Using brown midrib 6 dwarf forage sorghum silage and fall-grown oat silage in lactating dairy cow rations

Abstract

Double cropping and increasing crop diversity could improve dairy farm economic and environmental sustainability. In this experiment, corn silage was partially replaced with 2 alternative forages, brown midrib-6 brachytic dwarf forage sorghum (Sorghum bicolor) or fall-grown oat (Avena sativa) silage, in the diet of lactating dairy cows. We investigated the effect on dry matter (DM) intake, milk yield (MY), milk components and fatty acid profile, apparent total-tract nutrient digestibility, N utilization, enteric methane emissions, and income over feed cost. We analyzed the in situ DM and neutral detergent fiber disappearance of the alternative forages versus corn silage and alfalfa haylage. Sorghum was grown in the summer and harvested in the milk stage. Oats were grown in the fall and harvested in the boot stage. Compared with corn silage, neutral detergent fiber and acid detergent fiber concentrations were higher in the alternative forages. Lignin content was highest for sorghum silage and similar for corn silage and oat silage. The alternative forages had less than 1% starch compared with the approximately 35% starch in the corn silage. Ruminal in situ DM effective degradability was similar, although statistically different, for corn silage and oat silage, but lower for sorghum silage. Diets with the alternative forages were fed in a replicated 3 × 3 Latin square design experiment with three 28-d periods and 12 Holstein cows. The control diet contained 44% (DM basis) corn silage. In the other 2 diets, sorghum or oat silages were included at 10% of dietary DM, replacing corn silage. Sorghum silage inclusion decreased DM intake, MY, and milk protein content but increased milk fat and maintained energy-corrected MY similar to the control. Oat silage had no effect on DM intake, MY, or milk components compared to the control. The oat silage diet increased apparent total-tract digestibility of dietary nutrients, except starch, whereas the sorghum diet slightly decreased DM, organic matter, crude protein, and starch digestibility. Cows consuming the oat silage diet had higher milk urea N and urinary urea N concentrations. Milk N efficiency was decreased by the sorghum diet. Diet did not affect enteric methane or carbon dioxide emissions. This study shows that oat silage can partially replace corn silage at 10% of the diet DM with no effect on MY. Brown midrib sorghum silage harvested at the milk stage with <1% starch may decrease DM intake and MY in dairy cows.

Total replacement of corn silage with sorghum silage improves milk fatty acid profile and antioxidant capacity of Holstein dairy cows

“…In agreement with NRC (2001) tables, the NDF, ADF, and ADL concentrations for SS were greater (P < 0.05) than those of CS (Table 1). Harper et al (2017) reported the greater NDF and ADF concentrations in SS compared with CS (62.7 and 40.8 vs. 40.2 and 25.9% of DM, respectively). The SS CP was greater than that reported by Oliver et al (2004); however, the CP content in the SS was lower than that reported by Harper et al (2017), and this inconsistency is probably due to differences in some factors such as plant (sorghum) species, stage of maturity, climate, soil conditions, and fertilization (McDonald et al, 2011).…”

“…In a study by Oliver et al (2004), the digestibility of CP was similar for cows fed either on a diet containing ensiled sorghum or diet containing CS. In contrast, Harper et al (2017) observed that digestibility of CP and DM was higher in cows fed CS compared with SS, which may have been due to the greater lignin content in the SS (4.89 vs. 3.7% of DM, respectively), since lignin is considered the main limiting factor of the digestion of nutrients in the rumen (Van Soest, 1994). However, recently Raffrenato et al (2017) indicated that the content of lignin is not directly responsible for digestibility; more likely, the degree of cross-linking of phenolics within the cell wall carbohydrate directly influences the nutrient digestibility.…”

Comparison of feeding diets diluted with sorghum-sudangrass silage or low-quality grass on nutrient intake and digestibility and growth performance of Holstein dairy heifers

“…Digestibilities of OM and NDF were greater for CSS than for PSS within the SS diets (P ≤ 0.04). Previous studies also found that the digestibility of OM was greater for lactating dairy cows fed diets containing corn silage compared with those fed sorghum silage (Dann et al, 2008;Harper et al, 2017). However, Colombini et al (2012) found that digestibility of OM was not different between corn silage and whole-plant grain sorghum silage diets for dairy cows.…”

Performance of oat (Avena sativa L.) sown in late summer for autumn forage production in Central Europe

“…Harper et al. () reported that autumn‐grown oat, conserved as silage, can replace corn silage at 10% of the ration with no impact on dry matter intake or milk yield. Coblentz, Brink, Hoffman, Esser, and Bertram () reported that grazed autumn‐grown oat can replace 50% of a basal ration of alfalfa‐grass silage, with dairy heifer weight gains of 0.85 kg/d, greater than heifers fed only the control basal ration.…”

“…Greater IVTD and NDFD were observed in all three cultivars when sown 15 August or 1 September, relative to 1 August ( Feeding trials have confirmed that laboratory measures of superior nutritive value of autumn-grown oat support high levels of livestock performance. Harper et al (2017) reported that autumn-grown oat, conserved as silage, can replace corn silage at 10% of the ration with no impact on dry matter intake or milk yield. Coblentz, Brink, Hoffman, Esser, and Bertram (2014) reported that grazed autumngrown oat can replace 50% of a basal ration of alfalfa-grass silage, with dairy heifer weight gains of 0.85 kg/d, greater than heifers fed only the control basal ration.…”