Correlação entre métodos tradicionais e espectroscopia de ultra-som na determinação de características físico-químicas do leite / Correlation between traditional methods and ultrasonic spectroscopy for measurement of milk physical-chemical characteristics

Compararam-se a espectroscopia de ultra-som (US) e os métodos tradicionais (MT) utilizados para a determinação de características físico-químicas do leite e estimaram-se as correlações entre esses métodos e suas acurácias. As características densidade, extrato seco desengordurado (ESD), teor de proteínas e teor de gordura foram determinadas em 65 amostras de leite cru por ambos os métodos. As densidades médias determinadas pelo US e pelos MT não diferiram entre si (P=0,14), e a correlação encontrada entre os dois métodos para a determinação da densidade não foi significativa (P= 0,08). Os teores médios de ESD, proteína e gordura encontrados pelo US e pelos MT foram diferentes (P=0,04, P<0,0001 e P<0,0001, respectivamente), as correlações entre os dois métodos utilizados para a análise dessas características foram positivas e significativas (r=0,0109, r=0,0007, r= <0,0001, respectivamente) e as acurácias dos métodos para essas determinações foram de 0,160, 0,062 e 0,145, respectivamente. Foi determinada a equação de regressão linear, que associa o teor de gordura obtido no método de espectroscopia de ultra-som ao do método butirométrico, que apresentou coeficiente de determinação de 0,5936

The ultrasonic spectroscopy (US) and the traditional methods (TM) used for the measurement of milk physical-chemical characteristics were studied and the correlations between these methodologies and their accuracies were estimated. Milk density, solids-non-fat (SNF), protein and fat contents were determined in 65 raw milk samples by both methods. Means of density determined by US and TM did not differ (P=0.14), although no significant correlation was found (P=0.08) between the methods used for the determination of this characteristic. Means of SNF, protein and fat contents determined by US and TM differed (P=0.04, P<0.0001 and P<0.0001, respectively). Correlations between both methods used for the analysis of these characteristics were positive and significant (r=0.0109, r=0.0007 and r= <0.0001, respectively), and the accuracies of the methods for these analysis were 0.160, 0.062 and 0.145, respectively. The regression equation of US results on TM for fat content showed a coefficient of determination of 0.5936

[Experimental trial to reproduction enzootic haematuria in cattle by feeding bracken fern [Pteris aquilina (Kuhn)] (author's transl)]. / Tentativa de reprodução experimental da hematúria enzoótica em bovinos pela administração de samambala.

Cattle were fed with a diet containing bracken fern in order to study the development of chronic bovine haematuria. The experimental 25 animals were randomly divided into 5 groups and such groups received different amounts of the plant. All groups were fed for 36 months, while no clinical effect of the disease was noted. After that time, the supplement of bracken fern to the diet was suspended and the animals still remained under observation. One of the animals (from group I) exhibit haematuria one month after the fern was removed from the diet. In the same occasion, four animals were slaughtered and only one of them presented haemorragic lesions in the urinary bladder. After 34 days another four animals were slaughtered and 114 days later three more were killed. All animals were chosen randomly and in spite of no clinical signs of the disease, all of them presented haemorragic lesions in the urinary bladder. The results obtained in this experiment confirmed that bracken fern (Pteris aquilina) is responsable for the development of chronic bovine haematuria in cattle. The disease is challenged by continuous ingestion of small amounts of bracken fern during a long period of time.