<b>Influence of racial and nutritional management factors on somatic cells count and milk composition of Holstein and mixed breed cows in the north of <em>Paraná</em> State, Brazil</b> - DOI: 10.4025/actascianimsci.v25i2.2016

Abstract

474 milking herds from the north region of Paraná State were analyzed in this study. The herds were characterized for average productivity, genetic group, exploration and milking systems. Two milk samples (bulk or brass) were collected monthly from each farm, totalizing 21.957 samples. They were processed to determine fat, protein and somatic cells count (SCC) at Centralized Analyses Laboratory from Milking Herds Analyses Program of Paraná State. The data was submitted to analysis of variance (proc glm), regression analysis (proc reg) and correlation analysis (proc corr) in SAS to determine the influence of environmental and racial factors on SCC and milk composition, as well as SCC influence on protein and fat levels. Except for the milk system (p > 0.05), all other studied effects were highly significant (p < 0.0001) on SCC. For the studied effects on protein and fat, the only one showing no significance (p > 0.05) was the herd average production, on protein level. The effect of SCC on milk protein and fat was statistically relevant (p < 0.0001). With the increase of SCC, there was a reduction in protein level and an increase in fat level, although only 0.53% and 3.02% of the variation of these solids, respectively, can be credited to SCC.