Dairy Sheep Symposium - the Department of Animal Sciences ...

Table 5. Repeatabilities and phenotypic correlations among scores from 3 qualifiers (A, B y C)
Correlations
Trait r A-B A-C B-C
Udder depth 0.57 0.81 0.77 0.86
Udder attachment 0.61 0.75 0.77 0.79
Udder shape 0.68 0.87 0.84 0.85
Teat placement 0.73 0.86 0.85 0.85
Teat size 0.60 0.77 0.72 0.79
Heritabilities, repeatabilities and variation coefficients are included in Table 6 (Fernández et
al., 1997). These values do not greatly differ from those obtained in other species such as cattle
using a linear scale and although heritabilities are not high they allow for a selection program
with a non-negligible expected response. This method has been experimentally applied to three
Spanish sheep breeds: Churra, Latxa and Manchega (Table 7) (de la Fuente et al., 1998) and it is
currently used in Churra sheep aiming at improving aptitude for mechanical milking (de la
Fuente and San Primitivo, 1997).
Table 6. Heritabilities, repeatabilities, and coefficient of variation of linear udder traits
Trait Heritability SE r CV
Udder depth 0.16 0.04 0.51 18.32
Udder attachment 0.17 0.05 0.48 27.79
Udder shape 0.24 0.06 0.62 31.23
Teat placement 0.24 0.06 0.64 37.19
Teat size 0.18 0.05 0.54 24.60
Table 7. Mean and standard deviation for udder traits in Churra, Latxa and Manchega
breeds
Trait
Churra
(n = 10762)
Latxa
(n = 2707)
Manchega
(n = 7171)
Udder depth 4.64 ± 1.35 5.87 ± 1.42 5.34 ± 1.28
Udder attachment 4.89 ± 1.44 5.64 ± 1.18 5.08 ± 1.29
Udder shape 4.58 ± 1.58 - 4.57 ± 1.31
Teat placement 4.33 ± 1.67 4.77 ± 1.18 4.64 ± 1.51
Teat size 4.36 ± 1.37 5.22 ± 1.19 4.92 ± 1.04