Can forage lose quality due to frost?
Sebastian asks: Hello Dario. I would like to know why a frost causes a decrease in the quality of a pasture. Response from Daro Colombatto: Sebastin, in the case of temperate grasses, I do not see that a frost generates a decrease in the digestibility of the grass, since the plant maintains its capacity for vegetative growth once the threshold of 5 degrees centigrade is exceeded. What does happen is that the growth rate decreases a lot. In the case where the nutritional value decreases, it is in those tropical grasses such as sorghum and corn, where strong frosts irreversibly interrupt the filling of the grain or the apical growth (depending on whether it is a frost at the end or at the beginning of the cycle) . They also dry out the fibrous component, so there are several aspects to the effects of frost on the protein. If the plant is frozen, the protein decreases its degradability, with the exception of legumes such as alfalfa and clovers, where a frost can make the cell more fragile and explode when ingested by the animal, releasing components cells (protein among them) with high tympanizing potential. In natural grasslands the profile of plants you have depends a lot. In temperate zones, if you can get C3 populations of the autumn-winter-spring type (OIP) then you can think of having qualities of the order of up to 13-14% of CP and digestibilities of approximately 60-65% (especially in winter). In the case of having PVO, often associated with C4 grasses, then the protein threshold drops to 11-12% and digestibilities that would be around 60% maximum, but this is highly variable. Greetings! Agroconsultas is a #ComunidadDigitalColaborativa that aims to #DemocratizeKnowledge among technicians and producers. More information in www.agroconsultasonline.com.ar