Table 5.
Effect of feeding inorganic plus organic selenium supplement on milk yield, composition, and pH of milk of dairy cows at 0, 21, and 49 days of experiment.
| Item | CON Ration 1 | IOSe Ration 2 | SEM 3 | p-Value | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| T0 4 | T21 | T49 | T0 | T21 | T49 | Ration (R) | Day (D) | R × D | ||
| Milk yield (L/d) | 30.9 | 33.4 | 29.4 | 27.1 | 31.4 | 29.4 | 1.771 | 0.583 | 0.770 | 0.216 |
| Milk composition | ||||||||||
| Fat (g/100 g) | 4.56 | 4.31 | 3.58 | 4.05 | 4.56 | 3.54 | 0.115 | 0.657 | 0.019 | 0.423 |
| Protein (g/100 g) | 3.25 | 3.02 | 3.08 | 3.41 | 3.18 | 3.05 | 0.035 | 0.199 | 0.027 | 0.395 |
| Lactose (g/100 g) | 4.77 | 4.72 | 4.80 | 4.95 | 4.68 | 4.81 | 0.019 | 0.244 | 0.026 | 0.130 |
| Ca (mg/100 g) | 118 | 113 | 119 | 122 | 113 | 119 | 3.27 | 0.838 | 0.809 | 0.460 |
| P (mg/100 g) | 85.4 | 81.3 | 91.1 | 86.3 | 83.6 | 87.7 | 1.69 | 0.981 | 0.132 | 0.360 |
| Zn (mg/100 g) | 0.447 | 0.449 | 0.418 | 0.456 | 0.442 | 0.412 | 0.013 | 0.958 | 0.047 | 0.655 |
| Cu (mg/100 g) | 0.007 | 0.003 | 0.003 | 0.006 | 0.004 | 0.004 | 0.000 | 0.675 | <0.001 | 0.120 |
| Se (µg/100 g) | 1.54 | 1.33 | 1.26 | 1.64 | 1.94 | 1.80 | 0.047 | 0.001 | 0.789 | 0.167 |
| Milk pH | 6.61 | 6.79 | 6.65 | 6.64 | 6.67 | 6.62 | 0.023 | 0.418 | 0.611 | 0.177 |
1 Total mixed ration with inorganic Se. 2 Total mixed ration with inorganic plus organic Se. 3 SEM = standard error of the mean (n = 10 per treatment). 4 Tn = number (n) of days after starting the experiment.