Myth of High Forage Diets
How much forage should one feed their herd? it seems like everyone is recommending a high forage diet but is that the right thing to do?
Let us look at some diets and the challenges and opportunities of each diet:
Diet 1: High forage, high corn silage
This is a high forage (70%) diet that has high amount of corn silage.
This diet fits the criteria of a high forage diet.
Milk production is estimated to be around 43 kg but there are some concerns.
Starch levels at 30.6% and peNDF at 19.2%, it seems like this diet has insufficient amount of fibre and too much starch to maintain a health rumen pH.
The diet could probably be adjusted with a little more haylage, hay or straw.
High moisture shell corn can also be replaced with dry ground corn.
Diet 2: High forage, high haylage
Haylage is increased for this diet.
One low quality haylage and one high quality haylage is utilised.
This diet can be frustrating to nutritionists who are strapped with high forage and high performance requirement.
NDF levels at 32.8% will restrict intake.
Starch levels at 19.3% without another source of fermentable carbs will limit production.
Rumen will likely be healthy but the cows may lose body condition score (BCS).
Maintaining DMI of 25kg is not realistic.
Predicted milk production of around 38kg is optimistic.
Forage levels will need to drop in this scenario to improve production.
Diet 3: High forage with reasonable expectations
Instead of forcing high forage %, many farms are looking for diet that has more forage as compared to 20 years ago.
Generally, most producers are most concern about the cow's health.
This diet has a modestly high level of forage (65%), 63% corn silage and milk production is predicted to be around 43 kg.
peNDF is at 21.7%. peNDF is a better measurement of effective fibre than forage percentage.
Although forage levels are lower than Diet 1, this is a much safer diet. It supports high milk production and keep cows healthy.
Diet 4: Mid forage, healthy cows
This diet is not better or worse as compared to Diet 3.
It has 55% forage with 54% corn silage. peNDF is at 21.7%.
This diet supports another kg of milk compared to Diet 3 in theory.
A more important thing to note is that both these diet will keep the cows healthy.
Economics rather than forage level
Rather than having a set of number of forage % in the diet, a more important question to ask is what are the criteria that will support milk production and healthy cows.
Effective fibre, particle length, consistency of diet and sortability are all important factors to be considered.
Forage % is far too vague to have a real meaning in dairy rations.
Sometimes, it is crucial to think long term and run some hypothetical diets in order to decide what is best for the future of your farm.
Get past the idea that "high forage" is a requirement.
Ensure there is a consistent ration that will keep the rumen healthy, keep the cows healthy and increases profitability for your farm.