Farm Ireland

Tuesday 20 February 2018

Spring growth means we can hit our grazing targets

Grass growth should at least be meeting demand
Grass growth should at least be meeting demand

Mary Kinston

May has arrived and ideally grass growth should be at least meeting grass demand with surpluses expected as we progress towards June.

The cows should have also peaked in milk supply within the last few weeks and should be achieving greater than 1.8kgMS/cow and ideally around 2kgMS/cow (give or take 0.1kg).

While the main focus is on mating as we head into the breeding season it's also a great time to reflect on how the spring has treated us and how it has set up the cows for breeding.

For our farm in Kerry it has been a great spring. Turnout may have been a bit slower than desired, with our underfoot conditions being too wet in February, but March and April were kind months. This has provided the opportunity to manage grazing as desired.

This means feeding the cows well on pasture and adding a few kilos of meal to maximise production and minimise condition score loss.

The aim is to achieve good grazing residuals and reduce the pasture cover to a level that sustains the cows and maximises pasture quality. For our farm this is around 500kgDM/ha.

Having been well trained in spring grazing management and also having assisted my husband in its management for a numerous years on our own farm, I find managing the supply of grass relatively straight forward.

A weekly walk, combined with monitoring the soil temperature, helps you determine whether you are facing a feed deficit that will reduce your cover too fast or whether it will hold its own.

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However, when you do make a mistake it's important to recognise it and understand how to mitigate its impact in future seasons.

These days I find that the biggest challenge on our farm is managing the cows around the weather. Grazing was rather marginal at times and without using spur tracks into the paddocks, the grazing ground would have looked a sight worse than it did.

At numerous instances grazing was about having to make the call to continue or pull the cows off.


Luckily once past mid-March we managed to keep grazing this year, which is a blessing in itself. As we start breeding, the cows are in good condition and have plenty of good quality pasture ahead of them. Except for a bit of sunshine, what more could we ask for?

Having reached 12 weeks post calving it is also a time when many of us make the call to wean heifer calves off milk.

After years of wanting them, we finally got weighing scales, and have already put them to good use to determine when calves should be weaned.

The weight of some calves can be very deceptive and, in hindsight, it's likely that in the past we have weaned off some calves with liveweights below target.

While recommendations vary a little, with many quoting a target based on breed, the table below takes away any confusion for crossbreds.

Weaning calves based on weight helps maximise their reproductive performance. Light heifers are too often the cause of delayed first calving and delayed interval from calving to next conception.

However, I do know that many farmers that weigh heifer calves find that the oldest calves (February) can be weaned at slightly (5-10kg) less than the target but would actually wean younger (March and April) calves at slightly greater than the target (5-10kg) in a bid to even them up.

Ideally, these would then be subsequently weighed no more than three months later, with lighter heifers given preferential feeding.

At weaning it is recommended that heifer calves are eating at least 1kg of concentrate per day to avoid a growth check.

Calves should also be weaned gradually by reducing the volume of milk fed over a seven to 10-day period, with twice-a-day feeding being cut down to once-a-day.

Another point to consider is dosing. With favourable April weather, it is likely that many heifer calves have been at grass for a number of weeks. If they have been grazing for three or more weeks, a dose should be given to cover worm infestations.

Mary Kinston is a discussion group facilitator and consultant, and farms with her husband in County Kerry.


Indo Farming