Effect of cut number, stage of maturity and method of conservation on digestibility and mineral content of a grass-clover mixture

During three years, samples of a grass-clover mixture from the first and third cut were collected at two stages of maturity (30 days apart) on the same experimental plot. After cutting, the forage samples were either frozen (-20 °C), artificially dried (forced air at 30 °C, 45% relative humidity), wilted on the field and subsequently barn dried, field dried, ensiled at a 30% or 50% dry matter (DM) content. A total of 42 forage samples were analysed for in vivo digestibility using adult sheep and for mineral contents. Although digestibility only slightly varied with conservation method, the cut number and stage of maturity were the most important factors affecting digestibility. Except for the calcium content, which was decreased by field drying, mineral contents were not affected by conservation method. These results emphasize the importance of a careful handling of the forage during harvesting and conservation. If the forage is accurately treated, losses in digestibility and mineral content due to conservation may be prevented.