Recent research in Ireland has concluded that stocking rate has a minimal impact on fertility rate if nutrition is managed correctly.
This, in hand with careful selection, means that increased stocking rates can be achieved without adverse effects on the overall pregnancy rate.
Brendan Horan, a researcher from the study, says the implication for the dairy industry is that it can become more productive and environmentally efficient in the future.
Stocking rate and grass growth
The key is to match overall farm stocking rates to the farm’s grass growth capability and to maintain a predominantly grazed-grass died with improved grazing and nutrient management practices.
Animals capable of highly compact seasonal calving should be selected, as reproductive performance is the most important driver to profitability in grass-based systems.
A balance needs to be achieved between stocking to allow growth in the business and the feed required – buying in feed could introduce risk.
Piers Badnell, pasture-to-profit consultant at LIC, says the key is to grow quality grass and to match the amount to the cow numbers.
He said, “Getting the correct stocking rate means having enough grass grown to feed the cow well to match her requirements.
“Good genetics have the potential, so if the cow is managed well and fed enough quality grass, reproductive performance follows as long as she is in the correct body condition and there is a good plan in place for getting her back in-calf.’’
Mr Badnell suggests grassland farmers should aim for a stocking rate of 3-3.5 cows a hectare on the grazing platform and 2.5 cows a hectare across the whole farm. But there are provisos.
“The amount of pasture grown, the size of cow and imported feed all influence the ideal stocking rate so numbers will vary from farm to farm, but these figures are a good benchmark,” he said.
Getting a cow in calf is down to feeding her well to be in the right body condition, he added. “This is down to recording and monitoring grass production and grazing so that the farm can accommodate the right number of cows for that farm.’’
Keith Davis stocks his grazing platform at Lydney Park, near Chepstow, at 3.6 Jersey-cross cows a hectare. He feeds just 250kg of concentrates a cow a year but, at 10%, the herd empty rate has halved since he ran a housed system .
His whole-farm stocking rate is 2.5 cows a hectare and the emphasis is on producing quality grazed grass to promote herd fertility and health.
He plans his spring grazing rotation using a grazing management tool and strictly adheres to this. From turnout on 1 February, one-hundredth of the milking platform is used for grazing.
“We will graze one-third of the platform in February and as the season progresses we allocate a bigger area every week, so we might allocate 1ha on the first day and that will increase to 5ha by the end of March,’’ Mr Davis explains. “When we get to 20 March, we will graze the second third and the last third by 2 April.”
He only deviates if, in a cold spring, the average cover threatens to fall below 1,900 kg DM/ha. “If we get to that point we won’t increase the area fed until it comes right.
“When we get past magic day – the day when grass growth is faster than the amount of grass the cows can graze – we look to maintain average covers of 2,100-2,200kg.’’
The herd calves in an 11-week block from 1 February. “As the spring gets going the herd gets less silage and more grazed grass.”
Cows receive up to 17kg of DM of grass a day but if there is insufficient grass, the shortfall is plugged with concentrates.
“During the first 60 days of grazing we feed an average of 1kg concentrates and 4kg of silage dry matter per day,” says Mr Davis.
A month before AI is due to get under way, heat detection patches are secured to cows’ backs.
For the first cycle of AI all cows and heifers are served to a Jersey-cross sire. Hereford semen is then used for 10 days followed by Angus semen.
AI runs for between six and seven weeks, depending on repeats, and Angus bulls are then run with the herd for five weeks.
Mr Davis will calve 1,000 cows and heifers this season.