The objective of the present study was to compare the efficacy of estrus synchronization protocols through estrus response and fertility rate in non-descript cattle of Azad Jammu and Kashmir during the non-breeding and breeding seasons. A total of 312 non-descript cows (192) and heifers (120) with body condition score ranging between 3.0 to 3.5 were randomly assigned to receive Ovsynch (159), CIDR alone (74) and CO-Synch+CIDR (79) protocols. Animals were inseminated at 16 h after the second GnRH injection in Ovsynch, and 48 h after CIDR removal in CIDR alone and CO-Synch+CIDR groups. The results revealed that during non-breeding season, the tendency for success of the Ovsynch protocol was higher in terms of inducing heat and conception rate (CR) in non-descript cows under farm (87.5%) and field (50.0%) conditions compared to CIDR alone and CO-Synch+CIDR groups (P<0.05). Whereas, in the case of non-descript heifers, the CO-Synch+CIDR protocol significantly increased the CR at timed artificial insemination (TAI) under farm (50.0%) and field (33.33%) conditions compared to Ovsynch and CIDR alone groups (P<0.05). During the breeding season, CR/TAI was almost similar in all groups of non-descript cows under field conditions (P>0.05). CO-Synch+CIDR treatment yielded the higher conception rates (46.15%) in non-descript heifers compared to Ovsynch and CIDR alone groups. It is concluded that treatment of cows with Ovsynch, and heifers with CO-Synch+CIDR protocols may lead to higher CR/TAI and thus have the potential to improve the reproductive performance that can accelerate the rate of genetic improvement through AI.