Evaluationof a forage-fat blend as an isocaloric substitute for steam-flaked wheat in finishing diets for feedlot cattle: Growth performance and digestive function

Professional Animal Scientist, Sep 2002 by Plascencia, A, Zinn, R A

Abstract

Two trials were conducted to evaluate the addition of a forage-fat blend (FFB) as a substitute for grain in finishing diets for feedlot cattle. Treatments consisted of a steam-flaked wheat-based finishing dies containing 15, 29, or 45% FFB. The FFB contained 80% chopped alfalfa hay and 20% yellow grease and was formulated to have NE^sub m^ and NE^sub g^ values similar to that of wheat. In Trial 1, 126 crossbred steers (225 /- 5.4 kg) were used to

evaluate treatment effects on growth performance and dietary NE. In Trial 2, three Holstein steers (448 /- 21 kg) with cannulas in the rumen and proximal duodenum were used to evaluate treatment effects on characteristics of digestion. Increasing the FFB did not affect (P>0. 10) ADG, but decreased gain efficiency (linear effect, NO. 05) and dietary NE concentration (linear effect, NO. 01). Increasing the FFB did not affect

(P>0. 10) ruminal digestion of starch, N, or microbial N (MN) efficiency, but decreased (linear effect, P0.10) postruminal digestion of OM, starch, and N, but decreased postruminal digestion of fatty acids (linear effect, NO. 05). Increasing the FFB did not affect (P>0. 10) percentage of total tract starch, N, and ADF digestion, but decreased the percentage of total tract digestion of OM (linear effect, P15%, dietary NE and, hence, BW gain efficiency may decrease. The magnitude of the effect of FFB inclusion rate on energy recovery is a predictable function of the relationship between fatty acid intake and intestinal fatty acid digestion.

(Key Words: Feedlot Diets, Fat, Forage, Performance, Digestion.)

Introduction

The tabular NE^sub m^ and NE^sub g^ values of fat are 6.00 and 4.50 Mcal/kg, respectively (21). However, these values are considered valid only when the level of fat intake is low [

Results and Discussion

Implications

A FFB comprised of 80% alfalfa hay and 20% yellow grease can replace steam-flaked wheat at up to 45% of the DM in growing-finishing diets for feedlot cattle without affecting daily BW gain. However, at dietary inclusion rates >15%, dietary NE and, hence, feed efficiencies are decreased. The magnitude of the decrease in energy recovery is a predictable function of the relationship between fatty acid intake and intestinal fatty acid digestion. More work is needed to evaluate treatment effects on digestive function and growth performance when using a grass hay as the forage source in the FFB.

Literature Cited

1. AOAC. 1984. Official Methods of Analysis. (12th Ed.). Association of Official Analytical Chemists, Washington, DC.

2. Bartle, S. J., R. L. Preston, and M. R Miller. 1994. Dietary energy source and density: Effect of roughage source, roughage equivalent, tallow level , and steer type on feedlot performance and carcass characteristics. J. Anim. Sci.72:1943.

3. Bergen, W. G., D. B. Purcer, and J. H. Cline. 1969. Effect of ration on the nutritive quality of rumen microbial protein. J. Anim. Sci. 27:1497.

4. Brandt, R. T. 1992. Fat in diets for feedlot cattle. In Proc. Southwest Nutr. Manage.

Conf., Scottsdale, AZ. p 27. Dep. Anim. Sci., Univ. Arizona, Scottsdale, AZ.

5. Calderon-Cortes, J. F., and R. A. Zinn. 1996. Influence of dietary forage level and forage coarseness of grind on growth performance and digestive function in feedlot steers. J. Anim. Sci. 74:2310.

6. Colin, J., H. E. Kiesling, T. T. Ross, G. M. Southward, and J. F. Smith. 1993. Effect of gosypol on growing Holstein heifers. Proc. West. Sect. Am. Soc. Anim. Sci. 44:398.

7. Devendra, C. A., and D. Lewis. 1974. Interaction between dietary lipids and fiber in the sheep. Anim. Prod. 19:67.

8. Erwin, E. S., J. A. Dyer, and M. E. Sminger.1956. Effect of chlortetracycline, inedible fat, stilbestrol and high and low quality roughage on performance of yearling steers. J. Anim. Sci. 15:710.

9. Ferlay, A., J. Chabrot, Y. Elmeddah, and M. Doreau. 1993. Ruminal lipid balance and intestinal digestion by dairy cows fed calcium salts of rapeseed oil fatty acids or rapeseed oil. J. Anim. Sci. 71:2237.

10. Garton, G. A. 1967. The digestion and absorption of lipids in ruminant animals. World Rev. Nutr. Diet. 7:225.

11. Goering, H. K., and P. J. VanSoest. 19 70. Forage fiber analysis (apparatus, reagents, procedures, and some applications). Agric. Handbook No 379. ARS, USDA, Washington, DC.

12. Hale, W. H., and R. S. Swingle. 1984. Summary of whole cottonseed experiments with beef cattle at the University of Arizona. In Proc. 25th Annu. Arizona Cattle Feeders Day, Casa Grande, AZ. p 4. Dep. Anim. Sci., Univ. Arizona, Tucson, AZ.

13. Hicks, C. R. 1973. Fundamental Concepts in the Design of Experiments. Holt, Rinehart, and Winston, Inc.

14. Hill, F. N., and D. L. Anderson. 1958. Comparison of metabolizable energy and productive energy determinations with growing chicks. J. Nutr. 64:587.

15. Huerta-Leidenz, N. D., H. R. Cross, D. K. Lunt, L. S. Pelton, J. W. Savell, and S. B. Smith. 1991. Growth, carcass traits, and fatty acid profiles of adipose tissues from steers fed whole cottonseed. J. Anim. Sci. 69:3665.

16. Hussein, H. S., hI. R. Merchen, and G. C. Fahey, Jr. 1995. Effects of forage level and canola seed supplementation on site and extent of digestion of organic matter, carbohydrates, and energy by steers. J. Anim. Sci. 73:2458.

17. Johnson, R. R., and K. E. McClure. 1972. High fat rations for ruminants. 1. The addition of saturated and unsaturated fats to high roughage and concentrate rations. J. Anim. Sci. 34:501.

18. Krehbiel, C. R., R. A. Stock, D. H. Shain, C. J. Richards, G. A. Ham, R. A. McCoy, T. J. Klopfenstein, R. A. Britton, and R. P. Huffman. 1995. Effect of level and type of fat on subacute acidosis in cattle fed dry-rolled corn finishing diets. J. Anim. Sci. 73:2438.

19. Murillo, M., E. G. Alvarez, J. Cruz, H. Castro, J. F. Sanchez, M. S. Vazquez, and R. A. Zinn. 2000. Interaction of forage level and fibrolytic enzymes on digestive function in cattle. Proc. West Sect. Am. Soc. Anim. Sci. 51:324.