Brian J. Rude, Darrell L. Rankins, Jr., and Rob W. Peacock

Stocker steers and replacement beef heifers frequently are raised on broiler litter-based diets that typically contain equal feed, or other grain. The use of supplementary roughage, such as hay, with this type of diet is recommended but not well understood. In addition, adding a source of readily soluble carbohydrate, such as molasses, appears to help beef animals better utilize the abundant amounts of nonprotein nitrogen in the broiler litter.

An AAES study conducted at the E.V. Smith Research Center in Shorter focused on the addition of molasses and/or hay to broiler litter-based diets. Sixteen steers (average weight of 660 pounds) were housed in individual pens and fed one of four diets for 84 days. The diets included: (1) 50% broiler litter and 50% cracked corn; (2) the broiler litter and corn mix supplemented with 3.5 pounds of hay per day; (3) 45% broiler litter, 35% cracked corn, and 20% molasses; and (4) the broiler litter, molasses, and corn mix supplemented with 3.5 pounds of hay per day. The broiler litter had been deep-stacked and covered prior to feeding. The hay used to supplement diets 2 and 4 was medium quality (10% crude protein, 77% neutral detergent fiber) bermudagrass. All diets contained Bovatec, which is a feed additive used to enhance feed efficiency and, in this case, used as a bloat preventative. A digestibility trial was conducted during the last 10 days of the feeding trial.

The diets were fed ad libitum with the exception of the hay, which was explained previously. Addition of molasses did not effect average daily gain, feed intake, or digestibility. It is surprising that the addition of molasses did not increase intake because broiler litter-based diets are quite dusty and the molasses can make them more palatable; however, no differences were observed.

Conversely, hay supplementation had dramatic effects on cattle performance (see the table). Total daily intakes were not different among hay supplemented and nonsupplemented steers. However, steers supplemented with hay gained 1.7 pounds per day, about twice as fast as those consuming the broiler litter mixes without hay supplementation, which gained 0.86 pounds per day. Steers consuming the amount of energy found in these broiler litter dietsshould gain approximately 1.6 pounds per day. Gains for steers supplemented with hay were similar to what would be expected; however, gains were markedly depressed in the steers consuming broiler-litter only diets, following the same pattern as seen for daily gains.

To evaluate why these gains and feed efficiencies were dramatically different, digestibilities were determined for these steers. However, no differences in diet digestibility were found. Likewise, ruminal volatile fatty acids and ruminal ammonia, which are indicators of the ruminal function and efficiency of diet utilization, were not different between steers supplemented with hay and those not supplemented. So the suppressed performance of steers not receiving hay can not be explained by a decrease in ruminal digestion of these diets.

Even though broiler litter contains appreciable amounts of fiber, such as wood shavings or peanut hulls, it is apparent from these results that additional sources of roughage are needed by cattle consuming litter-based diets. However, producers must be cautious about ad libitum access to supplemental hay because cattle may fill up on hay and not get enough litter and grain to produce sufficient gains.

It is possible that diets containing broiler litter alter rumen function and the addition of hay to these diets offsets this effect, but the precise mechanism is not known at the present time. This possible negative effect may be occurring immediately after food consumption, and was not noticed in the present study using ruminal volatile fatty acid and ammonia concentrations because ruminal fluid samples were collected after a 12-hour fast. It may also be possible that hay effects the efficiency of diet utilization after the rumen, primarily in the small intestine.

Further research is needed to fully explain the differences observed in this study. In addition, it is important to determine the amount and frequency of feeding supplemental hay that is necessary to alleviate the suppressed performance. However, the results do strongly suggest that producers using broiler litter as a feedstuff for growing beef cattle should supplement the diet with hay or have animals on pasture to obtain maximum utilization of the diet. Based on this study, level of hay supplementation would be 0.5% of body weight per day, but further work is needed in this area.

Rude is a Research Associate and Rankins is an Associate Professor of Animal and Dairy Sciences; Peacock is Herd Supervisor at the E.V. Smith Research Center Beef Unit.