Striking the Balance Between Buffer Feed and Grass

Buffer feeding is usually a necessity at spring turnout so cows achieve adequate intakes when grass dry matter is low and grass growth is slow, but how do you get that all-important balance between grazed grass and buffer?

Gradually introducing grazed grass into the diet and allocating the right amount of a suitably balanced buffer feed is key to ensuring a smooth transition at spring turnout.

Opening the gates in the spring should have little effect on milk in the tank if ration balance requirements are met. Essentially, you’re trying to create the same type of overall ration as the winter diet, so yield at turnout should be unchanged.

To ensure a smooth transition, it’s worth thinking about the following:

1. Introduce grazed grass slowly

Slowly introduce grazed grass into the diet and avoid any rapid changes. In the winter, you’d never change from one silage clamp to another straight away. You need to give the rumen bugs time to adjust to the protein in grass, the change in dry matter and feed in general.

For high production cows or cows used to a TMR, you should start by grazing cows for 2-3 hours a day to begin with, gradually increasing time at grass over 1 week to 10 days. For block calvers going onto a full grass diet, providing dry haylage, wholecrop or maize is advisable (see point 2).

2. Think about energy

To make efficient use of higher crude protein levels in grazed grass (up to 30%), it’s important to provide enough energy in the diet.  Where rations are short of energy, milk proteins will drop which can take 2-3 months to recover.  To get around this, maize silage, wholecrop and/or straw can be added to the diet. Wholecrop and straw bring the added benefit of adding fibre to the diet which complements the low fibre levels in spring grass. This will help maintain milk constituents.

3. Provide the right protein

Grass is high in crude protein, but low in rumen bypass protein so it’s important to bridge this gap using a suitable protein source such as soya or protected rape. If this is not addressed, cows will produce milk, but can waste energy getting rid of extra protein. This is where body condition and milk proteins can be compromised.

4. Select the right parlour cake

Choose the right type of high energy, high fibre parlour cake at turnout to complement the high crude protein, lower dry matter and lower digestible fibre levels in grass. This will again help to maintain milk constituents.

5. Think about oil levels

With high input herds trying to make better use of grass, whilst still feeding partial mixed rations, take care to balance the oil level of the ration. Spring grass can have quite high oil levels which, when combined with a slightly acidic rumen, can lead to significantly depressed milk fat levels if biohydrogenation of oil occurs.

6. Measure and allocate grass accordingly

It is important to regularly monitor grass covers to enable appropriate allocation of both grazed grass and buffer. Monitoring is particularly important so intakes from grazed grass are not over or underestimated.

Typical grass growth in early spring should be able to provide 5-6kg of dry matter intake, which can replace the same amount of grass silage in the ration. This amount can quickly increase as growth rates increase.

Monitoring grass growth weekly and tracking the results on a spreadsheet or grass management programme makes rationing much easier. It is possible to do a grass budget, which takes cow numbers and kg DM required (i.e. grass demand and grass supply) into account. This makes it easier to predict when buffer feeding will be required and how much is likely.

7. Put cows out with an edge on appetite

To maximise grazing intakes, turn cattle out with an edge on appetite. Ensure feed troughs are empty prior to milking and turn cows out onto fresh grass.

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