Advice for grazing high-yielding Holsteins

It is no surprise that many year-round calvers with higher-yielding cows find grazing stressful.

Allocating grass is difficult when cows are at different stages of lactation, and, unlike a total mixed ration, grass quality can be highly variable throughout the season.

However, it can be cost-effective to turn higher-yielding Holsteins outside, providing farmers manage grass quality and are flexible when it comes to buffer feeding.

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This is according to independent nutritionist Hefin Richards of Rumenation Nutrition Consultancy.

Below, Hefin offers advice alongside Farmers Weekly 2020 Dairy Farmer of the Year Robert Mallet.

Robert milks 237 autumn-calving Holsteins at Northleaze Farm, near Swindon, Wiltshire, supplying Freshways.

Cows are yielding 10,974 litres at 4.05% butterfat and 3.32% protein and graze from March to November.

1. Work out if it is worth it

Grazing can be beneficial for higher-yielding herds, but farmers should monitor any savings versus a potential loss of milk income.

While there may be labour savings from reduced scraping and bedding requirements, the calculations “need to allow for the fact the grazed grass is not free”, says Hefin.

“This monetary value could be less if you are on A-B pricing, and your B litres are worth very little in the spring,” he adds.

He points out that, unless grazing cows are all in late lactation, there could be a significant reduction in lactation output.

However, some milk contracts stipulate that cows must graze, so it may need to be done regardless.

But in such cases, grazing still needs to be planned and well utilised, he advises.

At Northleaze, Robert calculates that replacing 10kg dry matter (DM) of total mixed ration (TMR) with grass saves £1.24/day.

This equates to about £25,000 when 200 cows graze for 100 days.

2. Group cows to make it easier

It is easier for block calvers to manage grazing efficiently because cows are all at the same stage of lactation.

“The difficulty with high-yielding Holsteins is getting enough energy into them when they are trying to reach peak milk and get pregnant within the target window.

“You run the risk of negative energy balance, which affects milk yield persistency, milk quality and reproduction,” explains Hefin.

Grouping cows and only turning out lower-yielding, in-calf cows that are in mid- or late lactation, can be easier to manage, he says.

This minimises the effect of fluctuating grass quality and intakes caused by variable weather conditions.

“Another thing that can work effectively is using a segregation gate and auto identification to direct fresh cows back into a shed and allow the rest outside,” he adds.

Hefin says which animals are chosen to graze – preferably in a rotational grazing system – will be depend on the farm and will relate to how much milk animals are giving, alongside average days in milk.

“It comes down to several factors, including your anticipated grass growth pattern, grazing area and shed capacity.”

At Northleaze, cows calve from August to December and are back in-calf by the time they are turned out in March.

The herd is split into two groups, with cows milked three times daily.

High yielders (38 litres-plus) condition score once daily, usually after morning milking, and lows (28 litres-plus) graze after each milking.

3. Consider grazing as a supplementation

Hefin suggests higher-yielding dairy producers approach grazing differently to those operating systems whose primary focus is milk from grass.

“Rather than think about going out to grass, consider you are bringing grass into the ration,” he says.

Robert believes the key to success is ensuring cows have a good appetite for grass by striking the right balance between buffer feed and grazing.

He cuts buffer back by one-third. High yielders will be allocated 20kg DM of grass, and lows 15-16kg DM, if conditions are perfect.

Only high-yielding cows are topped up with a TMR of grass and maize silages to meet total DM intakes of 28kg daily.

In the parlour, lows receive up to 6kg of concentrate daily; highs are given a flat rate of 3.5kg in the parlour.

4. Plan to manage grass variability

Another challenge to manage is grass variability, says Hefin.

“Sward quality, management and weather conditions will affect intakes. Water availability and heat stress further exacerbate this.”

He says farmers must have a plan and turn out early to create a wedge. Otherwise, the fields will have heavy grass covers when grazing rotationally, and intakes will fall as quality diminishes.

“You create a wedge by getting cows out early for a few hours every day and working your way around the platform so that every field is at a different growth stage,” he explains.

He also encourages farmers to take regular grass samples – weekly or fortnightly – and measure grass covers so grass and buffer feed can be accurately allocated.

Robert measures paddocks weekly. He will use a plate meter and input the data to Agrinet.

“Walking paddocks and looking at quality and residuals is as important as measuring [grass growth rates] to maintain quality later in the season,” he stresses.

He says good infrastructure is essential to make the job easier. His grazing platform is divided into 1ha (2.5-acre) paddocks using permanent tracks and fences. Each paddock has a water trough.

Robert adds that all 38 paddocks are close to the parlour. This is important to limit walking distances since the cows are milked three times daily.

The aim is to turn cows into covers of up to 3,000kg DM/ha and allocate sufficiently to hit residuals of 1,500-1,800kg.

To achieve this, he will sometimes run a leader-follower system, using lows or youngstock to mop up paddocks after highs.

“It’s not a deliberate policy, but there’s always that option if the highs don’t clean out a paddock.

“If it’s hot, cows stay in during the day and go out at night. We flooded last year in May on the grazed block, so grazing was limited to specific paddocks. You must be flexible.”

5. Be flexible when it comes to buffer feeding

Hefin warns that one of the biggest mistakes farmers make is being inflexible when feeding buffer.

When conditions are good, the buffer feed can be scaled back by 20%, and on wet days, when grass intakes are likely to be compromised, or if grass supply is limited, an extra 20% can be offered, he says.

“There’s often a tendency to panic, overcompensate and feed more because farmers are afraid of losing milk, but you need to be confident and cut feed when grazing conditions are good.”

When late-lactation cows are grazing, care must be taken to avoid underconditioned cows at drying off.

For cows with higher yield potential, there is a risk that underfeeding, even in mid- and late lactation, will lead to excessive condition loss, which will affect milk output.

He says cows should start and end the dry period at condition score 3-3.5.

6. Mindset

Mindset is key to making grazing a success, advises Robert.

“You have to want to do it,” he says, adding that he believes joining a grazing discussion group was a turning point for him.

His group, which includes a mix of dairy systems, gave him confidence by opening his eyes to what could be achieved.

“It is challenging to get it right but satisfying when you do.”