Oat Forage Research Articles

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

AbstractSpring‐sown oat (Avena sativa L.) is well adapted for forage production in Central Europe; however, environmental conditions make this crop susceptible to crown rust disease (Puccinia coronata) when grown in summer. The objective of this study was to assess oat cultivars sown in late summer, when conditions for crown rust are less favourable, and harvest in autumn for forage with potential use for feeding lactating dairy cows. Three oat cultivars: Berdysz, Zuch and ForagePlus, the first two from Poland and the latter from United States, were sown 1 and 15 August, and 1 September, over three consecutive years, and harvested for forage in late October. The two Polish cultivars had 61% leaf area affected by rust with 1 August sowing, but ForagePlus was not affected by rust with any sowing date. Sowing 15 August significantly reduced crown rust incidence and increased DM yield of the Polish cultivars 21% relative to the 1 August sowing date, but decreased ForagePlus DM yield by 35%. Sowing 1 September resulted in best forage nutritive value, but the lowest DM yields for all cultivars. Calculated milk production per ton of forage for all cultivars was lowest with the 1 August sowing date. Calculated milk production per hectare was greatest for Berdysz sown in mid‐August. Oat can be sown 15 August and harvested in autumn for forage production, avoiding crown rust disease during summer in Poland. Nutritive value of autumn oat forage is adequate to meet forage requirements of lactating dairy cows.

Performance and nutritional quality of forage oats in the region of Puno

El estudio se realizo con el objetivo de determinar el rendimiento, composicion quimica y valor nutricional del cultivo de avena forrajera, bajo condiciones del altiplano de Puno. Las muestras fueron analizadas para determinar la composicion quimica del forraje mediante el metodo de analisis de Weende, asi como la determinacion de fibra detergente neutro (FDN) y fibra detergente acido (FDA) mediante el metodo de Van Soest; con estos resultados fueron calculados los valores nutricionales de materia seca digestible (MSD), el consumo de materia seca (CMS), el valor relativo del forraje (VRF) y la energia neta de lactancia (ENL). Los resultados, evidencian un rendimiento promedio de 23.04 ± 3.86 t ha -1 de materia verde; el promedio de la composicion quimica fue 27.95 ± 1.58 % de MS, 5.60 ± 0.67 % de ceniza total (CT), 8.67 ± 0.64 % de proteina cruda (PC), 7.99 ± 0.70 % de extracto etereo (EE), 30.77 ± 3.33 % de carbohidratos no fibrosos (CNF), 46.97 ± 3.59 % de FDN, 28.78 ± 1.94 % de FDA, 18.19 ± 2.56 % de hemicelulosa (HC), siendo los valores nutricionales 66.48 ± 1.59 % de MSD, 2.63 ± 0.26 % de CMS, 136.39 ± 15.85 de VRF y 1.33 ± 0.04 Mcal kg -1 MS de ENL. Se concluye que el cultivo de avena forrajera, es una excelente alternativa productiva para el ganado lechero bajo condiciones del altiplano de Puno, con gran potencial de rendimiento y calidad nutritiva. Palabras clave : Avena sativa , rendimiento, composicion quimica, calidad nutritiva

Soil water dynamics, herbage production and water use efficiency of three tropical grasses: Implications for use in a variable summer‐dominant rainfall environment, Australia

