Abstract
Background: Fixed Timed Artificial Insemination (FTAI) is nowadays very popular, and it becomes cost-effective reproductive technology. Select-synch is a widely accepted estrus synchronization protocol for improving the reproductive performance of dairy cows that is having apparent low reproductive competence. Recently, some modified protocols based on Select-synch are introduced to enhance the reproductive potential. In the present study, a meta-analytical assessment was performed to evaluate the reproductive performance and blodd parametrs of post-partum anestrus cows synchronized with Select-synch and modified Select-synch programs. The Select-synch protocol was modified by increasing the dose of buserelin acetate injection @ 20 µg along with vitamin A injection. The post-AI progesterone injection was given to all the treated animals on days 10 and 17 in the modified Select-synch program.

Methods: The study was conducted on 164 crossbred cows. The experimental cows were divided into two groups comprising 82 animals in each group. In group A, the modified select-synch protocol (named Seld-synch) was applied and in group B, select-synch protocol was applied. Ten (10) ml of blood samples were collected from the experimental animals on day 0 (before starting the protocols) and day 1 (before AI) for the estimation of blood glucose, total cholesterol, calcium (Ca), phosphorus (P), estrogen and progesterone. The pregnancy was confirmed by per rectal examination after 90 days of gestation.

Result: It was observed that the majority of post-partum anoestrus cows (86.66%) exhibit oestrus in group A in comparison to group B (13.34%). The majority of post-partum anoestrus cows of group A exhibit oestrus signs before 48 hours of the second post PGF2α injection (60.97%). There was a significantly (P<0.01) low level of blood glucose, total cholesterol, Ca, P, estrogen and progesterone at day 0 in comparison to day 1 within the groups. The level of blood glucose, total cholesterol, Ca, P, and estrogen was significantly (P<0.01) increased after post-therapy as well as the conception rate (87.81%) in the treatment group A in comparison to group B (12.19%). In conclusion, a modified select-synch protocol (Seld-synch) can be used as a Fixed Timed Artificial Insemination protocol to treat post-partum anoestrus cows.

Key words: Cattle, Select-synch, modified Select-synch, post-partum anestrus, pregnancy