A total of 70 Damascus goats (1.5-8 years old) taken from Sakha Research Station, Kafr EI·Sheikh Governorate, belonging to the Animal Production Research Institute was used to study the possibility of inducing oestrous and ovarian activity by hormonal treatment during anoestrus, and synchronization of oestrus and ovulation during the breeding season for the purpose of Irr.proving fertility and multiple kidding. New protocol for GnRH treatment was assessed during different times of the year. Seven experiments were carried out during different times of the year throughout the period from September 1999 to August 2002. Does in each experiment were divided into two similar groups according to age, body weight and physiological condition. In the first group (treated), does were i.m. injected (Day 0) with 1 ml GnRH analogue, fallowed 7 days later by i.m. injection with 0.7 ml PGF2cr- A second dose cf 1 ml GnRH analogue ,. JS given on day 9, and artificial insemination of all treated does was carried out 24 h later. Does In the 2114 group were allowed for natural mating. They were exposed to fertile bucks from the time contemporary to that of the start of hormonal treatment up to the end of the breeding season (end of January, experiments 1, 3 and 5) or for a period covering 2 cycles (experiments 2, 4, 6 and 7). Occurrence of oestrus following treatment, ranged frem zero% in deep anoestrus season to 70% in the breeding season. Gradual decrease in incidence of oestrous occurred with advance In age. Treated does were distributed almost conSistently over 28 h In onset of their oestrus. Values of fertility rate In treated group was highest (90.9%) in September, while it was (40%) In early August and (60%) in late August.Out of the breeding season, no response occurred in treated does. Does of control
group conceived only in September (breeding season) with conception rate, being 47.6% and significantly (P<0.05) deviating frem that of treated groups. Treatment during the breeding season (September), in addition to improving fertility rate shortened the duration of kidding to 37% of that in control group (7 and 19 d, respectively). Treatment during the transition period to the breeding season (early and late August) resulted In 1·2 months earliness In kidding time. Acccrding to results of the present study. it could be recommended to use the present protccot of GnRH treatment during the breeding season for synchronization of ovulation and, subsequently, kidding with insemination to be based on pre-determined time. GnRH is time saving (10 day), resulting in high fertility rate (90.9%). Hormone treatment can be
used in the transition period to the breeding season (August) to enhance kidding dependent upon the requisite and economics of Damascus kid and milk production needed. If out of season breeding is settled, GnRH -treatment is not recommended to be used and artificial insemination based on either overt oestrus or pre-determined time.