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The objective of this study was to assess the reproductive performance of two Nguni ecotypes (Nguni and Landim) raised in a subtropical environment to enhance strategies for livestock development and restocking programmes within the southern African region. Reproduction data collected between 1996 and 2009 from 365 cows of the Landim and Nguni ecotypes were analysed. From the results, ecotype, place of birth, year and season of birth/calving had significant effects on age at first calving (AFC) and calving interval (CI). Overall means for AFC and CI were 1,071 ± 166 days and 432 ± 85 days, respectively, while average calving rate was 88.0 ± 4.7%. Heifers born in the dry season had lower AFC than heifers born in the wet season. Heifers born at Impaputo Breeding Center were the youngest at first calving, followed by the South African born ones. Heifers of the Landim ecotype also calved younger than heifers of the Nguni ecotype. CI was shorter in wet seasons (main breeding seasons) than in dry seasons. Interaction between ecotype and year-season (p < 0.005) showed that, in wet and dry seasons, Nguni cows had shorter CI than the Landim. This study demonstrates for the first time a possible genotype-by-environment interaction between Nguni ecotypes. This might aid future cattle development and restocking programmes in southern Africa taking into consideration the adaptation of indigenous genotypes and climate change.

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Introduction The high emergency in the control of the pandemic has determined that the scientific community is dedicated to the production of effective vaccines for immunization against SARS-CoV-2. With the emergence of new variants of SARS-CoV-2, there was a need to increase immunity in the vaccinated population through a booster dose. The booster dose is allowed to increase the immunity of individuals and, consequently, reduce the probability of reinfection, as well as severe symptoms associated with COVID-19. Objective To evaluate the acquired immunity to COVID-19 through vaccination, and to verify the influence of the booster dose on the antibody’s concentration. Materials and Methods Data were collected from 965 individuals of both genders and vaccinated for COVID-19. Results 91.8% of the sample had neutralizing antibodies against SARS-CoV-2, and the group of fully vaccinated individuals had a higher percentage of neutralized antibodies compared to individuals who did not have a booster dose (53.2% vs. 38 .7%). Discussion Neutralizing antibodies were found in 91.8% of the sample, which demonstrates the effectiveness of vaccination in the production of antibodies. The results demonstrated the effectiveness of the booster dose in the production of neutralizing antibodies against SARS-CoV-2. Conclusion Vaccination was quite effective in producing neutralizing antibodies. In addition, booster vaccination increased humoral immunity.

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The objective of this study was to assess the effect of place of birth on the reproductive performance of two Nguni ecotypes (Nguni and Landim) raised in a sub-tropical environment to enhance strategies for livestock development and restocking programmes within the southern African region. Reproduction data collected between 1994 and 2009 from 301 cows of the Landim (n = 122) and Nguni (n = 179) ecotypes were analysed. Results indicated that ecotype and place of birth had significant effects on age at first calving (AFC) and calving interval (CI). The means for AFC were 1085 and 1003 days, those for CI were 422 and 436 days, while the calving rate (CR) was 90.0% and 85.7% for the Nguni and Landim, respectively. This study demonstrates for the first time a possible genotype by environment interaction between Nguni ecotypes. This might aid future cattle development and restocking programmes in southern Africa, taking into consideration the adaptation of indigenous genotypes and climate change.

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