AbstractIn the moist mid‐latitudes of eastern Australia, soil water dynamics, herbage production and water use efficiency (WUE) were monitored during 2006–2008, for five perennial pastures: digit grass (Digitaria eriantha), Rhodes grass (Chloris gayana), forest bluegrass (Bothriochloa bladhii), native grass (Bothriochloa macra and Rytidosperma bipartita dominant), lucerne (Medicago sativa); and two forage crops: oat (Avena fatua) and sorghum (Sorghum bicolor). Ground cover formed more quickly in Rhodes grass and lucerne (>70% ground cover in 120 and 175 days after sowing [DAS] respectively) than in forest bluegrass and digit grass (245 and 365 DAS respectively). Values of maximum extractable water (MEW) for Rhodes grass and lucerne were similar (180–242 mm), while values for digit grass and forest bluegrass (129–175 mm) were equal to or greater than those for native grass, and two annual forage crops (77–144 mm). Lucerne expressed the maximum root depth (1.46 m), while values for the tropical grasses (0.96–1.39 m) were greater than native grasses and forage crops (0.87–0.96 m). Native grasses (6.5–12 t DM/ha) had the lowest herbage production, which resulted in values of WUE that were significantly less than most other treatments (16–21 vs. 23–43 kg DM ha−1 mm−1). Digit grass (33–34 kg DM ha−1 mm−1) had higher WUE compared with the other tropical grasses (20–27 kg DM ha−1 mm−1). The data collected here suggest that a forage system comprising digit grass, lucerne and forage oat would provide high production and WUE in this environment.

Characterizing nitric oxide emissions from two typical alpine ecosystems.

A portion of alpine meadows has been and will continue to be cultivated due to the concurrent increasing demands for animal- and crop-oriented foods and global warming. However, it remains unclear how these long-term changes in land use will affect nitric oxide (NO) emission. At a field site with a calcareous soil on the Qinghai-Tibetan Plateau, the authors measured the year-round NO fluxes and related variables in a typically winter-grazed natural alpine meadow (NAM) and its adjacent forage oat field (FOF). The results showed that long-term plow tillage, fertilization and growing forage oats significantly yielded ca. 2.7 times more (p < 0.01) NO emissions from the FOF than the NAM (conservatively 208 vs. 56 g N/(ha·year) on average). The spring freeze-thaw period and non-growing season accounted for 17%-35% of the annual emissions, respectively. The Q10 of surface soil temperature (Ts) was 8.9 in the NAM (vs. 3.8 in the FOF), indicating increases of 24%-93% in NO emissions per 1-3 °C increase. However, the warming-induced increases could be smaller than those due to land use change and management practices. The Ts and concentrations of ammonium, nitrate and water-extractable organic carbon jointly explained 69% of the variance in daily NO fluxes from both fields during the annual period (p < 0.001). This result indicates that temporally and/or spatially distributed NO fluxes from landscapes with calcareous soils across native alpine meadows and/or fields cultivated with forage oats can be predicted by simultaneous observations of these four soil variables.

‘Hi-early’, Early Heading and Harvestable Winter Forage Oats Cultivar

‘Hi-early’, Early Heading and Harvestable Winter Forage Oats Cultivar

‘Dakyeong’, Earley-heading, Resistance to Lodging and High-yielding Forage Oats Cultivar

‘Dakyeong’, Earley-heading, Resistance to Lodging and High-yielding Forage Oats Cultivar

Ensilage of oats and wheatgrass under natural alpine climatic conditions by indigenous lactic acid bacteria species isolated from high-cold areas.

Five different species of selected broad-spectrum antibiotic lactic acid bacteria isolated from extremely high–cold areas were used as starters to ferment indigenous forage oats and wheatgrass under rigid alpine climatic conditions. The five isolates were Lactobacillus plantarum QZ227, Enterococcus mundtii QZ251, Pediococcus cellicola QZ311, Leuconostoc mesenteroides QZ1137 and Lactococcus lactis QZ613, and commercial Lactobacillus plantarum FG1 was used as the positive control and sterile water as the negative control. The minimum and maximum temperatures were −22°C and 23°C during the fermentation process, respectively. The pH of wheatgrass silage fermented by the QZ227 and FG1 inocula reached the expected values (≤4.15) although the pathogens detected in the silage should be further investigated. All of the inocula additives used in this study were effective in improving the fermentation quality of oat silage as indicated by the higher content of lactic acid, lower pH values (≤4.17) and significant inhibition of pathogens. QZ227 exhibited a fermentation ability that was comparable with the commercial inoculum FG1 for the whole process, and the deterioration rate was significantly lower than for FG1 after storage for 7 months. The pathogens Escherichia coli, mold and yeast were counted and isolated from the deteriorated silage. E. coli were the main NH3-N producer while F. fungi and yeast produced very little.

