مرکز منطقه ای اطلاع رساني علوم و فناوري - ارزيابي ارتباط غلظت هاي ماهانه و فصلي كلسيم ، فسفر، سديم و پتاسيم سرم شير در گاوهاي هولشتاين شيري

چكيده لاتين :

This study was conducted among minerals in Holstein cows, milk 1) to determine the range and concentrations of milk serum calcium (Ca), phosphorus (P), sodium (Na) and potassium (K); 2) comparison of the monthly and seasonal concentrations among milk minerals, and 3) to find out the monthly relationship among milk minerals. A total number of 957 milk samples from 100 dairy herds were prepared from milk factory in Urmia. lOmls milk was taken monthly up to 12 months from each herd, and the milk fat was separated by centrifugation. The milk serum was prepared after casein precipitated by 0.1 normal HC1. Ca and P were estimated by spectrophotometer method (RA-1000) using commercial Ca and P kits (Ziest Chimi). Na and K were measured by flame-photometer using standard Na and K (Pars-Azmon). SPSS, one-way ANOVA and Pearson correlation tests were used to analyse the data. The overall mean±SE milk serum Ca, P, Na and K concentrations were 61.7±0.32, 26.8±0.12, 32.6±0.18 and 17.8±0.17 mmol/1, respectively. The comparison of the mean mineral concentrations showed differences among months and seasons (P<0.001). The highest monthly difference for Ca and Na was observed in April-May, for P in May-June and for Na it was in March-April. The seasonal comparison of the mean milk mineral concentrations showed that the lowest and highest concentrations for Ca and P belonged to the Spring and Winter and for Na and K were Autumn and Summer. The results of Pearson correlation among macro-minerals in the milk serum between the months and seasons showed significant and positive correlations between Ca and P (r=0.27), Na and K (r=0.88) and significant negative correlation between Ca and K (r=-0.23) concentration. The correlations between Na and K were observed for the whole year but the correlations between Ca and P were for 6 months of the year. The rate of seasonal correlation between Ca and P was 0.74 and for Naand K it was 0.88. It is concluded that the concentrations for Ca and P in the cow milk serum were at the range recommended in references but it was high for Na and low for K. The significant differences among months and seasons in concentration of macro-minerals showed that macro-minerals in the milk serum were varied during the study in that Spring was critical for Ca and P and Autumn was for Na and K. Significant positive correlations between Na and K and Ca and P revealed their close corporations in the milk in that they were similarly observed in other tissues. Therefore, by organizing the appropriate macro-minerals in the ration, it will help increase the ruminant husbandry profits.