Limagrain’s Martin Titley attributes part of their rise in popularity to the improved varieties, which offer better yields and feed values.
“Producers want more milk from home grown forages and a range of fodder crops that can take the pressure off grass or silage,” he says.
“And a crop like forage rape or stubble turnips, which slots in between grass crops or after harvest and helps break the insect cycle, is also valuable in today’s grass rotations.”
Incorporating any green manure after the crop has been grazed or lifted improves soil structure and health. “And for the same reasons, there’s a role for these fodder crops in arable rotations.”
“These crops have far more potential now than, say, 10 years ago, thanks to new varieties with improved genetics and with more knowledge about their growing patterns.
“We’ve now got forage rape varieties with crude protein contents above 20% and fodder beet varieties with dry matter yields above 20 tonnes per hectare.”
He uses the developments in fodder beet varieties as an example. Table 1 shows 2017 trial data for three key varieties; Kyros introduced in 1995, and two more recent varieties; Tarine and Brick, introduced in 2015 and 2016 respectively.
“The dry matter yields of these newer varieties are a staggering 11% and 24% higher than Kyros; one of the main varieties 25 years ago. Brick has a dry matter content over 5% higher than Kyros. Both Tarine and Brick are Rhizomania tolerant with high feed values making them ideal for dairy diets.”
Fodder beet is a nutrient hungry cop and requires a careful weed control programme. “But it does yield double the energy supply of other fodder crops – and can now achieve a ME of well above 200,000 MJ per hectare.”
Most fodder beet is lifted, stored and used in winter rations for housed cattle. “This can mean for some it’s a non-starter, but producers in current or previous sugar beet growing areas may find they have access to contractors with the right equipment. Grazing in situ is an option if conditions are favourable; for dry cows and young stock.”
Table 1: Yield and dry matter contents of ‘old’ and ‘new’ fodder beets
|Variety||Relative DM yield %||Relative fresh yield %||DM content %|
Limagrain UK Trials 1998-2018
Relative dry matter yield 100% = 18.3 tonnes/ha
Relative fresh yield 100% = 88.2 tonnes/ha
RT = Rhizomania tolerant.
The ‘easier’ fodder crops for dairy units are forage rape and hybrids and stubble turnips. These crops can follow grass – or cereals – and are sown between May and August. Quick growing, in between 10 and 12 weeks, there’s a fresh fodder crop to graze, and with few inputs, they are relatively cheap to grow. Stubble turnips are an estimated £305 per hectare, with forage rape at £408 per hectare.
“The growing and management will also have a bearing on the crop’s success,” says Mr Titley. “Sowing dates are a case in point. Dry matter yield can fall by more than 50% in crops sown four weeks apart.”
Limagrain ran trials with its highest yielding and most popular, in terms of preferential grazing, stubble turnip variety; Samson and the rape/kale hybrid variety; Interval. Three crops of each were sown three weeks apart at two-week intervals from July 28, 2017. Fertiliser (20:10:10) was applied into the seedbed at 35kg of nitrogen per hectare.
The crops were harvested in mid-December and oven-dried to establish their dry matter content.
“The results showed that the highest dry matter yields came from those crops sown earliest. In the stubble turnips, dry matter loss was 33% in crops sown two weeks later and 59% in crops sown four weeks later.” Table 2 shows the dry matter yield from the three crops.
Table 2: Dry matter yield of Samson stubble turnips t/ha
|Samson DM (t/ha)||6.6||4.4 (-33%)||2.7 (-59%)|
The trial also highlighted the change in the ratio between leaf and bulb yield over time. Earlier sown crops produced higher yields of bulb to leaf (76% to 24%) compared with later sown crops (38% to 62%).
Likewise, crops of forage rape variety; Interval, sown in mid-August had dry matter yields 22% less than those sown at the end of July. Yields from the crop sown at the end of August yielded 51% less dry matter per hectare than the late July sown crop.
“This doesn’t mean that stubble turnips can’t be sown later in the season if a feed crop is needed. As the trials show, they will provide a good leafy crop, albeit lower yielding. It’s still worth doing,” adds Mr Titley.