Short‐Term Dynamics of Soil Physical Properties as Affected by Compaction and Tillage in a Silt Loam Soil

Core Ideas Compaction deteriorated soil physical quality especially for the top 0.1‐m layer and tilled soils. Tillage temporarily improved soil physical quality in compacted soils. No‐till for establishing autumn forage crops can be used to mitigate the compaction effect. Short‐term variation in hydraulic properties may be significant for soil and crop modeling. This study investigated short‐term dynamics of soil physical properties as affected by tillage and compaction in a silt loam soil. After establishment of an autumn‐sown forage oat (Avena sativa L.) crop with either NT or intensive tillage (IT), five degrees of livestock compaction (0–261 kPa) were applied in winter using a “cow treading implement.” A barley (Hordeum vulgare L.) crop was then sown following shallow cultivation of the soil in spring. After 2 yr of sheep‐grazed pasture, tillage significantly improved the soil physical quality in the 0‐ to 0.2‐m layer. Compaction significantly deteriorated soil physical quality, by, for example, decreasing macroporosity, available water content, and saturated hydraulic conductivity. Compared with IT and the top 0.1‐m soil layer, soil physical properties in NT and the subsurface 0.1‐ to 0.2‐m layer were more resistant to compaction. Irrespective of tillage, the topsoil (0–0.1 m) was more susceptible to physical degradation than the subsurface soil (0.1–0.2 m). Compaction and tillage effects on soil physical quality declined with time because of natural recovery and the shallow tillage used to establish the subsequent barley crop. This study demonstrated that using NT to establish an autumn‐sown forage crop can mitigate the adverse impacts of livestock treading on soil physical quality during subsequent grazing. Although tillage and compaction effects were short lived, soil physical properties were significantly different between every two adjacent measurement times. This highlights the need to consider the short‐term changes in soil hydraulic properties when modeling soil–crop systems.

Impact inoculum dosage of lactic acid bacteria on oat and wheat silage fermentation at ambient and low temperatures

Lactic acid bacteria (LAB) can be used as silage additives to ensure rapid and vigorous fermentation at early stages of ensiling. We predicted that the optimal LAB inoculation dosage for forage at ambient temperature (15–38°C) would be different from that at cold temperature (4°C). In this study, Lactobacillus plantarum QZ227, isolated from a wheat landrace in alpine regions of Qinghai, China, and commercial L. plantarum FG1 were used as inoculum, with sterile water as control. The effects of inoculum dosage on the fermentation quality of oat (Avena sativa L. cv. Qinghai) and wheat (Triticum aestivum L. cv. Yumai No. 1) silage at ambient temperature (15–38°C) and at 4°C were investigated in laboratory experiments. Little or no improvement in silage quality occurred upon increasing the inoculum dosage at ambient temperature. By contrast, a lower pH and NH3-N content, and a higher LAB count and lactic acid content, were observed at 4°C. Furthermore, the growth of Escherichia coli was inhibited effectively at the lower temperature, and silage quality was positively correlated with increasing inoculum dosage (P&amp;lt;0.05). These results suggest that increasing the inoculum dosage could improve the quality of silage at lower temperatures of 4°C, whereas an appropriate dosage was a key factor for silage at ambient temperature. In this study, oat forage could be used as raw materials for ensiling only at low temperature but was not suitable for ensiling at ambient temperature without wilting due to the high moisture content (86.55%). QZ227 isolated from the roots of wheat in alpine regions displayed superior antimicrobial properties against yeast at ambient temperature and E. coli at 4°C compared with commercial strain FG1. This is the first study to explore the effects of inoculum dosage on silage quality at low temperatures, and provides a basis for low-temperature silage technologies.

