Under their animal welfare regulations, the Ministry of…
Karen Phillips, BVSc, MANZCVS: CHB Vets, Waipukurau
This article was first published in the magazine of the Black and Coloured Sheep Breeders’ Association, in September 2015. It is reproduced here with permission.
I was wondering if you could answer a question arising from the earlier article you wrote about lambing. In it you described the stages of labour and said “Once a ewe enters 2nd stage labour, a lamb should be born within an hour.”
Last year I had a ewe who was obviously lambing, so I was keeping an eye on her. I started to get concerned when I could see the fluid filled bag had come out, but she didn’t seem to be having any active contractions and time ticked by. My question is: once you can see the fluid filled sac, is she in second stage of labour, and if so, how long should you wait before you intervene if there is no sign of any progress? Is it different for a first-time lamber? Is there any cause to be concerned about possible infection once you see membranes like this outside a ewe’s body?
In the event, I waited for over two hours, then got her in and pulled the lambs out. I know you are meant to pull with contractions, but she didn’t seem to be having any, so after I’d checked that the legs were properly extended and I could feel two legs and one head in the right place, I just pulled gently but firmly on the legs. It was a battle – I’ve never had to work so hard to get lambs out, but eventually they came, both alive and the ewe no worse the wear for it all. I’ve just never been sure whether I should have left it longer to see if she could have done it on her own. I’ve still got her, and she raised both lambs successfully, but she didn’t go to the ram this year, as I wondered if she might have a narrow pelvis which caused me to have to work so hard.
Once the fluid filled sac appears the ewe is definitely in second stage labour and the lambs are most likely in the pelvis. Progress should happen fairly quickly but if she isn’t straining, you could leave it for an hour without any harm to the lambs. If she is straining hard, you may need to check her after half an hour if the lambs haven’t been born. First time lambers do take a bit longer to give birth generally, just because everything needs to open up and stretch as the lambs come through. Even so, the same principles apply with how long before you need to intervene.
If you have assisted a ewe to lamb and have had your hand inside her, an injection of penicillin may be needed to avoid an infection and possible toxaemia. Live lambs gives a better outlook than those born dead especially if the lambs have started to decompose.
If a ewe doesn’t have definite contractions, she is showing signs of a condition called uterine inertia. This can be caused by a number of factors from body condition, magnesium or calcium deficiencies, pregnancy toxaemia (sleepy sickness or twin lamb disease) and general poor health. If you assist her to lamb it is a good idea to give her a dose of Ketol Xtra or Headstart to try and correct the metabolic issues that are present. To avoid problems in the future, paying careful attention to the feeding and nutrition of the pregnant ewe is a great place to start.
There are two types of lambing difficulties – those due to maternal factors and those due to the foetus. Maternal factors include uterine inertia, failure of abdominal contractions and obstruction of the birth canal (ringwomb). If a ewe suffers from one of these then she may have problems again in the future so it is a good idea not to breed from her again. Foetal factors include the lamb in the wrong position or being too big compared to the ewe. You can breed from a ewe that has these problems as it may not happen again.