Effect of the percentage of Bos taurus inheritance on the fertility of Holstein×Zebu and Brown Swiss×Zebu crossbred cows in the Mexican tropics

Background: No dairy breed or crossbreed has superior overall performance in all environments; therefore, it is necessary to determine which the most suitable for Mexican tropic and what proportion of European optimum reproduction. Objective: To assess effect Bos taurus (Bt) genes on reproductive Holstein×Zebu (HZ) Brown Swiss×Zebu (BZ) cows, compare these genotypes a dual-purpose production system. Methods: Cows were maintained rotational grazing system African star grass (Cynodon plectostachyus) Veracruz, Mexico. milked twice daily. Calves kept tied side their dams while cows milked. Results: The percentage Bt did not affect (p>0.05) fertility traits (age at first calving, days service after services per conception, conception rate service, open until gestation length, calving interval) BZ cows. In contrast, HZ with less than 75% Holstein (H) 0.3 years younger (p<0.05) had 39.8 fewer H more. addition, interval was 44.8 shorter that five pregnant 22.8 kg heavier Conclusions: cow depends used. general, present similar performance.