Managing the move from TMR to grass

Published 19 June 15

That tricky period when cows move from a TMR system out to graze can mean a milk yield reduction, but managing it correctly and looking at the figures behind the drop is important, says AHDB Dairy Technical Extension Officer, Piers Badnell.

All-year-round calving herds, with medium to high yields, wanting to put low yielders out to graze, do have to face the hurdle of dropping a considerable amount of milk at this stage. If she is in calf, and yielding below 30 litres at this stage, this cow can make you money at grass. Look at the figures and see what really pays in your system.

HY cows at grass

Image 1 An in-calf cow, yielding less than 30 litres can make money at grass.

The answer to this drop is not to buffer feed her, as this strategy kills off quality grazing, unless you are short of grass. Buffer feeding, when grass supply is adequate, only teaches the cow bad habits and, ultimately, leads to a downward spiral. Instead, look to persevere at grazing and supplement when necessary.

With a cow yielding 30 litres when turned out to grass, the drop in milk yield is probably going to be quite significant, somewhere in the region of 10 litres. While this can be quite a shock, particularly in terms of reduced revenue, it is important to concentrate on the return, not the litres.

The reasons why this cow drops her yield is also part of the solution. Moving the cow outside to graze means she changes social groups. The cow, and her new ‘group mates’, need to sort out the group hierarchy, which is stressful, reduces grazing time and, therefore, reduces dry matter intake. Secondly, the change in diet takes a while to get over and, thirdly, instead of feed being supplied to the cow, in a trough, she has to work to harvest it herself.

All three of these reasons lead to stress, a reduction in dry matter intake and a drop in yield. It will take the cow three to seven days to get over these changes but, after this period, the effects will be pretty minimal. Once settled, her dry matter intake goes up and, with it, yields should bounce back to about 25 litres (+/- 2L), and I have come across people who say their cows get back nearer to the 30 litres yield level.

The one proviso to this is it needs to be high quality, well managed, 11.5/12ME rotational grazing, with  a low stalk to leaf ration, fed at 2.5 to 3 leaves, and at about 2,800Kg DM/ha on the plate meter, not stalky set stocked grazing.

In addition, and if you feel it is necessary, you can feed parlour concentrates when the cow goes out to grass, and step this down in the first week or so. This will ‘cushion’ the cow, but it must be done at a low level so that she does not substitute concentrate for grass for too long.

Whatever measures you take to try and alleviate it, you are still very likely to see yields drop by five litres or so. The question is what does this mean to returns? The example below, which uses seven litres as a yield drop, demonstrates what this means on a day-to-day basis.

Income reduction

A 7-litre drop @ 20p/L = £1.40 fall in revenue per cow

A 7-Litre drop @ 30p/L = £2.10 fall in revenue per cow

Cost savings

Assume TMR @ £2.50/per cow/day saving

Assume housing cost saving @ £1.50 per cow per day. (The cost of housing a cow for 24 hours, including – slurry disposal, from it hitting the concrete to being spread, time spent scraping and bedding, cost of bedding material, cost of running machinery to bed and scrape. I have monitored this cost on a number of farms and it varies between about £1 and £2/cow/day, this is not taking into account feed cost or the time and machinery cost to feed the cow)

= Total saving of £4 per cow

For the 20p/L scenario, the net gain is £2.60 and the 30p/L scenario the gain is £1.90 per cow per day.

There is one more cost that needs to be taken into account. In this system, the cow will eat more grass, and that has a cost, let us say 16kg DM/cow/day @ £0.06/kg DM is equal to about £1/ day. Having said this, the harder you work grass the more grass you get, so there may be a dilution effect on this figure.

These are my standard figures and the key is to do the calculations with your figures. Is the yield drop worth it in your system? Remember that the number on the milk meter or recording sheet is not profit, further calculations are needed to determine that.