Farmer Experiences With Alfalfa in the Southern U.S.A.

Alfalfa (Medicago sativa L.) is a forage crop of primary importance in the United States (USA); however, adoption and use in the southern USA region has been limited. The combination of adapted alfalfa cultivars and management strategies which demonstrate extended forage growing season length, improved forage nutritive value, and reduced N fertilizer inputs have renewed interest in forage-livestock farmers to consider planting alfalfa. A series of Extension-based educational strategies have been used in the southern USA to 1) create awareness on the use of alfalfa, 2) educate farmers regarding establishment and management practices, and 3) showcase opportunities and challenges of on-farm alfalfa use in the region. Educational initiatives included on-farm demonstrations and farmer testimonials, field days, integrated lecture and field-based workshops, and web-based content delivery. Across multiple educational methods, farmers reported increased awareness and understanding of management requirements to incorporate alfalfa into their operation. However, on-farm management challenges were also noted as the primary reason of hesitance towards adopting alfalfa in the region. Targeted education to farmers with a greater level of familiarity regarding stand management requirements, such as dedicated hay growers or row crop operators, were identified as audiences where alfalfa may be more readily adopted. Continuing education areas to demonstrate value of alfalfa include an emphasis on timeline for breakeven economic returns following establishment and ecosystem benefits of using legumes in forage management systems

Development of Forage Curriculum for Extension Educators in the Southeast USA

In the Southeast USA, livestock production is one of the largest agricultural activities, and forages are the primary feed source. Most livestock systems are highly dependent on off-farm inputs to support forage production and animal performance, which elevates production costs and the activity\u27s carbon footprint. There is a strong need to develop forage educational resources to enhance productivity, environmental sustainability, resilience, and profitability of agricultural systems in the region. This multi-disciplinary initiative was a collaboration among several land-grant Universities across the region. The objective was to develop decision tools and provide in-classroom training associated with hands-on demonstrations to Extension agents and agricultural educators in the Southeast. A textbook was developed for the two-day training, and the in-person program was held in Columbiana, AL, through a collaboration among 20 Specialists from several land-grant Universities. The book included basic concepts and management strategies for forages, livestock (e.g., beef, horse, small ruminants), soil, economics, nutrient management, animal genetics, and marketing strategies for forage-based systems. There were 62 participants from Alabama, Florida, Georgia, Louisiana, North Carolina, South Carolina, and Tennessee. The majority of the participants were Extension agents or educators, and close to half of them had been in the job position for less than five years (n= 28 participants). A significant emphasis was set on newer agents` participation aiming to allow them to address gaps in knowledge. The training sessions supported critical thinking and deepening of knowledge and network. Post-training surveys were applied to gather change in knowledge and feedback from participants and identify potential barriers to be used in structuring future curriculum development and trainings. Regional joint efforts can be a tool to address multi-disciplinary training while incentivizing collaboration across regions for Specialists and agents through their programming activities

Evaluation of Limpograss (\u3cem\u3eHemarthria altissima\u3c/em\u3e) Breeding Lines under Different Grazing Managements

Limpograss (Hemarthria altissima (Poir.) Stapf et C.E. Hubb.) is a stoloniferous, warm-season perennial grass from South Africa. It is frequently used to extend the grazing season in poorly drained soils of subtropical regions (Quesenberry et al. 2004). The cold tolerance of limpograss allows it to grow at temperatures below which other commonly used warm-season grasses (e.g. bermudagrass) remain productive. Use of limpograss has helped to reduce forage shortfall during winter, therefore, reducing feeding costs. In the past 30 years, the area planted to limpograss in Florida, USA has grown faster than that of any other forage grass species. It is estimated that over 0.2 million ha are planted to limpograss (Quesenberry et al. 2004). Recent University of Florida research with limpograss has focused on developing new hybrids which incorporate the persistence of the most widely used cultivar ‘Floralta’ with the digestibility of ‘Bigalta’. Preliminary clipping and grazing trials evaluated 50 breeding lines and identified 5 lines (designated 1, 4F, 10, 32 and 34) with superior performance. With an overall program goal of identifying the best limpograsses for cultivar release, the specific objective of this experiment was to investigate the forage productivity and sward canopy characteristics of these 5 breeding lines, compared to Floralta, in response to different grazing management strategies

In Vitro Methane Production from Heifers Offered Four Bermudagrass Cultivars

Though bermudagrass (Cynodon dactylon [L.] Pers.) is one of the predominant warm-season perennial forage supporting the southeastern United States livestock production systems, little is known about its influence on parameters of ruminal metabolism, including carbon loss as methane. With the multitude of cultivars of this grass that have been developed and released, one may question whether the physiological cultivar differences will manifest varying results in digestive efficiency and subsequent methane emissions. Thus, the objective of this study was to evaluate in vitro methane (CH4) production as influenced by four bermudagrass cultivars. Ruminally-fistulated heifers (n = 4) were assigned randomly to one of four bermudagrass cultivars (Coastal [COS], Russell [RUS], Tifton 44 [T44], or Tifton 85 [T85]) for four 30-d in vivo periods in a Latin square design. On d 28 of each period, rumen fluid was collected from each heifer for use in CH4 production evaluation. Samples of each bermudagrass, corresponding to the cultivar fed, were weighed into duplicate 10-mL serum bottles and incubated at 39°C for 0, 2, 4, and 24 h. Following incubation, headspace samples were assayed for CH4 concentrations by gas chromatography. There was an interaction of cultivar and time (P \u3c 0.01). There was no difference among cultivars (P \u3c 0.05) at 0, 2, or 4 h of incubation. After 24 h of incubation, however, CH4 concentrations were greater (P \u3c 0.05) from T44 and T85 (7.7 and 6.2 mmol/L, respectively) than from RUS and COS (3.4 and 3.0 mmol/L, respectively). Results are interpreted to mean that cultivar type has an influence on the potential CH4 production of bermudagrass

