Determinação da concentração de nitrogênio uréico no plasma como ferramenta auxiliar no manejo sustentável em rebanhos leiteiros sergipanos

Abstract

The dairy cattle is a source of income for thousands of producers in Brazil, with growing production data, especially in the Northeast, making it essential that they be encouraged to create sustainable processes, causing producers to be competitive, earning profits and quality of life in a responsible manner. In this sense, monitoring the remnants of the protein intake in the diet of lactating cows, allows a rational use of concentrate supplementation, promoting a reduction in production costs, and prevent loss of nitrogen to the environment. The concentration of plasma urea nitrogen (PUN) can be an important auxiliary tool in the implementation and adjustment of feeding strategies, because it reflects the nutritional protein, the efficiency of nitrogen utilization by the animal and the ruminal balance between nitrogen (N) and energy. Its use as a routine, can help professionals in rural technical assistance, the ease of performing the examination in any laboratory animal or human clinical analysis, and can be used in non-lactating animals and other animal categories. The aim of this study was to evaluate the concentration of plasma urea nitrogen (PUN) in different dairy herds in order to obtain a diagnosis of levels of dietary protein utilization of lactating cows and to relate these levels with economic and productive aspects. The experiment was conducted in 25 farms with the exploitation of dairy cattle in the town of Nossa Senhora da Glória (SE), where blood samples were collected in five cows per farm, every 30 days over a period of three consecutive months, to determination of the PUN. Then, we selected 10 properties, valued between 25 and showing greater zootechnic control, to analyze possible PUN associations with nutritional parameters, productive and reproductive, as well as assess the commitment of the income of milk with concentrate supplementation. The experimental design was completely randomized split plot in time, obtaining variations of PUN between 6.97 and 29.2 mg / dL (P <0.05) and overall average of 15.46 mg / dL between the properties, where only 37.33% of them presented PUN within the patterns, and found that increasing levels of crude protein (CP) in the diet resulted in elevated values of PUN and reduced reproductive efficiency. It was also observed, that the mean of a 38.17% of income from milk, with the use of concentration between the properties. Under the conditions of this diagnosis, it appears that the present levels of PUN is not standard in most properties, possibly influenced by crude protein (CP) in the diet, resulting in higher production costs of dairy.