On our way out of a drought it can be hard to decide which of our stock types should be the priority for feed and care. While often not the first to mind, your ewes should be forefront at this time as we head into midwinter, and here is why.
By now the placenta will have finished growing (the best time to influence that is pre-scanning), however 90% of fetal growth is between scanning and birth. Good feeding now will affect lamb birthweight, ewe condition at birth and colostrum / peak milk production. Tightening feed levels in late pregnancy does not reduce birth difficulties or bearings. However, it will increase the risk of sleepy sickness. Underfeeding at this time is likely to result in smaller, less vigorous lambs and weaker mothering behaviour. Colostrum and milk intake will be reduced and lambs will be lighter at weaning.
Body condition scoring ewes at scanning is a valuable way to set up for lambing. The ideal body condition score (BCS) is 3 at lambing – which will help prevent metabolic issues or bearings. Maintaining ewe body condition during pregnancy at BCS 3 requires an increase in weight by 8-10kg, and up to 20kg in twin bearing ewes, so weight gain is not as useful in this instance as body condition scoring.
Older, younger or lighter ewes (<3 BCS) should be fed preferentially over winter. Multiple bearing ewes have a higher energy requirement so if scanned, separating into single and multiple mobs is also recommended. If you scan your ewes, dry ewes can be sent to the works, reducing the feed demand.
Stress or feed restrictions in the last 30-40 days of pregnancy can have a big effect on lamb peri-natal mortality, so ensure they are are not restricted during this time. Pre-lamb shearing or crutching in late pregnancy is particularly hard on ewes and can have a large knock-on effect on lamb survival, so consider shearing mid pregnancy if required.
Sleepy sickness (pregnancy toxaemia) is one of the consequences of stress or under nutrition, and can cause loss of lambs and/or ewe. Clinical signs include depression, blindness, staggering, muscle twitching, teeth grinding and becoming cast. Ultimately, coma and death can occur. Early treatment with oral propylene glycol or intravenous dextrose can bring ewes back, but the lambs may be stillborn. Prevention is key!