Selecting replacements, both male and female, has long-term impacts on the future direction of a flock. As discussed in detail on pages 48 and 49, replacements joining as ewe lambs can directly influence performance during their five- to six-year lifetime, while if these sheep are in turn being used to breed flock replacements, their influence can last much longer.

Crosby Cleland started collecting a range of production records as part of AFBI related on-farm trials. At first, management practices increased labour, but Crosby’s views quickly changed from recording potentially being associated with more labour to now being a critical component of the day-to-day running of the flock. In fact, recording is now used as a large component in reducing labour.

“When you don’t have an animal’s actual performance, it is easy to make decisions with preference given to how animals look or how you perceive they are performing. Ewes that are in good condition at weaning can be animals that put all the attention on themselves and reared poor lambs while others can be ewes that are very efficient, reared two good lambs and still able to maintain their condition. Without some level of performance recording, it is hard to tell what the reason is, this is near impossible in a large flock”.

Positive experience

Crosby’s positive early experiences with performance recording led him to rolling out recording across all the flock. Lambs are now tagged and weighed at birth, with all records fed into a software package and correlated with the sire and dam. Lambs are weighed regularly throughout lactation with a six-week weight serving as especially beneficial.

“I like to work off six-week weights when selecting potential replacements. Lambs that have performed well up to this stage are likely to be from ewes that have a good milk yield and have attributed good growth characteristics into their progeny.

“I can use the computer program to select lambs that have achieved a favourable six-week and weaning weight and use it to identify lambs bred from certain ewes or sires. I also generally only select lambs reared as twins as replacements unless single lambs are from a very particular breed line while lambs reared as triplets generally don’t make the cut as they don’t hit the performance levels set.

“That’s not to say these lambs are any less useful for breeding but in my high-stocking-rate system I don’t have the capacity to give these lambs extra time to get them where they need to be.”

Additional lambs that are required for breeding are selected by the computer program. This then allows Crosby to visually assess the selected ewe lambs for breeding credentials or any faults with lambs deemed not suitable culled at different stages post-weaning.

Identifying poor performers

The system has bedded in well and is now also used for identifying poor-performing ewes for culling.

“About 10% of our ewes are now selected at weaning from performance records. This includes ewes that are continually underperforming in areas such as progeny growth rates or litter size. For example ewes that rear lambs below targets rates without having any associated reason for doing so are identified for culling as are ewes that rear single lambs three years in a row.

“Other performance recorded related reasons for culling include bad udders, prolapse and repeat lameness offenders.”

These physical faults are recorded on a continuous basis, with Crosby operating a strict culling policy that takes no prisoners on repeat breeders. That said, this emphasis is delivering the required results for the farm.

“I have found that performance and weaning weights have gradually increased since I started culling hard on the poorer-performing ewes and selecting replacements from the best. In a high stocking rate, the pressure is greater on ewes and there is no room for ewes that need a lot of special attention. The Psion reader is invaluable for quickly recording faults. I can record lame ewes or those that are consistently falling behind when flocking or giving more problems in seconds and use this to draft ewes at alter stage.”

Patterns emerging

Crosby says that results from recent years show the performance of ewes drops off after five lactations (one as yearling hogget and four thereafter).

“Litter size is not affected but I find that the liveweight gain of lambs suckling older ewes suffers when ewes reach five years of age. Ewes may last longer if run more extensively but for me once ewes reach five years of age and rear their fifth crop of lambs I start to move them on. The impact also shows on condition with ewes taking longer to recover.”

Read the full focus section on sheep breeding here