Digestibility of whole-crop barley and oat silages in dairy heifers

Abstract

This study evaluated the digestibility of whole-crop cereal silage (WCCS) made from oats and six-rowed barley harvested at the heading, early milk and early dough stages, and two-rowed barley harvested at the early milk and early dough stages of maturity. The eight WCCSs were fed to 32 Swedish Red heifers in a changeover design over three periods of 28 days each. The heifers were first fed ad libitum for 17 days and then at 0.95 of ad libitum for 11 days of each period. During the last 5 days all faeces and orts were collected to determine the digestibility of the silages. Only the maturity stage effect was significant for the WCCS organic matter (OM) digestibility and the average OM digestibility was higher at the heading stage (698 g/kg) than at early milk (647 g/kg) and early dough (652 g/kg) stages of maturity. For neutral detergent fibre (NDF) digestibility the crop 3 maturity stage effect was significant. The NDF digestibility decreased from the heading to the early milk stage for both six-rowed barley (746 to 607 g/kg) and oats (698 to 596 g/kg). There was no further significant decrease in NDF digestibility for six-rowed barley at the early dough stage (577 g/kg), but for two-rowed barley it decreased from the early milk (682 g/kg) to the early dough (573 g/kg) stage, and also for oats the NDF digestibility was lowest at the early dough stage (507 g/kg). The decrease in NDF digestibility during maturation was to a large extent compensated by an increase in starch concentration in the crops. The starch digestibility was lower for six-rowed barley at early dough stage (948 g/kg) than at early milk stage (977 g/kg), and was also lower compared with oats (979 g/kg) at early dough stage. The average crude protein (CP) digestibility was higher at the heading (646 g/kg) and the early milk (642 g/kg) stages than at the early dough stage (599 g/kg), and oats had higher average CP digestibility (650 g/kg) than six-rowed (613 g/kg) and two-rowed (624 g/kg) barley. Delaying the harvest of WCCS from the heading to the early milk and dough stage of maturity will decrease the OM digestibility; as a result there is a decreased NDF digestibility.Keywords: Avena sativa, Hordeum vulgare, whole-crop cereal silage, utilization, maturity ImplicationsThis study covers the utilization (digestibility) of whole-crop cereal silages (WCCSs) under some of the conditions used in practice (heifers fed at high intakes). These results can therefore be used by farmers and advisors to predict the energy content (based on the organic matter digestibility) of WCCS harvested within the range of maturity stages investigated in this study, when making feed rations for these kind of animals. The results also show that harvest without a grain processor is also possible at early dough stage without a decrease in starch digestibility, and that conventional grass silage machinery therefore can be used at harvest.

Cell wall chemical characteristics of whole‐crop cereal silages harvested at three maturity stages

“…A total of 27 samples of nine different WCCS from two feeding experiments with dairy heifers were analyzed . The WCCS used were oats ( Avena sativa L.), six‐rowed barley ( Hordeum vulgare L.) and wheat ( Triticum aestivum L.) (all Swedish varieties) harvested at the heading, early milk and early dough stages of maturity.…”

“…Three bales were selected from each stage of development for each cereal. Multiple cored subsamples were taken from each bale and combined to create the replicate sample for analyses …”

“…Detergent fiber fraction information (NDFom, ADF, ADL) was complied from previous work on the same cereal silages …”

“…Producing forage crops that meet nutrient requirements is a challenge especially in regions of northern latitudes with restricted growing season limiting the range of cropping alternatives. Cereals such as wheat, barley, and oats are well suited for production in cooler shorter growing seasons found in Sweden . Production of cereals in cooler environments can be challenging since the goal is to maximize total nutritive value .…”

Silagem pré-secada de cereais de inverno em estádio de pré-florescimento: Revisão

“…Já Wallsten and Martinsson (2009) observaram que o avanço do estádio de maturação da cevada proporcionou redução na FDN e na digestibilidade da matéria seca. Da mesma forma, Wallsten et al (2010) avaliando silagens de aveia e de cevada, relataram que o avanço da maturidade proporcionou decréscimos nas digestibilidades da matéria orgânica.…”