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Monday 25 September 2017

Without measuring sheep growth rate, you won't manage

How many sheep farmers really know what growth rate they are getting out of their lambs?
How many sheep farmers really know what growth rate they are getting out of their lambs?
Tommy Boland

Tommy Boland

At 80kg/ha of daily grass dry matter growth, the hill at Lyons is looking as well as it has in many years. This is the portion of the farm which is dedicated to sheep grazing during the summer.

While we refer to it as the hill, it might be more accurate to simply describe it as high ground. A considerable portion of this has been reseeded in recent years, which has also helped increase herbage supply on these paddocks.

Twin lambs have grown at a rate of 290g per day over the first eight weeks of their lives. Single suckled lambs have gained at a daily rate of 340g during the same period. This means the twins and singles have a live-weight of 20.5kg and 24kg at eight weeks of age respectively. This is slightly ahead of target for lambs at this age. Target live-weights for singles at five and 10 weeks of age are 16.5kg and 27.5kg. For twins these figures are 14kg and 23.5kg.

These figures represent a sheep-only enterprise. The targets should be at least 1kg higher for a mixed grazing set-up.

But how many sheep farmers really know what growth rate they are getting out of their lambs? I'm sure many people are tired of me saying this but 'If you don't measure, you can't manage'.

Recording growth rate on a representative sample of your lambs will reveal what your lambs are doing, thus allowing you to take remedial action if required. But it will also enable you to benchmark your performance against targets and industry norms. Additionally, recording growth rates is a qualifying task for STAP.

In order to achieve this, you will need some reliable method of identifying your lambs and a measure of their birth dates and weights. It becomes quite a simple practice then to weigh these lambs each time they move through the handling unit.

Despite the good performance of our lambs, these figures actually represent a drop in growth rate over the last two weeks. This is not completely unexpected. At this stage the ewes have passed their peak milk production. This occurs at three weeks after lambing for twin suckling ewes and five weeks after lambing for single suckling ewes.

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Efficiency

This means that the lamb is more dependent on the consumption of grass. The reliance on grass brings a decline in efficiency, therefore it is of the utmost importance that grass quality is maximised. We do not offer concentrate feed to our lambs or ewes post-turnout.

Another reason why performance can decline when the lamb starts on pasture is the issue of parasite challenge. The two main offenders are coccidia and nematodirus in young lambs.

We treated lambs for coccidia at seven weeks of age as dung samples were coming back with high levels of oocysts present.

We have not yet treated for nematodirus. Faecal egg counts at six weeks of age indicated a reading of 250 eggs per gramme (epg). This had increased to 350 epg at eight weeks of age. We will test again this week and make our decision according to the new results.

Our artificially reared lambs were weaned at seven weeks of age with an average live-weight of 22.1kg. This represented an average daily growth rate from birth to seven weeks of 365g, which is an excellent performance for triplet and quad lambs.

The key aspect of weaning these lambs is to ensure they are consuming a minimum of 250g of concentrate per day prior to weaning. These lambs will remain indoors on ad-lib meals now until slaughter.

Foot care is always on our minds at Lyons. Sheep are foot bathed each time they pass through the handling unit. The first time the new lambs pass through the foot bath can often be a noisy and, sometimes, an infuriating experience. It is hard to say if more noise is generated by the sheep or the shepherds!

Regardless, the main foot condition of concern at the moment is scald. This is particularly an issue where there is lush grass as this can irritate the sensitive skin between the digits. It's this irritation that allows the bacteria which causes scald access to the foot.

This bacteria can be found throughout the sheep's environment, which makes it almost impossible to completely eliminate this condition.

However, scald is relatively easy to control through regular foot bathing, so it should not cause a problem if it's addressed in an appropriate and timely manner. However, if it goes untreated it can develop into the much more problematic condition of foot rot.

On a side note, I was fortunate to be able to attend the Zurich Farming Independent Farmer of the Year awards. The finalists were of an exceptionally high standard and I would like to congratulate Gordon and Yvonne Johnson on being recognised as the Sheep Farmer of the Year.

Hopefully this event can become a fixture in the farming calendar.

  • Dr Tommy Boland is a lecturer in sheep production at Lyons Research Farm, UCD

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