Updated: Jun 1
Lambing Dystocia or lambing troubles are when a lamb is either too big for the birth canal, the birth canal is abstracted and or the lamb is presented where a ewe can’t physically push the lamb out, e.g. breach or front legs pinned back.
Whilst dystocia and slow birthing can have a negative effect on the lamb, ewe health can also be affected with some lambs and ewes dying because of the issue. The single biggest effect both positive and negative on dystocia is nutrition. A prime example of this is when over conditioned ewes lamb, which cause slower births which effect lamb survivability because these ewes have excess fat through the pelvis area restricting the space the lamb has to exit the ewe.
Research has shown that Ewes that had prolonged and difficult births did not show competent maternal behavior compared to mothers with short and un-complicated deliveries. This means that ewes that had trouble lambing were slower to begin grooming their lambs after birth, spent less time licking their lambs, and were more likely to show rejection.
Similarly, lambs from a prolonged and difficult birth were significantly less vigorous after birth, as they had taken more time to stand, reach the udder and to suck successfully. They also had a reduced ability to maintain body temperature after birth. Lambs that were born from a slow birthing process had a higher rate of death in the first week then lambs born quicker.
How do we have a positive effect on the time spent lambing?
Providing accurate nutrient to the class of animal. Scanning pregnant ewes allows us to know how many foetuses each ewe is carrying, some scanners can even tell what cycle it was conserved in. This allows us to draft into groups and target the feeding program to each animals needs. Ewes carrying twins will need the most attention whist single bearing ewes are more robust
Lifetime ewe research has shown that maintaining a condition score above 2.7, during pregnancy results in higher lamb survival at birth, especially twin lambs, Increased lamb growth rate from birth to weaning as well as reducing ewe mortality.
For the people growing wool a half condition score lost during pregnancy, reduces the lambs clean fleece weight by 100g every year of its life whilst increases fibre diameter by 0.2micron each year.
Drafting animals into body condition scores and pregnancy status will give to the best ability to minimise lambing dystocia and issues associated with ewe time to lamb.
The last trimester of the ewes pregnancy is where the lamb puts on up to 70% of its birthweight. So a ewe in better condition at lambing will produce bigger lambs. Optimal birthweight for both the ewe and the lambs is 4.5-5.5kg. Ewes that are challenged in late pregnancy can have lambs that are 400- 500g grams lighter. On the flip side ewes that have accelerated nutrition above requirements can grow the lamb 400- 500g bigger.
From the graph below we can see that if we get the ewes in too good of BCS or over 3.5+ we start to have an increase in the death rate, due to lambing Dystocia
Ewes are also affected by weather, their age, pregnancy status and feed on offer at lambing (source: GSARI 2001-2004 lambing data)
For more information on how to prevent Lambing Dystocia in your flock, contact your local TRAC Expert.
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