Background:

Climatic conditions in tropical countries have a significant effect on milk production.

Aim:

Analyze the climatic conditions at the Los Naranjos Genetic Livestock Company and its possible relationship with the behavior of milk production at 305 days.

Materials and methods:

A database of 12,625 milk production records was available, from cows that gave birth between the years 2002 -2020, which corresponded to 7,711 animals. There were monthly records of the minimum temperature (Tmin), average (Tmed) and maximum (Tmax) at 0C, relative humidity (RH) in % and the temperature-humidity index (ITH) was generated, and from this the performed the calculation of the Accumulated Caloric Load (CCA) for the three months before delivery. In addition, heritabilities (h2) and genetic correlations (rg) were estimated for the different CCAs.

Results:

The general means obtained were: PL305: 1 624.45 ± 360.40 (kg/lactation), ITH 76.34 ± 18.70 and CCA 229.21 ± 128.5. All sources of variation studied significantly influenced milk production at 305 days. The h2 ranged between 0.25 and 0.38 and the rgs were all positive and higher for the closer CCA groups.

Conclusions:

There was an inverse relationship between ITH and CCA with milk production. Additive genetic variability is evident for the different CCA groups and the rg were positive denoting certain genetic variability for adaptation to climatic stress.