Abstract:
The seasonal growth and low forage quality of kikuyu restrict milk production. The aim of this study was to
determine the yield and nutritional value of irrigated kikuyu over-sown with perennial, Italian or Westerwolds
ryegrass grazed by dairy cows. The three pasture systems reached optimum growth during different months and
seasons. Lowest growth rates occurred during winter. Peak growth rates occurred during spring for the Italian
ryegrass–kikuyu, summer for the Westerwolds ryegrass–kikuyu, and late spring and early summer for perennial
ryegrass–kikuyu pasture. All three pasture systems had similar total annual dry matter yields (kilograms dry matter
[DM] per hectare) during year 1, but the perennial ryegrass–kikuyu pasture achieved a higher annual DM yield
during year 2. As kikuyu density increased in kikuyu–ryegrass pastures from winter to summer, the DM and neutral
detergent fibre content increased, whereas the metabolisable energy content decreased. All three treatments
were deficient in calcium during all seasons and in phosphorus during summer and autumn as a pasture for
high-producing dairy cows.
