Field Crops 28.31-11
Brown Midrib Corn
Joe Lauer and Jim Coors
Corn Agronomist and Corn Breeder
Currently there is much interest in the dairy industry about brown midrib corn.
Brown midrib corn was first discovered in dent corn at St. Paul, MN in 1924. It
was thought to occur as a natural mutation of regular dent corn. Since its initial
discovery a total of four brown midrib mutants have been identified:
- bm1 (Jorgenson, 1931)
- bm2 (Burnham and Brink, 1932)
- bm3 (Emerson et al., 1935)
- bm4 (Burnham, 1947)
Brown midrib corn plants exhibit a reddish-brown pigmentation of the leaf midrib
at V4 to V6. The pigmentation is also seen in rind and pith. Coloring eventually
disappears on leaves, but remains in the stalk. The brown midrib phenomenon is also
found in sorghum, sudangrass, and pearl millet.
About 40 years after the initial discovery, bmr mutations were found to have a drastic
effect on lignin (Lechtenberg et al., 1972) and that digestibility of corn silage
was improved in ruminants. Below are the initial studies involved with various ruminants:
- sheep (Muller et al., 1972)
- goats (Gallais et al., 1980)
- heifer cattle (Colenbrander et al., 1972, 1973, 1975)
- beef cattle (Keith, 1981)
- dairy cows (Frenchick et al., 1976)
A total of 18 agronomic and dairy cattle feeding trials comparing brown midrib corn
and regular dent corn were summarized (Fig. 1). Usually either yield or quality
results were published, rarely both. In these studies, brown midrib corn produced
on average 6% less yield than regular dent corn. Fiber as measured by ADF and NDF
was 3 and 2% lower for brown midrib than regular dent corn. Using MILK91 (Undersander
et al., 1993), milk per ton and milk per acre were calculated and brown midrib corn
increased milk per ton 4%, but decreased milk per acre 2%.
In the U.S. results of feeding bmr corn are either inconclusive or trended slightly
in favor. A significant increase in milk production was observed only once (Keith
et al., 1979). Increased body weight was noted every time bmr was fed. Energy intake
was not limiting in these studies and it seems that extra nutrients digested in
bmr corn are partitioned into meat or fat body tissues rather than milk. Feeding
results from England (Weller and Phipps, 1986) and France (Hoden et al., 1985) indicate
increased milk production.
Some things to think about as you consider using brown midrib corn as a corn silage
in your dairy operation. Advantages include:
- Increased silage intake
- Increased digestibility of stover
- Lower yields: Whole plant silage and Grain
- Susceptibility to lodging
- Poor early season vigor
- Delayed flowering
- Slower early season growth rates
Barriere, Y. and O. Argillier. 1993. Brown-midrib genes of maize: a review. Agronomie
Barriere, Y., O. Argillier, B. Chabbert. M.T. Tollier, and B. Monties. 1994. Breeding
silage maize with brown-midrib genes. Feeding values and biochemical characteristics.
Block, E., L.D. Muller, and L.H. Kilmer. 1982. Brown midrib-3 versus normal corn
plants (Zea mays L.) harvested as whole plant or stover and frozen fresh or preserved
as silage for sheep. Can. J. Animal Sci. 62:487-498.
Burnham, C.R. 1947. Maize Genet Coop News 21:36.
Burnham, C.R., and R.A. Brink. 1932. Linkage relations of a second brown midrib
gene (bm2) in maize. J. Am. Soc. Agron. 24:960-963.
Cherney, J.H., D.J.R. Cherney, D.E. Akin, and J.D. Axtell. 1991. Potential of brown-midrib,
low-lignin mutants for improving forage quality. Advances in Agronomy 46:157-198.
Colenbrander, V.L., L.F. Lechtenberg, L.F. Bauman, L.D. Muller, and C.L. Rhykerd.
1972. Nutritive value of brown midrib corn silage. J. Animal Sci. 35:1113.
Colenbrander, V.L., L.F. Lechtenberg, and L.F. Bauman. 1973. Digestibility and feeding
value of brown midrib corn stover silage. J. Animal Sci. 37:294-295.
Colenbrander, V.L., L.F. Lechtenberg, and L.F. Bauman. 1975. Feeding value of low
lignin corn silage. J. Animal Sci. 41:332-333.
Emerson, R.A. et al. 1935. Cornell Univ. Agric. Exp. Stn. Memoir 180.
Frenchick, G.E., D.G. Johnson, J.M. Murphy, and D.E. Otterby. 1976. Brown midrib
corn silage in dairy cattle rations. J. Dairy Sci. 59:2126-2129.
Gallais, A., L. Huguet, H. Berthet, G. Bertin, B. Broqua, A. Mourguet, and R. Traineau.
1980. Preliminary evaluation of brown midrib maize hybrids for their feeding and
agronomic value in France. In W.G. Pollmer and R.H. Phipps (eds.) Improvement of
quality traits of maize for grain and silage use pp. 319-339.
Gentinetta, E., M. Bertolini, I. Rossi, C. Lorenzoni, and M. Motto. 1990. Effect
of brown midrib-3 mutant on forage quality and yield in maize. J. Genet. and Breed.
Hoden, A., Y. Barriere, A. Gallais, L. Huguet, M. Journet, and A. Mourguet. 1985.
Le mais brown midrib plante entiere. 3. Utilisation sous forme d’ensilage par les
vaches laitieres. Bull. Tech. CRZV Theix INRA 60:43-58.
Jorgenson, L.R. 1931. Brown midrib in maize and its lignage relations. J. Am. Soc.
Keith, E.A., V.F. Colenbrander, V.L. Lechtenberg, and L.F. Bauman. 1979. Nutritional
value of brown midrib corn silage for lactating dairy cows. J. Dairy Sci. 62:788-7
Keith, E.A., V.F. Colenbrander, T.W. Perry, and L.F. Bauman. 1981. Performance of
feedlot cattle fed brown midrib-three or normal corn silage with various levels
of additional corn grain. J. Animal Sci. 52:8-13.
Lechtenberg, V.L., L.D. Muller, L.F. Bauman, C.L. Rhykerd, and R.F. Barnes. 1972.
Laboratory and in vitro evaluation of inbred and F2 populations of brown midrib
mutants of Zea mays L. Agron. J. 64:657-660.
Muller, L.D., V.L. Lechtenberg, L.F. Bauman, R.F. Barnes, and C.L. Rhykerd. 1972.
In vivo evaluation of a brown midrib mutant of Zea mays. J. Animal Sci. 35:883-889.
Rook, J.A., L.D. Muller, and D.B. Shank. 1977. Intake and digestibility of brown-midrib
corn silage by lactating dairy cows. J. Dairy Sci. 60:1894-1904.
Undersander, D.J., W.T. Howard, R.D. Shaver. 1993. Milk per acre spreadsheet for
combining yield and quality into a single term J. Prod. Agric. 6:231-235.
Weller, R.F., and R.H. Phipps. 1986. The feeding value of normal and brown midrib-3
maize silage. J. Agric. Sci., Camb. 106:31-35.
Weller, R.F., R.H. Phipps, and A. Cooper. 1985. The effect of the brown midrib-3
gene on the maturity and yield of forage maize. Grass and Forage Sci. 40:335-339.
Weller, R.F., R.H. Phipps, and E.S. Griffith. 1984. The nutritive value of normal
and brown midrib-3 maize. J. Agric. Sci., Camb. 103:223-227.