Although I am not a vet, I can only offer advice on possible reasons as to why this is occurring and from experience that I have received. Many people run their Cattle operations differently and may be hard to pinpoint exactly why this is occurring. I will say that the animal may already have Tetnus or received shortly after and as a result is probably caused from the Castrating process.
Whether it was a surgical method or band method, the results more than likely would have been the same. In some areas, Tetnus is more of a problem than others. In general, when administering a Tetnus shot, it doesn’t take full effect for a full week or two. And in many cases, if the shot isn’t a booster, than the strength of the shot may be decreased up to 60%. If you delay castrate, make sure you give a Tetnus Toxoid injection during the first vaccination period. We use Covexin 8 when doing this. Give another Tetnus Toxoid injection a minimum of two weeks prior to time of Castration and another at the time of Castration. This may vary according to your area. You may be able to just give a Tetnus Toxoid injection during the first vaccination and at the time of Castration. I quote from a box of Covexin® 8. “For Cl. perfringens types B, C and D, revaccinate two weeks prior to parturition, introduction to lush pastures or finishing programs. Calves vaccinated under 3 months of age should be revaccinate at weaning or 4 to 6 months of age.