Estrus Signs and Estrogen Levels in Brahman Cross and First-Generation (F1) Crossbred Cattle: Implications for Pregnancy and Repeat Mating

Brahman Cross cattle are grown extensively in Indonesia due to their outperformance compared to local cattle in reproduction and daily weight increase. Although it may result in reproductive problems, crossbreeding with Bos taurus breeds, such as Belgian Blue cattle, increases growth potential. In Brahman Cross and first-generation F1 Crossbred cattle, estrus signs and estrogen levels are recommended to be examined during artificial insemination (AI) and 30 days after AI. Twenty blood samples consisting of ten samples of F1 crossbred cattle with Belgian Blue bullsand Brahman Cross dams, and ten samples of Brahman Cross cattle grown at PT. Widodo Makmur Perkasa were taken. Estrogen levels and visual indicators of estrus were tracked both during and 30 days after AI. Both Brahman Cross and F1 Crossbred cattle showed strong estrus signals during AI, with estrus signs of 125.50±5.64 for Brahman Cross and 128.30±5.41 for F1 Crossbred, decreasing to 120.80±6.05 after 30 days. Estrogen levels were 463.60±76.98 for Brahman Cross and 475.94±38.92 for F1 Crossbred during AI, dropping to 276.44±119.04 and 326.64±147.42, respectively, after 30 days. After AI, F1 Crossbred cattle in particular exhibit the lowest levels of estrogen, which is correlated with conception.On the other hand, non-pregnant Brahman Cross cattle exhibit lower levels of estrogen and estrus, probably as a result of repeated mating. The significance of keeping an eye on estrogen levels and estrus signs in cattle breeding programs is highlighted in these findings. © 2024 Copyright: 2024 by the authors. Licensee ResearchersLinks Ltd, England, UK. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/)