Estudo retrospectivo dos sólidos não gordurosos em amostras de leite cru no estado do do Rio Grande do Sul

Abstract

Milk quality bovine’s determined by the concentration of solids, the health of the mammary gland and the hygiene with which it was obtained and stored. Among the possible quality problems, the reduction of non-greasy solids (NGS) generates economic losses for the industries and the producers due to the decrease in the industrial yield, the assessment by the inspection agencies and the decrease in the price paid to the producer. The aim of this study is to describe the behavior of NGS present in bovine milk produced in the north of Rio Grande do Sul considering, the somatic cell count (SCC), average precipitation, average temperature, the season and the production micro-regions. 1,281,234 records of raw milk samples collected from cooling tanks between January 2014 and December 2018 were used, analyzed at the Milk Herds Analysis Service (SARLE) at the University of Passo Fundo. The means, standard deviations, standard errors, minimum and maximum values and frequencies were studied to describe the data statistics. In order to estimate the probability of the NGS to meet the IN 76, binary logistic regression was used and, finally, to study the correlation between the independent and dependent variables, Pearson's correlation. The somatic cell count (SCC) showed a negative correlation with lactose, being one of the causes of the decrease in NGS. The average recorded rainfall did not influence the milk components. In the spring and summer seasons, NGS levels were more likely to be below the standards established by legislation (BRASIL, 2018). The micro regions of Passo Fundo, Santa Maria, Caxias do Sul and Porto Alegre, were more likely to produce NGS below the standard of legislation. The highest concentration of SNG occurred in the winter in the micro-region of Passo Fundo and the lowest, in the summer, in the micro region of Porto Alegre. NGS levels were influenced by protein, lactose, SCC and seasons. The protein was more likely to be below the law during spring and summer. Lactose was more likely to be below the law during the summer and fall. SCC was more likely to be above the limits established by legislation during the spring, summer and autumn. During the studied period, 18.2% of the analyzed samples presented NGS below the parameters established by IN 76 (BRASIL, 2018).