Farmers should focus on growing a TMR as a complete ration rather than making best use of ingredients that just happen to be available, says Simon Broddle, Forage Manager for Nickerson Direct.

Dairy farmers’ naturally want to optimise herd performance, but when it comes to TMR most are missing a trick. Rather than focusing on getting the best from the forages that they happen to produce, most would derive tremendous benefits from adopting a more holistic approach. Instead of just feeding a Total Mixed Ration, they should focus instead on growing a Total Mixed Ration. There’s a big difference!

Traditionally, farmers have tended to produce a mismatch of different forage products purchased from different suppliers which split into four categories: silage, grazed grass, maize and fodder crops. The result is often disjointed, with no real thread or logic hanging it together. Only after forages have been harvested and analysed do farmers normally sit down with their nutritionist and consider how to feed what’s available.

A better way is to work back from what you want to achieve in terms of herd performance, which will allow you to calculate your forage requirements. In turn, that enables you to develop a cropping plan to ensure that forages are complementary to one another, not antagonistic. ‘Antagonistic’ is where two forages contribute to the same dietary requirement, maize and high-quality grass being good examples. The opposite is where two silages offer high fibre with low ME, such as late-cut grass and wholecrop.

In the 60s and 70s very high quality grass silages were produced, at a time when nothing else was available. Now, most modern dairy units have access to high ME silages, but the problem is that these are often viewed in isolation. Farmers usually have all the ingredients analysed individually, but hardly ever the TMR. That’s staggering, because if, for example, you feed four different forages and three straights you’ve seven different analyses. Add to that the vagaries of ‘bucket chemistry’ in terms of approximating the weights/volumes that go into a TMR and there’s considerable scope for error.

Every farm is different, so it’s difficult to quantify precisely the potential performance and profitability gains from adopting a holistic approach to forage production, but undoubtedly most would benefit from a more joined-up approach. For example, many farmers harvest grass in early May because it’s traditional and they believe that good weather is the most important factor in making good silage. At that time they think only about harvesting that crop, but in fact that’s exactly when they should be considering what other forages they will be feeding it with. Of course the weather plays a huge part, but should it be the only factor? For example, re-growth is usually better quality than the earlier-cut material, although nitrogen levels can be high and transfer into the clamp, so caution is needed.

Cutting early produces high quality forages with high ME & D values, but the downside is that yields are lower and the cost-per-tonne is far higher. However, when fed with maize, this early-cut material can have negative connotations because both forages are similar in many respects, being high in ME and energy, with medium protein but relatively low in fibre. Consequently, having produced two high-quality individual ration components the farmer has to slow the diet down by adding straw. Why incur extra expense producing high-quality forages only to dilute the energy density of the diet with straw, when you could have left the grass growing for longer and benefited from higher yield and a lower cost per tonne?

When I see stacks of sodium bicarbonate on a farm it immediately signals problems in terms of low rumen pH, often caused by poorly-chopped (too short) silage and poor fibre, which lowers saliva production and leads to other health issues. It is a reactive way of dealing with a problem that shouldn’t be there in the first place. Planning a TMR as part of an overall forage strategy will reduce the need for ‘fire brigade’ tactics and allow pro-active herd management rather than being re-active.

Maize feeds well in almost any circumstances but using a higher-fibre grass, i.e. one which is cut slightly later, or perhaps an Italian ryegrass-based ley such as Green Circle, will improve intakes and ruminant function, as well as reducing the need for straw. Go one step further by using Lucerne and you will have what is probably the most synergistic base diet you could hope for under UK conditions.

Is wholecrop really ‘the poor man’s maize’? Certainly not in my view, and the biggest problem with it is usually not by the forage itself but that other forages fed with it create an antagonistic relationship. When using wholecrop, the animal will benefit from the inclusion of an early-cut perennial ryegrass rather than an Italian-ryegrass based product.

Drymatter is crucial in producing quality forage, but this is often overlooked. Twenty years ago, maize was harvested when it was well and truly dead, so it contained over 35% drymatter and was often used to ‘dry’ the diet. However, in modern cropping systems, especially where the latest stay-green hybrid maize varieties are grown, we cut at around 30%. Given that modern grass silages are often 30%+ and wholecrop 40%+, maize is frequently the wettest forage on the farm.

Feeding maize to cows in summer is useful to help combat the highly degradable protein and low drymatter of grazed grass. However, the drymatter of maize silage fed in summer can be lower because it increases the acidity, and stability, of the clamp in warm weather.