Feeding To Decrease Post Rut Mortality

Written by: Bobby Deeds

Fall has arrived and many ranch managers will opt to shut off their protein feeders and fire up the corn/spincast feeders in preparation for hunting season. This corresponds with the nutritional requirements of whitetail deer if we consider that bucks are done with antler growth and most doe will start to wean off fawns alleviating the demand of lactation. Basically, we go into a holding pattern for a few months as deer are able to cruise without having to meet the higher nutritional demands that are required in the Spring and Summer. What is often overlooked is the fact that some properties will lose as much as 80% of their 3.5 year and older bucks due to malnutrition and post rut stress. 

It is important to realize that although the nutritional demands of whitetail deer have fallen off, managers should not completely pull the plug on their supplementation program. Most people are surprised to know that more mature bucks are lost every year to malnutrition and post rut stress than those harvested by hunters. This is due mainly to the fact that bucks will lower total daily intake during the winter and especially during the rut. With lower consumption rates, it is not uncommon for mature bucks to lose as much as 30% of their body weight due to the stress of the rut. Providing a supplement will not eliminate the fact that bucks are going to lose some body condition, but they will still utilize it as a portion of their diet even if total daily intake has fallen off. Although requirements have lightened from a protein standpoint, managers have to be careful with what they are feeding as deer are much more sensitive nutritionally when they are stressed.

If we allow bucks to severely drop in body condition, many of the commercial nutritional supplements available can actually do more harm than good. Most have heard of the term acidosis and its affect on ruminant animals, but fewer know that it is typically caused by increased starch levels in the diet due to overconsumption of high grain rations. Most commercial pelleted deer protein supplements have at least 30% starch due to high grain inclusions. If we take a deer that is run down after the rut and has lost most of their body condition, then offer them free choice grain or a deer supplement that has a high starch level, we are basically driving the last nail in the coffin. Deer that are stressed will die just as quick from acidosis as they will from a 30-06 bullet.

So, how do we solve this problem? Though not economically feasible for some, the best solution is to offer a balanced free choice supplement year-round. We have learned that nutrient requirements (excluding energy) for most deer drop in the fall and winter. Typically, the highest nutritional demand from a protein standpoint will come from younger deer that are not yet mature physiologically, but their growth demand will still not exceed 14% protein in their total diet. The best recommendation would be to offer a lower protein 14%-16% pelleted ration that has high fiber, high fat and contains a low starch level. I do not recommend going and finding the cheapest 14% ration available and feeding it though, due to many economical feeds not being nutritionally balanced correctly.

We work too hard improving habitat and managing our herds, to grow quality deer, just to have half of our mature bucks to succumb to post rut stress every year. The best recommendation is to provide your deer a more economical, balanced supplement September through December. This will decrease post rut mortality simply by allowing your deer to maintain adequate body condition through the rut and allow them to recover and replenish body condition before they drop their antlers. It is important to remember that body condition will always take precedence over antler development. Supplementing during this time will enable bucks to maintain adequate condition through the winter. By doing this, we not only increase post rut survival, we improve antler production for the coming year as bucks are able to apply nutrition toward antler growth as soon as they drop their old set and do not have to first replenish depleted body condition.

If you would like to discuss your current supplementation, contact us or start with our FAQs. Have a great season!