Keeping the cost of production down by maximising milk from grazed grass is the main focus for father and son Philip and David Clarke on their 80-cow dairy farm near Augher, Co Tyrone.

The cows calve in a tight interval from February to mid-April and are mostly New Zealand Friesian and Jersey crossbreds. “We want as much grass grazed as possible as early as possible,” Philip told members of the Ulster Grassland Society during a visit to their farm last week.

Milk yield last year of 4,967 litres/cow (4.3% fat; 3.51% protein; 388kg solids per cow) was lower than usual as the decision was made to milk once a day from September due to low milk prices and a difficult grazing season. Each year, the entire herd is dried off by Christmas allowing a break in the milking routine. A good work-life balance is important to the Clarkes, with David also running a poultry business and Philip working off-farm.

Out early

The key to getting cows out early is being strict in closing paddocks up in the autumn with the last round on the Clarke’s farm starting at the beginning of October. “Ground can recover from damage early in the year but not at the back end so we take a few more chances in the spring,” Philip said.

Cows were turned out as they calved in February this year but wet weather meant housing was needed again for two weeks in February and two weeks in March.

Growth

Covers are measured weekly by clipping and weighing. Agrinet is then used to create a grass wedge for supply and demand. The average cover was 2,150kg dry matter per hectare (DM/ha) last week and daily growth was equal to demand at 55kgDM/kg.

Concentrate feeding is kept to a minimum with 340kg fed per cow last year meaning milk from forage stood at 4,209 litres/cow. Last week, concentrates were being fed at a rate of 2kg/ cow/day with this set to reduce to 1kg/cow/day by the weekend.

The total cost of production currently stands at 22p/l, although the cash cost of milk production is 11p/l. For a low-cost, grass-based system the total cost may seem slightly high, but the figure includes 1.5p/l for paid labour and 3.5p/l for own labour.

What also should be factored in is a relatively new cubicle house. It is an investment probably not made (or necessary) in comparable low-cost, spring-calving herds in the Republic of Ireland.

Fertility

Back in 2002, with the herd split between autumn and spring calving, the decision was taken to change the system to spring calving only. Since then, there has been a strong emphasis put on cow fertility.

“We had to sort fertility by being ruthless and taking out the bull and culling empty cows. It seems expensive but it is worth it. We no longer have to cull hard on fertility, so it is now easier to improve the herd,” David said.

Breeding starts at the beginning of May with AI carried out for six weeks and then a Hereford bull is used as a sweeper for six weeks.

Bulls with a high EBI for fertility and milk solids are used and all replacement heifers are synchronised and fixed-time artificially inseminated.

“We are going for a cow that is around a quarter Jersey and three quarters Friesian. The ideal cow is 500kg liveweight and will produce the same weight in milk solids in a lactation,” David said.

Six-week calving rate is 87% and overall empty rate is 8%. ‘‘Fertility improved as we became better at heat detection. We also tail-paint all cows from the start of April and anything that does not come on heat before May is then scanned by a vet,” David added.

Soils

Another focus has been on growing more grass with David highlighting some paddocks that have increased annual grass yields from around 9tDM/ha to 12tDM/ha in the past three years, despite the fertiliser regime remaining consistent. He maintained that applying ground lime to low pH paddocks (below pH of six) was a significant factor. The average soil pH across all paddocks now stands at 6.7.

Alluvial soils with a sandy component means that paddocks are generally low in potassium, so high potash fertilisers are used in June and towards the end of the season.

The decision to reseed is based on sward performance, and is usually undertaken in May or June. Grass varieties are selected for palatability and persistence, with use made of the Irish pasture profit index (PPI).

Roadways extending to 800m to the furthest point have been constructed on the farm to improve grazing infrastructure.

Pre-mowing and topping is carried out if needed, although the main emphasis is on achieving maximum intakes and optimum residual covers from grazing. “We ideally graze cows in 36- or 48-hour paddocks, although this can be less as some paddocks are smaller. The bigger breaks allow us to guarantee that cows are full for at least two or three grazings,” David said.