Comparison of energy level, corn type, and corn processing for bison bulls in the feedlot during four seasons of the year

Bryan Miller and Vern Anderson
Double MM Bison Ranch
and
Carrington Research Extension Center-NDSU

Abstract
Yearling bison bulls (n=80) were randomly allotted to one of four feedlot pens in a Latin Square design experiment using 80 day feeding periods. The four diet treatments were differences in the concentrate portion of the diet. They were 1) pelleted wheat screenings ; 2) rolled conventional corn, 3) rolled waxy corn, and 4) whole waxy corn. Hay was offered free choice in each pen. No differences (P<.05) were observed for average daily gain, intake of concentrate per head per day, dry matter intake per head per day, dry matter intake in relation to body weight of bison, or feed per unit gain. Hay intake was greater (P<.05) for the screenings based diet than the two waxy corn treatments with conventional corn intermediate. Feeding periods were closely associated with summer, fall, winter and spring seasons. Differences were observed due to season (P<.05) for concentrate intake, hay intake, total dry matter intake, dry matter intake in grams per kilogram of bison body weight, average daily gain and feed per unit gain.

Introduction
The bison industry is experiencing tremendous growth in the Northern Plains. However, bison bulls in the feedlot are the segment of the bison industry of most concern due to seasonal variation in feed intake, limited gains, and marginal profits. Little research has been conducted on nutrition and feedlot management for bison. The National Bison Association has established quality control guidelines for bison finished on grain in order to develop a more consistent and palatable meat product. Many feeders are using the lowest cost feeds available , i.e. screenings, as a major ingredient in the feedlot ration (Anderson and Sexhus 1996; Anderson, 1995). Increased gains would be expected from increased energy density in the diet. The major energy source available is corn. The performance and economics from higher corn levels, type of corn and processing are not known.

Experimental Procedure
This study was conducted at the Double MM Bison Ranch at Carrington ND. Home raised and purchased bulls were fed in four pens using self feeders for the grain component and large round ring feeders for the hay. Twenty animals were randomly allotted to each pen by rotating assignment based on sequence through the chute. The Latin Square design study compared four rations during four 80 day feeding periods so each pen was exposed to each ration. The treatments were differences in the concentrate portion of the diet. Treatments were 1) 85% wheat screenings with 15% corn pelleted as a homogenous product(SCRN), 2) 75% rolled conventional corn with 25% pelleted screenings based supplement (CONV), 3) 75% rolled waxy corn with 25% pelleted screenings based supplement (RWXY) and 4) 75% whole waxy corn with 25% pelleted screenings based supplement (WWXY). The SCRN diet and pelleted supplement added to the other three diets were formulated to provide approximately equal amounts of molasses and minerals on a per head per day basis.
Animals remained in their respective pens and the rations were rotated randomly to different pens at the end of each period. The concentrate and hay portions of the diet were weighed when placed in the feeder. At the end of the period, remaining feed and hay was cleaned out and reweighed to calculate feed consumed.
Each animal was weighed individually at the start of the trial and at the end of each period. The trial started on June 21, 1995 and concluded on May 6, 1996. One animal was removed at the end of the first period due to health reasons, an apparent chronic respiratory problem. One animal in pen 3 exhibited significant hostile behavior towards humans, however that animal completed the study.
Feed consumed and animal performance were summarized by period for each pen. Statistical analysis was conducted using analysis of variance for main effects of diet treatment, season and pen. The 80 day feeding periods were closely associated with summer, fall, winter and spring respectively.
This project was supported by the North Dakota Agricultural Products Utilization Commission, North Dakota Waxy Corn Growers, and the North Dakota Buffalo Association.

Results and Discussion
Results by period are presented in table 2. Differences (P<.05) were observed between summer and fall vs winter and spring for dry matter intake per unit body weight expressed as grams per kilogram (29.12 and 27.42 vs 18.37 and 17.64). Average daily gains were greater (P<.05) during the summer and fall (1.85 and 1.95 lb) vs winter (.99 lb) with spring gains intermediate. Dry matter intake was reduced during the winter and spring enough to offset the reduced gains and render feed efficiency similar (P<.05) over all periods. This data agrees with reduce animal performance during the winter observed by Rutley and Church, (1995); Stanton et al.,(1996); and Anderson and Miller, (1995, 1996).
Performance data by ration treatment is presented in table 3. Gains increased numerically but not to a significant level (P<.05) with 75% corn in the diet. Hay dry matter was higher (P<.05) for SCRN than RWXY and WWXY with CONT intermediate. Stanton et al (1996) observed increased gains (P<.05) with increasing levels of corn in the diet using 30, 50, 70 and 90% corn in bison finishing diets.
Feed costs should be calculated on current market prices. As fed intake and feed costs per pound gain are reported in table 4. Prices assigned are theoretical but reflect relationships in price of the commodities used. Each producer will have to calculate his own feed costs based on local prices and feed intake of his animals.

