# Fertility of Crossbred Dairy Cattle After Progesterone‐Supplemented Co‐Synch in Southwestern Ethiopia

## TL;DR

This study in Ethiopia found that adding progesterone to a synchronization protocol improved estrus response and pregnancy rates in crossbred dairy cattle.

## Contribution

The study evaluates a progesterone-supplemented Co-Synch protocol's effectiveness in crossbred dairy cattle in Ethiopia.

## Key findings

- 80% of animals showed estrus response to the treatment.
- 59.17% pregnancy per artificial insemination was achieved.
- Primiparous cows had the highest pregnancy rates.

## Abstract

In Ethiopia, the reproductive efficiency of dairy cattle utilizing artificial insemination (AI) is low, and implementing estrus and ovulation synchronization protocols could enhance the efficiency. Therefore, this study was designed to evaluate the effect of progesterone (P4) supplementation during Co‐Synch on estrus response (ER) and pregnancy per AI (P/AI) in crossbred dairy cattle breed in Southwestern Ethiopia. In the trial, heifers and cows (n = 120) were enrolled in the study. All animals received 100 μg of gonadotropin‐releasing hormone (GnRH) and had a progesterone‐releasing intravaginal device (PRID) inserted intravaginally on Day 0. On Day 7, they received 25 mg of prostaglandin (PGF2α), followed by the removal of the PRID. On Day 9, animals received 100 μg of GnRH concurrent with insemination. Estrus signs were monitored to assess heat response during morning and evening for at least 30 min at approximately 12‐h intervals from PRID removal on Days 7 through 9. Trans‐rectal ultrasonography was used to diagnose pregnancy 60 days after AI. The P/AI was recorded as the total number of pregnant females from the total number of animals involved in the synchronization program. A logistic regression analysis was performed to test the effectiveness of the treatment on ER and PR. 80% of animals showed ER to the treatment. A greater percentage of primiparous cows (93.33%) responded to the treatment, followed by heifers (83.33%), while the lowest response was seen in cows with a parity of 3 (66.67%). A total of 59.17% of the overall P/AI was achieved. The P/AI was affected by parity; a higher P/AI was obtained from the primiparous group. Statistically, no bull or BCS effect on P/AI was observed in the current study. Supplementation of P4 improved pregnancy outcomes, surpassing the national average, suggesting the protocol’s success in synchronizing estrus and ovulation among crossbred cows and heifers.