title: Intake and digestion of whole-crop barley and wheat silages by dairy heifers.
abstract: The effect of maturity at harvest on the digestibility and intake of large bale silage made from whole-crop barley and wheat when fed to growing heifers was evaluated. Two crops of spring barley (Hordeum distichum cv. Filippa and Kinnan) and 1 of winter wheat (Triticum aestivum cv. Olevin) were harvested at the heading, milk, and dough stages of maturity. The silage was fed to 36 dairy heifers in a balanced crossover experiment with 3 periods and 9 treatments (diets based on 3 crops and 3 stages of maturity), organized into 6 pairs of 3 × 3 Latin squares. No clear relationship was observed between intake and stage of maturity of whole-crop cereal silage, but intake was positively correlated to silage DM content (P < 0.001, r = 0.46) and negatively correlated to NDF content (P < 0.001, r = -0.42). Organic matter digestibility decreased between the heading and milk stages of maturity in all crops (P < 0.001), did not differ between the milk and the dough stages in the 2 barley crops, but increased in the wheat silage (P = 0.034). The NDF digestibility decreased between the heading and milk stages in all crops (P < 0.001), whereas it decreased in 1 barley crop (P < 0.001), increased in the other barley (P = 0.025), and was unchanged in the wheat between the milk and dough stages of maturity. Starch digestibility was less in the 2 barley crops compared with the wheat at the dough stage of maturity (P < 0.001). The feeding value of the whole-crop barley and wheat declined between the heading and milk stages of maturity, but thereafter the effect of maturity on the feeding value was minor.
authors.affiliation: Department of Animal Environment and Health, Swedish University of Agricultural Sciences, Skara, Sweden. Bengt-Ove.Rustas@slu.se
authors.forename: B-O
authors.initials: BO
authors.lastname: Rustas
authors.forename: J
authors.initials: J
authors.lastname: Bertilsson
authors.forename: K
authors.initials: K
authors.lastname: Martinsson
authors.forename: T
authors.initials: T
authors.lastname: Elverstedt
authors.forename: E
authors.initials: E
authors.lastname: Nadeau
mesh_terms: D000818:Animals; D002417:Cattle / Q000502:physiology*; D018592:Cross-Over Studies; D003612:Dairying; D004063:Digestion / Q000502:physiology*; D004435:Eating / Q000502:physiology*; D005260:Female; D001467:Hordeum / Q000737:chemistry* / Q000254:growth & development; D012820:Silage / Q000032:analysis*; D014908:Triticum / Q000737:chemistry* / Q000254:growth & development