Weather woes and grass growth slows

While soil temperatures have bounced in the last week, they are still only hovering at around 60C, which is about two degrees behind the long-term average for this time of year.

Grass growth rates have increased, but only marginally and still behind what most farmers would be expecting.

It’s all very demoralising, particularly as another cold snap is due to move in this week bringing night frosts with it. But it’s not as if we haven’t been here before. Both 2013 and 2016 were cold springs.

It wasn’t until the end of March in 2016 that grass growth rates went into double figures, and even at that it was only 13kg/day of growth. It was only by mid-April that growth was in the mid-twenties, around six weeks later than budgeted. It was a similar story in 2013.

So where does this leave us now? On top of the spring being cold, it has also become wet.

Heavy rain over the past week has made land wet and getting cows out to grass is a challenge. It’s all adding to extra costs with more silage and meals being fed, but it’s also affecting yield and fat and protein percent, which will have long-term implications. What to do over the next few weeks depends on what situation you are in now. There are a couple of scenarios. There are two vital bits of information every farmer should know. The first is how much grass is on the farm, and the second is how much of the farm is grazed now.

You must walk the farm to know how much grass you have. Score each paddock. Those with experience of measuring will be able to estimate grass covers pretty accurately. But most farmers aren’t experienced at measuring. The following is a cheat sheet for measuring grass. Pretend you are in midsummer and ask yourself four questions:

If paddock size is relatively even, add up all the covers and divide by the number of paddocks to get your average farm cover.

Discussion group

At a discussion group meeting in Waterford on Monday, there was a good discussion on grass. Considering the weather, the group felt that having an average farm cover greater than 700kg/ha and about 40% of the farm grazed is probably the best position to be in. This is because grazed paddocks grow fastest. About half of the group was in this position.

When it comes to average farm cover, the magic number is 500kg/ha. No matter what the stocking rate or percentage grazed is, you don’t want to drop below this level. This is because grass grows grass. And when farm cover is depleted, it takes longer for it to recover. Michael Egan from Moorepark says that on-farm work has shown that if average farm cover drops below 500kg/ha on 1 April, subsequent growth rate declines by 30% over the next three weeks. Therefore, running down farm cover too low is a bad idea.

So, if average farm cover is around the 700kg to 800kg mark, then they can afford to drive on and get more of the farm grazed and back growing, but not let it fall below 500kg/ha. One farmer in the group has a cover of 750kg and is just going to ration out what grass he has left until he starts the second round on 15 April.

If there are 30 days left in the first round, he will graze one-thirtieth of the farm per day (divide the area left to be grazed by 30 to get daily allocation). Whatever amount of grass is in the area is what the cows get, but they will get meal and silage back in the yard.

The half of the farmers in the group who have an average farm cover of close to 500kg now need to tread very carefully. Regardless of how much of the farm is grazed, they can’t afford to let cover drop any more. Their only option is to maintain average farm cover by setting demand the same as growth rate.

This means heavy feeding will be needed if farm cover is to be maintained as growth rates are only around 8kg/day to 10kg/day. So, if the current stocking rate is 2.2 cows/ha, only 4.5kg of grass can be fed per day (growth rate divided by stocking rate). In this example, cows will have to be fed silage and extra meals to make sure they are well fed. Total intake at this stage will be around 14kg of dry matter per day. Cows on 4kg or 5kg of meal, silage at night and 4kg or 5kg of grass are on a reasonably good diet. Keeping some grass in the diet is important as it is high in energy and protein.

Some of the farmers were feeding up to 7kg of meal because they said growth rates were only 2kg/day or 3kg/day. This was probably the case up to last weekend. But growth has improved a lot and if 2kg or 3kg of meal per cow per day can be saved then it should be. Farmers should be walking two or three paddocks near the yard every day to see if growth is improving fast enough to cut some supplement.

Because recovery on grazed paddocks has been poor, pushing out the start of the second round will be necessary. It’s hard to say now by how many days it should be delayed. I think at this stage most farmers should be aiming to push it back by between five and 10 days to 15 April. But the final decision will depend on growth rates between now and early April.