Document Type: Original Article
Department of Clinical Sciences, Faculty of Veterinary Medicine, Urmia University, Urmia, Iran
Milk samples from high and low milk producer Holstein cows, were obtained during the morning and afternoon milking over a one week period. Overall, 1064 samples were tested within 14 times sampling in Urmia, Iran. Milk macro-mineral concentrations in the morning milking and in low producers were greater than in the afternoon and in high producers. The highest and lowest concentrations were observed in Na+ and Mg++, respectively. Mean milk values between low and high producers in the morning, afternoon and daily milking times were different (p < 0.05). The individual comparison of milk parameters between both groups in the different milking times were also different (p < 0.05). The results of correlation among macro-minerals in the morning, afternoon and overall milking showed significant and positive correlations among all macro-minerals except for Na+ and K+, in which there was a significant negative correlation (p < 0.05). The highest and lowest correlations were found between Ca++ and inorganic phosphorus (IP) (r=0.37, p < 0.05) and Na+ and IP (r=0.10, p < 0.05), respectively. It is concluded that the concentration of macro-minerals in different producers varied between milking times. The sodium concentration was the highest while Mg++ was the lowest among macro-minerals. The correlation between Ca++/ IP was the highest, while Na+/K+ revealed a negative correlation. Therefore, by organizing the appropriate macro-minerals in the ration, it would be possible to achieve an optimal purpose from animal husbandry.