What strategies work to keep feed from heating on these hot summer days?
What strategies work to keep feed from heating on these hot summer days?
Feed (meaning TMR) should not have excessive heating much beyond ambient, even during hot weather. However there is a phenomenon called Q10 for biological systems which is the multiple in which a physiological reaction rate increases with each increase in temperature of 10 degrees Celsius. So if there are conditions where feed will heat – that reaction rate will probably increase with increasing temperature. There is probably unstable silage – mostly likely high levels of yeast that cause the heating. So first step would be to identify the culprit feed(s) and determine if anything can be done about it at the source, e.g is silage being knocked down for the next day and starting to heat already. If silage is heating then silage management (packing etc) should be evaluated for future harvests and consider buchnerii inoculant on corn silage and high moisture corn. There are several commercial TMR additives based on one or more acids, with some containing ethoxyquin (to prevent fat oxidation) that are effective at reducing heating of TMR in the feed bunk. I would usually start with the most economical one first – which would be propionic acid or calcium propionate (dry) added to TMR mixer. Inclusion rate varies with moisture content – I don’t remember exactly – Kemin has a Ca prop product called Shield – you might start with a couple pounds per ton of TMR. Others might know of specific acid combinations that are most effective.
Oh disclaimer since I mentioned a commercial product – I have no ties to Kemin.
After recent discussions with Rich Muck, USDA, he convinced me that with high heat (above 115 f or so) the culprit is actually B subtilis as yeasts generally do not survive high temperatures . Think of making bread – too hot of water will kill the yeast. B. subtilis is an aerobic bacteria that generates high heat and is easy to mistake for yeast. As Jim points out, propionic acid is a strong inhibitor of yeasts and molds. Acetic acid was added to blends of organic acids to address the aerobic bacteria problem. As a disclaimer, American Farm Products sells a 80:20 prop:acetic acid liquid organic acid product. I usually suggest adding it to the source as Jim recommends. In some cases the source of the problem is a byproduct like wet brewers or unstable forages. I tend to like dry products for the TMR over liquid simply for handling and safety. Some add it to a liquid molasses mixture and apply it that way. My standard recommendation is to start at a couple pounds per ton. If that does not fix the problem, increase the dose. Once it is fixed, regulate up or down based on ambient temperature/humidity.