“These guys are the future of grazing based dairying in the UK and they got a lot out of this trip by sharing their passion and expertise; they know that you get out what you put in,” report facilitator Dr George Fisher and organiser Lesley Innes, from the RDPE Livestock Northwest programme, delivered throughout Cheshire and Merseyside by Reaseheath College.
Discussions among the group at the start of the trip highlighted their desire to get detailed information on three main topics: grazing management and grass varieties, outwintering, and disease control for herd health.
Grazing heights to get output per hectare and grass utilisation right
“There was a lot of talk at the last Positive Farming Conference that keeping residual grazing heights at 3.5cm through the season would get us to the right balance between grass utilisation, milk output per hectare and fertility, but we discovered that this isn’t right,” commented Ed Dale, who had a number of his farm managers on the tour.
Grazing research scientist Elodie Ganche explained, “We grazed paddocks down to 2.7 cm, 3.5 cm or 4.2 cm residual heights for the first two rotations, and then these paddocks were split and grazed at either 3.5cm or 4.5cm for the bulk of the season.
“2.7 cm was too tight and 4.2 cm too lax for spring grazing. Keeping at 3.5 cm all the way through utilised the most grass, but going from 3.5 cm in spring to 4.5 cm in the main season produced the highest grass and milk solids yields per hectare,” she concluded.
Geoff Booth, Operations Manager for Andrew Fletcher’s Grassland Solutions set of farms, summed up for the whole group, “We got the strong message that grazing residuals down to 3.5 cm in spring, then relaxing to 4.5 cm for the main season, and making sure that they are down at 3.5 cm again before the end of the season gets optimum cow fill, grass growth, grass utilisation and output per hectare, so that’s what we will be aiming for at home.”
Cows choose the best grass varieties
For many decades, new grass varieties have been tested for yield by simulating grazing with a mower cutting every four weeks. But are the varieties that are best under the cutting bar also the best under real grazing? After all, the action of grazing and feet with cows is very different from that of a mower.
This was the question that researcher Mary McEvoy is working to answer in a radical and detailed set of experiments. “The reason that we used mowers to simulate grazing is that doing experiments on a large scale with cows is very, very much more expensive. If different varieties perform in the same rank order under real grazing as they do under the mower, then we can have more confidence in our development of varieties to meet the practical needs of dairy farmers.” She added, “And farmers need grasses that don’t just yield, but are palatable and produce the best intakes and milk yields – and you can’t measure these with a mower.”
So, what is the answer? “This work is unique in the British Isles,” Mary continued. “And it’s telling us a mixed story on the rankings, and some powerful lessons in terms of production. The top two yielding varieties under the mower [AberMagic and AberChoice] were also the top two under real grazing, but the rankings for other varieties were not the same.”
Mary added, “This work is telling us that grazing intake is influence by a number of factors that do not work in isolation; little things that add up to make the difference. So varieties with high sugar content, higher leaf-to-stem ratio and larger leaves give better intakes, but the amount of leaf-to-stem is the most important. Farmers don’t tend to use just one variety in a field, but a tetraploid like Spelga will give 1.2 kg milk/cow/per day and 0.2 kg milk solids/cow/day more than a diploid variety like AberMagic; and whereas we can get grazing residuals down to 3.5cm with the tetraploids, we struggle to get below 4.2cm with the diploids.”
Monitor Farm facilitator Lesley Innes concluded: “A grazing sward needs a balance of varieties to suit the needs of the system; tetraploid and diploid, and various maturity classes. But this work is showing us how varieties really impact on milk production, and that’s exciting and useful.”
Bold and flexible approach works for outwintering
“There has not been much research on outwintering systems,” commented George Fisher after the group had discussed the issues involved. “And this applies to Moorepark too. The farmers are way ahead of the scientists and the great thing about a group like this is that they ask the right questions and share their knowledge to get the best answers, even in the absence of research data.”
Senior Researcher Paddy French told the group that, “Investing in cubicles and a slurry system can actually work out cheaper over 20 to 25 year period than going for outwintering pads, so we are seeing a shift away from pads in Ireland and most of the outwintering if with youngstock.” He added, “If this is done on the milking platform then we suggest outwintering on a mix of up to 70% fodder beet and 30% silage; off the milking platform, then you can go for forage kale.
The conclusion of the group was that they could go to 80% fodder beet / 20% silage for outwintering dairy stock, but this required a flexible approach – monitoring health and performance on a regular basis.
Noel Byrne, who has a long career in dairy systems studies and analysis behind him, spoke to the group about a recent disease survey in The Republic of Ireland. Bulk milk and blood antibody testing from 320 herds revealed that there were high rates of exposure to IBR, BVD, Leptospirosis and Salmonella. “However, this type of survey picks up vaccinated herds as well, so it’s not easy to interpret results,” Noel explained.
“Animals with persistent disease, or PI’s, must be a focus in our control programmes,” he said. “You can buy a clean in-calve cow and she is OK, but she might be carrying a PI, so if you are going to vaccinate, you need to vaccinate all calves early. From testing 2,200 weanlings, we know that 40% of herds in Ireland have an ‘active’ BVD problem, and it’s pointless vaccinating if there are PI’s in the herd, because the vaccination will not cure them and they go on infecting the rest of the herd, so we urge farmers to identify and cull out the PI’s.”
The group wanted to discuss Johne’s control, but Noel explained that the disease is not prevalent in Ireland. However, Ed Hayes of Wright Morten vets was with the group and lead a session on the issues. Ed advised, “If you are serious about getting on top of Johne’s, then you have to follow a rigorous programme. Anything less may turn out to be a waste of time.” The programme should contain:
• Milk test all cows four times a year (results: Green = OK, Yellow = possibly infected, Red = Infected)
• Blood test red cows to confirm disease identification before culling
• Calve all green and yellow cows separately from red cows
• Identify daughters from red cows and decide their future
• Do not pool heifer colostrum to feed to calves
• Keep the calving yard clean
• Remove calves from the calving yard soon after birth
• Don’t pool and use colostrum from yellow and red cows
A place for automatic milkers in the field?
Perhaps the most radical work that the group were show at Moorepark was a systems study comparing a conventional and automatic milking in a spring block calving, grazing based system.
Steven Fitzgerald, Manager and researcher at the Dairygold Farm where the study is underway, explained the reasoning. “The objective is to integrate an automatic milking system (AMS) into a grazing system. The trial is on a 24ha grass milking platform, with 63 cows; it cost €175,000, which includes the AMS, concrete infrastructure and automatic shedding gates to make sure that the cows go to the right paddocks after milking.”
It took 4 days to train the cows to use the system, which seems a short time considering the furthest paddock is 400m away. “It works very well,” Steven told the group, “There is no difference between the different breeds in using the system; Friesians, Norwegian Reds and Jersey crosses have all used the system equally as well. The cows are milked 1.8 times per day on average and the practical outcome is that one person can operate this system, with time released for concentrating on the cows and working at alternative employment.”
Steven admits that the place for the system is probably where a farmer has alternative employment and the AMS allows them to hold down several jobs, otherwise the investment has a payback time which is too long.