Sixty samples of 6 cultivars of annual forage crops: ryegrasses (Lolium multiflorum) cvs. Bill (RGB), Florida (RGF) and Quehue (RGQ); wheat (Triticum aestivum) cvs. Charrua (WC) and Guapo (WG); and triticale (X Triticosecale Wittmack) cv. Don Santiago (TDS), were harvested. Five replicate samples from each of these forage crops were cut at the end of the winter (first growth) and 1 month later (first regrowth). The average mean, minimum and maximum temperatures were as follows: in August 9·4, 0·4 and 16·0°C and in September 11·8, 0·4 and 20·0°C respectively