engleski

Development and selection of optimal statistical models to evaluate the effect of microclimate parameters on the variability of production traits in dairy cows

Currently we are living and producing in the world characterized by a climate change. For agriculture and livestock production, this change means, in most cases, deterioration of the environmental effect in numerous regions globally and consequently significant effect on livestock production in the world. Modern livestock production, most frequently implies high production per animal, meaning high milk production per cow in terms of dairy cattle production. The increase of production makes cows more susceptible to heat stress, meaning that heat stress will become an acute problem regardless of climate changes, that will only further emphasize this problem. High-producing dairy cows lose the ability to regulate their body temperature when the ambient temperatures reach 25-29oC. Furthermore, the intensive genetic selection for high milk production resulted in changed thermoregulation physiology meaning that the high-producing cows have larger frames and consequently larger gastrointestinal tracts that enable them to digest more feed. This creates more metabolic heat and reduces the ability of cows to regulate normal temperature at heat stress conditions. Finally, by increase of milk yield, feed intake and metabolic heat, the thermoneutrality of animal shifts to lower temperatures. Accordingly, to many researches, heat stress environment induces reduction in dry matter intake, milk production and reproductive performances. Also, heat stress conditions affects milk composition, somatic cell counts (SCC) and mastitis frequencies. Since Pannonian region is characterized by the high prevalence of heat stress days, mostly during the summer season, the aim of this paper was to develop and select optimal models for evaluation of the effect of microclimate parameters on the variability of production traits in dairy cows.

statistical modeling; microclimate; production traits; dairy cattle

nije evidentirano