The effect of stage of maturity on the yield and chemical composition of oats for haymaking

Abstract

1. Ayr Line Potato oats was studied in the later stages of development for 3 years under upland conditions in Kincardineshire, Scotland. Some major changes in yield and chemical composition of the crop and certain effects of haymaking have been demonstrated.2. In each year, between the ‘milky’ stage and full ripeness of the grain, the growth curve falls into the distinct phases of growth, maturity and senescence when dry-matter loss occurs. The position of the peak yield in terms of stage of maturity varies from year to year.3. Percentage crude protein is low throughout, falling to a minimum after the early ‘milky’ stage and rising again to a maximum at the last cut. Yield of crude protein is highest at the last cut in one year and at the penultimate cut in two years.4. Percentage crude fibre tends to decrease with increasing maturity, while crude fibre yield is low at both extremes of the experimental period.5. More detailed chemical analyses at different stages of maturity show total ash content to be low. The content of calcium is especially poor.6. Separation of the whole of the aerial part of the plant into leaf, stem and inflorescence shows that chemical constituents are being actively re-distributed throughout the plant during the experimental period; with the exception of crude fibre and calcium all constituents estimated tend to be concentrated in the grain with advancing maturity.7. In one year, dry-matter losses during curing range from 22 to 7% at the first and last cuts respectively, while corresponding figures for crude protein are 18 and 10%.8. In the absence of digestibility data and feeding trials under Scottish conditions, the tentative conclusion is drawn that in the higher rainfall areas of the north and west where the crop is most likely to be used, cutting between the late ‘milky’ and late cheesy' stages should give optimum results.9. Attention is drawn to the need for caution in the general application of the results.