Replacing a proportion of starch in beef finisher diets with a molasses-based liquid feed has been shown to be worth £6 per animal in addition margins.

The two key objectives in finisher diets are to optimise energy density through high starch content while also boosting dry matter intakes to optimise daily gain. According to Dr Phil Holder from molasses blend specialists ED and F Man, these objectives can conflict.

“While high starch content can increase energy density, these diets can increase the risk of rumen acidosis which in turn will reduce appetite and rumen efficiency. In addition, high cereal diets can be dry and dusty, compromising palatability and further depressing dry matter intakes.

“In dairy diets, replacing a proportion of starch with sugars has been proven to have a positive effect on rumen health and intake and performance. So the question was would similar benefits be seen in beef cattle.”

Dr Holder says an ED and F Man commissioned large scale trial at the University of Milan has now shown that a partial replacement of starch with sugars has a positive impact on rumen efficiency, animal growth rates and reduced health issues.

In the trial, 196 Charolais cross Limousin were placed on an intensive fattening regime and TMR fed for 186 days. Half were fed a typical diet containing 3.7% sugar and 41% starch on a dry matter basis. The other half were fed a higher sugar content of 8.0% with 1kg/day of a 65%DM, 40% sugar (as fed) liquid feed replacing some of the cereals. The starch content in this diet was 37%. The diets had identical energy and protein contents.

During the trial, average dry matter intakes, daily liveweight gain and feed conversion were recorded along with rumen pH and Dr Holder says the results show that beef producers would see benefits from increasing sugar content in finishing diets.

“Over the course of the trial, the animals fed the higher sugar diet gained at additional 12.5kg, gaining weight at 1.486kg/day compared to 1.419kg/day. Dry matter intakes were increased by 0.45kg/day and feed conversion was marginally increased.

“Notably, the effect of reducing starch intake was that rumen pH was less variable and there was significantly less time spent below pH5.8. This will have contributed to improved intakes.”

Dr Holder says that although daily feed costs on the enhanced diet were slightly higher at £2.46/day compared to £2.39, in part due to the increased intakes, there was an increased margin.

“If cattle were being marketed at the liveweight achieved by the control group, the animals fed the high sugar diet could have been sold eight days sooner, saving over £6 per animal in feed costs. To this can be added savings in bedding and the option to increase unit throughput.

“Alternatively, if cattle had been sold at the same age, the extra liveweight achieved from increasing sugar would have allowed an increased margin per animal after additional feed costs of £18.

“When these increased margins are applied across a whole unit, the additional margin achieved by feeding a more rumen friendly diet can be considerable.”