No studies have been carried out on the new udder health trait differential somatic cell count (DSCC) in the Burlina and Alpine Grey local breeds so far. Milk DSCC represents the proportion (%) of polymorphonuclear neutrophils out of the total somatic cell count (SCC). The present study investigated the factors determining the phenotypic variability of SCC and DSCC in such breeds. Restrictions allowed outliers elimination and, finally, 4,355 test-day records from 257 Alpine Grey and 434 Burlina cows in 62 herds were available to estimate the least square means of udder health-related traits through a linear mixed model. The fixed effect of breed, parity (1, 2, 3 and ≥4), lactation stage (6 classes), and sampling season were considered together with the first-order interaction between breed and other fixed effect. The random effects were: cow, herd‐test‐date, and residual. DSCC was greater for Alpine Grey (66.20±0.77 %) compared to Burlina (63.70±0.70 %) and both SCC and DSCC tended to increase across lactation and parity regardless of the breed. In both breeds the greatest DSCC percentage was estimated in summer. Results suggest that the conventional DSCC threshold proposed for Holstein cows (65%) should be adjusted to better fit the udder health status of local breeds used for milk production.
Non-genetic factors affecting udder health traits in milk of italian local cattle breeds
S. Magro;M. De Marchi
2022
Abstract
No studies have been carried out on the new udder health trait differential somatic cell count (DSCC) in the Burlina and Alpine Grey local breeds so far. Milk DSCC represents the proportion (%) of polymorphonuclear neutrophils out of the total somatic cell count (SCC). The present study investigated the factors determining the phenotypic variability of SCC and DSCC in such breeds. Restrictions allowed outliers elimination and, finally, 4,355 test-day records from 257 Alpine Grey and 434 Burlina cows in 62 herds were available to estimate the least square means of udder health-related traits through a linear mixed model. The fixed effect of breed, parity (1, 2, 3 and ≥4), lactation stage (6 classes), and sampling season were considered together with the first-order interaction between breed and other fixed effect. The random effects were: cow, herd‐test‐date, and residual. DSCC was greater for Alpine Grey (66.20±0.77 %) compared to Burlina (63.70±0.70 %) and both SCC and DSCC tended to increase across lactation and parity regardless of the breed. In both breeds the greatest DSCC percentage was estimated in summer. Results suggest that the conventional DSCC threshold proposed for Holstein cows (65%) should be adjusted to better fit the udder health status of local breeds used for milk production.
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