Herbage Accumulation and Nutritive Value of Limpograss Breeding Lines Under Stockpiling Management.

Supplements or conserved forage are often used to overcome forage quantity deficits for beef cattle, but stockpiled forage can be more economical. Limpograss [Hemarthria altissima (Poir.) Stapf & C.E. Hubb.] is the best available species for stockpiling in Florida because it is productive in autumn and maintains greater digestibility than other grasses at advanced stages of maturity. New limpograss hybrid breeding lines have been developed, but they have not been tested under stockpiling. Three limpograss breeding lines (1, 4F, and 10) and the most-used cultivar, Floralta, received 50 or 100 kg N ha?1 at initiation of stockpiling and herbage accumulated for 8, 12, or 16 wk. Entry 4F had greater herbage accumulation (7.3 Mg ha?1) than Entries 10, 1, and Floralta (6.1, 6.0, and 5.4 Mg ha?1, respectively). Entry 4F also had greater in vitro digestible organic matter (IVDOM) concentration (530?594 g kg?1) than Entries 1 and Floralta, but 4F was not different from Entry 10 (519?531 g kg?1) after 12 and 16 wk of accumulation. As stockpiling period increased from 8 to 16 wk, herbage accumulation increased from 5.3 to 7.4 Mg ha?1, dead material proportion increased from 1 to 10%, and herbage crude protein (CP) decreased from 44 to 32 g kg?1. Limpograss hybrids 4F and 10 are superior to Floralta for stockpiling, stockpiling period should not be longer than 12 wk, and protein supplement will be required to achieve satisfactory animal performance on stockpiled limpograss

Deletion of L-Selectin Increases Atherosclerosis Development in ApoE−/− Mice

Atherosclerosis is an inflammatory disease characterized by accumulation of leukocytes in the arterial intima. Members of the selectin family of adhesion molecules are important mediators of leukocyte extravasation. However, it is unclear whether L-selectin (L-sel) is involved in the pathogenesis of atherosclerosis. In the present study, mice deficient in L-selectin (L-sel−/−) animals were crossed with mice lacking Apolipoprotein E (ApoE−/−). The development of atherosclerosis was analyzed in double-knockout ApoE/L-sel (ApoE−/− L-sel−/−) mice and the corresponding ApoE−/− controls fed either a normal or a high cholesterol diet (HCD). After 6 weeks of HCD, aortic lesions were increased two-fold in ApoE−/− L-sel−/− mice as compared to ApoE−/− controls (2.46%±0.54% vs 1.28%±0.24% of total aortic area; p<0.05). Formation of atherosclerotic lesions was also enhanced in 6-month-old ApoE−/− L-sel−/− animals fed a normal diet (10.45%±2.58% vs 1.87%±0.37%; p<0.05). In contrast, after 12 weeks of HCD, there was no difference in atheroma formation between ApoE−/− L-sel−/− and ApoE−/− mice. Serum cholesterol levels remained unchanged by L-sel deletion. Atherosclerotic plaques did not exhibit any differences in cellular composition assessed by immunohistochemistry for CD68, CD3, CD4, and CD8 in ApoE−/− L-sel−/− as compared to ApoE−/− mice. Leukocyte rolling on lesions in the aorta was similar in ApoE−/− L-sel−/− and ApoE−/− animals. ApoE−/− L-sel−/− mice exhibited reduced size and cellularity of peripheral lymph nodes, increased size of spleen, and increased number of peripheral lymphocytes as compared to ApoE−/− controls. These data indicate that L-sel does not promote atherosclerotic lesion formation and suggest that it rather protects from early atherosclerosis

Defects in Regulation of Local Immune Responses Resulting in Atherosclerosis

Atherosclerosis is nowadays generally accepted as an inflammatory disease but the mechanism of its origin and development have not yet been fully clarified. The present review focuses on the role of the local immune system as one of the key players in the pathogenesis of the complex process. Its part represented by vascular-associated lymphoid tissue (VALT) within the arterial wall participates directly in the vascular wall's homeostatis. Its inordinate activation during ontogenic development of an individual, this formerly defensive and physiologic mechanism transform into a pathological process resulting in an impairing inflammation. Hsp60, CRP and oxidized or otherwise modified LDL are serious candidates for triggering these pathological changes. The principal role is played by anti-Hsp60 antibodies and by shear stress originating on the surface of endothelium due to blood flow. The experimental and clinical data supporting this immunological hypothesis of atherosclerosis are discussed

Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases

The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular "reactive oxygen species" (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation. We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation). The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible. This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference