Brix refractometry of colostrum from primiparous dairy cows and new-born calf blood serum in the evaluation of failure of passive transfer

Failure of passive transfer (FPT) of immunoglobulins (IgG) is associated with increased morbidity and mortality of calves. In this study we evaluated the digital Brix refractometer usefulness for the assessment of FPT. A number of 16 colostrum samples from the first milking (2-3h post-partum) of Holstein-Friesian dairy heifers and 29 blood sera of 3-6 days old calves were analyzed with a digital Brix refractometer. Total proteins were determined by the biuret reaction. Colostral IgG were determined by radial immunodiffusion (RID), and colostral whey and blood serum. globulin (composed almost entirely of IgG) were determined by agarose protein gel electrophoresis (APE) and densitometry. Colostral % Brix score was 25.5 +/- 3.4%. Concentrations of colostrum IgG and colostral whey. globulin were 130 +/- 33 g/L and 100 +/- 24 g/L respectively. The concentration of total proteins in colostral whey was 134 +/- 30 g/L. The correlations between Brix values and the concentrations of IgG determined with RID and the concentrations of. globulin determined with APE were positive and highly significant (P lt 0.001 and P lt 0.01). The concentration of serum proteins of new-born calves was 57.75 +/- 11.8 g/L, the concentration of. globulin was 14.4 +/- 7.8 g/L, and the Brix score was 8.6 +/- 1.0%. FPT (serum. globulin lt 10 g/L) was detected in 34.5% (10/29) calves. Brix score correlated with the concentration of blood serum. globulins in all examined calves. The results have confirmed that digital Brix refractometry allows the producers to use this technique in order to estimate colostral and calf serum IgG, thereby monitoring both colostrum quality and success of passive transfer

Effect of non-genetic factors on standard lactation milk performance traits in simmental cows

The effect of systematic and continuous environmental factors on milk performance traits over standard lactations in 2805 Simmental cows was evaluated using the general linear model. The systematic factors included the effect of farm or breeding area, calving season, year of birth, season of birth, lactation group and their interactions. The continuous factor analysed was the effect of age at first conception. The effect of farm, lactation group and calving season on standard lactation milk performance was found to be highly significant (P lt 0.01), excepting the effect of calving season on milk fat percent in standard lactations which showed statistical significance (P lt 0.05). The interactions between year and season of birth, farm and calving season, and farm and lactation group had a highly significant effect (P lt 0.01) on all performance traits studied. Age at first conception, as a continuous factor, had a highly significant effect (P lt 0.01) on milk yield and milk fat percent, and a non-significant effect on milk fat yield. The model used to correct the performance traits over standard lactations for the effect of systematic factors was highly significant (P lt 0.01). The variance of the model accounted for 20.06 and 37.31% of the total variance of milk fat yield and milk fat percent, respectively. The resulting coefficients of determination (R-2) ranged from 0.20 for milk fat yield to 0.37 for milk fat percent