Karyne Oliveira Coelho

Fatores não-nutricionais e concentração de nitrogênio uréico no leite de vacas da raça Holandesa

The objective of this study was to evaluate the association of non-dietary factors on the concentration of milk urea nitrogen (MUN), as an indicator of efficiency of nutrient utilization by lactating dairy cows. A dataset containing 7,006 observations from 855 lactating Holstein cows were used. Milk yield, body weight, days in milk and number of lactation were collected on the milk sampling days. Monthly samples of milk were collected to determine contents of milk fat, protein, lactose, total solids, MUN and somatic cells count (SCC). Yield of milk components (fat, protein, lactose and total solids) as well as 4% fat-corrected milk (FCM) were also used in the study. Regression analyses of MUN, as the dependent variable, on FCM, SCC and content and yield of milk components were done to analyze the data. Mean MUN and milk yield averaged 13.3 mg/dL and 35.8 kg/day, respectively. Milk contents of fat, protein, lactose and total solids as well as SCC (natural logarithm transformed) were negatively associated with MUN while the opposite was observed for yields of milk lactose and total solids and milk production. Yields of milk fat and milk protein (kg), FCM, days in milk and number of lactation all were correlated with MUN, however there was lack of fit for the linear equation. No significant correlations between MUN and body weight and MUN and fat:protein ratio were observed. Among the non-dietary factors, milk yield and milk protein concentration correlated most with MUN.

Níveis de células somáticas sobre a proteólise do queijo Mussarela

The aim of this trial was to evaluate the effect of somatic cells count on the microbiota and proteolysis of Mozzarella cheese during the storage period. Cows presenting different levels of SCC were selected: 200,000 cells/mL; >200,000 to 400,000 cells/mL; >400,000 cells/mL to 750,000 cells/mL and >750,000 cells/mL, which were not treated with antimicrobial prior or on the milk sampling day. The cheeses produced were evaluated after 1, 15 and 30 days of storage for coliforms count at 35oC, coliforms count at 45oC, psychrotrophic and lactic acid bacteria. Meanwhile, extent and depth of proteolysis indexes were determined. The complete trial was repeated four times and experimental design used was randomized blocks. ANOVA was used for repeated measurements and the p-value was adjusted for multiple comparisons by Tukeys test. High somatic cell count milk showed lower concentration of protein and higher of non-protein nitrogen. There was a decrease of lactic acid bacteria in cheese made from milk containing high somatic cells count (>750,000cells/mL). Nevertheless, during the storage period, a significant increase in the extent and depth of proteolysis occurred in cheeses produced from milk with SCC higher than 400,000 cells/mL. Therefore, in order to produce a high quality Mozzarella cheese, it is necessary to control the raw material, so that SCC should be lower than 400,000 cells/mL.

Contagem celular somática nos grandes constituintes do leite

The objective of the present study was to evaluate the relationship between somatic cell counts (SCC) and the fat, protein, lactose and total solids from raw milk from 160 dairy cows. They were tabulated data from SCC and chemical composition for the period of six months. The SCC determined by flow cytometry and the percentage composition by differential absorption of infrared waves. To evaluate the influence of SCC on the fat, protein, lactose and total solids, it was calculated the correlation coefficient. The concentration of protein, lactose, and total solids inversely correlated with the SCC.

Microbiological Quality on Food Handles Hands

Sarah Hellen Mendonca Ferreira, Karyne Oliveira Coelho, Aracele Pinheiro Pales dos Santos, Claudia Peixoto Bueno. Microbiological Quality on Food Handles’ Hands. In: Anais do 12o Congresso Latinoamericano de Microbiologia e Higiene de Alimentos MICROAL 2014 [= Blucher Food Science Proceedings, num.1, vol.1]. Sao Paulo: Editora Blucher, 2014. DOI 10.5151/foodsci-microal-227 Microbiological Quality on Food Handles’ Hands

Validation of models for predicting milk urea nitrogen concentrations, estimating dry matter intake by the NRC (2001)

The objective of this study was to validate three different models for predicting milk urea nitrogen using field conditions, attempting to evaluate the nutritional adequacy diets for dairy cows and prediction of nitrogen excreted to the environment. Observations (4,749) from 855 cows were used. Milk yield, body weight (BW), days in milk and parity were recorded on the milk sampling days. Milk was sampled monthly, for analysis of milk urea nitrogen (MUN), fat, protein, lactose and total solids concentration and somatic cells count. Individual dry matter intake was estimated using the NRC (2001). The three models studied were derived from a first one to predict urinary nitrogen (UN). Model 1 was MUN = UN/12.54, model 2 was MUN = UN/17.6 and model 3 was MUN = UN/(0.0259 × BW), adjusted by body weight effect. To evaluate models, they were tested for accuracy, precision and robustness. Despite being more accurate (mean bias = 0.94 mg/dL), model 2 was less precise (residual error = 4.50 mg/dL) than model 3 (mean bias = 1.41 and residual error = 4.11 mg/dL), while model 1 was the least accurate (mean bias = 6.94 mg/dL) and the least precise (residual error = 5.40 mg/dL). They were not robust, because they were influenced by almost all the variables studied. The three models for predicting milk urea nitrogen were different with respect to accuracy, precision and robustness.