Thursday, 7 October 2021
The case for making milk and meat from grass could scarcely be stronger, according to dairy consultant, Tony Evans, from Andersons Farm Business Consultancy.
And whilst it could be argued that this has always been the case, numerous external factors – ranging from the price of bought-in protein to consumer preference in favour of pasture-fed livestock – are elevating the importance of grass in ruminant production.
There are countless forces driving production in this direction, not least of which is economics.
The 1-2-4 theory
At the top of the list, according to Mr Evans, is the 1-2-4 theory, which apportions a cost to grazed and conserved grass and compares this with concentrates.
“If it takes one unit cost of grazed grass to produce one litre of milk then it takes two units of silage to achieve the same production,” he says. “However, if you’re using concentrates, the cost is four times that of grazing.”
He cites an approximate cost of 3.5p per litre of milk from grazed grass, rising to 7p per litre for silage and 14p per litre from concentrates, and says a similar cost-benefit ratio exists in beef and lamb production for liveweight gain.
“But this is purely the cost of the feed itself, and not the cost of getting it to the animal,” he says.
For this, he says, extra labour and machinery are likely to be required for any feed that’s not grazed.
“If you graze the cow she gets the feed herself; if she is housed indoors she waits for it to be delivered,” he says, remarking that there’s also the storage and disposal of manure to add to the cost of feeding housed stock.
“I am not saying cows indoors are not looked after well but they do demand a much higher intensity of care, and the capital investment is huge,” he says.
“It’s far preferable to invest in tracks, fencing and water troughs than machinery to deliver a diet – at least in the west of the country where grass grows so well,” he says.
This is reflected in the policies across the four farms and almost 1,200 dairy cows in which Mr Evans has an investment and where he and his respective partners in these farms have divested themselves of machinery, wherever they can, and invested in assets which grow the businesses.
“We don’t have much kit and don’t have feeder wagons,” he admits, also remarking that he hires machinery each winter to work the owned block cutter for silage feeding, so the machine costs him nothing through the summer months.
Nutritional considerations: pH
Nutrition is also uppermost in Mr Evans’ thinking and this starts with the basics – the pH of grass.
“The pH of grass is almost neutral which is exactly where we want the pH of the animal’s rumen,” he says. “Anything you put in the animal which moves away from this position, has a cost implication.
“This includes feeding silage with a pH of four or feeding high starch ingredients such as corn or maize, which break down into acid,” he says.
“If you put in too much acid you have to add an alkali to neutralise it,” he says. “That’s the Gaviscon principle, which is the same as adding sodium bicarbonate to the ration.
“If you can maintain an animal with a stable rumen, you must be on to a winner,” he says.
But the nutritional benefits of grass are not limited to pH and its digestibility is also a prime consideration.
“The digestibility of grazed grass is higher than that of grass silage as you graze grass at six inches [15cm] and you cut silage at 18 inches [46cm], when the crop is more mature,” he says.
This means a greater quantity of the higher D-value grazed crop can be digested in a given period of time – a principle which extends to multi-cut silage taken when the crop is younger.
However, when making a total mixed ration with lower D-value silages, he says the solution is often to add starch to improve the feed energy density.
“This revs up the bugs, but comes at a cost,” he says, remarking that increasing the TMR’s energy density is also often achieved with a fat feed additive.
“At around £600 per tonne, this makes the diet even more expensive,” he says.
Protein in grass swards
The protein content of grass swards is also becoming more relevant in both lowering costs of production and reducing the carbon footprint of milk and meat.
“When you feed starch, you have to feed protein and the price of that has gone through the roof,” he says. “Higher protein species of grass are therefore becoming increasingly important and are often being used in tandem with red and white clover.
“I am definitely seeing more red clover being grown this winter and at the same time we’re seeing a reduction in the acreage of maize,” he says.
Shorten the winter
To all ruminant producers he advises, ‘shorten your winter’, including those with all-year-round and autumn calving dairy herds.
He says: “Most grassland farms should target grass utilisation of 9-10 tonnes dry matter per hectare, and that means growing 12t DM/ha.
“I’d say there’s scope in the dairy industry for 500 litres more milk from forage per lactation, if grazing grass and silage are well managed, cutting costs of production by 2-3p per litre,” he says.
But he warns: “Milk from forage is best measured on an area rather than a per cow basis and is highly dependent on stocking rate, and should hit a target of 8-10,000 litres per hectare.”