EVALUATION OF PREGNANCY RATE THROUGH THE APPLICATION OF RECOMBINANT AND TRADITIONAL Ecg IN A FIXED-TIME ARTIFICIAL INSEMINATION (FTAI) PROTOCOL IN CHAROLAIS COWS

Abstract

Fixed-time artificial insemination (FTAI) is a reproductive biotechnology that enables the manipulation of the estrous cycle in cattle, improving genetic production efficiency and reducing calving intervals. This study aimed to evaluate the pregnancy rate in Charolais cows synchronized using a 5-day Co-Synch protocol, with the application of recombinant and traditional eCG. Twenty Charolais cows were randomly divided into two groups. All animals received a modified Co-Synch protocol: on day 0, 0.01 mg of GnRH (IM) was administered, and a 1.32 g intravaginal progesterone device was inserted for 5 days. Upon removal, 0.6 mL of cloprostenol (Estrumate®) and either 105 IU recombinant eCG (1.5 mL Folirec®) or 0.55 mL traditional eCG (Novormon 500®) were administered. Seventy-two hours later, FTAI was performed in cows showing estrus; those without signs received a second dose of GnRH before insemination. All cows had adequate body condition and functional ovarian structures. The group treated with recombinant eCG showed 45% estrus expression and a 70% pregnancy rate, compared to 35% and 30%, respectively, in the traditional eCG group. The total cost was slightly higher with recombinant eCG (USD 1214.10 vs. 1193.40), but the cost per pregnancy was considerably lower. In conclusion, recombinant eCG in FTAI protocols proved more efficient both reproductively and economically, offering a viable alternative to improve pregnancy rates in beef cattle.