الفهرس 
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Abstract
This study was carried to characterize the goat production systems and identify their production constraints. Personal interviews with 40 goat owners were conducted in three representative Governorates (Damietta, Port Said and Dakahlia). The survey was carried out using structured questionnaires, during the period from February to August 2010, containing a total of 90 items, grouped into the following sections; production resources, management practices, goat production performance and production constraints. The records of the does were collected from a Zaraibi goats herd raised on El-Serw Experimental Station, belong to the Animal Production Research Institute, Ministry of Agriculture, Egypt, over eighteen years from 1990 to 2007, A total of 3212 normal lactation records of 874 does out of these records 1626 record of 542 does were at first three parities. for constrict selection indexes for genetic improvement of some productive and reproductive traits for Zaraibi goats in Egypt, which, estimated the genetic parameters for (weaning weight, number of kids born, number of kids weaned and milk yield) at 1st parity and at first three parities.
The results obtained from the analysis of the data could be summarized as follows:
1- The majority of households (75%) kept only goat herds and 25% owned both sheep and goats.
2- The mean flock size was 12.6 heads, of which 53.74% consisted of does, 22.82% male kids, 19.15% female kids and 4.29% bucks.
3- About 60% of the goat keepers keep goats mainly for saving purpose, (30%) for income generation, (5.9%) and (4.5%) for meat and milk, respectively.
4- Usually the rate of majority of farmers Supplementing females at suckling and late pregnancy stages 82.5 and 70%, respectively.
5- In studied areas, 74.4% of breeders have their Zaraibi bucks.
6- Average weaning age and marketing age were 4 and 7.5 months, respectively.
7- Average weaning weight under household conditions was estimated as 14.8 kg.
8- Average litter size has been recorded as 2.16 kids.
9- Pre-weaning and post-weaning mortality were estimated as 11.47 and 2.76%, respectively.
10- Kidding interval of goat farmer’s is estimated as 250 days.
11-Female post-weaning sales (14.19%) was found to be lower than selling adult does (30%).
12-The poor fertility performance and cash need had higher reason for disposal for adult females were 85 and 70%, respectively.
13- Goat disease, low body weights and feed shortage are the major production constraints.
14- Estimates of heritability values were range from 0.21 to 0.29 for weaning weight in all models (1st parity and at first three parities). Which was higher value in 1st parity, while were range from 0.07 to 0.21 of number of kids born, from 0.05 to 0.16 of number of kids weaned and were range from 0.02 to 0.12 for milk yield in all models.
15- Estimates of heritability values were moderate values of heritability (0.20, 0.16 and 0.12) for number of kids born, number of kids weaned and milk yield at 1st parity.
16-The genetic correlations coefficients were positive between number of kids born and number of kids weaned (0.95), positive between number of kids born and milk yield (0.48) and positive between number of kids weaned and milk yield (0.20).
17- Expected genetic progress in each trait were 0.160 and 0.112 kids and 11.759 kg improvement for number of kids born, number of kids weaned and milk yield (index 4) at 1st parity. The efficiency of index was 0.426. The genetic gain was 21.747.
18- Expected genetic progress in each trait were 0.219 kg, 0.096 kids and 0.049 kg improvement for weaning weight, number of kids weaned and milk yield (index 6) at first three parities. The efficiency of index was 0.366. The genetic gain was 11.093.
This study show that goat diseases, low body weights and feed shortage are found to be the limiting factors for increasing reproduction and productivity of Zaraibi goats. Therefore, flock-owners need to be educate the importance of time of vaccination and feed supplement to the animals, during stages of production. In the same time the identification of alternative feed resources and strategic feeding management might be options for development of the Zaraibi goat sector of animal production in this area of Egypt.
Thus, recommended with use index (4) to genetic improvement for number of kids born, number of kids weaned and milk yield at 1st parity and use index (6) to genetic improvement for weaning weight, number of kids weaned and milk yield at first three parities (lifetime productivity) with the suitable environmental condition. of Zaraibi goats could be achieved through multiple trait selection indexes.