Dairy farmers need to not only consider what their cows eat but how they process it, according to a visiting forage nutritionist.
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Animal nutritionist Dr Glenn Judson, from Agricom in New Zealand, told a series of DLF Seeds innovation field days at Leigh Creek that processing speed can be as important as quality when it comes to feeding cows.
“You can have forages that have a similar amount of fibre but it’s all about making it easier for cows to digest what they eat, and reducing the amount of ‘sawdust’ they eat and that they can’t digest,” Dr Judson said.
The field days included a display of DLF Seeds’ new products and innovations and presentations by Dr Judson about their impacts on animal production and health.
“It’s about understanding how our forages change in terms of quality as they move into their reproductive phase and start producing seed heads, and the difference between high and low-quality forage and the need to reduce the indigestible parts of feed — or woodchips or sawdust,” he said.
The presentations included a blender display to show the differences in digesting low and high-quality forage, and a field day participant emulating a cow to harvest different grass and herb pastures.
“The dairy cow has to harvest and process a huge amount of forage — about 120 kilograms a day depending on dry matter — for it to be highly productive,” Dr Judson said.
“Some of the things we do make it incredibly difficult for those animals to consume that amount.”
The presentations, which were held over three days for farmers and agronomists from different companies, started with a tent-based discussion about what constitutes high-quality forage, particularly the amount of non-digestible material largely labelled as acid detergent fibre (ADF).
“That is highly correlated to digestibility and therefore the energy value of their feed,” Dr Judson said.
“The more sawdust we’ve got there, the lower the quality, the lower the digestibility and the lower the energy we get out of it.
“We need to reduce the level of undigestible stuff and build protein and water-soluble carbohydrates and plant sugars.”
Another important aspect of the digestion process is the speed in which digestibility occurs.
The blender demonstration showed how forage herbs are very quickly processed while grass can sit around for longer periods in the rumen while being processed by animals.
This was further confirmed during a field demonstration when a participant tried to harvest different grasses and herbs, finding it easier to grab the herbs.
“That was done to demonstrate the point around the ability of animals to harvest out of the paddock,” Dr Judson said.
“The key message is around understanding how animals graze and how we can help them to reach the high intakes they require to be highly productive.”
Dr Judson said all forage products would flower at some stage and change in quality.
“The new innovations on display at the DLF field days are about shortening the period of time when those grasses, clovers or herbs have that poor quality material.
“We know they have to do it but the innovation is the later flowering, we’re not putting the seed head up early in the season.
“The term low ‘aftermath heading’ is around letting the plant produce a reproductive stem once for breeding but don’t continually throw up seed heads through the summer.
“We try to narrow the window in which our pasture plants have lower quality so animals have more time grazing good quality forages with less sawdust.”
Field day participants were told one product that could become increasingly important in Australia is Ecotain Environmental Plantain, because it lends itself to high intake, fast processing speed and holds up quality in the diet while serving an environmental functionality in reducing nitrate leaching from urine patches.
“It’s useful for agronomists to understand there are some forage tools that have been well researched in New Zealand that could be used for similar application in Australia,” Dr Judson said.
“We see the results of poor-quality feed at the vat every day. The dairy cow has the largest appetite and therefore we need to pay attention to what she eats.
“In terms of milk production, we need to be offering them as high-quality feed as we possibly can.”
Dr Judson said the same principles could apply across the Tasman.
“We have different systems and this shouldn’t be seen as a Kiwi coming over and saying you’re doing it all wrong,” he said.
“While the systems are similar, Australia has unique environments, for instance the summer heat and the patterns of growth can be quite different, but the same principles are universal and can be applied in the Australian context.
“Agronomists can deliver the information about how these forages can work in a way that is appropriate for Australian systems.”