We explored how a new form of zinc, an elemental zinc bolus, affects sheep in potentially preventing facial eczema, specifically by comparing it to a well-established zinc oxide bolus. In our study, we used a 2×2 factorial design with 40 Romney-cross ewes divided into groups receiving either the novel zinc treatment or the zinc oxide control.
To assess any interactions with copper, we also administered a capsule containing copper oxide to half of the animals in each zinc group. Over the course of several weeks, we monitored the sheep for signs of photosensitization and collected samples to measure serum zinc concentrations, among other variables.
Our findings revealed that serum zinc levels were significantly higher in the group treated with the novel elemental zinc compared to the zinc oxide group. This increase was consistently observed over time, and we found a positive correlation between serum zinc and fecal zinc concentrations. Interestingly, the copper treatment did not appear to have an impact on zinc levels, nor did it change liver copper concentrations in the different zinc treatment groups.
Overall, the study indicates that the new elemental zinc bolus can elevate serum zinc levels in sheep, which may help in preventing facial eczema. However, it also highlights that interactions with copper do not significantly affect zinc absorption or effectiveness.