One of our clients wants to feed their PI calves and had some questions about the best "PI Feeding Practices." This sparked an internal conversation within CST and we came up with some tips that can help increase the survivability among PI animals.
Short disclaimer: While these tips can increase survivability, there has been no study performed to evaluate them and PI’s could still die, we are just trying to mitigate the risk as much as possible.
When most people find a PI they will throw it in a “PI Quarantine Pen” and hope it lives and gains enough to be slaughtered. More often than not most of the PI’s will die before slaughter weight. The best way to increase survivability is to mix the cattle as much as possible (I will explain down below), put them in small groups and give them plenty of room so there isn’t much competition.
Mixing the Cattle – When I say mix the cattle, I mean mix by BVD subtype. PI’s of the same subtype can kill each other if the virus mutates and becomes cytopathic. BVD is naturally noncytopathic, meaning it doesn’t destroy its culture i.e. it’s host cell. Sometimes, when BVD reproduces, it can mutate and become cytopathic, meaning it will destroy its culture. If one PI has a virus that mutates, it will infect all other PI’s of the same subtype and they will die by mucosal disease, which is not curable.
The best way to combat this is to mix the PI’s as much as possible. This means you have to know the subtype of the virus, which can be pretty pricey to find out – about $140 per head. Generally, what we have noticed over the past 15 years is about 70 – 80% of all PI’s are 1b, while the remaining 20 – 30% are 1a and 2a. When you mix the cattle, you decrease the probability of multiple animals of the same subtype being in the same pen.
Put them in small groups – This goes back to the mixing subtypes, the less of one subtype you have in a group, the less that can possibly die if one mutates and becomes cytopathic. Plus, there is less socializing pressure among the cattle when there aren’t as many in a pen.
Give them plenty of room – Cramming cattle into a small pen puts stress on the animal, which the stress causes a greater effect on an already sick/chronic animal. Give them room to roam around at their leisure.
Also, it is good practice to make sure your PI Quarantine pen(s) does not border other non-PI pens.