By Phil Durst
The most important step in protecting cattle from getting tuberculosis (TB) is to protect feed intended for cattle from deer. With key personnel from the Michigan Department of Agriculture and Rural Development and USDA Wildlife Services, Michigan State University Extension has been conducting enhanced wildlife risk assessments on farms since 2015. We are primarily looking for ways that deer could get to cattle feed.
There are three stages of feed that we consider: growing feed, including pasture, stored feed after harvest and fed feed before it is consumed by cattle. In each case, we talk with cattle producers about protecting feed from deer. An integrated approach, that uses several methods and is focused on each stage of the process, will be most effective.
Deer that graze pastures, and are subsequently grazed by cattle, can be a transmission point for the bacteria that causes TB. While it is very difficult to keep deer out of pastures, there are some areas which have greater risk than others. Therefore, management practices can reduce risk.
Wet areas, where forage still grows when other areas are dry, will attract deer as well as cattle. Fencing cattle out of these areas is important. In addition, deer will likely explore the edges of pastures near woods or corn fields. Times of the year for greater risk include when acorns or apples drop at wood’s edge into pasture and when adjacent fields of corn provide an edge for deer to slip into. Understanding times and locations of higher risk enable you to reduce risk by keeping cattle out of certain areas or at certain times.
Deer are less likely to go into a pasture paddock crowded with cattle. Therefore, rotational grazing, where the pasture is divided into paddocks and cattle are confined to an area of the pasture until they have grazed it, is less risky. Rotational grazing is also a great way to improve the use of forage from pasture.
Once feed is harvested, whether as hay, haylage or corn silage, the stored feed may be desirable for deer. Deer seem to prefer corn silage, but they will readily eat haylage and hay when provided the opportunity. Protecting stored feed means keeping them from getting a taste of the feed. It may be that feed is stored in or under plastic. Maintaining the integrity of the plastic may be a sufficient deterrent, but when the plastic is opened to begin feeding from the storage, deer may have open access unless additional steps are taken to prevent them from eating.
Fencing feed storage is one of the best ways to keep deer away from feed, if diligence is taken to make sure that deer are excluded. Research by Lavelle found “exclusionary fences can reduce use and thus potential contamination of stored cattle feed by deer by at least 82 percent, and cause a shift in deer use away from livestock areas, further decreasing potential for direct and indirect interaction between deer and livestock.”
As a part of our on-farm risk assessments, we have examined many feed enclosures and have seen problems that enable deer access. Deer will use open gates. When gates are opened to access feed, they need to be closed immediately after getting the feed. Gates should also be checked to make sure that they actually exclude deer. Gaps between gates, or between the gate and the ground, of greater than eight inches can allow deer to slip between or under them. Farmers should check the openings between and under their gates. If the gates are too high, using gravel to build up under them will be effective. Conversely, hanging pipe under them may be as effective.
Some farmers may think that deer have not bothered their stored feed and therefore, wonder why they should do anything to exclude deer because it creates more difficulty in feeding cattle. Yet, research has repeatedly recorded cattle intrusion to stored feed. Even if someone is correct about lack of current deer activity, situations constantly change and the best time to prevent deer from getting to feed is before they find it.
Keeping deer excluded from stored feed doesn’t fully protect cattle herds. Deer need to be kept away from feed that is presented to cattle as well. This is why we talk about feeding no more than what cattle will consume in a day when feed is fed out in a lot or on pasture. However, it goes beyond that.
We have seen barns where cattle are confined that have an exposed feed table (the concrete pad on which feed is placed for cattle). Deer could come up and eat on one side while cattle are on the other side of the feed. It may occur at times when few cattle are up eating, but the key is, it may occur. Feed tables need to be protected. It may be that fencing needs to include the feeding areas as well as the storage areas.
Even spoiled or refused feed will attract deer. When feed is removed from the edge of a silage pile that will not be fed to cattle or when feed that is not consumed by cattle is scraped up, that feed needs to taken to farther fields and distributed using a manure spreader. The key is to reduce the chance of drawing deer toward cattle areas. Feed storage and feeding areas need to be kept clean of spilled or wasted feed to reduce opportunities for deer to eat it.
Lastly, it is important to remove deer that come to the farm. Deer that become habituated to farm feed, even when practices to exclude them are implemented, need to be killed. Contact the Michigan Department of Natural Resources for permits to remove deer out-of-season. The risks of disease transmission from infected deer to cattle are too great to tolerate any deer near cattle or feed.
Deer will eat feed that is intended for cattle as long as they can. Keeping them from it is the best way to break the cycle of TB that continues to plague Michigan after almost 20 years. We encourage farmers to develop their eye for the risk of deer getting to the feed for their cattle, and take the steps needed to protect their herd. Talk with the Alpena County Conservation District to learn more about funding opportunities for feed protection or about the enhanced wildlife risk assessment. Cattle producers need to be the chief protectors of their herds.