Age at first mating and season of dam birth affect reproductive and productive traits of Mozambican Angoni cattle

This retrospective observational study aimed to evaluate the effects of age at first mating (AFM) and season of dam birth (SB) on age at first calving (AFC), birth weight of calves (BW), and calving interval (CI) in Angoni cattle in Mozambique. A total of 1418 records collected over a 25-year period (1995-2020) at the Angonia Research Station were analyzed using R software (version 4.3.2). The effects of AFM and SB on reproductive and productive traits were determined using the Kruskal-Wallis test and further analyzed with Dunn's test to compare means between groups in case of showing significance. The least squares method was applied to assess the relationship among AFM, BW, and AFC through simple linear regression analysis. AFM significantly influenced BW (17.5-18.3 kg; <i>P</i> < 0.05), AFC (839-1431 days; <i>P</i> < 0.001), and CI (493-533 days; <i>P</i> < 0.05). SB significantly affected BW (17.5 vs. 18.2 kg; <i>P</i> = 0.025) and CI (502 vs. 521 days; <i>P</i> < 0.001), but not AFC (<i>P</i> > 0.05). These results highlight that both AFM and SB are critical factors influencing reproductive performance and should be considered in future breeding and selection strategies to optimize herd efficiency in tropical beef systems.