Volatile milk prices, high animal feed costs and uncertainty over the effect quota removal may have, are driving many dairy farmers to reassess the role grass plays within their business.
Well-managed grazed grass costs £97/tonne of dry matter (t DM) to grow, but has a feed value of £197/t DM. These figures come from a study* of 12 dairy farms monitored between 2011 and 2013, which set out to identify how farmers can increase milk output while lowering overall costs.
The farmers that grew and utilised the most grass per hectare and produced more milk from forage, made the most money.
And with land prices reaching record levels, expansion plans based on maximising grassland productivity on existing fields, rather than buying more, will generate more immediate returns.
More grass from what you’ve got!
The presence of broad-leaved weeds will always hijack grass yield and quality. The main problems on dairy farms are docks, chickweed and nettles, which all relish nutrient-rich areas where cattle regularly manure and trample.
Research at SAC showed that a 10% infestation of docks leads to a 10% reduction in grass yield – essentially where weeds grow, grass cannot grow.
Docks have only 65% of the feed value of grass and are less digestible. Where silage is baled, their tough stalks can puncture the plastic wrap letting in air, leading to spoilage and wastage. Dock seeds can also survive in silage and pass through the cow, infesting a field where slurry has been spread.
Tackling infestations
The best defence against perennial broad-leaved weeds is to stop them establishing in the first place. This can be achieved by having a well-managed, dense sward, growing in well-structured non-compacted soil. Over or under-grazed leys that have been poached, offer perfect conditions for weed seeds to germinate.
Topping or mowing weed plants provides short-term visual satisfaction but stimulates active regrowth – so the problem gets worse not better.
Spot treatment with herbicide through a knapsack sprayer can be cost effective when weed levels are less than 5%. Where infestations cover a greater area, spraying the whole field is advised.
“The long-term solution for controlling persistent weeds in grass is to use modern systemic herbicides, for example DoxstarPro where docks are the main culprit, or Pastor where there is a broad spectrum of perennial weeds present,” says William Corrigan, grassland agronomy specialist for Dow AgroSciences.
“A well-timed treatment with an appropriate herbicide can transform a weedy pasture into a productive ley, without the need for costly reseeding.
“Farmers may have to be more pro-active this year, as weeds have generally survived the mild winter and kind spring, so weed numbers are likely to be higher than usual this spring.”
Mr. Corrigan continues: “It is important to plan weed control to make full advantage of translocated products like DoxstarPro. The reason they do such a good job is the way they work – travelling around the plant’s internal transport system, killing it from within. To do this they need time to reach all parts, including deep into the roots. Spraying a silage crop three to four weeks before first cut will give good control and really benefit silage yield and quality.”
DoxstarPro gives excellent control of mature and seedling docks – both broad-leaved and curled. Spray the weeds when they are actively growing and at rosette stage, 15 to 20cm across or high. Use 2l/ha once per year, or split the application into two at 1l/ha each, one in spring and one after the last cut. Apply in a water volume of 300l/ha; increasing this to 400l/ha if dock numbers are particularly high or the grass sward is dense.
This product can be applied to grassland used for grazing or cutting. Stock should be taken out during spraying and return no sooner than seven days later. If spraying DoxstarPro after a silage or hay cut, allow two to three weeks for sufficient weed growth to occur.
DoxstarPro has been designed to be effective against broad-leaved weeds but safe to grass. Trials have shown that even at double the label recommended rate there is no reduction in grass yield.
DoxstarPro is not approved for use by handheld equipment such as a knapsack or lance. Choose GrazonPro in these instances.