With lots of diets in the South West solely reliant on grass silage as a winter forage the correct selection of starch sources to balance the grass silage is paramount.
FeedCo are constantly carrying out research and analysis to understand the efficiency of energy usage, and whether starch is fermented in the rumen or passes through to be digested in the small intestine. Understanding this starch digestion rate is key to rumen function to drive performance, avoiding acidosis or starch passing through to the dung. Lab testing is used to determine the rate of the starch we are dealing with, research showing this combined with diet starch content and particle size being key balancing factors.
Dairy farmers Neil and Kath Baldwin, of Bourne Park Farm, have been working alongside FeedCo Nutritionist Matt Norman, to maximise starch intake whilst avoiding ruminal acidosis. The preferred starch source for this has been grain maize as well as wheat and barley. Since the diet changes yields have risen 3 litres per cow per day and rising steadily with impressive butterfats and proteins of 4.45% and 3.45% respectively.
The diet is currently 6kg of blend consisting of ground Maize, Sugarbeet, Wheat, Soya, Barley, Molasses, rumen protected fat, Rapemeal and Minerals and Vitamins alongside good clamp and baled silage. Out of parlour feeders provide a top up feed of Megastarch Gold 18 compound, with increased sources of maize in the diet Neil and Cath have seen increased body condition on cows leading to increased fertility rates.
Dry cows were also an area whereby improvements needed to be made and Matt Norman has made a specific transition blend with dry cow minerals and increased sources of DUP, mixed with straw and grass silage. This has led to a reduction in retained cleansings and cows entering the herd with increased milk yields.
Maximising starch within the diet has shown increases in both milk yield and milk protein. This is because increasing ruminal starch digestion improves microbial protein synthesis – the best source of protein for the cow. To maximise starch in the overall ration where maize silage is not an option, the feeding of maize grain which is slower digested within the rumen is a popular option to combine with cereals. Due to the slower rate of ruminal maize digestion more passes through to the small intestine and is then digested straight into glucose which is more readily available for the cow to use.
Starch is a great nutrient for dairy cows, but needs good understanding to get the best from it. Knowledge of the digestion dynamics of different starch sources, and how to balance these will get the best from dairy rations this winter.
