Population genetic structure analysis of Shall sheep using pedigree information and effect of inbreeding on growth traits

Figures & data

Table 1. Summary statistics for growth traits in Shall sheep.

Item	Trait
	BW	3MW	6MW	ADG1	ADG2	KR1	KR2
No. of observations	12786	9521	5106	8543	4303	8543	4303
Mean (kg)	4.13	22.19	33.10	0.199	0.159	0.0098	0.0048
SD (kg)	0.75	4.85	5.59	0.051	0.031	0.0005	0.0001
CV (%)	18.12	21.85	16.88	25.710	19.320	5.8100	3.1600
Minimum (kg)	2.00	9.00	16.00	0.061	0.066	0.0058	0.0036
Maximum (kg)	6.40	38.00	50.00	0.389	0.257	0.0104	0.0053

BW: Birth weight; 3MW: 3-month weight; 6MW: 6-month weight; ADG1: average daily gain from birth to 3-month of age; ADG2: average daily gain from birth to 6-month of age; KR1: Kleiber ratio from birth to 3-month of age; KR2: Kleiber from birth to 6-month of age; CV: coefficient of variation.

Figure 1. Pedigree completeness up to three generations back in Shall sheep. GD: Grand dam, GS: Grand sire, GGD: Grand-grand dam, GGS: Grand-grand sire.

Figure 2. Inbreeding trend over the years in Shall sheep.

Table 2. Population parameters of Shall sheep obtained from pedigree analysis.

Parameter	Value
No. of animals	64,964
Founder genome equivalent $(f_g)$	6921.15
Effective number of ancestors $(f_a)$	8366.46
Effective number of founders $(f_e)$	8372.39
Effective number of non-founders $(N_{\mathit{enf}})$	40064.50
Ratio of the effective numbers of founders and ancestors $(f_e/f_a)$	1.001
Average inbreeding (F)	1.62%
Average coancestry $(AC)$	0.0072%
Changes in inbreeding $(\Delta F)$	0.0005493
Generations interval (L)	3.755
Effective population size (Ne)	910.25
Average number of discrete generation equivalents (ge)	0.458568
Maximum number of discrete generation equivalents (Max ge)	4.125
Minimum number of discrete generation equivalents (Min ge)	0

Table 3. Regression coefficients (±SE) of growth traits on inbreeding of Shall lambs for a change of one percent in inbreeding.

Trait	Male	Female	All population
BW	−1.149 ± 0.404**	−0.861 ± 0.390*	−0.965 ± 0.288**
3MW	−5.804 ± 3.093*	−13.523 ± 2.830***	−9.740 ± 2.120***
6MW	−0.915 ± 5.071	−13.673 ± 4.426**	−8.697 ± 3.499*
ADG1	−0.108 ± 0.036**	−0.120 ± 0.033***	−0.156 ± 0.024***
ADG2	0.002 ± 0.034	−0.057 ± 0.030*	−0.039 ± 0.024*
KR1	−0.0008 ± 0.0003*	−0.0008 ± 0.0003*	−0.0008 ± 0.0002**
KR2	−0.0004 ± 0.0001*	−0.0004 ± 0.0002*	−0.0004 ± 0.0001**

BW: birth weight; 3MW: 3-month weight; 6MW: 6-month weight; ADG1: average daily gain from birth to 3-month of age; ADG2: average daily gain from birth to 6-month of age; KR1: Kleiber ratio from birth to 3-month of age; KR2: Kleiber from birth to 6-month of age.

*p < .05; **p < .01; ***p < .0001.