Stone pine (Pinus pinea L.): an interesting species for agroforestry in Chile

Pinus pinea is native to the Mediterranean basin, being an interesting species due to its high-value edible pine nuts (prices between €20 and €45 kg−1), its ability to adapt to differing environmental conditions and its relative fast growth in Chile. The species was introduced to Chile more than one century ago by European migrants, who used it for dune stabilization, soil improvement and livestock shading. Agroforestry systems including stone pine and agricultural crops (forage oat and potatoes) and sheep grazing for mutton production were tested in two experimental plots located in El Carmen, Biobio region. The plots were evaluated during 5 years after planting. Crop yields were lower than the region average, reaching nearly 60% of national average yields of forage oat and 66–86% of potato. Forage production in these plots was not enough to sustain permanent grazing; however, sheep grazing in regulated periods contributes to mutton production. Grazing reduces weed and shrub growth, fire risk and the cost of periodic mechanical cleaning. Stone pine annual growth in height and diameter at collar height (ground level) were on average 50 and 2.5 cm, respectively, and was found to be a suitable species for agroforestry systems. Net present value was almost seven times higher in the agroforestry system than in pure stone pine plantations; therefore, this system can contribute to the local and national economy.

Pronóstico productivo de la avena forrajera de temporal por efecto del cambio climático en el noroeste de Chihuahua, México

El cambio climático puede afectar la productividad de los cultivos en una región determinada. El objetivo fue identificar la variabilidad en la producción de avena forrajera (Avena sativa L.) de temporal utilizando una función estocástica y analizar sus relaciones con la temperatura y precipitación, ante escenarios de cambio climático en la región noroeste de Chihuahua, México. Se obtuvo información estadística de 13 años (2001-2013) en las estaciones meteorológicas de los municipios de Bachíniva y Namiquipa utilizando la información de julio, agosto y septiembre, en cuyo periodo se concentra alrededor del 80% de la precipitación anual. Se tomó información del modelo HadCM3 (Modelo acoplado del Centro Hadley versión 3, 2001) que describe el comportamiento de variables climáticas bajo escenarios de emisión de contaminantes A2 y B2 para los años 2050 y 2080. Los cambios en las variables climáticas en el corto plazo (2050) se esperan con un aumento tanto en la temperatura como en la precipitación, lo que permite en el caso de Bachíniva mejorar la producción de avena de 3.57 t/ha a 8.11 t/ha bajo en escenario de emisión de contaminantes A2. A largo plazo (2080) se espera un incremento permanente en la temperatura y sin importar que tanto mejore la precipitación, esto provocara que en las actuales regiones productoras de avena no se logren desarrollar los cultivos para su cosecha.

Surface application of acidified cattle slurry compared to slurry injection: Impact on NH3, N2O, CO2 and CH4 emissions and crop uptake

Intensive cattle production has a severe environmental impact due, partly, to ammonia (NH3) and greenhouse gas emissions resulting from handling of the large amounts of slurry (liquid manure) produced. The present study aimed to compare, in terms of NH3, N2O, CH4 and CO2 emissions and crop yield, slurry injection in soil (reference technique) and a combined approach of slurry (S) treatment (by separation and/or acidification) followed by surface application. A pot experiment was performed over 67days with an oat forage crop amended with S or the separated liquid fraction (LF), with and without acidification to pH5.5. Injection of S was compared with surface application of treated S followed or not by soil incorporation. Soil injection reduced NH3 emissions to insignificant levels and did not increase N2O emissions, while maintaining oat yields similar to those for the surface application of S. Surface application of acidified S or acidified LF led to NH3 emissions <7% of applied NH4+-N, with no increase of N2O emissions relative to surface application of S. Furthermore, a stronger decrease of N losses can be achieved by surface application of acidified S followed by soil incorporation. However, surface application of LF without incorporation led to significant NH3 emissions and therefore is not recommended. Significantly lower (p<0.05) CH4 emissions were observed with application of acidified slurry and LF, relative to the respective non-acidified treatments. These results show that surface application of acidified slurry is a good alternative to slurry injection when the latter technique cannot be used.

