Father and son team, Philip and David Clarke, milk 84 crossbred cows, all spring calving, between Ballygawley and Augher in south Co. Tyrone.

The current target for the farm can be summarised as follows: An output of 500kg of milk solids/cow, per lactation, based on a meal feeding rate of 500kg/head.

Last year the Clarke herd averaged 5,848L with 4,370L of milk produced from grazed grass and silage.

“The meal feeding rate averaged 750kg, a bit higher than we had targeted,” Philip explained.

“But every year is different. We benchmark every performance-related aspect of the business on an annual basis.”

David explained the significance of the 60kg grass dry matter (DM) daily production target.

“Once we hit this target, we could, in theory, stop feeding meal to the cows. If grass growth rates drop below this figure, then we have to feed concentrate in order to keep milk output at targeted levels.

“During those periods of the year when daily grass growth rates exceed the 60kg target, we are looking to take surplus grass out of the system. So, in reality, we are not feeding cows at all, rather we are feeding the 65ac grass wedge that makes up the grazing block on the farm,” he added.

“Concentrates are only offered to the cows at those times when there is a need to fill the gap between the quantities of grass available to the cows and their overall nutritional requirement.”

Grass growth

But making accurate decisions of this nature is premised on the requirement of knowing what daily grass growth rates actually are to a very high degree of accuracy.

“The entire grazing area is walked on a weekly basis and more often is required to assess the actual state of the grass covers,” Philip stated.

“To be honest we found this to be the most difficult aspect of the grassland management systems that we need to implement on the farm.

“And it took three attempts to get it right. We have used both plate metres and quadrats to measure the grass covers on the grazing block. But, it really was a case of persevering until we came up with a plan that worked for us.”

Philip explained that once they know the difference in the weekly cover values, they can work out what the average daily grass growth rate has been during the previous seven days.

“Looking ahead, we can predict growth rates pretty accurately on the basis of the GrassCheck figures that are published each week by the Agri-Food and Biosciences Institute,” he continued.

“Also factored in, are the weather forecast predictions for the days ahead and soil temperature values. The AgriNet software package number crunches all of this information for us.

“We can also interact with other farmers within the AgriNet group.”

Flexibility on Tyrone farm

Flexibility is another core feature of the Co. Tyrone family’s business.

“Setting fixed targets, such as a 21-day grazing rotation period, are not really relevant,” David explained.

“It’s all about putting cows into pastures that are at an optimal growth stage. At certain times of the year, growing conditions could be such that rotation for a period of 17 days could be appropriate.

“But it’s all about managing the grass wedge accurately. And this includes taking out paddocks as baled silage, when required.”

The Clarke family has traditionally milked cows on their home farm. Philip decided to go down the road of block spring-calving 20 years ago.

“The milk price was pretty poor at the time and I was getting pretty tired of working for nothing,” he said.

“Initially I had two options – block calve in the autumn or look at the spring option. The final decision was pretty much taken on the basis that spring calving gave the family an opportunity to have some time off around Christmas.”


Once this decision was made, the genetics of the herd was tweaked accordingly. Today the cows have a breed make-up containing an almost equal mix of Jersey plus Irish and New Zealand Friesian bloodlines.

The cows’ ability to produce milk is assessed in terms of their economic breeding index (EBI) values. This approach is also reflected in the specific sires chosen for herd.

“The cows calve down during February, March and April. The plan is to have 90% of the cows calving during the first six weeks of this period,” David added.

“The cows are put out to grass as soon as ground and weather conditions permit. Some seasons this can be as early as February 4th. However, this year’s turnout date was in early March.

“The plan is to have the cows complete the first full rotation of the grazing paddocks by early April.”

The Clarkes try to keep the very early calvers out day and night on their Tyrone farm, simply because there is so much actual grass available to them at that stage. But this is dependent on weather conditions, they explained.

From a breeding point of view, Philip and David use bulls on the basis of their ability to improve milk solids per cow.

“Our current target is to have cows increase solids’ production by 10-25kg every year.”

Philip and David will be hosting a visit to their farm in Tyrone by members of the British Grassland Society at the end of June.