Nutrition (models) for better cow health

Schothorst Feed Research (SFR) is a well-known independent advice and research organisation for animal nutrition, based in the Netherlands. The SFR experts have clients all over the world. Regarding dairy cow nutrition, SFR has an impressive track record of research programmes. Dairy Global caught up with Wilfried van Straalen, research coordinator and dairy cow consultant at SFR about the changing way we feed today’s high producing dairy cattle and what the key topics are in diet formulation.

With the E-dairy model the nutritionist get an advise on how to feed the high producing cow. And this also entails that the nutritionist can steer better on milk protein, milk fat or lactose. Photo: Herbert Wiggerman

Dairy Global (DG): Is improving milk production still the main focus for dairy nutritionists around the world?

Wilfried van Straalen (WS): “We see that producing more milk is, on average, still the main goal for many dairy producers around the world. But we also see that farmers and nutritionists are more aware of fertility, health and sustainability and the role of nutrition in this. An exception is maybe the longevity issue. This is for example a big theme in some Western European countries like the Netherlands, spurred by the phosphate regulation. This means that Dutch farmers had to limit the number of cows on the farm, hence leading to a smaller number of youngstock for replacement. But in Asian countries for example, we see that the need to extend the longevity of dairy cows is less of an issue. But overall we can say that the aims of dairy farmers around the globe are the same, but the way farming is done and how cows are fed is changing.”

DG: Can you give a few examples of the changes seen in dairy cow nutrition?

WS: “We see a number of things happening in the dairy industry which has a direct effect on the way we feed the cows. One of them is the increasing demand from dairy processors regarding some ethical/environmental issues. An example of this is the demand to use GMO-free feed ingredients. In Germany known under ‘VLOG’. The farmers that produce for these processors therefore have less feed ingredients to choose from. At the same time, other types of protein sources are being looked into, such as lupines or peas, and research is being done in how to make protein in these ingredients less degradable to use in dairy cow diets. The problem of these top down approaches, demanded by the processors, is that the nutritional value of the ingredients used is not the main concern. The GMO issue or the fact that the ingredients are sourced locally is often the main reason. The use of soy or palm kernel meal for example are two types of ingredients that are often used for cows and have a good nutritional profile. But we can question if these types of ingredients will still be used in European diets in the future, because the environmental impact is bigger than some of the locally grown crops. In the Netherlands we also see initiatives from the animal feed sector on calculating the environmental impact of feed ingredients, so that the farmer knows the impact of certain choices and remain in control over the choices he makes.”

Wilfried van Straalen: “At Schothorst Feed Research we have invested a lot of time and effort in the feeding values of different raw materials. This means we can make reliable predictions”. Photo: SFR

DG: Sounds like diet formulation for cows is getting more complicated. How can the E-dairy model help with this?

WS: “To make better choices on what to feed, we need good and reliable models. At SFR we have developed the E-dairy model that describes all the steps in rumen fermentation, intestinal digestion and fermentation and metabolism. Different types of nutrients (glucogenic, lipogenic and aminogenic) can be calculated with this model. The model can help in making rumen fermentation more efficient and in turn prevent the onset of certain metabolic disorders like rumen acidosis. The latter is of particular interest in transition cows. Cows producing up to 30 litres per day can rely on the normal rumen fermentation, but animals that produce more than the 30 litres per day have higher demands and should also be fed with specific quality of rumen-undegradable protein, starch and fat feed ingredients to reduce the risk for ketosis. For a good model you also need good data of the feed ingredients. At SFR we have invested a lot of time and effort in deriving the feeding values of different raw materials. This means we can make reliable predictions. We also have unique data included in the model, such as the effect of storage time of maize on the fermentation and rumen degradability of starch and the effect of different particle sizes from a certain feed ingredient. Another hot topic at this moment is the reduction of the relatively large contribution by ruminants to methane emission. Linked to the rumen fermentation the E-dairy model can be used to reduce methane production by changing the dietary composition. The model is internationally used. Some clients use all the elements from the model and some clients still use their own energy and protein value system and take the calculations for rumen optimisation from the E-dairy model for example.”

