Australian Livestock Scanning Services Group

The results and recommendations from 23 years of on-property R&D with commercial sheep and cattle producers. We specialise in precision scanning for pregnancy, twinning, and ageing of foetus in sheep and cattle and in helping to raise lamb survival and cow fertility in stud and commercial breeding enterprises.

mob: 0428 667 567, email: fowler.doug@bigpond.com

17. The magnitude of national lamb losses

The loss of new born lambs in the Australian sheep flock is massive. National ewe breeding intentions (AWI Wool & Sheepmeat Survey 2014) estimate that about 41 million ewes will be joined in Australia in 2014. If the survival rates for lambs shown in Table 4 are realized for these ewes, over 10 million (10.5), of their lambs will die during or soon after birth.

These are large numbers and the manner in which they have been determined needs to be supported. Where there are 13.7% of ewes scanning as empty and 23.7% scanning with twins (Table 3) there will be 1100 lambs in 1000 ewes. Where lamb survival rates of the order of those shown in the Table 4, there will be a loss of 257 lambs

It is also very reasonable to question the accuracy of the joining and lamb marking percentages used to produce the estimate of lamb losses calculated here.

Lamb survival rates throughout eastern NSW

The following four tables show the scanning and lambing performance for reproducing flocks for three different enterprise types and four different regions in NSW. The results were obtained in a project funded by Meat and Livestock Australia (MLA) and conducted by ALSS during 2006. (Fowler 2007).

Table 1. Scanning Results for ewes in four different regions of NSW

REGIONS OF NSWNumber
scanned
Percent
empty
Percent
with singles
Percent
with twins
Overall Monaro13,07515.269.415.4
Overall Riverina6,59313.045.241.8
Overall Southern Tablelands40,16518.560.121.3
Overall Northern Tablelands38,4398.365.626.1

Table 2. Lambing Results for ewes in four different regions of NSW

REGIONS OF NSWMonaroRiverinaSouthern
Tablelands
Northern
Tablelands
Total ewes in all lambing mobs11,0225,71629,96431,668
Percent lambs marked from all pregnant ewes 90.8102.492.898.3
Percent lambs marked from all pregnant maiden ewes 73.873.176.979.8
Percent lambs marked from all mature single lambing ewes84.485.784.482.0
Percent lambs marked from all mature twin lambing ewes128.5132.7131.3144.1

Table 3. Scanning results for ewes in three different enterprise types
and over all regions and enterprise types

ENTERPRISE TYPESNumber ewes
scanned
Percent
ewes empty
Percent ewes
with singles
Percent ewes
with twins
Overall Merino x Merino54,95514.970.814.3
Overall First Cross Lamb Production22,09016.059.224.8
Overall Second Cross Lamb Production21,2278.344.747.0
Over all regions and enterprise types98,27213.762.623.7

Table 4. Lambing results for ewes in three different enterprise types
and over all regions and enterprise types

ENTERPRISE TYPEMerino
X
Merino
First Cross
Lamb
Production
Second Cross
Lamb
Production
All Regions
and
Enterprises
Total ewes in all lambing mobs45,92716,27316,17078,370
Percent lambs marked from all pregnant ewes 88.097.3114.995.4
Percent lambs marked from all pregnant maiden ewes 74.682.585.977.4
Percent lambs marked from all mature single lambing ewes84.282.083.483.5
Percent lambs marked from all mature twin lambing ewes123.7132.3152.0137.0

The results provided in these tables are from a study involving 98272 ewes. Although this is not a small number, it is a very limited sample from which to extrapolate to a national level. This is more so, when the results give rise to such alarming figures for lamb losses.

The estimates provided in the tables are very reasonable when compared to a large body of similar, but totally independent data reported by Alexander (1975). Using Alexander's data set, McGuirk et al (1982) reported losses to marking of 11 million lambs, a loss remarkably similar to that found here (10.5 million)

Clearly, these estimates of the loss of new born lambs are a very reasonable estimate of the true magnitude of loss. Where lambs are valued at around $100 each, the loss is of the order of a billion dollars annually, a loss that appears to have remained unchanged for thirty to forty years since Alexander and McGuirk first drew attention to the problem.

Pregnancy scanning is a pivotal strategy in addressing lamb losses because it enables the correct management strategies to be provided for each class of ewe. Management strategies aimed at saving new born lambs are provided in this website and ALSS will help our scanning clients to successfully implement these strategies.

References

Alexander G. 1975. Workshop on Perinatal Mortality in Farm Animals, Published Prospect, N.S.W. C.S.I.R.O. Division of Animal Physiology, 1975 Bookmark: http://trove.nla.gov.au/version/22530988.

Fowler D.G. (2007) Lamb marking performance for ultrasound scanned ewes in Australian sheep flocks. Final Report AHW.131, Meat & Livestock Australia, Sydney. 17 pp. http://www.mla.com.au/ click on Search on-farm R&D projects, enter title & click search.

McGuirk, B.J. Ferguson, B.D. Haughey, K.G. George, J.M. Piper, L.R. Hanrahan, J.P. Evans, R. Bindon, B.M. Donnelly, F.B. (1982) Improving Lamb Survival in Merinos. Proc. Aust. Soc. Anim. Prod. 14: 23-35. http://www.asap.asn.au/livestocklibrary/1982/McGuirk82.PDF.