By making use of grass quality data, grazing manager, Dane De Boorder, has been able to feed his 750 Holsteins with more precision and efficiency, increasing milk from forage and cutting concentrate use in a 9,000-litre herd.

Managing grass through June and July presents new challenges on Pomeroy Farm, where youngstock and grazing manager, Dane De Boorder, turns to the tools in his kit to make better use of what the farm grows.

Dane De Boorder

The very fact that this 750-acre (304-hectare), Wiltshire-based holding has a manager dedicated to youngstock and grazing in itself speaks volumes, reflecting the importance of grass to the profitability of milk production in this 750-head herd of Holsteins.

“We’re always working to better the business – to get more milk from forage, lower concentrate use, cut costs of production, and be more environmentally friendly,” says Mr De Boorder. “Grazing is essential in all of these areas as it’s our cheapest and most efficient feed.”

Producing 9,000 litres at 3.9 per cent butterfat and 3.2 per cent protein on twice-a-day milking presents grazing challenges in itself, with year-round calving adding to the complexity of grazing rotations.

This is assisted by splitting the herd into four groups, with the mid- and low-yielders, as well as dry cows, now having access to grazing 24 hours a day. 

“We’re completely committed to grazing, turning out at around the end of February this year, and offering as many days’ grazing as we are able to, given weather and ground conditions,” he says.

All of this has contributed to the herd’s gradual increase in milk from forage, now standing at 2,900 litres, alongside a reduction in the past 12 months from 3.2 to 2.9 tonnes of concentrates fed per cow per year.

“We’re striving to improve these figures all of the time,” he says.

Management of the 300-acre (121ha) grazing platform is best described as a hybrid between a paddock and strip-grazing system, with larger fields split into paddocks by semi-permanent, high-tensile wire.

“These have multiple entrances, so grass isn’t lost in gateways, and within these paddocks we strip-graze,” he says.    

Always offering cows fresh grass after every milking, he describes how the fields are split.

“If we took, say, a 50 acre [20ha] field, this is likely to be divided into six paddocks,” he explains. “A group of about 200 cows would graze this in roughly 1ha [2.5 acre] strips for 12 hours.”

Generally aiming for an opening cover of 3,200kg DM/ha, the target residual after grazing would be 1,600kg DM/ha.

However, the challenges of grass rejection increase through June and July and Mr De Boorder employs a range of tools to minimise waste from these patches and improve grass utilisation.

“My options are pre-mowing, post-mowing, grazing with dry cows or with youngstock,” he says.

Plate metering once a week, he says if he notes rejection patches across 25-30 per cent of the sward, he’ll go in with the mower.

“The pre-mowed grass seems to be more palatable so this way we can get residuals down to 1,600kg DM/ha,” he says, remarking that he’ll mow 24 hours-worth of grass for the following two grazings.

The alternative of post-mowing comes before dry cows are put in to clear up the paddock, or a further option used is simply to graze hard with the lower yielding group, followed by the dries.

“Milk may drop a touch but it’s all in the name of getting the residuals down,” he says. “But by taking a pro-active approach to managing post-grazing residuals, high grass quality can be maintained for longer, as older plant material is removed before becoming stemmy, allowing for optimum regrowth and green, leafy swards.” 

Plate metering also alerts him to under-performing swards, helping to identify those in need of reseeding.

Careful management of grass covers for both grazing and cutting has not only helped increase grass production (up from 8.5 tonnes/ha in 2018 to 10.2 tonnes/ha in 2020), and improve grassland utilisation, but also boosts quality of the farm’s swards.

As a participant in GrassCheckGB – an industry, academic and levy board collaboration designed to help British farmers improve their grassland management – as well as measuring quantity on a weekly basis, grass quality is also tested in collaboration with project sponsor Sciantec Analytical every two weeks.

“Our latest sample had an ME [metabolisable energy] of 11.9MJ/kg DM and a crude protein of 16.8 per cent,” he says. “We’re very happy with this for the time of year.”

This follows previous ME readings as high as 13.1MJ/kg DM from his medium to long-term (5-10 year) leys.

“Knowing the grass composition helps enormously when it comes to accurately rationing the cows,” he says.

Using the AHDB booklet, ‘Managing your feeding’, he is able to use his grass analysis to calculate the need for concentrate in the parlour or other supplementary feed.

“Based on grazing intakes of 17kg dry matter per 24 hours, the cows will consume 202.3MJ of energy from grass which has an ME of 11.9MJ/kg DM,” he says.

“Based on our cow weights, we know they need 70MJ for maintenance, which leaves the remaining 132.3MJ/cow [202.3 - 70] available from grazing, for milk production,” he says.

Based on the herd’s milk solids, the farm aims to supply 5.3MJ for every litre of production.

“We can feed up to 6kg cake per day in the parlour and assume we can get two litres of milk from each kilo of cake,” he says. “This takes our litres from cake and grazing up to a maximum of 36.9 litres.

“To give a bit of leeway we’d use 35 litres as a benchmark and anything below this level will go out with the lows, receiving only grazed grass and cake,” he says. 

Those giving over 35 litres will stay in the mid-yielding group, which is also offered buffer feed, and all groups are fed concentrates to yield in the parlour.

Also measuring rumen fill and body condition score every week, this helps gauge short-term intakes and longer-term health and energy balance.

“It’s hard to over-estimate the importance of measuring grass in terms of quantity and quality and it gives me confidence in gauging what we can get from this feed,” he adds. “If you don’t measure, you are only guessing, so when GrassCheckGB comes to an end, we will certainly consider continuing with grass analysis.

“Of course, there will be a cost involved but if you can get a couple of extra litres per cow out of it, it’s likely to be more than worthwhile,” he says. 

GrassCheckGB is a collaborative grass monitoring project run by CIEL (Centre for Innovation in Livestock), the Agri-Food and Biosciences Institute (AFBI) and Rothamsted Research, and supported by AHDB Beef & Lamb, QMS, HCC, Germinal GB, Handley Enterprises, Sciantec Analytical, Waitrose & Partners and Datamars Livestock.