Why does my protein test look like this?

Why does my protein test look like this?
Why does my protein test look like this?
Why does my protein test look like this? Don’t worry you are not alone. Many of our clients have a lower protein test this season.

We don’t have all the answers but here are some thoughts;

What affects milk protein%?

It is a reflection of energy intakes, stage of lactation and genetic make up of the herd.

Stage of lactation

As cows and the herd head toward peak milk (peak litres) the protein and fat % drop. So if the herd has calved faster than last year then that may be one explanation. If cows are doing more litres this season but their kg of protein is the same then the test will be lower.

Milking frequency

If cows are milked OAD then their milk protein test will be higher. So if last season a farmer was still on OAD with the milkers and this season he is on TAD then that may explain the difference.

Energy intakes

If cows are being fed less (either in total dry matter or in energy density/quality) then this may explain the lower protein test. In many herds this may be the case this season. Although on paper they appear to be feeding the cows well (dry matter intakes, grazing residuals for the milkers etc) in fact the composition of the pasture (predominantly what their diet is this year) may be driving these lower energy intakes. The rapid growth post drought and good winter growth rates, mean that our pasture composition is different to what we had this time last year.

Genetic make up

Jerseys will have higher protein tests than Friesians in general.

Does a lower milk protein test matter?

Well if it is indicating that energy intakes are lower for the herd for the same time as last year then yes it may be a concern. So how do we know this? Go through the A-D above – can anything else explain the difference such as calving pattern, heifers calving faster etc? If not then how does milk litres production match up with last year? Are the cows milking better or worse? Review feed intakes (how much, what, quality etc).

Assess BCS if excessive BCS loss is occurring to maintain production then potentially we do need to do something about it, as excessive BCS loss (>1 BCS) in early lactation will affect reproductive performance. At this stage of lactation monitoring BCS loss is tricky at the herd level (mobs scores don’t mean much for another couple of weeks until a big chunk of cows have been calved 4-6 weeks as there are lots of cows at different stages of lactation). Considering asking your vet to do some cow-side ketosis testing (15-20 cows that have been in milk for a couple of weeks) in the morning is a good approach to check in on energy status.

Date Added: Wednesday, 12th August 2020


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