G. L. Posler

Forage sorghum silage dry matter disappearance as influenced by plant part proportion

Abstract Forage sorghum ( Sorghum bicolor (L.) Moench) is widely grown for silage in the High Plains region of the U.S.A. The in vitro dry matter disappearance (IVDMD) dynamics of forage sorghum silage, as influenced by the proportion of ensiled plant parts, were examined. Five mid- to late-season forage hybrids were grown at Manhattan, Kansas, on a Smolan silty clay loam (fine, montmorillonitic, mesic Typic Agriustoll) in 1987. The hybrids were harvested at the hard dough stage of maturity. Grain yields ranged from 4.18 to 5.23 Mg ha −1 , and silage yields from 13.72 to 16.45 Mg ha −1 . At ensiling, five plants per hybrid were separated into grain, leaf, sheath and stalk parts, chopped, put into nylon bags and ensiled with their respective silages in pilot silos. The distribution of dry matter (g kg −1 ) among the plant parts was grain 282–413, leaf 208–229, sheath 107–170, stalk 195–401. The pH of each silage and plant part was determined at silo opening. The IVDMDs of plant parts were grain 769, leaf 577, sheath 527 and stalk 608 g kg −1 , and ranged from 582 to 617 g kg −1 for silages. For each silage, each plant part was individually increased to unity, then the IVDMD dynamics were plotted. The silages were reconstituted and the IVDMD determined. These ranged from 633 to 677 g kg −1 . Statistically, the reconstituted silage IVDMD is the sum of the plant part IVDMD values, but the actual silage IVDMD was not. Regression equations were generated to predict silage IVDMD based on the proportion of plant parts for each hybrid. Grain had the greatest and a positive effect on silage IVDMD dynamics, whereas the sheath component had a negative effect.

Forage quality of genetically diverse alfalfa germplasms at four phenological growth stages.

SummaryForage quality of various alfalfa (Medicago sativa L.) cultivars has been determined under different environmental conditions, and numerous trials with alfalfa have documented an inverse relationship between forage quality and maturity. Little information is available, however, regarding the comparative forage quality of the germplasm sources from which most USA cultivars were developed. We compared forage quality of these germplasm sources at four phenological stages under disease- and insect-free conditions in a greenhouse. Germplasm sources (cultivars) tested were: Indian (Sirsa #9), African (African), Peruvian (Hairy Peruvian), Flemish (DuPuits), Turkistan (Lahontan), Chilean (Kansas Common), M. varia (Grimm), and Ladak (Ladak). Four harvests were taken and forage was separated into four phenological stages: vegetative, early bud (1–3 buds-per-stem), late bud (>3 buds-per-stem), and bloom. The germplasm source X phenological stage interaction was significant for crude protein (CP) and in vitro digestible dry matter (IVDDM) concentrations. M. varia showed the least decline in IVDDM and CP with increasing maturity. M. varia had higher IVDDM than did African and Indian at late bud and bloom stages. Indian and Flemish had higher CP than did Turkistan and Peruvian at late bud and bloom stages. Alfalfa germplasm sources differ in forage quality when comparisions are made within similar stages of phenological development.

Forage quality of alfalfa protected by resistance to bacterial leaf spot.

Bacterial leaf spot (BLS), caused by Xanthomonas campestris pv. alfalfae Dye (Xca), can prevent stand establishment and decrease the yield and persistence of alfalfa (Medicago sativa L.) in the central USA. Previous studies have shown that BLS inoculation may affect concentrations of monophenolic compounds and thus alter the forage quality of alfalfa. In a controlled environment, comparisons were made of forage quality, including phenolic monomers, of alfalfa cv. Kanza (susceptible) and KS76 germplasm (derived from Kanza, resistant) with and without inoculation with Xca. The cultivar × inoculation interactions were non-significant (P > 0.05) for all parameters determined for leaves and stems. Leaves from Xca-inoculated plants had more neutral detergent fiber, acid detergent fiber, permanganate lignin and cellulose, and less true in vitro digestible dry matter, than did leaves from uninoculated plants. The nutritive value of stems was not altered by inoculation. Regardless of inoculation treatment, leaves had a five times greater consentration of total phenolics than did stems, yet neutral detergent fiber from stems was less digested than that from leaves. Across inoculations, leaves of BLS-resistant KS76 had superior forage quality, including lower concentrations of ferulic acid and p-hydroxybenzaldehyde, than leaves of BLS-susceptible Kanza. The Xca-inoculated stems had lower p-coumaric and ferulic acids and total phenolics than uninoculated controls. Stems of Kanza had higher concentrations of ferulic acid and total phenolics than stems of KS76. Resistance to BLS in KS76 protected nutritive value of leaves.

Effect of variety, location, and irrigation on selectedcriteria for evaluating wheat as a feed for ruminants

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Comparative nutritional compositionof selected grain sorghum varieties

This report is brought to you for free and open access by New Prairie Press. It has been accepted for inclusion in Kansas Agricultural Experiment Station Research Reports by an authorized administrator of New Prairie Press. Copyright 1986 Kansas State University Agricultural Experiment Station and Cooperative Extension Service.