19 September 1997

DM INTAKES CRUCIAL IN FEEDING TO NEED

By Jessica Buss

INTRODUCE your winter diet as quickly as needed when grass quality and availability decline or if weather worsens and grass intakes suffer.

According to Axient (formerly Genus Consultancy) nutritionist Andrew Marlow, the key to feeding cows successfully is maximising dry matter intakes, while working to achieve the correct energy and protein balance. "Cows not receiving a diet that satisfies their needs will suffer depressions in milk yield, quality and fertility."

In a wet autumn spell yields can fall suddenly and cows must not go hungry. But care is needed when introducing new ingredients, he adds. For example, when aiming to include 2-3kg of rolled wheat in the ration when cows have not, up to then, received a wheat based concentrate, increase the levels over about a week.

"The danger is that in high milk price months, when straights are cheap, buffer feeding starts, but it can continue at the expense of good grassland management. When formulating a ration do not forget the potential of grass.

"Having some grass in the diet adds variety and extended grazing, providing conditions are right, can increase milk yields because cows eat a little more – giving them extra energy. But avoid leaving cows out all day to poach ground."

Later in the season when maize becomes available it can be used to replace grass at up to 50:50 in the ration without gradual introduction. Digestion of maize grain can be poor initially but maize stimulates intakes. However, ensure its low protein level is balanced in the concentrate fed.

Concentrates used must include a range that will maintain a stable rumen environment while considering the relative cost of each straight.

High yielding cows giving 10,000 litres are generally fed high levels of concentrates, but good management and quality forages are just as important. There is no need for specialist concentrates provided the diet energy density is kept high enough, advises Mr Marlow.

It is also difficult for high yielders to milk efficiently on grass silage as their only winter forage. Mixed forage diets or feeding brewers grains will help increase intakes and reduce the acidity and variability of the ration. An extra 1kg of forage intake is worth two litres of milk, adds Mr Marlow.

There is less room for error with high yielders, he warns. Every mouthful must be high in energy, ideally 12.5 ME or above. But it is still all about intakes.

Producers keen to combat lower milk prices by increasing output can justify using cheaper feeds to make a small margin, but should not forget the cost of quota. "If you justify the quota cost now, you should reconsider plans to produce that milk," he says.n

MANAGING DAIRY DIETS

&#8226 Maximise dry matter intakes.

&#8226 Balance energy and protein.

&#8226 Introduce new feeds gradually.