Proper feeding makes for fewer lambing problems
Published 01/03/2011 | 05:00
Close to 70pc of lamb foetal growth occurs during the last six weeks of pregnancy. In fact, the weight of each foetus increases by nearly 2kg during the last three weeks of pregnancy. Milk-producing alveolar cells in the ewe's udder also develop during this period along with colostrum and its antibodies.
It is also during this period that the lamb lays down fat around its kidneys, often referred to as brown fat. This fat has the ability to produce large amounts of heat very rapidly and plays an important part in the survival of newborn lambs, particularly providing energy between birth and first feed.
As a result, there is a massive increase in the ewe's energy and protein requirements. Complicating the issue further is the fact that as the lambs grow within the ewe, they occupy more space and this can restrict the ewe's intake by 25-30pc.
Thus, it is easy to understand why it is necessary to provide high-energy concentrate supplementation during late pregnancy. Insufficient supplementation can result in decreased lamb birth-weight, insufficient colostrum and increased incidences of conditions such as vaginal prolapse and twin lamb disease (pregnancy toxaemia).
On the other hand, acidosis can result from feeding too much concentrates or where the concentrate results in rapid fermentation within the rumen.
Rapid fermentation, particularly where cereals have been finely ground, reduces the growth of bacteria that digest fibre. This leads to a fall in roughage intake and poor rumination. The concentrate becomes a substitute for roughage rather than a supplement. The tendency by some meal compounders to grind cereals rather than just break the grain is detrimental to good sheep nutrition. On the practical side, once feeding levels exceed 0.5kg/day, the animals should be fed twice daily.
Check ewe condition three to four weeks pre-lambing (this can easily be done when administering the pre-lambing clostridial booster) and adjust feed level accordingly.
Be careful with ewes carrying singles as high feed levels at this stage can result in oversized lambs. Take particular note of the first ewes that lamb. Do they have an ample supply of free-flowing colostrum? Adjusting feed/protein levels can rectify a low colostrum problem within a three or four-day period.