Beat the drop: Getting to the root of the problem

With most farms around the country nearly through calving and weather conditions on the up after a tough spring, farmers’ focus will be on maximising milk production from grass.

As outlined in the previous week’s article, there are problems historically associated with spring milk systems.

These are namely a drop in protein levels at around six weeks post-calving and a drop in butterfat (BF) levels when cows start second-rotation grazing.

During this period, farmers should be aware of fluctuations in milk solids (MS) and what the causes are. Keeping cows above 2kg MS for as long as possible is a target many should aim for, and this can be achieved in many ways.

This is outlined below:

  • (Milk yield L/100) x (fat % + protein %) x 1.03;
  • 26L at 4.0% BF and 3.5% protein = 2kg MS;
  • 2L at 3.8% BF and 3.2% protein = 2kg MS.

Farmers need to remember the specific MS calculation for their farm and complete the exercise regularly (detailed). Milk production should not fall more than 1–2% per week post-peak. Analysis of your co-op report should see multiples of this during the May–July period, which is lost production and, more importantly, revenue.

The use of buffer diets can help support intakes and the transition to full time grazing

First, we may find the problem of protein levels dropping in the milk particularly relevant, considering the wet weather and poor grazing conditions we have experienced around the country this spring.

Protein is driven by the starch and sugar content of the diet, and the focus should be on this, rather than on increasing the energy alone. Starch is usually derived from a grain source in the concentrate.

However, the most abundant form of sugar over the next while will be grazed grass. Getting cows out to grass is important, as not only is grass the cheapest feed available, but it is also a significant driver of milk production.

Better source of silage or forage

We see the effect of what going onto a better source of silage or forage can do to production levels, and spring grass is similar. Many farmers may find themselves in a situation of trying to play catch up, after falling behind on their spring rotation planner (SRP).

While the objective for farmers should be to ensure they are meeting residuals and controlling grass quality for future rotations, they must also ensure cows are meeting their dry matter intake (DMI) requirements.

Know your dry matter requirement and the amount they are getting from grass today. While a lot of farms shy away from grass measurement, at a minimum, you need to outline two figures.

Supplements in the form of concentrate and forages need to be used and based on feed demand, as well as based on the cow/MS production.

A drop in milk butterfat levels is an issue that farmers will typically encounter in the next month and onwards, as cows move into leafier, second rotation covers. Several issues can cause lower milk butterfat.

While we usually associate it with a lack-of-fibre issue in the diets, it is generally the result of a combination of factors resulting in compromised rumen function. Other contributing factors can include a lack of energy in the diet.

If cows are grazing, the discovery of fatty acids in grass can also have adverse effects. Linoleic acid, which is prevalent in most forage species, is especially abundant in lush grass and can lead to a higher-fat diet. This can cause reduced fibre digestion, lower rumen pH and, as a result, compromised rumen health.

Ultimately, this can lead to a reduction in butterfat percentage. Research data has shown that as little as 2g of conjugated linoleic acid (CLA) in the rumen can cause a 20% drop in butterfat.

If you are experiencing a lower butterfat percentage, then you first need to assess other issues/characteristics in the cows, such as manure consistency. It should not be loose or overly watery, but more like soft porridge in a grazing situation (slow clap sound).

Dropping butterfat can be somewhat unavoidable, as our focus should be on grazing high-quality, lush grass. However, other issues, such as dropping milk yield, body condition or milk protein, reduced intake or poor cud chewing, should be a cause for concern and acting to correct them in necessary.

Cow dungs appearing loose or bubbly are an indicator of SARA (sub acute rumen acidosis)

Take steps to ensure rumen health is the most crucial action. Avoiding rapid changes to any diet is essential. While the weather is unpredictable, adjust any dietary changes slowly and avoid sudden changes in rumen pH.

For more information on solutions to help “Beat the Drop,” click here.

Article 1: Beat the drop: Recognise it early and protect your profits

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