In a previous post we covered many of the issues facing triplet lambs especially survival.
The ewe-lamb bond is an important relationship for the survival of the lambs. A ewe will only provide care to a lamb that she has bonded with. Perhaps there is a way to improve this bond through nutrition?
The aim of this study was to determine if feeding ad lib vs medium feed levels had a difference in behaviour between triplet-bearing ewes and their lambs
Key Points
Feeding triplet-bearing ewes above pregnancy requirements has minimal effect on lamb behaviour.
Lambs born to ewes with BCS <2.0 offered medium feed may have experienced a weaker ewe-lamb bond compared with lamb born to ewe of BCS 2.5 and BCS >3.0 .
Ensure ewes are above a BCS of 2.0 throughout pregnancy to avoid any potential negative effects on behaviour of the lamb.
There were 88 first lambing triplet-bearing Romney ewes which lambed a total of 264 lambs.
The ewes were managed the same up until mid-pregnancy where they were randomly allocated to either the medium or ad-libitum feeding treatments.
Treatments
Medium (pasture mass 800-1200 kg DM/ha)
Ad-libitum (pasture mass 1500-2000 kg DM/ha)
The ewe BCS was also taken when feeding treatments were allocated to see if this had an effect on maternal behaviours.
Behaviours of ewes and lambs were recorded in the paddock at tagging for 5 consecutive minutes and a subset of lambs was subjected to a maternal-recognition test.
The lamb behaviours recorded were the time taken until the lamb stood, the time taken to follow the ewe and the time taken to suckle effectively. The high- and low- pitched bleats were counted for the 5 minute period. The maternal behaviour score was recorded for each ewe which is a five-point scale based on the distance the ewe retreated from her litter while they were being tagged (1 = at the approach of the shepherd, ewe flees and does not return, five = ewe stays within one metre of the shepherd and lamb).
The maternal-recognition test was performed in an enclosed area as shown on the right.
A random subset of lambs were tested with each lamb being tested individually.
Ewe 1 was the lambs actual mother and Ewe 2 was an 'alien' ewe, being the mother of one of the other lambs.
The lamb was released from the lamb holding pen and its location and activity was recorded at 10 second intervals for a total of 5 minutes. The high- and low- pitched bleats were counted for the duration of the test.
The high-pitched bleats indicate a degree of need and low-pitched bleats are considered an indicator of the strength of the ewe-lamb bond and are often considered the 'care-giver' bleats.
Ewe and lamb behaviour at tagging
In the graph below you can see that the ewe is predominately the one that will give the 'caregiver' bleats in all treatments during the observation period at tagging. The lambs will have low-pitched bleats but only around 3 or 4 on average over the 5 minute recording period.
Within the BCS≤2.0 ewe group, the lambs born to ewes on the medium treatment emitted more low-pitched bleats than the lambs born to ewes fed ad-libitum as indicated by the * on the graph.
There were no differences between the treatments on the number of low-pitched bleats.
For the high-pitched bleats between feeding treatments and BCS groups there were no significant differences, however, both the ewes and lambs had a similar number of high-pitched bleats.
In the paddock, there was no effect of ewe feeding treatment or BCS group on the median time taken for the lambs to stand, make contact with, suck from or follow their dam.
The author suggests that the similarities between treatments are due to the feeding treatments meeting the requirements of pregnancy, therefore, not experiencing any major differences at lambing time.
Maternal-recognition test
In the maternal-recognition test, the median time taken for the lambs to reach the dam and the time the lambs spent with her was not affected by ewe BCS or feeding treatment.
The only difference was the time spent walking for the lambs born to BCS≤2.0 ewes. These lambs spent less time walking, perhaps suggesting that they may have been weaker.
Overall the results indicate that feeding triplet-bearing ewes above pregnancy requirements has minimal effect on lamb behaviours. There is, however, some evidence to suggest that lambs born to ewes in the BCS≤2.0 group offered the medium treatments may have experienced a weaker ewe-lamb bond.
If this is the case then the aim would be to ensure the ewes are above a BCS of 2.0 throughout pregnancy.
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