Effects of stage of maturity and conservation strategy on fermentation, feed intake and digestibility of whole-crop pea-oat silage used in dairy production

Abstract

In two repeated 3×3 Latin Square design trials, dairy cows have been fed bi-crop pea-oat silage to investigate the effect of maturity stage and harvest strategy on feed intake and milk production. In experiment 1 the crop was harvested when the peas were at the flat pod (cut 1) or full pod (cut 2) stage. At the first cut half of the forage was wilted and half was acid-treated with a 2:1 mixture of formic and propionic acid. At the second cut all of the forage was acid-treated. Voluntary intake was highest for the cut 2 silage. In experiment 2 the crop was harvested when the peas were at the flat pod (cut 1), pod fill (cut 2) or full pod (cut 3) stage. The crop was pre-wilted overnight and then acid-treated. Voluntary intake was highest for the cut 3 silage, although the in vivo apparent digestibility was lowest. Milk and protein yield increased with crop maturity. It was concluded that pre-wilting and acid treatment produces good quality, palatable pea-oat bi-crop silage. In terms of feed intake and milk production, the optimal time of harvest was when peas were at the pod fill stage and the oats were in the late milk to early dough stage.