How to start and maintain the STAR accelerated lambing system
M. L. Thonney
23 July 2007

There are three groups of ewes during any 73-day period. The groups of ewes are those that are:

1. Lambing (first 30 days) and lactating ewes.
2. Breeding (first 30 days) and gestating ewes.
3. In the last half of gestation.

Groups 2 and 3 above are managed together because which ewes previously in group 2 that were bred is unknown.

Ewes that don't breed in any given period should conceive in the first 30 days of the next 73-day period so sometimes the groups can become unbalanced. It is more likely that ewes will breed in the autumn than in the spring and balancing may be required. One way to do this is to shorten the autumn breeding seasons to 20 days.

To start on the STAR system, decide on the beginning dates for the five 73-day periods. Then:

1. Breed 1/3 of the flock for the first 30 days of the first 73-day period.
2. Add the second 1/3 of the flock to the breeding group for the first 30 days of the 2nd 73-day period.
3. Near the end of the 2nd 73-day period, use udder palpation to sort out ewes for lambing in the first 30 days of the 3rd period.
4. Add the third 1/3 of the flock to the 30-day breeding period of the 3rd period (during which time any ewes bred during the first period should be lambing).

After the third period:

• Breed non-lambing ewes during the first 30 days of each 73-day period (about half should be pregnant so only about half should need to be bred).
• Near the end of each 73-day period, use udder palpation to sort out ewes for lambing in the first (20 to) 30 days of the next 73-day period.