BY: TREVOR COOK
Efficiency is a loosely used term to basically mean getting more from less. Or maybe making the best use of something. The sheep and beef industry has been doing this for decades.
It began with reducing costs and over the last 20 years it has been through increasing lambing percentages. More lambs from fewer ewes. But it also captures higher pasture utilisation, lamb and calf growth rate and in today’s environment producing more meat with less methane produced. The latest breed direction of selecting for low-input sheep is about efficiency.
Low-input sheep as a breed direction is complicated in the same way that many other traits are because management and environment have so much impact on the expression of the trait.
The expression of having a low input need is influenced by feed, terrain, stock mix, climate and grazing systems for example. A very simple policy difference that could make a huge difference in the extra support that a ewe needs is where the lambs go at weaning.
If lambs totally leave the lambing platform at weaning and don’t come back there is a massive drop in the level of worm larval contamination on that platform. For most ewes being fed enough at critical times grazing contaminated pastures would not impact on them. But if the feed supply gets short at these times some ewes would struggle without help. Selection for needing less inputs must be done in a challenging environment.
Lamb survival is a component of efficiency. Selection for lamb survival suffers from the same interaction with other factors. The above factors as well as shelter, pregnancy status, body condition score and late pregnancy feeding all have a huge impact on the outcome regardless of the genetic status of the dam. Comparing and ranking sheep of different genetic backgrounds in a single environment can only be valid in that environment. How can that be standardised for lamb survival?
Selecting for worm resistance has the same complication. Sheep that have been selected for having a lower faecal egg output and being less impacted on by worm challenges no doubt bring that ability to a farm. The management and policy on that farm then has a large impact on how much of that trait is expressed.
If all lambs leave at weaning as above, if all lambs go on to summer crops, if there is integration of lambs and cattle or lambs and ewes for example will all influence the level of accumulation of pasture worm larval contamination. And therefore how much the resistance status comes into play, or is needed. This if nothing else just highlights the value in having defined breeding objectives and selecting sires that best serve those.
A ewe that weans three lambs is very efficient. The extra feed required to do that is very small compared to one that weans two lambs. It is a very efficient use of feed, it has a low methane output per kilogram of lamb weaned and can be a low-input sheep.
The most successful ewes giving birth to and weaning three lambs are very often ones that are not given much extra priority. I see many ewes carrying three lambs that are overfed because they have been prioritised since scanning. This sets them up for metabolic issues at lambing with high ewe death rates and/or high lamb deaths. This outcome also is likely if that ewe is underfed or thin.
Triplet ewes do not need much more than twining ones, but they cannot tolerate being underfed. The value in having them out on their own is to be more sure that they do not get underfed. The quote that many farmers have heard from me is “if a lamb stands and suckles within 20 minutes of being born it has a 95% chance of still being alive 90 days later”. This is the conclusion from a large investigation into lamb survival.
We know that body condition score at lambing and energy status coming into lambing have a huge influence on lamb vigour at birth. For triplet ewes it is harder to get these spot on. As we get asked to lower our farm methane outputs, more ewes with triplets is one of the tools to achieve this but keep lamb production up.
I know that most sheep farmers would rather not have ewes with triplets. But I see enough embracing them and getting good results that helping farmers put a “best practice” plan around them is worthwhile. Results are varied but almost always improve as the bits of that best practice that are most important on that farm get embedded.
As I have discussed before, we need to be very careful about bringing the concept of efficiency into communication. It is more than speaking and listening which is what virtual communication largely is. Nothing will replace group meetings that create the atmosphere and forum for effective transfer of ideas and exploration.
