Agroscope, Institute for Livestock Sciences ILS, 1725 Posieux, Switzerland

Estimating the nutritional value of silages composed of protein plant and immature cereal mixtures

Three immature whole plant pea-cereal mixtures composed of triticale (90 kg/ha), oats (40, 30 and 20 kg/ha) and field peas (20, 30 and 40 kg/ha) were sown at Agroscope Posieux in October 2011 and ensiled in late June 2012. In vivo digestibility was determined with wethers, and in sacco degradability with rumen fistulated cows. Botanical compositions at harvest were not as hoped for at the time of sowing: the shares of peas (9.3, 9.5, 14 %) fell short of the intended (20, 25, 30 %). At 61.2 ± 1.5 %, average degradability of crude protein was low. At 63.6 ±1.8 %, in vivo digestibility of organic matter (DOM) was low, and scarcely differed between the mixtures (p=0.5). Estimation of the DOM via the in vitro method was very good in two cases (<1 %point), but also produced the highest discrepancy of the test (4.8 % points). Using the botanical analysis at the time of the harvest, the weighting of the DOM of the components of the mixtures published in the Swiss animalfeed database allowed a good approach. The average nutritional value of the silages stands at the level of a grass silage from a meadow rich in later-stage grasses. In the case of shortages, this type of forage offers a contribution for the less-demanding animals, allowing the high-value forages to be reserved for those in production.

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