engleski

Influence of temperature-humiditiy index (THI) on daily production of dairy in Eastern Croatia

With the aim of analysis the influence of temperature-humidity index (THI) on daily performance of dairy cows in Croatian Eastern region, test-day records collected from February 2004 until March 2010 were used. Based on temperature and relative humidity recorded in stable at each milking control the daily THI values were calculated using the equation by Kibler (1964). For estimation of the influence of exceeded THI (above critical value – 72) on daily production statistical model that take into account effects of lactation stage, breed, calving season, measuring season and THI group were used. The exceeded THI, in heifers, induce highly significant decrease of all analysed parameters. In cows in second lactation, only protein component was significantly influenced by enhanced value of THI. Deteriorate effect of THI higher than 72, in cows in third and higher lactations, was observed in all analysed production traits with exception of daily lactose content. Based on determined results it could be concluded that, in climatic condition of Croatian Eastern region, some management strategies are needed to minimize heat stress and attain optimal cow’s production.

temperature-humidity index ; daily milk yields and contents ; dairy cattle ; Eastern region

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