Farm Ireland

Wednesday 20 February 2019

Tommy Boland: Measuring ewe efficiency has produced some surprising results

Tommy Boland

Tommy Boland

The recent rainfall is welcome at Lyons farm, as it is around the country. We are seeing grass growth recovering somewhat, and the rainfall was certainly timely for the Redstart, which was sown following the harvest of whole crop wheat on July 27th.

Redstart is a crop we have used for the sheep for a number of years now at Lyons, and we are always happy with the performance of the crop and lambs grazing it.

Grass growth while recovering is still very slow on parts of the farm where we are struggling to get into double digit growth. To put some context on this our grass growth was five times higher this week last year!

Twenty five lambs were sold at a price of €5 per kg up to 21kg carcass on July 19.

They achieved an average carcass weight of 20.4kg returning €100.44 per head. Lambs are being weighed again at the time of writing.

One and perhaps the only benefit of the lack of rain fall is the lower parasite burden at pasture and lambs are requiring less frequent drenching. We are happy enough with the lamb growth rates to-date as they are not receiving any concentrate supplementation.

Our attention is once again turning to sourcing replacement stock for the breeding flock.

At the moment, we are not retaining replacement, but purchasing replacements each year. After the difficult spring we had, much of our culling decisions were taken out of our hands with a lot of involuntary culling taking place, due to mastitis particularly.

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However, we still have the opportunity to examine the individual performance of the ewes remaining in the flock and use this to steer our decisions on what replacements to purchase. One might say that 2018 is an unusual year and you shouldn't make too many decisions based on an extreme year.

I would agree with this to some extent, but would counter with the argument that if a ewe can perform well under such difficult circumstances, then she can perform under any circumstances.

There is ongoing discussion about the impending implementation of EID especially in relation to who will carry the costs of the technology. I don't want to enter that particular argument at the moment but there are benefits to EID as well.

At Lyons we have used EID tagging of lambs at birth for a number of years, which allows us to link the lambs to their dams, and monitor the performance of both the ewe and the lamb(s) over one or more years.

We use the Kingswood sheep software from TGM to analyse the data and it really is a very powerful tool, once you spend a bit of time getting to know the system. I appreciate it is not for everybody, but then what is?

A recent addition to the software is the ability to determine the ewe efficiency at various stages of the production cycle such as eight weeks of age, which indicates ewe milk yield, or at weaning.

The ewe efficiency figures are expressed as the kg of lamb(s) belonging to an individual ewe on a particular day, divided by the ewes' weight at mating.


When I looked at the efficiency figures for the Lyons flock, for all ewes that weaned at least one lamb we could see that individual ewe efficiency figures at weaning ranged from 20pc to 182pc.

When I looked at the live weight, BCS, age, etc. of the animals at the extremes of this range, there was nothing major to tell us that there would be a nine fold difference in their efficiency.

There are a number of factors which contribute to the variation in efficiency including lamb mortality, lamb birth weight, ewe milk yield, genetic potential for growth and litter size.

If we look within litter size, efficiency of the singles ranged from 20pc to 88pc at weaning, and for the twins ranged from 30-124pc. The point is that having the ability to collect and utilise this data should lead to better decisions being made at farm level, although the costs are not insignificant in terms of the hardware required.

The old adage 'you can't manage, what you don't measure' certainly applies here.

Professor Tommy Boland is an associate professor in sheep production at Lyons Farm, University College Dublin. @Pallastb

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