Perhaps among these three fodder crops, Mr Titley is seeing more ‘new’ interest in forage rape and hybrids. “I think this is because it’s flexible; more so than many other fodder crops. It can be grown on its own or with stubble turnips. And some like to sow forage rape with grass seed mixtures and grazed shortly after sowing while the grass seedlings are still establishing.
“Forage rape also has a crude protein among the highest of any forage crop of 19% to 20% and an energy content between 10 and 11 ME/kg DM. It’s got plenty to offer dairy producers. And as long as it’s strip grazed and intakes are kept around 30% of total daily dry matter to avoid any risk of milk taint, then it’s a high value crop that lasts longer than stubble turnips and can help to extend the grazing season.”
Fodder crops for dairy
|Forage rape hybrids||Stubble turnips||Fodder beet|
High protein content
Ideal break crop
Flexible sowing period
Winter hardy varieties
|Low growing costs
Flexible sowing options
Early sowing promotes yield
|High energy crop New high yielding varieties.
Suitable for storage and using in winter rations
Can be grazed in situ
Very palatable crop
|Ave DM yield t/ha||3.5-4t/ha||3-6 t/ha||15-18t/ha|
|Average fresh yields t/ha||24-35t/ha||40-50 t/ha||80-100 t/ha|
|ME||10-11MJ/kg DM||11MJ/kg DM||12.5-13.5MJ/kg DM|
Forage rape’s a winner
Forage rape has proved a winner for a spring calving cross-bred herd in west Wales. Simon and Alison Richards, and their son John, have sown two fields – about five hectares in total – of the 101-hectare unit based at Little Hasguard in Haverfordwest, Pembrokeshire.
“We introduced forage rape as a fast growing forage crop in 2018 to eke out the grass,” says Simon. “We’re on red sandstone and the land can dry out quickly. Believe it or not, this year has been drier in parts than the previous year – contrary to much of the country.”
With forage supplying two thirds of the dry matter intake for this spring calving cross bred herd, high-quality home-grown forages are paramount. “We rotationally graze paddocks, from mid-February with fresh calves, to late November, depending on conditions. Cows will typically only be grazing during the day in early spring and late autumn. We want about 4,000 litres of the average 6,000 litres of milk from home- grown forage.”
The challenge is having enough grass throughout the long season. So with advice from Hugh Roberts from merchants Spunhill, they introduced the forage rape Rampart – a relatively new Limagrain variety that in trials has a fresh yield 6% higher than the control variety and a dry matter 2% higher, and high scores for mildew and Alternaria resistance.
And it’s worked well. “It’s easy to grow and it suits our relatively simple system,” adds Simon. “We get three rounds of grazing before we burn the grass off, spread manure from the youngstock yards then plough before sowing the forage rape. We cheat a bit and use half the seed rate in the drill with the fertiliser, but go across the field twice in opposite directions so there’s no strips and the whole field is covered.”
And, with some rain to get a good germination, which was a bit touch and go this summer but came just in time, and no further inputs the forage rape crop is ready for grazing in eight weeks – by late July. Fields are drilled three weeks apart to stagger the crop.
“We strip graze the crop for two hours each evening. They never get more than 25% of their daily intake from the rape – so there’s absolutely no risk of milk taint. But it gives then a fresh forage daily and takes the pressure off the grass, giving it time to recover.”
He’s pleased too that the cows clean up the crop well. “They take a day or two to get used to it, then they’re really keen. After a couple of hours, they go back to the grass sward.” And while some could see moving cows each night as a bit of a faff, Simon finds it worthwhile. “Yields have held up, even when the grass growth has slowed down – it’s kept us going through summer and it gives the grass chance to recover and grow so we’ve got plenty right into the autumn.”
A grass reseed follows the forage rape, usually in early September, while there’s still some warmth in the soil to get a good germination.
“The rape’s a great break crop,” adds Simon. “Dung from the cattle, plus any green material that’s ploughed in post grazing improves soil fertility and soil health. And we’ve got rid of the bugs that affect grassland which is important now certain insecticides are banned. It gives us a clean start to a new grass crop.”
Simon admits that when they had arable crops, grass reseeds slotted into the rotation easily. But as more cows replaced corn, and the grass acreage increased, working out the reseeding rotation has not always been as obvious. He’s finding though that forage rape is a good solution and brings quite a few advantages.