Estimation of Genetic and Phenotypic Parameters for Production Traits and Somatic Cell Count for Jersey Dairy Cattle in Zimbabwe

Table 4

Variance components and genetic parameters (±s.e) for production and Log₁₀SCC traits by parity.

Parity	Trait	𝜎^2𝑎	𝜎^2pe	𝜎^2𝑒	ℎ^2	𝑐^2	𝑟
All	Milk (kg)	86263	25532	173158	0.30±0.10	0.09±0.10	0.39
	Fat (kg)	428	78	822	0.32±0.10	0.06±0.10	0.38
	Protein (kg)	201	36	371	0.33±0.10	0.06±0.10	0.39
	Fat%	0.0587	0.0095	0.0710	0.42±0.11	0.07±0.11	0.49
	Protein%	0.0105	0.0016	0.0117	0.44±0.12	0.07±0.12	0.51
	Log10SCC	0.0252	0.0224	0.2500	0.08±0.07	0.08±0.07	0.16
1	Milk (kg)	106632	—	172145	0.38±0.10	—	—
	Fat (kg)	482	—	750	0.39±0.10	—	—
	Protein (kg)	247	—	386	0.39±0.10	—	—
	Fat%	0.0364	—	0.0405	0.47±0.12	—	—
	Protein%	0.0122	—	0.0126	0.49±0.12	—	—
	Log10SCC	0.0357	—	0.2844	0.11±0.07	—	—
2	Milk (kg)	73587	—	205573	0.26±0.09	—	—
	Fat (kg)	533	—	1122	0.32±0.09	—	—
	Protein (kg)	207	—	399	0.34±0.10	—	—
	Fat%	0.0614	—	0.0910	0.40±0.11	—	—
	Protein%	0.0087	—	0.0122	0.41±0.11	—	—
	Log10SCC	0.0473	—	0.3039	0.13±0.07	—	—
3+	Milk (kg)	61399	18852	206258	0.21±0.08	0.07±0.08	0.28
	Fat (kg)	245	77	779	0.22±0.09	0.07±0.09	0.29
	Protein (kg)	139	53	409	0.23±0.09	0.09±0.09	0.32
	Fat%	0.0282	0.0081	0.0515	0.32±0.10	0.09±0.10	0.41
	Protein%	0.0081	0.0023	0.0136	0.34±0.10	0.09±0.10	0.43
	Log10SCC	0.0420	0.0350	0.1952	0.15±0.08	0.13±0.08	0.28

𝜎²_𝑎: additive genetic variance, 𝜎²_pe: permanent environmental variance, 𝜎²_𝑒: residual variance, ℎ²: heritability, 𝑐²: permanent environment, 𝑟: repeatability, and SCC: somatic cell count.