Large numbers of ewes have been scanned using vets as well as technicians since the early 1990s. Millions of sheep scanning records have been added to our clinic’s database in that time.
One of our senior sheep vets, having finally mastered the “art” of accurate ewe scanning said he hadn’t realised what he didn’t know about sheep until he started scanning. That is no throw-away comment because the combination of clinical experience with sheep breeding and the hands-on experience of scanning are a powerful tool. While scanning is an extremely taxing job mentally, it is also enlightening.
So where are these big returns for little effort? Use scanning results as your measure of success.
If your sheep farm is driven by money then surely you want more lambs at heavier weights at weaning? This is mentioned as a key performance indicator for profitable sheep breeding all the time. It must be a requirement for most sheep breeding and-or finishing units.
If ever there was an opportunity it is with the improvement of lambing percentages. When top farmers scan more than 100 more lambs per 100 ewes than the worst performers, the room for improvement is obvious.
We might try subtle manipulation of lambing management, adding trace elements, fancy drenches, new breeds or novel shelter. But the simple fact of the matter is that we will rarely get a decent lambing percentage from a poor scanning percentage.
Our top clients regularly achieve a scanning of more than 170%. They also dock 150% or greater. Hogget flocks have now exceeded 150% scanning – up to 162% this year. None of them does it by accident. When there is a drought or a prolonged dry spell close to tupping, top farmers leave nothing to chance. They might not monitor weights or condition scores in a formal manner but do have a plan. They apply excellent stockmanship and can virtually guarantee a top-end result, come what may.
Hawke’s Bay doesn’t often get ideal autumns for flushing ewes and tupping well. If we do, anyone can get a decent scanning result by accident if their ewes are well-fed. That is when the national flock does well too. But when things are tight – and they often are – that is when opportunities are missed.
You can virtually “dial up” the scanning percentage wanted, which might not be massive. But you should be able to get what you want for your farm reliably.
First, how high do you want to go? Are you happy with either your scanning percentage or your lambing percentage? Can you quote your true results for ewes to ram or ewes wintered.
There are some superbly fecund genetics available in New Zealand and sometimes a complete change of ram flock is the way to speed progress. Another is sourcing new ewes to replace a proportion of an existing flock. Breeding performance is a slow process so if you want prompt change you might need to be bold. I can think of several clients in recent years who have done just that, including ewe flock changes en masse.
How heavy are your ewes? In the bearing trial we ran in 2001-02, farmers were asked a myriad of questions. Nearly everyone had 65kg ewes before we started weighing but it turned out the Hawke’s Bay average pre-tup weight in the first year of the trail was about 58kg. In the second year the average weight in Hawke’s Bay was indeed 65kg and we saw the scanning percentages rise 15 points. Regular weighing and condition scoring (by the vets involved) assisted with that significant change.
Our trial data of about 40,000
recorded ewes showed incremental scanning percentage gains right across the weight ranges until we hit about 75-80kg – even then gains in heavier ewes were measurable but much less.
Most ewes underperform because they are simply not heavy enough. Weigh them.
How well can you feed ewes? The science behind flushing ewes is solid and we all know that we should put weight on ewes in the lead-up to tupping to improve ovulation rates and hence lambing results. In the bearing study most farmers were unable to put weight on ewes over tupping when we measured pre-tup and post-tup weights. That is not to say there was not a dynamic effect through tupping with weight gained and then lost but probably most farms did not manage gains.
However, two hill-country farms stood out for achieving 8-10kg weight gains in mixed-age ewes across tupping and their scanning results reflected that too. They were focused on weights of ewes, not weights of works lambs – they shifted ewes fast and one was even doing twelve-hourly moves.
And how well do you know your ewes? Record it all and refer back to it. One of our leading clients has weighed and condition scored various age groups of ewes in a good autumn when he felt he had done an excellent job of feeding. He has one of our top local Romney flocks.
We recorded all of this against his scanning results, using that as a base level. He will now weigh pre-tup every autumn to ascertain the need to feed and what to expect from the ewes. This was tested in the extreme situation of 2013 with yet another drought.
Careful feed management and timely allocation saw him achieve an identical scanning result in a dreadful autumn and then we recorded the management and feed systems (and the associated costs) so that they could be used in future without starting from scratch again. Are your scanning results repeatable and worth bragging about?
What feeds do you have available? Do you plan for a good tupping or wait for rain? There is a plethora of feedstuffs available for feeding ewes, all with a cost attached but most with nothing but benefits if you can work out how to incorporate them.
For instance, feeding grain to a well-performed flock when you get the timing right might cost only 2-3% of your final scanning or lambing result. Is spending 2% to retain maybe 20% in any autumn a bad spend? You must do your homework though – crops must go in early, ewes need adjustments times for new feeds and nitrate levels need checking.
How clever can you be? Vasectomised teaser rams are not widely used but the practice is gaining momentum, especially in eastern areas. They have a lot to offer when ewes join anywhere from mid-January to mid-March and can also make huge gains in hogget mating operations as well.
Tie the use of teasers in with supplement feeding and you have a very short and well-defined period of feeding – say two weeks pre-tup on grain or silage and just a week during tupping when maybe 95% of the ewes are mated. Then stop.
So are there some small changes for some big returns with:
- better fecundity?
- heavier ewes?
- use of supplements?
- real flushing and targeted feeding?
- planning and recording?
Get good advice when you consider change – find an adviser you trust to bounce ideas off and to bring a fresh perspective to the table. There are huge opportunities for big returns in sheep breeding. Use some of them.
Richard Hilson has been in vet practice for 25 years in Hawke’s Bay and works for Vet Services in Waipukurau. He also farms sheep, cattle and deer with his wife Karen on the Takapau Plains.