Implications
The relative cost of feed in relation to animal performance remains the major issue in all feedlot enterprises. Improved gains do not always offset increased costs. The relatively low cost of a screenings based diet is not always taken to greatest advantage if pelleting costs and feed waste are significant.

References
Anderson, V. L. and Dennis Sexhus. 1996. Current practices and priorities of bison feeders in the Northern Plains. North Dakota State University, Carrington Research Extension Center Livestock Field Day Proceedings, Vol. 19:25

Anderson, V. L. and Bryan Miller. 1995a. Effects of season and diet, including costs on feedlot performance of bison. Prof. An. Sci. (in review).

Anderson, V. L. and Bryan Miller. 1995b. Influence of diet and season on feedlot performance of bison. North Dakota State University, Carrington Research Extension Center Livestock Field Day Proceedings. Vol. 18:15.

Rutley, Bruce, D. and John S. Church. 1995. Effect of time of year on average daily gain of feedlot finished bison (Bison bison). Peace Country Bison Association, Northern Lights College, Dawson Creek, B. C. Canada.

Stanton, T. L., D. Schutz, M Mc Farlane, R. Seedig, and D. Stewart. 1996. Concentrate level in bison finishing rations on feedyard performance. Prof. An. Sci. 12:6.


Table 1. Nutrient analysis of ingredients in rations for feedlot bison
                           Pelleted                        Pelleted
                             Wheat     Waxy Conventional  Screenings   Grass
                          Screenings   Corn    Corn       Supplement    Hay
                          ----------  -----   -----       ----------   -----
Dry Matter, %                89.83    86.04   85.35          90.82     90.10
Protein, %                   14.95    10.20   9.62           20.88     10.97
Acid Det. Fiber, %           14.59     2.85    3.39           8.78     50.98
Neutral Detergent Fiber, %   22.97    15.19   15.87          22.32     73.94
Calcium, %                     .76      .07     .18           2.89       .41
Phosphorous, %                 .37      .18     .17            .34       .13
Fat, %                        4.43     4.74    4.25           3.84      1.21
Calories/gram              4448      573    4597           4076      4419


Table 2. Bison bull performance in the feedlot during four different seasons of the year.
                                          Season of the Year
                               -------------------------------------
                               Summer    Fall    Winter   Spring  SE
                               ------   -----    ------   ------
Concentrate DM intake, lb       13.77   17.11     10.49    12.22
Hay DM intake, lb                5.95    5.62      6.90     6.14
Total DM intake, lb             19.71   22.72     17.40    18.36
DM intake, g/kg                 29.12   27.42     18.37    17.64
Average Daily Gain, lb           1.85    1.95       .99     1.33
Feed/gain                       10.80   11.99     18.71    14.05


Table 3. Performance of feedlot bison on two energy levels, two corn types and two processing methods.
                                         Ration Treatment

                            Pelleted     Rolled    Rolled   Whole
                              Wheat   Conventional  Waxy     Waxy    
                           Screenings     Corn      Corn     Corn    SE
                           ---------- ------------ ------   ------
Number of animals per pen       20        20        20       20
Starting weight, lb
Conc. DM intake, lb             13.01     13.02     13.58    13.98
Hay DM intake, lb                6.69      6.43      5.82     5.67
Total DM intake, lbs/hd/day     19.70     19.45     19.40    19.65
Average Daily gain, lbs/hd/day   1.35      1.63      1.68     1.46
Feed efficiency, gain/unit feed 16.46     12.21     11.87    15.03


Table 4. Economics of feeding bison bulls by ration treatment.
                                                  Ration Treatment

                                     Pelleted     Rolled    Rolled  Whole
                                       Wheat   Conventional  Waxy    Waxy    
                                    Screenings     Corn      Corn    Corn    
                                    ---------- ------------ ------  ------
Daily concentrate intake, lb as fed    14.44       14.44    15.07    15.52   
Daily hay intake, lb as fed             7.42        7.14     6.45     6.30
Feed cost per head per day              1.05        1.01     1.06     1.08
Feed cost per pound of gain              .77         .62      .63      .74
----------------------------------------------------------------------------                                        
Feed costs used for this example are:   hay - $40/ton; conventional corn - $3.00/bu; waxy corn - 
$3.10/bu, pelleted screenings diet - $120/ton; and pelleted supplement - $160/ton.   

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