After what was a very promising start the spring has quickly turned into one of the wettest and coldest for many years. The most noticeable and talked about effect throughout the country has been the slow rate of grass growth, while many livestock, particularly cattle, are still to be turned out.
SAC maintains three grass variety trial sites at Auchincruive in SW Scotland, The Bush at Edinburgh and Craibstone outside Aberdeen. The results gathered at these sites so far show the variation across Scotland and the value of the trials network.
At Auchincruive, where conditions are always milder, there have already been two “cuts”. Principal Technician Lawrence Baker reports a higher than average yield in April (1.9 t/haDM) but balanced by a poorer result in May (0.85 t/haDM). Together the two results show reasonable growth but he believes regrowth will be slow. However, he notes ear emergence on control varieties is likely to be around 20th May this year, in line with 2008 to 2010.,
The only cut in Edinburgh yielded 1.84 t/ha DM, which is similar to the 2010 results, but well below the exceptional 3.3 t/ha DM of last year. However Trials Team Manager Alastair Drysdale notes that there has been almost no ear emergence, a real sign of a late spring.
Further north, in Aberdeen, there are also clear signs. Trials Officer George Carr says the mild autumn encouraged grass growth which then got badly scorched during a winter with no snow cover, biting winds and frosts. Growth has been 80% of normal although it was worse in 2004 and 1999 (30% and 25%). In those years silage yields were depressed by 10-15%.
According to SAC Grassland Consultant Peter Shipway the north-south variation is indicative of the patchy growth this season.
“Some places will have no real change, others a great deal. It can even vary across farms in the same locality. Under those conditions the old rules of thumb go out the window. Farmers wanting quality silage may well be cutting around the same time as usual, but getting lower yields. Those going for bulk will have to wait longer than they usually do. Although there will be some compensation in grass growth if and when the warmth arrives, there is no doubt that overall grass yields will be significantly below average this year. Contact your local SAC Farm Business Service Office for advice”.
For livestock the consequences of a shortage of grass are obvious –
- Poor fertility in spring calving herds.
- Lighter leaner store cattle/sheep with less animals finishing at grass.
- A shortage of winter forage.
According to SAC livestock experts there are many options producers can take, providing they start planning ahead now. One of the most important decisions will be to protect the performance of grazing animals and particularly first and second calvers, by giving top priority to grazing and planning ahead now for any forage shortfall next winter.
Gavin Hill, SAC Assistant Regional Manager argues there is no profit in having pits full of silage to over-winter barren cows and ewes!
“Parts of fields which have already been shut up for silage could grazed in an emergency if the grass height is below 25 cm. I know farmers will be tempted to cut silage early but they should remember the grass must have been given the chance to take up all the applied nitrogen.”
There are also health concerns. Gavin recommends farmers keep magnesium levels up, as the risk of staggers is high. The bulling period is not far off on many units and cows needing a good plane of nutrition with high energy levels might require supplementary feeding with cobs etc. or fodder from ring feeders.
“This may lead to heavy poaching”, warns Gavin. “So watch out for signs of Coccidiosis in the youngest calves and discuss with your vet. Coccidiosis risk increases in older, wet, poached areas”.
SAC Sheep specialist Dr. John Vipond is also concerned about health.
“Stressed ewes will have dropped more worm eggs and lambs pick up more on short grass swards when milk is in low supply” he reminds farmers. Check lamb faeces for worms and coccidiosis at 6-8 weeks and dose accordingly”.
“In most years I am encouraging farmers to increase ewe numbers to control grass in May. This year, with 25% less grass growth on the best of land and substantially less on wetter farms, it’s a case of, is there enough to go round?”.
John Vipond believes that as ewes meet peak lactation demands they will need sward heights of 4cm now, rising to 6cm by July. Without heat to drive growth lambs will be lighter at weaning and sale dates delayed.
“Farmers should check swards for height and supplement with 0.5kg/day of cereal or roots if below 4cm”, he says. “They might consider introducing creep feed, but avoid creating foot problems by moving troughs in wet weather”.