Genetic parameters of differential somatic cell count, milk composition, and cheese-making traits measured and predicted using spectral data in Holstein cows

Mastitis is one of the most prevalent diseases in dairy cattle and cause considerable economic losses. Alongside somatic cell count (SCC), differential (DSCC) has been recently introduced as a new indicator intramammary infection. The DSCC expressed or proportion (%) polymorphonuclear neutrophils plus lymphocytes (PMN-LYM) milk cells. These numbers are complemented to total 100 by macrophages (MAC). aim this study was investigate genetic variation heritability DSCC, its correlation with composition, udder health indicators, technological traits Holstein cattle. Data used analysis consisted single test-day records from 2,488 cows reared 36 herds located northern Italy. Fourier-transform infrared (FTIR) spectroscopy predict missing information for some coagulation cheese-making traits, increase sample size improve estimation parameters. Bayesian animal models were implemented via Gibbs sampling. Marginal posterior means estimates 0.13 score (SCS); 0.11 MAC proportion, count; 0.10 PMN-LYM count. Posterior additive correlations between SCS composition low moderate unfavorable. All relevant SCC considered (composition, coagulation, cheese yield nutrients recovery) showed ?0.30 protein ?0.56 lactose ?0.52 casein index. In case 0.38 curd firming rate (k20), 0.45 rennet time estimated using over equation (RCTeq), ?0.39 asymptotic potential firmness, ?0.26 maximum firmness (CFmax), ?0.31 recovery curd. Differential correlated (0.60) but had only 2 traits: (?0.32) CFmax (?0.33). highly log (0.79) (0.69). latter several fat (?0.38 ?0.43 counts, respectively), percentage (?0.40 ?0.46), RCTeq (0.53 0.41), tmax (0.38 0.48). Log k20 (+0.34), (?0.26) weight water processed (?0.26). results obtained offer insights into relationships indicators cows.