DG: Does this mean that the nutritionist can control the health of the cow better ?

WS: “Indeed. With the E-dairy model the nutritionist gets advise on how to feed the high producing cow. And this also means that the nutritionist can steer better on milk protein, milk fat or lactose. This is not so much to please the dairy processor or to get more money for high fat or protein contents of the milk (dairy processors still see milk as a bulk product), but the milk composition can give the farmer insights in the health and status of the cow. A high milk fat content after calving indicates the presence of chronic ketosis. A low level of milk fat during the whole life of a cow can mean that the cow suffers from rumen acidosis. Nutrition can thus be a great tool to minimise or prevent metabolic diseases in cows and we have now better tools to make the perfect diet. And considering that up to 25% of the dairy cows suffer from subclinical rumen acidosis, the need to prevent this costly condition is high on the agenda for researchers like us. Besides the E-dairy model, that we are constantly improving, SFR is also working together with Ghent University in Belgium to study the fatty acid pattern in milk and what this means for cow health. Next to this, the effect of rumen health on overall animal health remains a hot topic still, but we also see a global interest in other parts of the digestive system of the cow: acidosis of the hind gut for example. This disorder is linked with rumen acidosis, but we still don’t know a lot about it. The hind gut is more sensitive to acids and toxins than the rumen and the cow can become very sick from hind gut acidosis. We are doing research work to find ways to influence the whole digestive system through nutrition.”

DG: We see a trend of using more feed additives in cow nutrition. Do you think dairy cows can benefit from it?

WS: “We do see more use of feed additives in ruminant nutrition. A great deal of research has been dedicated to rumen undegradable amino acids. This is of interest because we tend to include less protein in the diet of high performing dairy cows. In addition, the use of high quality protein sources such as soybean meal is under discussion. The undegradable amino acids are included in the feed matrix and a nutritionist can then quickly see if the use of these supplements are also economically interesting or whether it is better to replace them with other protein feed ingredients or make the products less degradable through heat treatment for example. We also see a growing interest in the use of choline or vitamin (B) products in dairy cow diets. Especially B vitamins, which are good for high performing dairy cows as this supports the liver function. Regarding other feed additives that claim to increase immunity and reduce mastitis for example, it is a more complex issue. Antibiotics are mainly used in dry cows and decreasing its use is more linked with having a good farm management and hygiene protocol in place. In addition, prevention of diseases already starts with the calf, by making sure it gets enough colostrum and high quality solid feeds.”

DG: Will a typical dairy cow diet look the same ten years’ time?

WS: “I think we will see a few changes in the near future. We will have access to a larger pallet of feed ingredients. In some countries of the world, such as the Netherlands, we also see more focus on sourcing the feed material regionally instead of importing from far away. This will mean that Dutch dairy cows will have more grass and less corn in the diet. The quest for nutritionists is then to find the best compound feed to complement this new type of diet.At the same time, I hope that diet formulation in the coming years will be based more on digestible protein instead of crude protein. Most of the regulation and the models are still based on crude protein, because it can be measured easily and directly translated from the nitrogen total. The digestible protein levels are more complicated to measure and are based on calculations. Internationally we see a trend in using less GMO ingredients and the effect of dairy farming on the environment (greenhouse gas emissions), as mentioned before. This has a direct effect on the feed ingredients we use and are allowed to use in the future. We will also focus more on formulating diets for individual cows. This means that all cows get the same basal diet with roughage, but are supplemented separately with compound feed in a feed station. This is made easier through the use of sensors and other technology that gives insight in rumination and other parameters. Lastly, I see an increased interest in feeding calves and dry cows. Both of these groups are very important. A high producing dairy cow starts with a healthy calf. Still, some farmers don’t always realise that. With more attention to feeding calves at a young age, through the so-called metabolic programming – the chance that more milk is produced later in life is increased.”