Dry matter digestibility key to finisher success

Beef finishers using concentrates should test silage for dry matter digestibility (DMD) to ensure optimal supplementary feed rates.

Mark McGee, senior researcher at Ireland’s agriculture and food development authority Teagasc, said  even high-quality grass silage is incapable of sustaining adequate growth rates to exploit the growth potential in most cattle, so some supplementation is needed.

“Low DMD forage means higher levels of concentrate supplementation have to be used to achieve the same performance,” he added at a Tegasc open day titled The Business of Cattle.

And every 1% decline in DMD would require an extra 0.33kg concentrate/day to sustain performance in finishing cattle, explained Dr McGee.

Research at Grange showed finishing steers (600kg) achieving 1kg daily liveweight gain, required up to 4-5kg concentrate/day when grass silage DMD was 75%, but this increased to 7-8kg/day when silage DMD fell to 65%.

See also: Why not take our Spring Turnout Management Academy and earn valuable CPD points?

The optimal level of concentrate supplementation depends mainly on animal production response (kg gain/kg concentrate fed), quality/amount of forage being substituted and the relative prices paid at slaughter and for the feed.

Concentrate ingredients

Studies at Grange also showed that ration energy levels, and to a lesser extent protein content were more important than the actual ingredients used.

Cattle had similar carcass weight gains and feed conversion efficiency when either rolled barley or wheat were offered in the rations.

Teagasc’s nutritionist Siobhan Kavanagh said despite farmers paying a premium for wheat, it actually has the same energy value as barley, while maize came out top – 5% higher than barley.

She also advised farmers to check the label ingredients carefully and not go for the cheapest option.

“Good energy ingredients should be at the top of the list (highest inclusion rate). Low energy rations tend to be overpriced, whereas a decent quality ration isn’t much more.”