Frosty grass still has good value

Frosty grass still has good value

Thursday, February 3, 2011

Winter grass emerging from a blanket of snow and frost does so with a surprisingly high ME content, which could allow sheep farmers to delay compound feeding and conserve valuable forage stocks, according to Rumenco.

The company has just released new forage analysis data, based on samples of grass collected around the country in January (see table). Grass was collected from eight sites, all of which had suffered from prolonged snow cover during December and early January.

"We expected the grass to be of extremely low quality, but while dry matters and protein levels were notably reduced, energy levels, paradoxically, were consistently high," reports Rumenco technical manager David Thornton.

Average protein level was 16.8%, yet the mean energy level was 12.4MJ/Kg DM with sugars a reasonably healthy 14.4%. "That's enough to sustain a mid term, twin-bearing ewe provided she has access to Rumevite feed blocks to encourage foraging behaviour. The dry matters are low, but this is not a major issue in mid-pregnancy before foetuses begin their rapid growth," he points out.

"The results surprised us, but it has been suggested that the snow may have protected the grass from wind chill. It has also been shown that light passes through snow and, indeed, may even be magnified when it moves through the ice crystals. Consequently, the grass will continue photosynthesising well, even though it is covered by a white blanket."

The company believes this data suggests many sheep producers will have better than expected nutrition in their late winter pastures and may even be able to delay the introduction of expensive compounds.

"Many ewes are in quite a fit condition, having benefited from having access to conserved forages and feed blocks while snow lay on the ground," says David. "This means it should be possible to delay cake feeding on many units, even if forage stocks are short. Rumevite feed blocks provide all the supplemental nutrition the ewes need, and encourage the sheep to make the most of the winter grass that is available to them."

However, David cautions against grazing winter pastures too hard for too long at the end of the season, as this can delay spring grass growth needed for lactating ewes and lambs. 

Analysis of nationwide grass samples (January 2011)

Location                     DM%  CP%   ME Mj/kgDM    D value   Sugars%

Carmarthen                            13.1         16.9                     12.8                        80               15.3

Powys                                      15.3         16.5                     12.2                        76               14.4

Devon                                      11.7         19.3                     12.9                        81               16.6

Gloucestershire                    10.6         16.1                      12.5                       78                13.7

Cumbria                                 18.8         12.5                      11.9                       74                 7.1

Yorkshire                                22.3         17.2                      11.6                       72               16.5

Borders                                  15.9          18.0                     12.5                       78                15.2

Perthshire                              12.5         18.6                      13.4                       83                16.6

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Mean                          15.0    16.8                12.4                 77           14.4

(All data on a DM basis)

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