One of the most important breeds of Iranian goats is the Markhoz goat. Estimation of genetic parameters and genetic trend helps to select the best Breeding plan. The present study aimed to estimate the (co)variance components, genetic and environmental parameters, and the genetic trend of Markhoz goat body weight traits at different ages. To this aim the Bayesian statistical method was used. This research used the information about the birth weight (BW), weaning weight (WW), 6-month weight (6 MW), 9-month weight (9 MW), and yearling weight (YW) of 5.549 offspring of 262 bucks and 1620 does. The data were collected in 1992–2020 from the Markhoz breeding center, in Kurdistan Province. A total number of 5.159, 3.948, 3.759, 3.337 and 5.159 records of BW, WW, 6 MW, 9 MW, and YW were used, respectively. SAS9.4 statistical package was used to explore significant environmental factors affecting these traits. MTGSAM software and Gibbs sampling was used to estimate genetic parameters. Environmental factors including birth year, sex, birth type and the doe age at parturition were significant to all the mentioned traits and were included as fixed effect in the model. Direct heritability’s were estimated to be 0.29, 0.15, 0.16, 0.34, 0.33, for BW, WW, 6 MW, 9 MW, and YW, respectively. The genetic trend of these traits was 1, 27, 39, 81 and 78 g per year, respectively. The genetic and phenotypic correlations of the studied traits ranged from medium to high. Gibbs sampling could estimate the parameters in a reasonable range. The research findings suggested that growth traits in Markhoz goats, at different ages, were affected by the maternal genetic effects. The medium to high heritability obtained for the studied traits shows that selecting these traits can lead to a low to medium genetic improvement.
