Volume 44 Number 3 Fall 1997

Role of Fiber in Litter-Based Diets

Darrell Rankins, Jr, Jerry Van Dyke, Eddy Peacock, and Brian Gamble

REPLACEMENT BEEF HEIFERS and stocker steers are often fed diets containing broiler litter. The diet usually consists of equal quantities of litter and an energy source, such as corn or hominy feed. In a previous Highlights report (Spring 1996), the importance of feeding hay with this mixture was reported. However, many questions have been raised regarding the quantity and quality of the fiber source that should be offered in addition to the litter-grain mix.

Two studies were conducted to provide answers to these questions. Study 1 was conducted at the Sand Mountain Substation in Crossville. Forty-eight Angus x Charolais steers (average weight of 440 pounds) were placed in pens with four steers per pen. Steers were then fed one of four diets over a 112-day period. The diets were as follows: (1) 50% broiler litter and 50% cracked corn, (2) diet 1 plus daily hay at three pounds per steer, (3) diet 1 plus hay fed on Mondays and Thursdays to equal the amount fed in diet 2, and (4) diet 1 plus free-choice hay. The hay was primarily orchardgrass (80%) and some endophyte-free tall fescue (20%) and would be classified as high-quality hay (12% crude protein and 55% neutral detergent fiber). The broiler litter had been deep-stacked and covered prior to feeding. In addition, all diets contained Bovatec™, which is a feed additive used to enhance feed efficiency and, in this case, was used as a bloat preventative.

Study 2 was conducted at the Wiregrass Substation in Headland. Fifty predominantly Brangus steers (average weight 597 pounds) were placed in pens with five steers per pen and fed for 112 days. The diets were as follows: (1) 50% broiler litter and 50% cracked corn; (2) diet 1 plus daily hay at 3.2 pounds per steer; (3) 45% broiler litter, 45% cracked corn and 10% peanut hulls; (4) diet 1 plus free-choice hay; and (5) diet 1 plus free-choice peanut hulls. The hay was primarily bermudagrass and would be classified as medium- to high-quality (12% crude protein and 60% neutral detergent fiber). The peanut hulls would be classified as a low-quality fiber source. As in study 1, the litter was deep-stacked and covered and all diets contained Bovatec.

In study 1, the fastest and most efficient gains were observed in the cattle being fed hay on a daily basis or free-choice (Table 1). The slowest gains were observed for the cattle receiving no hay. In general, the increased weight gains were a result of increased intake, presumably stimulated by the additional fiber. If one simply considers feed costs, the most cost effective gains were produced using the hay on a freechoice basis. The most expensive gains were those using no hay or feeding the hay twice weekly. The following prices were used to calculate these figures: corn, $110 per ton; broiler litter, $20 per ton; hay, $60 per ton; and Bovatec, $5 per pound.

In study 2, the best daily gains were by the steers supplemented with hay; however, the most economical gains were by the steers fed free-choice peanut hulls (Table 2). The same prices were used to calculate cost of gain as were used in the first study. In addition, peanut hulls were free. If the peanut hulls were to be purchased, the price that could be paid based on these data (i.e., comparing free-choice hay to free-choice hulls) is $27.23 per ton and be equivalent to the hay results at $60/ton.

A point to note in each of these studies is that the daily gains were quite good. Most producers should expect daily gains of about 2 to 2.25 pounds per day. The reason for these differences is that, after cattle are received, they are held for about three weeks prior to beginning the study so they have time to adapt before initial weight. If daily gains were calculated as pay-weight to pay-weight, they would be about 2 to 2.25 pounds per day.

Average daily gains were similar for both studies; however, the lighter weight cattle used in the Sand Mountain study were more efficient than the heavier cattle used for the Wiregrass study. This would be true for most situations involving 150-pound weight differences. When using a high-quality hay, gains were increased by 0.2 to 0.3 pounds per day when the hay was offered free-choice versus a limit feeding. It is important to note that in these studies the free-choice hay was fed as square bales in a concrete feed bunk. As this information is applied to a field situation, one would assume that most hay would be offered freechoice in the form of a round bale, which would result in a considerable amount of the hay being wasted and would therefore increase the cost of this strategy. When comparing the high-quality roughage (hay) to the low-quality roughage (peanut hulls), daily gains were lower when the hulls were used, but as mentioned previously, the peanut hulls would be worth $27 per ton if hay is worth $60 per ton. As the price of hay increases, the value of the peanut hulls would also increase.

Based on these results, the most economical gains will be produced by offering the roughage in a free-choice manner. A low-quality source of fiber may be used if the cost of that fiber source is low enough. Low-quality, in this case, refers to the amount of digestible nutrients in the fiber source. If the roughage is moldy or unpalatable, this would not necessarily be true.

Rankins and Van Dyke are Associate Professors of Animal and Dairy Sciences; Peacock is Herd Supervisor at the Sand Mountain Substation; and Gamble is Associate Superintendent at the Wiregrass Substation.

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