Annual clovers performance in a dairy cows grazing system compared to perennial ryegrass . I – Yield , nutritive value and fatty acids composition of pasture during the spring grazing season
2016
Veiga, M | Botana, A | Resch, C | Pereira-Crespo, S | Dagnac, T | Valladares, J | Flores, G
This paper presents a comparison, in terms of dry matter yield, nutritive value and fatty acid composition of two swards: a mixture of a hybrid ryegrass with three annual clovers (Berseem clover, Crimson clover and Persian clover ssp. resupinatum) and a pure perennial ryegrass pasture which were rotationally grazed by dairy cows during the spring season in the Atlantic area of Galicia (NW Spain). Pasture quality quickly decreased with the advance of grazing season for both treatments, and the hybrid ryegrass with clovers sward showed higher average values for crude protein (133.55 vs 103.5 g kg-1 dry matter) and lower neutral detergent fiber content (471.9 vs 553.8 g kg-1 dry matter) compared with the perennial ryegrass all along the season whilst sugar content and digestibility was better for the perennial ryegrass pasture. The hybrid ryegrass with clovers sward showed lower concentration in the dry matter of total fatty acids, polyunsaturated fatty acids and alpha-linolenic acid compared with perennial ryegrass. Due to the semi-prostrated habit of annual clovers, post-grazing pasture mass in the mixture was much higher along the grazing season compared with the ryegrass sward. Despite the initially good nutritive value of the herbage from the hybrid ryegrass with clovers sward, the low efficiency of herbage utilization by cows in this sward and the rapid decline in quality possess a serious inconvenient for the inclusion of annual clovers in the dairy grazing systems
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