Pregnancy scanning ewes - are you maximising your returns? - 1 July 2009
Pregnancy scanning ewes is now common, but many producers are not fully maximising their return on investment. Ultrasound scanning of ewes has increased over the past 25 years so that now about one third of all ewes are scanned annually for pregnancy.
However, Chris Shands, NSW DPI Sheep and Wool Officer and Sheep CRC scanning workshop coordinator, said that there is more to scanning than just identifying wet (pregnant) and dry (non pregnant) ewes – scanning for singles and twins can also provide significant benefits of improved lamb survival.
"Once the ewes have been scanned for wet and dry then decisions can be made to cull, rejoin or run as a dry ewe until the next joining," Chris said.
"But single and twin bearing ewes need different management and this can start as soon as the ewes have been scanned."
Lamb losses at or about the time of birth can be significantly reduced if the birth weight of new born single and twin lambs is managed by targeted nutrition of the ewe after scanning.
"By using the scanning data, producers are able to develop an overall package to ensure optimum survival of twin and single born lambs," Chris said.
"These management differences include matching flock nutritional needs and applying fat or condition score targets to ensure correct levels of feed from scanning to lambing, as well as the selection of paddocks that suit the needs of twin lambing ewes compared to singles.
"Managing high birth weights of single born lambs in good seasons can be quite a challenge but knowing the pregnancy status of the ewe, six weeks prior to lambing enables different management of the single bearing ewes to avoid dystocia losses," Chris said.
Recent research by the Sheep CRC and the Lifetimewool project has measured the benefits from pregnancy scanning and developed strategies to optimise management of empty, single and twin-bearing ewes.
CJ Hawkins Homestead, University of New England, Armidale NSW 2351