Strategic dairy farm host, Matt Jackson, runs a spring block-calving herd of 300 cross-bred cows at Penllech Bach in North Wales. The farm consists of 100 hectares, managed by Matt as part of a share-milking agreement.
Matt has been focusing on getting the right quantity and quality of silage for the right cows. “We’re typically using between 1.3 and 1.5 tonnes of dry matter per cow per year,” says Matt. “The majority of the farm is grazed twice on rotation and then closed for silage.”The silage is split across two pits at Penllech. High-nutrient silage is fed to the milking herd and the remainder to the dry cows. “About 350 tonnes is used for dry cows. This would be from about 10 ME type grass, it’s stemmy and high fibre to keep condition on but not make them too fat,” says Matt.
To ensure he is optimising his forage quality, Matt has been working with Dr Dave Davies of Silage Solutions.
For Dave, the most important animal on any dairy farm is the dry cow. And getting the ration wrong for dry cows can have two big effects:
- A higher risk of production diseases around calving and, as a result, increased associated costs and potentially an increase in replacement rate.
- A lower peak yield, resulting in a lower lactation yield.
Nutritional value
“It’s really important to have two types of silage,” says Dave. “One should be high quality, about 12 to 12.5 ME with 16% crude protein, for the milking herd. The second should be specifically for your dry cows ideally about 10 ME.”While dry-cow silage should be of low nutritional value, hygiene should never be compromised. Common poor hygiene problems, including mould, will lead to a lower intake from the dry cow. “We want high intake to get the rumen working well and ensure that we can maximise forage utilisation in early lactation,” says Dave.
Low potassium levels are vital for ensuring cows stay healthy through calving. Ideal potassium content in silage should be no more than 1.0% and high potassium intake can lead to serious health problems including milk fever, hypercalcemia, and retained placenta.
“If we use too much potassium in our fertiliser regime, we have to overcome this with the addition of other things into the ration,” says Dave. “Ideally, we shouldn’t be using slurry on grass that will go into the dry cow silage, but this will be a challenge this year. I’d recommend using dirty water rather than slurry off the farm. We should also be looking at an eight-week re-growth as this does reduce the mineral content in the grass as well as achieving the low D high-fibre silage.”
Potassium uptake into grass increases in late summer/autumn so later cuts for dry-cow silage should be avoided.
Management strategies
With the extended grass growth over the last few years, Matt grazed the milking herd into December 2021, but he is worried this may impact the 2022 year’s growth.Dave recognises Matt’s concerns but doesn’t see an issue so long as the grazing and silage management is controlled to fit both requirements. “There is definitely an issue leaving an aftermath over the autumn/early winter period. It reduces the quality of spring growth because you've got dead material in the sward which will devalue your ME and you’ll also increase your risks of aerobic spoilage and mycotoxins because you’ve got a dead thatch potentially containing high populations of yeasts and moulds,” says Dave.
“Each year is different, and it takes careful management. Grazing it off to get a clean regrowth at the start of the season is beneficial. I would be grazing it with sheep or cattle over the autumn/early winter, up until New Year’s Day. This will allow the sward to be grazed down to the base and for fresh growth to start, allowing for an early first cut for the milking-herd silage or a later first cut for dry-cow silage.”
At Penllech, much of the silage for dry cows comes from land rented for 12–16 weeks at a time. With little control over the long-term management of this ground, Matt is keen to move away from this system.
To help relieve pressure on his silage ground, Matt has previously bought in hay for the dry cows. “Quality of hay is really important,” says Dave. “You need to be looking at the fibre content; seed heads are a good thing in dry cow hay. It’s also really important that it doesn’t smell musty or is dusty.” Intake of hay will be lower than silage, which may have a negative effect on building up the rumen ready for the lactating cow.
Dave is clear that the quality of silage is the most important thing to focus on. “When you’re making silage this year, focus on the nutritive requirements that your stock has from that silage,” says Dave. “It may mean a little extra hassle by making two different types of silage, but it will pay back. Especially in a year where we do not know what the cost of anything coming on to the farm is going to be.”
