Can fecal characteristics be used to predict the digestibility of certain macro minerals in dry and lactating cows?

This study aims to evaluate the relationship between mineral digestibility and fecal characteristics and compare digestibility in dry and late-lactating cows. A total of 107 multiparous Holstein and Simmental cows were included, with 66 cows in late lactation and 41 cows in the dry period. The apparent digestibility of key macro minerals, dry matter content in feces, dirtiness scores, fecal characteristics, and serum macro mineral levels were determined. Cows consuming the same diet were arranged according to a completely randomized design. Results showed that, compared to the late lactation group, the dry period group had a significantly lower total dirtiness score, higher phosphorus digestibility, and elevated serum calcium levels (p < 0.05). Additionally, fecal consistency and fecal height were greater in the dry period group (p < 0.05). However, the increased phosphorus digestibility observed during the dry period was not significantly associated with fecal consistency (r = +0.225, p < 0.05) or the total contamination score (r = -0.339, p < 0.05). Consequently, this study reveals that understanding the differences in mineral digestibility between different physiological stages can enhance nutritional approaches for better dairy cow management.