Many factors play a part in achieving target yields and a healthy cow, therefore, managing a healthy rumen is key to this, largely because of the nutrients it produces. Approximately 70% of cows energy requirements and 80% of cows protein requirements can be met by the nutrients that rumen bacteria produce. As efficient as this can be, there is still a requirement for nutrients that by-pass the rumen, this can affect performance but it can also be influenced by the season.
Firstly, how can we determine when more by-pass protein is needed?
A cows requirement for by-pass protein increases as her milk yield increases, this is because the rumen has a limit of how much microbial protein it can produce. Generally, this can be seen in early lactation cows failing to achieve the expected peak yield.
To achieve this level of by-pass protein, we can fall into feeding a high level of overall crude protein (both rumen available and by-pass protein) which can be expensive, detrimental to the environment and may encourage a loss of body condition in early lactation cows. So to avoid this, feeding lower levels of rumen degradable protein and therefore overall crude protein but feeding a higher percentage of by-pass protein can help achieve higher milk yields whilst not experiencing some of the detrimental effects of feeding too higher crude protein.
This is very much the case when grazing cows, a cows rumen protein is easily met with fresh grass (depending on grass intakes of course) but by-pass protein is often still needed to meet performance requirements.
What about by-pass energy?
In a similar scenario to protein, there is a requirement for rumen energy in the form of carbohydrates which is used by rumen bacteria. However, if we over feed carbohydrates, ruminal acidosis becomes a risk and this can limit the amount of rumen energy we can supply. This can limit both animal performance and health since energy is often the first limiting factor to production.
Therefore by protecting carbohydrates so they by-pass the rumen and get utilised in the hind gut, cows can consume the energy they need without putting added pressure on rumen health.
So what can we do about it?
To achieve a higher by-pass protein level, soya bean meal is the common ingredient used. Whilst this is an excellent form of both rumen and rumen by-pass protein, soya is expensive and its use is often questioned by retailers due to its sustainability and environmental impact. Therefore protected rapeseed meal such as UltraPro R can be used which at approximately 70% by-pass exceeds soya’s 40% level. This can be a viable alternative to both soya bean meal but also regular rumen degradable protein sources.
From an energy perspective, maize grain can be fed as an alternative to wheat and barley as maize contains more by-pass starch and is, therefore, healthier to the rumen. However, maize grain has variable availability and can be expensive which highlights a protected wheat such as Ultra Starch W as a viable alternative. Ultra Starch W supplies 30% more starch to the hind gut than regular wheat, which enables more digestible energy to be utilised by the cow whilst reducing the pressure on rumen health.
For information on the range of protected proteins available in dairy rations contact your local NWF Sales Specialist or call 0800 756 2787.
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