Suchergebnisse

Research was conducted in eight commercial herds located in the state of Rio Grande do Norte, Brazil. Properties were classified according to the production system, the seasons were divided into four and the genetic groups into six. Milk samples from morning milking were collected monthly, directly from a cooling tank. Protein, fat, lactose, total solids, casein, urea nitrogen concentrations/levels, somatic cell count (SCC) and total bacterial count (TBC) were determined. For milk composition, the detected results were satisfactory and met the requirements of Normative Ruling 62, but the averages for SCC and TBC were above the recommended limit. All variables, with the exception of casein from total protein were influenced (P < 0.05) by the production system used in the production unit. A lower fat content was recorded in 2010 compared to 2011. For the seasons, all the constituents of milk had lower values in drier season (seasons 3 and 4), with the exception of casein; SCC and TBC had higher values in periods 1 and 2, which are considered rainy periods. There was variation in the chemical composition of milk according to the genotypes. Milk chemical composition met the legal and market requirements, with a positive emphasis on specialized production systems. The variations over the year and according to the genetic group of the herd are also significant and should be taken into account in the search for improvements. As for the hygiene and health aspects of milk, the results portray the need for a greater focus by the entities involved in the sector, as well as the producers, on the viability of an adequacy program and monitoring of management practices related to this criterion.

The objective was to evaluate the physico-chemical composition, somatic cell count and electrical conductivity of the milk from lactating Zebu cows. For this, monthly milk samples were collected on the official milk control day intended for analysis of electrical conductivity of milk (ECM), somatic cell count (SCC) and milk composition. We used monthly data from 680 controls, from 10 Gyr and 17 Guzerat cows from a herd located in the city of São Gonçalo do Amarante/RN, from August to November 2013. Analyses of variance, mean test and Pearson correlation analysis were conducted. The levels of fat (% F), protein (% P), lactose (% L), total solids (% TS) and non-fat dry extract (% NFDE) were dependent variables for the ECM and SCC. The milk of Gyr cows for ECM, SCC, GOR, PROT, LACT, TS and NFDE were respectively, 3.88±1.18 mS/cm, 1629±2195 thousands cells/mL, 4.71±1.77%, 3.29±0.31%, 4.5±0.33%, 13.5±1.78%, 8.79±0.37%, and for the Guzerat breed 3.59±0.88 mS/cm 1356±1793 thousands cells/mL, 4.47±0.98%, 3.43±0.32%, 4.52±0.24%, 13.5±1.19%, 9.02±0.48%. No significant correlations between SCC and ECM characteristics were observed. However, when the correlation of each of these parameters and milk composition in different classes for each breed was analyzed, a significant correlation of the SCC was observed with the protein and lactose in Gyr, of the ECM with the lactose and SCC with total solids and fat for the Guzerat cows.