Deferred Grazing

Published 15 November 12

Deferred Grazing

For the last three years Tom Mitchell, who farms on the Wiltshire/Dorset border, has been using deferred grazing to feed youngstock and dry cows over the winter, reducing feed and housing costs dramatically.

"Rather than make late cuts of silage we shut up parcels of grazing land on the perimeter of our grazing platform from the end of August/beginning of September," explains Tom. "We keep the cows off these areas until the middle of November then use the ground for grazing about 40 in-calf heifers
and 60 yearlings.

"Last year one group of stock was not housed at all and we seem to get pretty healthy, hearty cows as a result, who know how to graze once the season starts again in spring," he says. "We do have to worm the youngstock an extra time but the savings we make are considerable.

"We let the cows harvest the grass where it is, greatly reducing feed costs and housing costs such as slurry disposal. We do keep them in three small groups in order to minimise mess so it probably works out as having a similar labour requirement to housing the cows, what with checking the cows and moving the fences.

"You do need to be flexible in your approach as you're never quite sure how much land to shut up and when, as autumn grass growth rates vary
 so considerably, but shutting a bit up at a time gives you more options."

Tom continues: "We will supplement the cows in the field if necessary and we have the option to use sacrifice paddocks at the end of grazing, in mid-January, or if the weather dictates. Last year we let the weeds grow in a field of barley stubble and grazed round bales of grass silage in-situ. The
bales were placed in the field when ground conditions were good and then an electric fence moved over each one daily. This carried about 30 heifers from mid-January until grazing started at the end of March. They were never housed and seemed to thrive on the system.

"This year we're using fields we plan to reseed as sacrifice paddocks but the cows aren't really making a huge mess, even on our heavy ground," he says.

"Even in December and January there is still value in the grass. Some stores from last year, who spent the whole winter outside, sold for 20-30% over what we usual sell at. 

"When using deferred grazing I make sure we work with the slope in fields, getting cows to graze at the top during wet weather and at the bottom during dry periods," Tom explains. "By grazing a square, rather than a strip, I think the cows make less mess as they're not repeatedly pacing the same strip.

"Deferred grazing is only really an option while stocking rates are low here (Tom milks 150 cows on a 200 acre grazing platform, with a further 100 acres available for youngstock). As cow numbers rise in the future we may well look to put in some winter forage crops, but at the moment deferred grazing really does make economic sense."


The grass Tom is using as deferred grazing was analysed and showed the following results:

11.6ME

16.2% CP

23.5%DM.

Piers Badnell, DairyCo extension officer, comment on the analysis and what it demonstrates to us.

"The dry matter is high and will be a reflection of the dry day the sample was taken. This time of year, if the grass is being grazed normally, DM would be somewhere in the top teens on dry days, and about 15% on wet days.

"So what does this provide nutritionally? Take, for example, a seven month, 200kg heifer, that requires 50 MJ of energy to live and grow. On this grass, if we budget it at 11ME, the heifer requires 4.54Kg dry matter per day to achieve this. 

"We can measure and calculate this by using plate metering to find out what entry covers and residuals are, and if we know the area of the allocation we can calculate this dry matter figure.

"For an older animal, that can eat 3% of its body weight, the calculation would run as follows: a 300kg animal at 3% is 9kg dry matter per day requirement.

"Remember calculations are not real life, so monitor what you do, how much cows are eating and of what quality (use a plate meter and send off a grass analysis to get an accurate picture).

"Be aware that in harsh wet windy conditions they will need extra intake, so keep an eye on conditions and how exposed the site is.

"Monitor growth rates," he adds. "This does not mean bringing cattle in through a crush and weigh scales, a good assessment is withers height see picture and table from section 10 of DairyCo Feeding+ Managing youngstock feeding.   /resources-library/technical-information/feeding/feedingplus-section-10-managing-youngstock-feeding/

"Monitor this growth and performance and supplement if necessary.  The deferred grazing will most likely do much more than you expect, so question yourself before going to  concentrate, do they need it and if so how much?"