The two-months post-weaning are the best time to preferentially feed lighter ewes to ensure they are at an optimal Body Condition Score of at least 3 going into mating.
A Beef + Lamb New Zealand Knowledge Hub learning module explains that there are generally four months between weaning and mating. Getting the feed management right in the two-months immediately after weaning, will make hitting pre-mating Body Condition Score (BCS) targets much easier.
It can be a balance trying to maintain pasture quality for growing stock while trying to lift ewe condition in the lead-up to mating, but that’s where Body Condition Scoring is so valuable.
An ideal time to score is three to four weeks after weaning when ewes are often yarded for mouthing and to have their udders checked. Lighter conditioned ewes can then be separated out and preferentially fed, while ewes that are at or close to their ideal BCS can be maintained.
To maintain ewes that are at a BCS of 3 or better, they typically need a daily allocation of 1.0-1.3 kg DM of medium to good quality feed (with an ME of 10-11) depending on liveweight (use the FeedSmart tool to get an exact amount for an individual flock).
This is grazing pastures that are around 5-6cm in height. Grazing below 3cm or 1500 kg DM/ha may result in a loss of body condition. Ewes grazing slopes need 15 percent more feed for maintenance than ewes grazing a flat paddock.
For ewes with a BCS below 3, it takes a 10 percent increase in their liveweight to lift one BCS.
Ewes that need to gain 50gm/day to meet their BCS targets before mating need to be fed 30 percent above their maintenance requirements, while ewes that need to gain 100gms/day need 60 percent about maintenance requirements.
For more information go to Principles of feeding: From weaning to mating (sheep).