The aim of the present study was to evaluate the genetic parameters and genetic trends for birth and weaning weights, and to quantify the inbreeding characteristics for a population of Zandi sheep. Genetic parameters from both single- and two-trait analyses were estimated using restricted maximum likelihood (REML) with animal models. Genetic trends were estimated by averaging estimated breeding values on year of birth. Full pedigree was analyzed for estimation of inbreeding characteristics. The results obtained confirmed relatively low additive genetic variation in the population, especially for weaning weight. Estimates of direct and maternal heritability were 0.12 and 0.20 for birth weight and 0.08 and 0.02 for weaning weight, respectively. Estimates of breeding values averaged by year of birth for birth weight and weaning weight increased over time. However, there was little genetic progress for birth weight (0.002 kg yr1), whereas the tendency for weaning weight was 0.020 kg yr
1. Inbred animals consisted of 25% of the population. The effective population size (Ne) was 66 individuals. The inbreeding rate per generation (DF) was 0.76%. The average value of inbreeding (F) in the Zandi population was 1.05% and the average relatedness (AR) coefficient reached 1.64% in the whole pedigree. A range of 2.84 to 4.01 yr was obtained for the average generation interval in different pathways. Selection of rams with the lowest AR was recommended for better management of inbreeding and avoidance of relative mating.

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