Extrusion of grass silage and its effect on feed intake, milk production and ingestive behaviour of dairy cows
Grass and clover ley is the main forage crop in Sweden, however, its restrictive role in feed intake limits the total amount included in the diet of a dairy cow. This study examined the effect of extrusion on grass silage intake, milk production, ingestive behaviour and rumen pH. Eight Swedish Red d...
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| Formato: | Second cycle, A2E |
| Lenguaje: | sueco Inglés |
| Publicado: |
2020
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| Acceso en línea: | https://stud.epsilon.slu.se/16259/ |
| Sumario: | Grass and clover ley is the main forage crop in Sweden, however, its restrictive role in feed intake limits the total amount included in the diet of a dairy cow. This study examined the effect of extrusion on grass silage intake, milk production, ingestive behaviour and rumen pH. Eight Swedish Red dairy cows in mid/late lactation were fed grass silage of early or late harvest, extruded or control, in a 4x4 Latin square design with four periods of three weeks. Diets were supplemented with a mix of soybean meal, compound feed and minerals. Extrusion increased daily silage dry matter (DM) intake by 1.84 kg/d (p < 0.001), neutral detergent fibre (NDF) intake by 1.04 kg/d (p < 0.001) and decreased physical effective NDF (peNDF8) intake by 1.37 kg/d (p < 0.001). Total DM intake increased by 1.74 kg/d (p < 0.001) while the dietary DM percentage of peNDF8 decreased by 6.9 units (p < 0.001). Milk yield increased by 1.32 kg/d (p = 0.008), Energy corrected milk (ECM) yield increased by 1.87 kg/d (p = 0.004), milk protein concentration increased by 0.09 percentage units (p < 0.001) while total fat and protein production increased by 72.4 g/d (p = 0.015) and 73.7 g/d (p < 0.001), respectively. Extrusion decreased average rumen pH by 0.1 units (p = 0.008). The time rumen pH was below 5.8 increased by 2.97 h/d (p = 0.038) while the curve area below this cut-off point was not affected (p = 0.166). Rate of intake of silage DM and NDF was increased by 20.3 and 11.3 g/min respectively (p < 0.001), daily silage eating time decreased by 0.6 h/d (p = 0.006) and daily rumination time decreased by 1.96 h/d (p < 0.001). Daily chewing time decreased by 2.49 h/d (p < 0.001), with rumination and chewing time per kg of silage NDF intake, decreased by 18.9 and 26.3 min/kg (p < 0.001) respectively. In conclusion, extrusion increased silage intake, eating rate and milk production but decreased chewing activity. |
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