Genetic and economic benefits of selection based on performance recording and genotyping in lower tiers of multi-tiered sheep breeding schemes

Table 1 Parameters describing the structure and performance of different tiers within the three-tiered breeding scheme

Parameter	Unit	Tier within the breeding program
Parameter	Unit	Nucleus	Multiplier	Commercial
Flock breeding ewes	Head	826	7000	180,000
Flock breeding rams	Head	10	70	1800
Ewes mated to terminal sires	%	0	0	20
Ewes/ram	Head	80	100	100
Ewe replacement rate	%	35	35	30
Mixed age ewe lambing rate^a	%	210	190	165
Ewe lamb lambing rate	%	100	90	80
Lamb survival	%	79	79	82
Weaning rate	%	166	150	135
Lambs sold as stores^b	%	–	–	20

ISSN: 1297-9686