I was called to see a sick calf on a large dairy farm towards the end of the day. The farm is nestled right in beside the Pureora forest up the end of a long gravel road. Absolutely beautiful part of the country with gorgeous views from the road. So I made my way up there wondering what I would find when I got there. I met the farm worker and he showed me to the calf which they had noticed earlier that day was not right and had later gone down.
Well things had got a lot worse since they had seen it last because it was now dead. Since I was already there, I decided that if we open the calf up we may discover why it died. So I began the post mortem and the calf was still warm so had only just died. The first issue I noticed was digested milk in the abdomen. That's not where it was supposed to be and I immediately suspected a hole in the abomasum (4th stomach). I searched for the likely organ and sure enough there was a hole in the abomasum, leaking stomach contents all where it was not supposed to be.
I explained to the farmer that it was probably a good thing it died before I got there as I was unlike to diagnose that in a live calf and it would have died regardless.
What is interesting about this is last season they had several dead calves and I had done post mortems on a couple and they had both had the same thing. So this farm clearly has factors that make it higher risk for abomasal ulcers. So I looked into things that cause stomach ulcers in calves.
Turns out the stomach ulcers in calves are quite common and if they get severe enough, this can result in a stomach perforation. What is less clear is the factors that cause them. Some say not enough fibre in the diet can lead to ulcers, others say too much fibre is the cause. A colleague had an outbreak of stomach perforations years ago where they attributed it to having the fibre length too short. Overseas stomach perforations are mainly found in veal calves which are feed a lot of milk. The farm I have found them in does give ad lib milk to their calves, so that may be a factor, but we can’t be sure. A quick look in the text book mentions the following risk factors: bacterial infection of the abomasal wall, failure of passive transfer from colostrum, foreign body ingestion, poor milk hygiene, once a day feeding and the use of cold milk.
This case does highlight the benefits of post mortems on animals if you are getting more deaths than expected. Because we at least know why these calves have died.