Part two of the recent Teagasc sheep conference included a presentation delivered by Áine O’Brien, post-doctoral researcher on sheep genetics and genomics with Teagasc.
The topic of discussion outlining how labour at lambing can be reduced by improving lamb vigour and ewe mothering ability through breeding has been covered in-depth previously in a report from a Sheep Ireland conference.
The question is one of great interest, given that lambing accounts for 25% of the labour invested into a typical flock, and more than the labour invested in housing, weaning and mating combined, as reflected in Figure 1.
The take-home messages from the presentation was that ewe mothering ability and lamb vigour should be incorporated into breeding indexes, as they fulfil the three parameters that dictate this – socially or economically important, exhibit genetic variation and measurable on a large scale.
Áine said both traits are economically and socially important.
From an economic perspective, ewes with better mothering ability are likely to have a better chance of keeping their lambs alive, while lambs possessing greater lamb vigour are likely to be up to suckle faster, with both of these reducing mortality and contributing to the bottom line by having more lambs to sell.
Áine says it is important to think about this from the perspective of farmer welfare and burnout
From a social perspective, animals that require greater attention at lambing increase stress levels and can drain your energy at the busiest time of the year. Áine says it is important to think about this from the perspective of farmer welfare and burnout.
In terms of exhibiting genetic variation, there is a major difference in prevalence between sires.
While a high percentage of rams perform well, with progeny exhibiting good vigour at birth and eventually make good mothers, there are some rams that are dreadful in this regard. Both of these traits are heritable, so will be influenced by the genetics of the sire or the dam. Identifying these breeding lines has the potential to greatly deliver for the national breeding programme.
The final question on whether these traits can be measured on a large scale is answered by the fact there are already 21,826 mothering ability records and 44,619 lambing vigour records on file. Table 1 details a breakdown of records analysed to-date.
I was talking to a sheep farmer who runs a large-scale business the day after the conference, and he made the point that in his system, labour availability is lacking – as is the case on many sheep farms at lambing – but he has seen the benefit in even taking simple records.
A couple of simple things he does is write down on his sheep dispatch booklet the reason why, in his opinion, every lamb died.
He also does the same for ewes and writes this note on the yellow copy of the dispatch for ewes sent to the knackery.
Anything out of the ordinary or a spike in mortality for an unknown reason is investigated through submitting samples for post-mortem analysis.
My favourite ewes are the ewes I want to keep daughters from
The farmer said that at the time, he takes no real in-depth view on what the level of mortality is like, but explains that having the records available allows him to assess his performance after lambing has finished.
In her presentation, Áine gave an example of how easy it is to lose sight of important records that can deliver such a positive effect on flock performance.
She said: “My favourite ewes are the ewes I want to keep daughters from, but those are the ewes I don’t tend to remember. When I walk out into the field after lambing two or three weeks later, there are certain ewes I’ll remember. I’ll remember the one I was lambing for ages in the middle of the night, or maybe the one that had mastitis. But you might not remember the ewe that’s in the field, she has her two lambs, she must have lambed down herself, the lambs must have gotten up and drank themselves. She must have just gone through the system and landed outside in the field.”
She pointed out that it is these ewes that make a difference. The point is that there is merit in equal measure in identifying the top-performing animals to select replacements from and the problem ewes or issues that are dragging the system back.
There is a growing range of equipment available to record this data, while traditional methods of tagging poor-performing ewes or permanently identifying potential replacements and collecting useful information for future analysis should be something every farmer tries to adopt this lambing season.