Preparation and time is crucial for good pre-tupping nutrition
I guess we all assume that the new sheep we buy have all been grazing grass and perhaps having a few concentrates before they go to the sales – but do we really know? Be sure to ask the vendor what the animals have been getting before you buy.
It takes a couple of weeks for a sheep to acclimatise to a new diet, as the rumen bugs need to change to accommodate a different balance of nutrients (starch, sugar, fibre, protein sources) between a high concentrate diet and a forage only diet. So if you buy rams that have been fed a lot of concentrates, it is little surprise that they lose weight rapidly when turned out to grass with the ewes. The stress of the sales, a change of environment and a new diet can easily knock a ram off its stride when it first arrives on a new farm.
Ideally ask the vendor what the animals have been eating in the run up to the sale. Have they been running on grass alone or have they been getting a lot of compound/home mix feed? If they have been getting concentrates then ask what and how much and make sure to provide something similar at least for the first week or two after arrival, allowing the rumen to adjust to the different dietary balance that you want.
Depending on grass availability and body condition, you may need to feed rams throughout tupping. A daily feed of 0.5kg of a specialist ram compound (18% crude protein with the correct mineral balance) will help to maintain condition and allow for raddle changes. You are aiming for body condition score of 3.5-4.0 at the start of tupping for males. Overfed rams are lazy and fat and tend to have reduced libido and fertility.
Likewise with ewes – the all important factor in pre-tupping nutrition is body condition score. Sort ewes carefully and divide by condition so you achieve 90% of the flock in the ideal condition score when the rams go in. This would be condition score 3.5 for most lowland ewes, 3.0 for upland ewes and 2.5 for hill ewes. Thinner ewes should be given priority grazing to gain condition and fat ewes held on barer fields to shift a bit of body fat (taking them down half a condition score).
All ewes should be brought together for flushing three weeks before mating, but remember for prolific breeds (such as Aberdales and Lleyns) it is best to hold condition at about 3.0 and not to flush or you will get too many triplets and quads.
Replacement ewes should be on farm at least a month before mating to allow time for biosecurity treatments, pre-tupping vaccinations for abortion, a good four week quarantine period and for them to settle into their new environment and diet.
Does your farm have specific trace element deficiencies? Then also make sure new sheep are supplemented like the resident flock so that deficiencies do not impact on fertility.
This article, by independent sheep consultant Kate Phillips, first appeared in the August / September 2015 edition of Sheep Farmer.