Comparison of Barley and Sorghum Grain Processed at Different Densities for Lactating Dairy Cows

Abstract

To vary ruminally degradable starch, sorghum grain was dry-rolled or steam-flaked to different densities and compared with dry-rolled barley in total mixed diets fed to 40 lactating cows (111 d of lactation) assigned to five dietary treatments. Diets contained (percentage of dry matter) 35% alfalfa hay, 4.1% cottonseed hulls, 10% whole cottonseed, 2% fish meal, 4% soybean meal, and 4.9% of a molasses, mineral, and vitamin supplement. Treatments were 40% sorghum grain either dry-rolled or steam-processed at flake densities of 437, 360, and 283 g/L. A fifth diet containing 42% dry-rolled barley was fed. Cows were blocked according to pretreatment (14 d) milk yield and received experimental diets for 56 d. Increasing ruminal starch degradability by including steam-flaked sorghum grain or barley in the diet did not increase milk yield or milk protein percentage and yield, as was shown in eight previous studies. Steam-flaked sorghum or dry-rolled barley in the diet decreased dry matter intake, resulting in a 10 to 19% higher efficiency of conversion of feed dry matter to milk than that for dry-rolled sorghum. Milk urea N was decreased, and milk casein yield tended to be increased, by steam-flaking sorghum at the moderate density compared with dry-rolling or fine flaking. Dietary protein was more efficiently converted to milk protein and casein from flaked sorghum and dry-rolled barley than from dry-rolled sorghum. In this study, increasing ruminal starch degradability resulted in higher feed efficiency and lower feed intakes, bu optimal flake densities for steam-processed sorghum gain to maximize milk and milk protein yield were not clarified.

Influence of Cracked, Coarse Ground or Fine Ground Corn on Digestion, Dry Matter Intake and Milk Yield in Holstein Cows

“…Improved total tract digestibility of OM, starch and NDF has been a consistent observation in studies comparing SFC-with DRC-based diets (Plascencia and Zinn, 1996;Theurer et al, 1999 'CG = coarse grind (density = 0.55), MG = medium coarse grind (density = 0.50), FG = fine grind (density = 0.45). SFC = steam flaked corn.…”

“…improved starch utilization and energy value of corn as a result of processing is well documented (Theurer et al, 1999). Increasing the intensity of processing, decreased the density of grain and increased the extent of total tract digestion of starch (Plascencia and Starch is a primary Source Of energy in ruminant diets and represents 70 to 80% of most grains that are fed to high producing dairy cows' The for Zinn, 1996; J o y e t al., 1997).…”

“…However, et al., 1997). The final density of steam-flaked corn is a practical tool to determine optimal degree of grain processing in feedlot (Zinn, 1990) and lactating cows (Theurer et al, 1999). However, little is known about the optimal density of dry rolled corn for lactating cows.…”

Substituição do milho pela farinha de varredura de mandioca (Manihot esculenta Crantz) em rações de ovinos: consumo, digestibilidade, balanços de nitrogênio e energia e parâmetros ruminais

“…Também reduções no consumo de MS foram observadas para vacas leiteiras quando fontes de amido de rápida degradação ruminal foram fornecidas (Sauvant et al, 1994;Overton et al, 1995;Santos et al, 1997), no entanto, fontes de amido de menor degradação levam a uma fermentação ruminal relativamente mais equilibrada não alterando a ingestão de MS (Nocek & Tamminga, 1991;Sauvant et al, 1994).…”

Nutritional value of high moisture corn silage in the diet of Holstein cows

“…Overton et al (1995) reported decreased linear effect for DM intake, when corn was replaced by barley in the diet of lactating dairy cows. Santos et al (1997) observed a reduction in the DM intake, working with sorghum and barley, processed in different ways (dry-rolled and flaked) in the diets of dairy cows. Aldrich et al (1993) also reported lower dry matter intake for the treatments using high moisture corn grains, when compared with dry corn grains.…”