POSTFLOWERING FORAGE POTENTIAL OF SPRING AND WINTER CEREAL MIXTURES

Forage quality of small grain cereals harvested after flowering affects animal performance adversely. The feasibility of using mixtures (MX) of spring-planted winter cereals with spring cereals to improve forage quality at the late milk stage of the spring cereal was investigated at Lacombe and Brooks, Alberta during 1987 and 1988. Spring monocrops (SMC) of oats (Avena sativa L.) and barley (Hordeum vulgare L.) and winter monocrops (WMC) of wheat (Triticum aestivum L.) and winter triticale (x Triticosecale Wittmack) were compared with binary MX of spring and winter combinations using a randomized complete block design. Dry matter (DM) yield and concentrations of in vitro digestible organic matter (IVDOM), crude protein, neutral detergent fibre (NDF), acid detergent fibre (ADF) and lignin were determined. Dry matter yields of MX as a percent of their SMC counterparts ranged from 84 to 99% at Lacombe and from 82 to 113% at Brooks; no crop combination was consistently superior. For forage quality the cropping systems ranked WMC > MX > SMC. The effects of winter wheat and triticale on forage quality in the MX were similar. However, MX containing barley generally had higher IVDOM and lower NDF, ADF and lignin concentrations than those containing oats. At Lacombe and Brooks, IVDOM and crude protein concentrations of the MX were increased by 6.5 and 7.2% and by 21.2 and 23.6%, respectively, while NDF, ADF and lignin concentrations were decreased by 6.7 and 6.5%, 9.9 and 7.5%, 10.9 and 20.4%, respectively, compared with the SMC group. While the extent of compensation is not known the improved forage quality of the MX should partially offset the slight reduction in DM yield compared to the SMC.