Abstract

Researchers studying acclimation of cattle to heat stress want to know if exposure to heat stress in controlled chambers will help cattle adjust to climatic conditions in the field. The four parameter nonlinear PET model is used to study the relationship between core body temperature and ambient temperature. This model works well when cattle are challenged by heat stress but the model is less useful for thermoneutral conditions. Both proc Nlin and Nlmixed are used to compare and contrast the field parameters between the controlled and the potentially acclimated group. Simulation studies were used to compare the effectiveness of proc Nlin versus proc Nlmixed. The results are helpful, not only for researchers who study acclimation, but also for those who study sensitivity, tolerance and robustness of cattle during heat stress.

Keywords

Acclimation, PET model, Nlin, Nlinmixed

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Apr 28th, 3:00 PM

USING NONLINEAR FIXED AND MIXED MODELS TO STUDY ACCLIMATION TO HEAT STRESS IN CATTLE

Researchers studying acclimation of cattle to heat stress want to know if exposure to heat stress in controlled chambers will help cattle adjust to climatic conditions in the field. The four parameter nonlinear PET model is used to study the relationship between core body temperature and ambient temperature. This model works well when cattle are challenged by heat stress but the model is less useful for thermoneutral conditions. Both proc Nlin and Nlmixed are used to compare and contrast the field parameters between the controlled and the potentially acclimated group. Simulation studies were used to compare the effectiveness of proc Nlin versus proc Nlmixed. The results are helpful, not only for researchers who study acclimation, but also for those who study sensitivity, tolerance and robustness of cattle during heat stress.