Connectedness across flocks of the registered population of the Sardinian dairy sheep breed was evaluated. Used criteria were: number of sires used in the same contemporary group; number of direct links and the average within and between contemporary group relationship coefficients. Dataset including yearlings’ first lactation records of 1990 and 2008 were compared to evaluate the effect of coupling artificial insemination with controlled natural mating on connectedness. An increase of number of sires and direct links were registered between 1990 and 2008. These results confirm that the across years prolonged use of well planned moderate rates of artificial insemination had a strong effect on the overall statistical connectedness across flocks so permitting more accurate estimations of the management and genetic effects. As a whole, the decreasing of the average relationship within flock coupled to a marked enhance of the average relationship between contemporary groups, indicates that the genetic connectedness of the Sardinian registered population presents a clearly increasing trend. This fact assures that current genetic evaluations are reliable across flocks.

Evaluation of connectedness in the registered population of the Sardinian dairy sheep breed8:Suppl. 2(2009), pp. 141-143. [10.4081/ijas.2009.s2.141]

Evaluation of connectedness in the registered population of the Sardinian dairy sheep breed

Salaris, Sotero Luca;
2009

Abstract

Connectedness across flocks of the registered population of the Sardinian dairy sheep breed was evaluated. Used criteria were: number of sires used in the same contemporary group; number of direct links and the average within and between contemporary group relationship coefficients. Dataset including yearlings’ first lactation records of 1990 and 2008 were compared to evaluate the effect of coupling artificial insemination with controlled natural mating on connectedness. An increase of number of sires and direct links were registered between 1990 and 2008. These results confirm that the across years prolonged use of well planned moderate rates of artificial insemination had a strong effect on the overall statistical connectedness across flocks so permitting more accurate estimations of the management and genetic effects. As a whole, the decreasing of the average relationship within flock coupled to a marked enhance of the average relationship between contemporary groups, indicates that the genetic connectedness of the Sardinian registered population presents a clearly increasing trend. This fact assures that current genetic evaluations are reliable across flocks.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11388/261805
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