Latest Teagasc research examines the effect of partially replacing rolled barley with processed maize on the performance of finishing cattle offered a high concentrate diet.
In feed nutrition databases processed maize grain has a superior nutritive value compared to barley, and for this reason it is included in cattle rations to increase performance.
Anecdotal evidence suggests that including maize in concentrate rations increases the rate of fat deposition in cattle and thus achieves earlier ‘finish’. However, at research level the effects of replacing processed barley with processed maize are inconsistent in terms of cattle growth and carcass fatness.
The objectives of this 89-day finishing study were to examine the effects of partially replacing rolled barley with maize meal or flaked toasted maize (the two most common forms of maize available) on intake, growth and carcass characteristics of suckler-bred bulls offered a high concentrate diet.
Sixty autumn-born Limousin and Charolais bulls (mean initial weight 554kg) were used.
They were housed in pens in a slatted floor shed and gradually adapted to one of three concentrates offered ad libitum: 1) barley (B) (86.2% rolled barley, 6% soyabean meal); 2) maize meal (MM) (42.6% rolled barley, 42.6% maize meal, 7% soyabean meal); or, 3) flaked maize (FM) (42.6% rolled barley, 42.6% flaked maize, 7% soyabean meal), with grass silage to appetite. All concentrates contained 5% molasses, 2.8% minerals and were formulated to have similar levels of protein (PDI). Concentrate DM intake per day was 10.3kg, 9.4kg and 10.4kg for B, MM and FM, respectively.
Bulls offered MM had significantly heavier carcasses (420kg) than those offered B (406kg), with FM being intermediate (409kg). Carcass fat score tended to differ between the concentrate types, with bulls offered B fattest and those offered FM leanest.
Feed conversion ratio was poorest for B and greatest for MM, with FM being intermediate.
In summary, bulls offered concentrates containing MM (but not FM) had superior performance and feed efficiency compared to those offered concentrates based on rolled barley.
Including maize in the diet did not enhance carcass fat deposition.
By M. McGee, C. Lenehan, E. O’Riordan and A. Moloney, AGRIC, Teagasc, Grange.