Track 1-07

Description

Pastures for milk production in the southern Cape of South Africa are based on no-till systems where kikuyu (Pennisetum clandestinum) is over-sown with ryegrass during autumn to improve seasonal pasture production and forage quality. The aim of the study was to quantify the pasture and milk production potential of kikuyu over-sown with Italian ryegrass (Lolium multiflorum var. italicum), Westerwolds ryegrass (L. multiflorum var. westerwoldicum) or perennial ryegrass (L. perenne). The study was conducted for 2 years on existing kikuyu pastures grazed by Jersey cows. Growth rate, dry matter (DM) production, botanical composition, forage quality, grazing capacity, milk composition and milk production were determined. Whilst each pasture type reached their peak growth rates during different months, the perennial ryegrass treatment maintained DM production during periods when the remaining pastures experienced a decrease in production. As a result, perennial ryegrass pasture maximised annual DM production and annual grazing capacity, and achieved a more constant grazing capacity. The butterfat and milk production per lactation were lowest for the perennial ryegrass treatment, but it recorded the highest milk production per ha. As ambient temperatures increased from winter to summer, the proportion of kikuyu increased for all pastures as did the DM and NDF content, although the ME content decreased. In summary, grazing capacity is the determining factor for milk production per ha on kikuyu-ryegrass based systems.

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The Production Potential of Kikuyu (Pennisetum clandestinum) Over-Sown with Ryegrass (Lolium spp.) in a No-Till System

Pastures for milk production in the southern Cape of South Africa are based on no-till systems where kikuyu (Pennisetum clandestinum) is over-sown with ryegrass during autumn to improve seasonal pasture production and forage quality. The aim of the study was to quantify the pasture and milk production potential of kikuyu over-sown with Italian ryegrass (Lolium multiflorum var. italicum), Westerwolds ryegrass (L. multiflorum var. westerwoldicum) or perennial ryegrass (L. perenne). The study was conducted for 2 years on existing kikuyu pastures grazed by Jersey cows. Growth rate, dry matter (DM) production, botanical composition, forage quality, grazing capacity, milk composition and milk production were determined. Whilst each pasture type reached their peak growth rates during different months, the perennial ryegrass treatment maintained DM production during periods when the remaining pastures experienced a decrease in production. As a result, perennial ryegrass pasture maximised annual DM production and annual grazing capacity, and achieved a more constant grazing capacity. The butterfat and milk production per lactation were lowest for the perennial ryegrass treatment, but it recorded the highest milk production per ha. As ambient temperatures increased from winter to summer, the proportion of kikuyu increased for all pastures as did the DM and NDF content, although the ME content decreased. In summary, grazing capacity is the determining factor for milk production per ha on kikuyu-ryegrass based systems.