Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 7/23/2003
Publication Date: 11/3/2003
Citation: Oliver, A., Grant, R., Pedersen, J.F. 2003. Dairy cattle response to bmr-6 and bmr-18 forage sorghum hybrids. Agronomy Abstracts. Interpretive Summary:
Technical Abstract: Diets of normal sorghum, brown midrib bmr-6 sorghum, bmr-18 sorghum, and corn silage were fed to determine their effect on lactational performance, ruminal metabolism, and digestion. Sixteen multiparous Holstein dairy cows (including four ruminally fistulated) averaging 124 +' 68 days in milk were assigned to one of four diets in a replicated Latin square design with 3-week periods. Diets comprised of 40 % test silage, 10 % alfalfa silage, 3.7 % whole cottonseed, and 23.6 % concentrate mix. Lignin was decreased in the bmr-6 and bmr-18 sorghum silage when compared to the normal sorghum silage. Normal sorghum silage had greater NDF and ADF than bmr-6, bmr-18, and corn silage. There was greater DMI for bmr-6 (25.2 kg/d) sorghum silage than bmr-18 (23.4 kg/d) sorghum silage while no difference was seen between sorghum silages and corn silage. Milk production and 4% fat corrected milk were greater for those consuming the bmr-6 sorghum and corn silage than normal sorghum silage. Silage source had no effect on overall chewing time. Eating time was increased with the normal and bmr-18 sorghum silages. Rumination time was greatest with bmr-6 sorghum silage. Corn, bmr-6, and bmr-18 sorghum silage had greater DM digestibility when compared to normal sorghum silage. Corn silage and bmr-6 sorghum had higher NDF digestibility when compared to bmr-18 and normal sorghum silage.