Genetic parameters for somatic cell score, differential somatic cell count, and milk electrical conductivity in dairy buffaloes

Abstract

Understanding the genetic architecture of economically important traits in dairy buffaloes is essential for implementing genetic selection and breeding strategies aimed at improving the productivity and profitability of dairy buffalo farming. Our objective was to estimate genetic parameters of udder health indicators, that is, electrical conductivity (EC), total somatic cell score (SCS), and differential somatic cell count (DSCC), in Mediterranean buffalo populations. Data were collected from six dairy commercial herds located in the Basilicata Region (Italy) including 14,571 records from 1501 Mediterranean buffaloes. Covariance components and genetic parameters were estimated using a multi-trait animal model by a Bayesian inference approach. The animal model accounted for the systematic effects of herd, days in milk (DIM), parity order, year-season of calving, year-season of sampling, milk yield class, and temperature – humidity index (THI) as well as the random effects of additive genetic and permanent environmental effects. The heritability estimates (95% credibility interval) for EC, SCS and DSCC were 0.18 (0.12–0.23), 0.11 (0.05–0.17) and 0.085 (0.04–0.12), respectively. The genetic correlations were all positive and ranged from 0.045 (−0.26 to 0.32) (DSCC-EC) and 0.76 (0.55–0.92) (DSCC-SCS). Our findings highlighted that udder health indicators have additive genetic variation which is potentially exploitable for breeding purposes. However, the response to genetic selection will likely be slow, so selection should be practiced jointly with improvements in animal husbandry and environmental conditions.

Keywords

• buffaloes, dairy genetics
• mastitis detection
• udder health