Careful management, a degree of realism and measurement will be key to getting the most from grazing this season.
This is the message from Tom Goatman of Trouw Nutrition GB, who says many dairy farmers are looking to turnout as a chance to reduce costs and make better margins from the low milk prices.
While this is a realistic expectation, Mr Goatman says the aim must be to maximise the season-long contribution from grazing which will need attention to detail.
He says: “While it is understandable farmers will want to maximise production from grazing, it is essential to be realistic about what is achievable.
“While underestimating the value of grazing can lead to higher feed costs than necessary, trying to take too much from grass can store up problems for later.
“The aim must be to understand grass’ worth, to challenge cows to deliver this and supplement it to meet cows’ nutritional requirements. To do this accurately will require measurement.”
Quoting data from the company’s GrassWatch service, which uses growth and quality information to predict the potential of grazing, he says milk from grazing follows a pattern (see table).
Mr Goatman says: “Production from forage peaked in early June at maintenance [M] plus 18.2 litres from a grass dry matter intake of 14.7kg/day, requiring a freshweight intake of 74kg of grass.
“Research suggests cows will consume 1.5kg dry matter [DM] per hour, so in June they needed to be grazing for 10 hours to achieve the required intake.
“It is important to be realistic about how much grass is in front of cows and how much they eat.”
Mr Goatman says an ideal entry grazing cover is 2,800kg DM/hectare (1,133kg DM/acre) and should be grazed down to 1,500kg DM/ha (607kg DM/acre).
Grazing on this basis will provide 1,300kg DM/ha (526kg DM/acre), meaning 1.1ha (2.7 acres) is required per 100 cows per day to allow 14kg DM intake.
Mr Goatman says: “To manage grass availability to allow cows to have adequate grazing, it is vital to measure covers and growth rates.
“Data allows effective decision-making. It allows you to balance buffer feeds and concentrates to exploit the value of grazing.”
Average growth in 2015 peaked in June at 80kg DM/ha/day (32kg DM/acre/day), but in some places, growth rates of more than 100kg DM/ha/day (40kg DM/acre/day) were recorded.
In July, growth dropped to about 60kg DM/ha/day (24kg DM/acre/day) and in late summer it was closer to 45kg DM/ha/day (18kg DM/acre/day).
He says: “To return a paddock from 1,500kg DM/ha to the opening level of 2,800kg DM/ha would have taken 16 days last June, 21.5 days in July and 29 days as the season drew to a close.
“If cows had to go back sooner, expected production from grazing would have to be stepped back.
“No farm is average and each year will be different, but measuring growth is time well spent and something which will have an impact on margins. The most profitable strategy will be to know what yield level your grazing will support and balance it with buffer feeds or concentrates.”
Mr Goatman says some farmers will look to take too much production from grazing in an attempt to reduce costs. He says this can cause problems in late season.
“If cows are pushed too hard at grass, they will lose condition which they look to put back on in winter. Each 0.25 body score lost in summer, made up over three months in winter, uses the equivalent of a litre of energy/day.
“This means cows will not perform as well in winter when feed prices are higher, so be realistic about the true value of grass.”
Mr Goatman says it is key to use supplementary feeds to complement grazing effectively. As spring grass will be high in fermentable protein, it is important supplements maximise rumen energy supply without inducing acidosis.
|Month||Potential yield from grazing (litres/cow/day)||Possible dry matter intake (kg/cow/day)|