The Effects of Weather on Nutritional Value of Timothy in Northern Sweden

Abstract

Results from a series of harvest time experiments were used together with meteorological data, to estimate the effects of weather variables on the nutritional value of timothy. Nutritional value declines with time. In the first crop, no single weather variable was found that definitely better represented these changes than the number of days from onset of growth. In the second crop, the change in crude protein depended most on the radiation sum and the change in digestibility on the temperature sum. Weather was used to explain some of the deviations from average decline in nutritional value with time. The rate of decline in digestibility was most affected by the temperature. The rate of daily decline increased 0.047 percentage units for each 1°C increase in temperature. In the second crop increased radiation delayed the rate of decline in digestibility, but increased the rate of decline in crude protein content. Water deficiency tended to increase the rate of decline in crude protein content. Decline in digestibility was delayed when the soil water was adequate in the first crop. Different statistical models describing the level and the change in nutritional value were compared and tested.