The flavor of feed, especially for young animals, can be an important consideration when developing the animal’s diet. Taste can either stimulate or suppress appetite and feed intake. A total of 3 experiments were carried out to study the effect of trace mineral inclusion on feed intake of dairy calves.
Study 1
In a preference study[3], 16 calves were offered 3 supplements simultaneously. The 3 supplements contained either hydroxy-based trace minerals, sulphate-based trace minerals or organic trace minerals. The supplements were offered for a 14-day period. Intake of the hydroxy based supplement was higher throughout the entire 14 day period (see Figure 1).
Figure 1, Percentage intake of calves of the total offer of supplements based on hydroxy trace minerals, organic trace minerals or sulfates.
Over the total period of 14 days, calves almost exclusively consumed (p < 0.001) the hydroxy trace mineral source (see Table 1).
| Hydroxy trace mineral |
82.9% |
| Organic trace mineral |
10.4% |
| Sulphate trace mineral |
6.7% |
Table 1: Preferential intake of calves offered 3 different sources of trace minerals simultaneously. Intake is expressed as the percentage out of the total intake.
Study 2
This study was conducted at the University of Florida[4]. A total of 139 pairs of calves were included in the study. They were on a feeding schedule with limited intake of creep feed from 104 days before weaning. Half of the calves were fed a creep feed supplemented with sulphate trace minerals, the other half were fed a creep feed that was supplemented without using sulphate trace minerals. Intake of the creep feed without sulphates was higher. There was about an 8-fold difference as the average supplement intake increased from 20 g/day to 160 g/day during the 14-week trial (see Figure 2).
Figure 2. The effect of removing sulphate sources of Cu, Zn and Mn from the supplement, calves supplement intake increased from 20g to 160g/calf/d during the 14-week trial period.
Study 3
In a third study, also conducted at the University of Florida[3], 3 different supplements were compared. One supplement did not contain trace minerals, one contained a blend of copper, and zinc from a sulphate source with manganese from an oxide source. The third supplement contained a hydroxy-based mineral sources. Creep-feeding supplements were provided starting 84 days before weaning.
Calves ate the largest amount of creep feed containing the hydroxy-trace minerals, followed by intake of the control feed. Intake of the sulphate-fortified diet was significantly lower, with the hydroxy trace mineral supplemented feed having a 26% increase in consumption (see Table 2).
| Hydroxy trace mineral |
0.109 kg/day |
9.2 kg |
| Sulphate trace mineral |
0.088 kg/day |
7.4 kg |
| No trace mineral |
0.100 kg/day |
8.4 kg |
Table 2: Voluntary feed intake of dairy calves of Cu, Zn and Mn sulphate trace mineral fortified grain-based supplements compared to Cu, Zn and Mn hydroxy trace mineral fortified supplements and supplements without Cu, Zn and Mn trace minerals.
Study 4
In this study[3], a supplement containing hydroxy trace minerals was compared to a supplement containing sulfate trace minerals. Calves fed the hydroxy trace mineral supplement had a higher bodyweight gain after weaning compared to calves supplemented with sulfates (see Figure 3).
Figure 3, Bodyweight gain of calves during the 16 day the post weaning period, one group of calves was fed hydroxy trace minerals, the other group was fed sulfates.
The trial also demonstrated that calves with a higher mineral intake had lower cortisol levels and higher plasma ceruloplasmin and haptoglobin levels, indicators of a faster post-weaning recovery (see Figure 4).
Figure 4. Cortisol levels, and plasma ceruloplasmin and plasma haptoglobin levels in calves during the first 16 days after weaning, one group of calves was supplemented with trace minerals and compared to a group of calves not supplemented.
