENERGY) were calculated as the % ratio between the nutrient in curd and the corresponding nutrient in processed milk. Animals (n=1,043) from 85 herds were genotyped with the Illumina SNP50 Beadchip v.2. A single marker regression was fitted using the GenABEL R package (GRAMMAR-GC). The %CYCURD was linked to chromosome 6 (P