Making the most of scanning

Actions to take at ewe pregnancy scanning

The most important action to take at scanning is to take off multiple ewes that are light. That is, those below body condition score 3. These ewes can be given some priority feeding before they lamb which will enable them to produce more colostrum, have higher lamb survival and produce more milk. The feed consumed to do that earns over 35cent/kgDM. That is one of the most profitable uses of feed on the standard hill country farm.

Should single ewes be separated from the multiples at scanning? For ewes wintered totally on pasture and in the North Island, generally the value of keeping an efficient rotation outweighs the benefit of the separation. That separation can happen when within five or six weeks of lambing. However if feed is very short it is most important that multiple ewes are protected as much as possible and separating them at scanning is a way to do that. The singles become the sacrificial stock in this case.

The value in maintaining winter rotations should never be ignored. It is so powerful in not running out of feed as lambing approaches. Keeping the bigger mob together enables control over allocation of feed, at a time when restriction is still all that is needed. Having the feed to gradually lift the multiple ewes once within five or six weeks is crucial to maximising all of the outcomes from lambing. 

When ewes are wintered on crop and where winter pasture growth rates are very low, separating the singles and multiples at scanning is more common. This to be sure to be able to protect the multiples.

The overwhelming action at this end of pregnancy is to ensure that the multiple ewes do not lose any body condition in the five to six weeks before they lamb. Losing condition in that window results in them producing less colostrum, have lower lamb survival and produce less milk. So even weaning weights are influenced by feeding at this stage.

Body condition score has a huge influence on all aspects of a ewe’s performance. Most condition scoring is done by eye and is relatively accurate if less than a month’s wool on them. Beyond that the eye picks out only the very light ones. The biggest opportunity is to lift those between two and three condition score because these make up the biggest number. But a big proportion of these are missed by visual scoring. Physical scoring by just feeling how sharp the ends of the short ribs are will pick out the ones needing rescuing. As a guide, at body condition score two the ends of the short ribs feels like the running your fingers over your knuckles. At condition score three they feel like the back of your hand. Lumpy but relatively smooth. Obviously it is an imprecise monitoring tool but good enough to make a difference. Just like pasture scoring.

To leave the lambing outcome totally in the hands of what the season delivers is like betting. But there are actions which can really buffer the impact of bad weather. The time that ewes need to be fed is totally predictable, months in advance in fact. So planning to have that is real. The big buffer is ewe condition score which is also known and manageable. These two points of influence puts you more in control of the outcome than just hoping.

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