## 3 Results and Discussion
### Mineral Content  
The mineral content of S1, S2, and S3 are presented in Table 3. Macro-minerals and oligo-minerals are those bioelements needed in relatively large and small amounts, respectively. It is important to discuss these results comparing the mineral content of _IP_ samples against NRC recommendations [60] and alternative livestock feed supplements. Ca is the most abundant mineral in a cow's body. The NRC recommendations are defined by the Ca needs of lactating dairy cattle and dairy cattle. The Ca content in _IP_ samples was higher than the Ca content recommended by the NRC. It also resulted in \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multicolumn{1}{c}{**Elements**} & **S1** & **S2** & **S3** & **NRC** & **MG** & \multicolumn{2}{c}{**Mineral Content in Common Feed**} \\ \hline Ca & [\%] & 0.58 & 0.63 & 0.75 & 0.43–0.66 & 0.34 & RGT, corn, sunflower, flax: 0.06–0.38 \\ \hline P & [\%] & 0.11 & 0.12 & 0.13 & 0.28–0.41 & 0.14 & RGT: 0.26, corn: 0.22 \\ \hline Mg & [\%] & 0.62 & 0.45 & 0.49 & 0.20–0.25 & 0.26 & RGT: 0.16, corn in plant: 0.14 \\ \hline K & [\%] & 1.62 & 1.31 & 1.43 & 0.90–1.00 & 0.17 & barley, sunflower, sorghum, wheat: 0.76–1.08 \\ \hline Na & [\%] & ND & ND & ND & \(\sim\)0.18 & 0.04 & Corn: 0.06 \\ \hline S & [\%] & 0.20 & 0.10 & 0.12 & \(\sim\)0.20 & - & RGT: 0.15, corn in plant: 0.20 \\ \hline Cl & [\%] & 0.52 & 0.16 & 0.16 & \(\sim\)0.20 & - & Plant matter: 0.2–2 \\ \hline Zn & [ppm] & 64 & 64 & 72 & 40 & 34 & Corn: 46 \\ \hline Mn & [ppm] & 3329 & 1861 & 1599 & 40 & 467 & Corn: 10 \\ \hline Cu & [ppm] & 11 & 8 & 9 & 10 & 7 & Corn: 13 \\ \hline Fe & [ppm] & 199 & 299 & 264 & 50 & 695 & Corn: 48 \\ \hline Al & [ppm] & 440 & 422 & 413 & - & - & Plant matter: 1–500 \\ \hline B & [ppm] & 71 & 63 & 71 & - & - & Corn: 5, corn in plant: 10–20 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Mineral content in _IP_, NRC recommendations, and alternative livestock feed supplements. higher than that in Misiones grassland, RYE GRASS TAMA, corn in plant, sunflower, and flax-based feed supplements. The Mesopotamian region of Argentina, including the Province of Misiones, is characterized by soils with less than 5 ppm of P. The low amount of P in the soil is reflected in the low content of this element in natural grasslands. The amount of P in _IP_ samples is nearly half of the NRC recommendation. However, it is comparable to that of the Misiones grasslands. The Mg content in _IP_ samples is between two and three times higher than NRC recommendations and nearly four times higher than the Mg content found in Misiones grasslands, RYE GRASS TAMA, and corn-in-plant-based feed supplements. K is the third most abundant bioelement in a cow's body. The K content in _IP_ samples and the Misiones grasslands are comparable. Both greatly exceed the NRC recommendations and alternative feed supplements, such as oats, barley, sunflower, flax, garneiferous sorghum, and wheat. However, it must be controlled. High levels of K in spring pastures and silages have been reported to cause grass tetanus and hypomagnesia in lactating cattle [61, 62]. The NRC recommendation for S is to be nearly 0.20% of the ash. In addition, an N/S ratio of around 12 is also recommended. The S content of _IP_ samples ranged from 0.20% for S1 to 0.10% for S2. This is equivalent to the S content found in corn in plant and a little lower than that in RYE GRASS TAMA. The S content in _IP_ samples can be considered within specification. Supplemental S should not be required in _IP_ based rations. Na is needed by the cow for maintaining osmotic regulation of body fluids. Na can be a limiting nutrient in the diet. Therefore, salt is commonly supplemented to dairy cows. Na was not detected in any of the _IP_ samples. Na content in the grasslands of Misiones is also very low. This deficiency could be corrected by adequate salt supplementation and should be provided to dairy cattle on pastures to ensure that they meet their needs for Na.