Genetic evaluation of Iraqi local goats and their crosses depending on their growth rates

Abstract EN

-Body weights of 505 kids at birth, 3, 6, 9,12,15 ana is montns oi age were u.cu ...

The kids were born at the Agargouf Goat Breeding Station during 1994-1999 and comprised of different genetic groups namely Local (L) and Damascus (D) purebreds as well as those obtained by 2- and 3- way crossbreeding between L, D and Saanen (S).

Growth curve was tested for orthogonal polynomial and it shown that it was in linear type.

Growth rate for each kid was recomputed before US‘nS The ^overall means of weights at birth (BWT), 18 months of age (WT18M) and growth rate from birth to 18 months of age (GR) were 3.17, 25 59 kg and 0.042: kg / day, “ |™UP had no effect on studied traits.

Age of doe had a significant (P<0.01) effect on BWT only.

Year ot kidding affected all studied traits significantly (P<0.01).

Kids born m winter had ^ignific y (P<0.01) higher WT18M and grew faster than those born m spring.

Ma e and single born kids were heavier (P<0.01) than females and twins in all traits.

Heritability and repeatability 1Tor GR we determined by REML method after adjusting the records for fixed effects as 0.54 and CL73, respectively.

The animal model (AM) program was used to predict breeding values (P^V) individually for kids and their parents.

Genetic and phenotypic trends of GR were estimated as regression of breeding and phenotypic values on birth year, respectively.

The overall mean of predicted breeding value for GR was-0.079 kg.

GR had a positive (P<0.05) genetic trend over the years of pooled records (0.042 kg / year).

The average phenotypic trend of GR was 0.150 ke/year (P < 0.01).

In order to improve breeding values, selection must be based on genotypic rather than phenotypic superiority.

Thus variation due to fixed effects must be removed by the use of suitable adjusting model.