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The season of the year (ES), maximum temperature (Tmax) and relative humidity (RH) affect gestation success of Tropical Milking criollo (TM) heifers, but their effects on the gestation of TM cows are not completely known. The study aimed to determine the effects of environmental factors along with artificial insemination (AI) service and calving on the gestation success of TM cows. Data were collected during 14 years, 959 records of AI of 155 cows in three seasons: hot-dry (HD), hot-humid (HH) and fresh-dry (FD). The response variables were gestation success of cows at first service after first calving (GF), first calving first to fifth service (GS) and global gestation success (GG). Model effects were ES, Tmax and RH seven days before the AI (PRAI), the day of the service (DAI) and seven days after (POAI); and days open (DO), cumulative milk production (MP), number of service (NS) and calving number (CN). GF was analyzed with logistic regression, and GS and GG with generalized linear models. Over 50 % of estrus occurred in the HH season. Tmax affected GF b1 = -0.13 ± 0.07 (p ≤ 0.05) and GG b1 = -0.08 ± 0.04 (p ≤ 0.05) in PRAI. There were no effects of ES, RH, NS or MP on GF, GS and GG for PRAI, DAI and POAI (p > 0.05). DO affected GG in PRAI, DAI and POAI b2 = -0.005 ± 0.002 (p ≤ 0.01). GG were as close to 52.0 % for the three seasons. Although with no statistical differences in multiparous cows (p > 0.05), for NS maximum gestation were 60 % at first and third, and minimum 40 % at fourth services; for CN they were 60 % at fourth, and 40 % at sixth and seventh calving, respectively. TM cows are adapted to a hot tropical Climate and their seasonal changes, showing similar pregnancy frequencies among seasons.

Objective: To analyze the importance of local livestock resources facing climate change. Methodology: A review of studies referenced in scientific databases disclosed in the livestock sector and animal genetic resources was made within the context of climate change. Results: Livestock breeding is an economic activity that contributes to the food security of the country; in view of its importance, technologies and necessary changes to perform this according to the accelerated changes that occur in the environment, brought by human activity, should be implemented. Implications: Using highly productive races that depend on external inputs and are not adapted to face the effects of climate change, make it a priority to appraise the use of local races that contribute to production under adverse conditions that prevail in warm weathers in the inter-tropical zone. Conclusions: Adapted local race breeders should preserve local animal genetic resources so that they perform as a climate change adaptation alternative that will have repercussions on livestock production systems.