When it comes to nutritional management of growing and finishing cattle, the scientific aspects tend to get the most attention. Hours are spent getting the formulations right and debating the merits of different ingredients and additives.
In truth, feeding cattle successfully is as much art and judgment as science. Judgment is required to balance between over- and under-feeding. Under-feeding limits performance and possibly Quality Grade. Feeding too much increases feed waste and more importantly can trigger acidosis, poor performance, and increased death loss.
Tracking Feed Bunk Scores
An SDSU research study conducted by Bierman and Pritchard (1996) compared cattle fed all they would eat to those fed just enough so that all the feed was consumed in a 24 h period. They observed that the steers fed with the slick bunk strategy had similar ADG but improved feed efficiency compared to the steers fed to appetite. There was also more variation in ADG among the steers fed all they would eat, suggesting that some of the steers may have experienced subclinical acidosis from over-consumption.
A successful slick bunk feeding program matches dry matter intake (DMI) to the cattle’s appetite as closely as possible and keeps DMI consistent from day-to-day. To do so requires that managers know how much feed has been delivered previously and a way to track how the cattle respond. Dr. Robbi Pritchard at SDSU developed a widely-adopted scoring system to help cattle feeders monitor eating behavior for a particular pen (Table 1). A record of bunk scores and feed deliveries will help identify pens that are right on track, those that should be offered more feed, and those that should be fed less. Over a period of 7 to 10 days, seeing bunk score of 1/2 two or three days with scores of zero for the balance of the period would indicate a good balance between high intake to support performance with minimal DMI variation.
Some guidelines for managing feed deliveries include:
Feed calls should be made at the same time every day.
Feed should be delivered at the same time every day, ideally within a 15-minute window.
Do not increase feed offered by more than ¾ pound of dry matter.
In adapted cattle, feed should not be increased more frequently than every third day.
Remove stale feed; watch for sorting
Cattle behavior and aggressiveness in coming to the feed bunk can tell a great deal about whether or not feed deliveries should be increased.
The Iowa Beef Center at Iowa State University has recently released an updated Feed Bunk Management factsheet that covers this subject in much greater detail, including pictures showing examples of different bunk scores.