FUTURE performance and milking ability can be severely affected by expecting autumn calvers to rely on grass growth alone.

Instead, Jim Howie, of ED and F Man Liquid Products, advises adopting a more measured approach.

“It is important to ensure autumn calvers are well-prepared for the next lactation and this means not over-estimating the contribution from grazing,” he said, highlighting the period from four months pre-calving is crucial.

“They can struggle to meet these demands unless grazing supply is sufficient and is appropriately supplemented. In recent years, autumn calvers failed to milk to potential following calving and this can be put down to pushing too hard at grass in late lactation.

“The consequence of an over-reliance on grass was that they lost too much condition and this had knock-on effects on subsequent fertility. Another risk is varying grass availability and quality. If grass quality or quantity drops, cows that are being expected to do too much off grass will struggle,” said Mr Howie Instead, he said maximum production from mid and late lactation animals can be obtained by ensuring sufficient DMI from grazing and rumen efficiency, while also ensuring condition score, which can be improved by ensuring sufficient sugars in the diet.

According to Mr Howie, mid and late lactation cows need 5-6% sugars in the diet and while grazed grass can be high in sugar, many diets fail to supply sufficient quantities. It is likely that a typical grazing diet will only provide around 4% sugars.

It is also important to fill the sugar gap with the correct form of sugar.

Six carbon sugars such as sucrose and glucose, found in feeds such as sugar beet pulp, molasses and grazed grass, are proven to be more beneficial to cows than the five carbon sugars including xylose and ribose that are found in fermentation co-products, wheat syrup, processed feeds and silages.

“They are more highly rumen digestible and more effective at improving fibre digestion, increasing microbial protein production and stimulating rumen fungi. “Better fibre digestion means more use can be made of the available energy. This can be particularly important with poorer quality, later season forages, added Mr Howie.”