Optimization of alternative breeding schemes for the genetic improvement of common Tigray highland sheep in northern Ethiopia

Table 1 Biological, technical and economic parameters for four alternative breeding schemes for common Tigray highland sheep

Descriptors	Village-based breeding scheme		Central nucleus breeding scheme
Descriptors	Scheme 1	Scheme 2	Scheme 3	Scheme 4
Proportion of populations in the production unit	1.0	0.9905	0.95	0.95
Village nuclei		0.0095		0.02
Central nuclei			0.05	0.03
Number of villages in the production unit	7	127	127	127
Village nuclei	–	2
Multiplier units				7
Lifetime use (years) of rams in the central nucleus			2	2
Lifetime use (years) of rams in villages	2	2	2	2
Lifetime use (years) of ewes in the central nucleus			7	7
Lifetime use (years) of ewes in villages	9.0	9.0
Mating ration (F/M)—villages	35	35
Mating ration (F/M)—central nucleus			25	25
Lambing interval (years)	0.66	0.66	0.66	0.66
Conception rate—central nucleus			0.90	0.90
Conception rate—villages	0.85	0.85
Age at first lambing (years)
Age of ewe at first lambing	1.5	1.5	1.5	1.5
Age of rams at first mating	0.70	0.70	0.70	0.70
Twinning rate	1.12	1.12	1.12	1.12
Survival of rams—villages	0.90	0.90
Survival of rams—central nucleus			0.95	0.95
Survival of ewes—villages	0.90	0.90
Survival of ewes—central nucleus			0.95	0.95
PWLS rate—village	0.89	0.89
PWLS rate—central nucleus			0.95	0.95
Suitability for breeding	0.90	0.90	0.90	0.90
Fixed costs per ewe (Birr)	46.55	50.36	74.42	116.99
Variable costs per ewe (Birr)	25.37	28.25	40.42	74.76
Investment period (year)	10	10	10	10

ISSN: 1297-9686