Resumo

TREJO-CASANOVA, Carmen del Rocío et al. Effect of environmental temperature on milk production of Holstein cows in the department of Nariño, Colombia. Acta Agron. [online]. 2023, vol.72, n.1, pp.97-102.  Epub 29-Abr-2024. ISSN 0120-2812.  https://doi.org/10.15446/acag.v72n1.97481.

Environmental temperature is an influential factor in animal welfare and its impact reflects mainly on health and productivity. The objective of this study was to evaluate the effect of the minimum environmental temperature on the production and quality of milk of Holstein cows, performing milk controls in farms of the department of Nariño (Pasto, Pupiales and Guachucal). The milk volume produced per cow was recorded on the control day and milk samples were obtained for subsequent compositional analysis (fat, protein, total solids, and somatic cells). The information about the environmental temperature was obtained from the weather stations of the Institute of Hydrology, Meteorology and Environmental Studies (Ideam) close to the herds. A linear mixed model was used to determine the fixed effect of the minimum environmental temperature, calving rate, lactation cycle and, as a random effect, the dairy district. The results showed that neither the milk composition nor the somatic cell count were affected by the minimum environmental temperatures, but there was a significant effect on the production of cows with six or more calves, with a decrease of up to 2.6 l. This reduction in milk production is possibly attributed to the decrease in consumption and the energy used to generate heat and maintain body temperature as a survival mechanism. For further investigations, it is suggested to include physiological variables of the animal (body temperature, respiratory rate, dry matter intake, cortisol levels) and of the environment (precipitation, wind, relative humidity, solar radiation).

Palavras-chave : cattle; somatic cell; composition; cold stress; grazing.

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