Milo stover and forage sorghum silages for growing heifers

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Introduction
Milo stover silage and dehydrated milo stover pellets were compared with forage sorghum silage in two previous heifer growing trials at this station (Prog. Rept. 210, Kan. Agr. Expt. Sta., 1974 andProg. Rept. 230, Kan. Aqr. Expt. Sta., 1975). Results showed: (1) milo stover had a feeding value of 63 to 67% that of forage sorghum, (2) cattle consumed 12 to 14% less milo stover silage than forage sorghum silage, and (3) growing calves fed milo stover silage as the major energy source should gain about 1.0 lb. per day and require about 10 to 14 lb. of dry matter per lb. of gain, less than acceptable performance for most cattle feeders.
Could milo stover provide only a part of the energy in growing rations? Our objective in this trial was to measure performances obtained with various percentages of milo stover and forage sorghum silages.

Experimental Procedure
Milo stover and forage sorghum (high-grain variety) each was obtained from a single source in October, 1974. The forage harvester was equipped with a two-inch recutter screen and both forages were ensiled in upright concrete stave silos (10 ft. x 50 ft.). Moisture content of the milo stover was about 65%; that of the forage sorghum, about 30%.
Compositions of the four experimental rations and their supplements are shown in table 18.1. All rations were formulated to be equal in crude protein (12.5%), minerals, vitamins and additives. Rations were mixed twice daily and fed free-choice, Initial and final weights of the heifers were taken after they went 15 hours without feed or water.

Results
Dry matter (%) and crude protein (% on a dry matter basis) for the milo stover were 33.6 and 4.25; for the forage sorghum silage, 29.8 and 7.1.
Heifer performances are shown in table 18.2. Heifers fed the 100% forage sorghum silage ration gained faster (P<.O5) and more efficiently (P<.05) than heifers fed any of the other three rations. Heifers receiving 100% milo stover silage had the slowest (P<.05) and least efficient (P<.05) gain. As forage sorghum increased and milo stover decreased in the ration, rate of gain increased and feed required per lb. of gain decreased. Dry matter consumption tended to increase as forage sorghum replaced milo stover.
Light-weight and heavy-weight calves had similar gains, but light-weight calves gained more efficiently (7.98 lbs. vs. 9.60 lbs. of feed per lb. of gain).
Estimated net energies for the two silages were calculated from gains and feed intakes obtained from the 100% milo stover and 100% forage sorghum silage rations. The estimates gave predicted daily gains for heifers fed the 67% and 33% milo stover rations to be 1.29 and 1.58 lbs., respectively, but actual daily gains were 1.50 and 1.66 lbs., respectively. These results suggest that milo stover silage may have greater value than expected when it is fed in combination with a higher-energy forage.