Preference, Yield, and Forage Nutritive Value of Annual Grasses under Horse Grazing

Core Ideas Horses preferred winter wheat, annual ryegrass, and spring wheat. Annual ryegrass, spring oat, and winter barley were the highest yielding species. Spring oat, spring barley, and spring wheat had little to no regrowth. Winter wheat and winter rye consistently had higher forage nutritive values. Annual ryegrass can extend the grazing season or provide emergency forage for horses. Annual grasses such as oat (Avena sativa L.), wheat (Tricum aestivum L.), and barley (Hordeum vulgare L.) can serve as alternative forage but little research exists under horse (Equus caballus) grazing. The objectives were to evaluate annual cool‐season grasses for preference, yield, and forage nutritive value under horse grazing during the summer and fall in Minnesota. Spring‐planted grasses included spring barley, spring oat, spring wheat, winter wheat, and annual ryegrass (Lolium multiflorum L.). Summer‐planted grasses included the same five species plus spring forage oat, winter barley, and winter rye (Secale cereal L.). Beginning in June and September of each year, horses grazed grasses at a vegetative stage. Plots were mowed, allowed to regrow, and grazed again. Although spring oat, spring forage oat, and winter barley were often among the highest yielding grasses (≥3.0 Mg ha−1), they were also among the least preferred grasses (≤32% removal). Annual ryegrass, winter wheat, and spring wheat were among the most preferred grasses (≥35% removal). Among these highly preferred grasses, annual ryegrass was typically higher yielding (≥2.7 Mg ha−1), while winter wheat and spring wheat were among the lowest yielding species (≤4.7 Mg ha−1). All grasses contained ≥130 g kg−1 crude protein (CP), ≤610 g kg−1 neutral detergent fiber (NDF), ≤220 g kg−1 nonstructural carbohydrates (NSC), and ≥2.02 Mcal kg−1 equine digestible energy (DE). Annual ryegrass appears to be a viable forage alternative to maximize yield, preference and forage nutritive concentration in horse pastures.

Morphological characteristics, dry matter production, and nutritional value of winter forage and grains under grazing and split nitrogen fertilization

Morphological characteristics, dry matter production, and nutritional values of winter forage and grains were evaluated. This study was conducted from April 24, 2012 to November 7, 2013 in the Western Parana State University (UNIOESTE), Marechal Cândido Rondon, Brazil. Pastures under one grazing and non-grazing conditions were evaluated under 120 kg N ha-1 fertilization split into two 60 kg N ha-1 treatments. Two pastures received 40 kg N ha-1 three times. IPR 126 oat, BRS Taruma wheat, and IPR 111 triticale were the test crops. Topdressing with 40 or 60 kg N ha-1 did not change morphological characteristics until 60 d after sowing. Pastures under non-grazing that received 120 kg N ha-1 treatments were taller than the controls, whereas those under grazing that received 80 or 120 kg N ha-1 presented with higher leaf production than did the controls. Total average dry matter (DM) production in 2012 and 2013 was, respectively, 5,275 kg ha-1 and 6,270 kg ha-1 for oat, 3,166 kg ha-1 and 7,423 kg ha-1 for wheat, and 4,552 kg ha-1 and 7,603 kg ha-1 for triticale. Split N fertilization did not cause differences in the levels of crude protein (CP), neutral detergent fiber (NDF), and acid detergent fiber (ADF) in the forage. Nevertheless, increases in in vitro dry matter digestibility (IVDMD) were observed in oat and wheat receiving 60 kg N ha-1 during the first graze. IVDMD did not change in oat, wheat, and triticale forages receiving 80 or 120 kg N ha-1 during the second graze. Grazing did not affect the nutritional values of wheat and triticale grains, but reduced those of oat. Therefore, the results of the present study suggest that grazing lengthens the crop cycles, and so allow the staggered sowing of summer crops.

Produtividade de biomassa e composição bromatológica de genótipos de aveia forrageira em Vitória da Conquista, BA

O presente trabalho foi conduzido com o objetivo de avaliar e selecionar genótipos de aveia forrageira adaptados às condições edafoclimáticas de Vitória da Conquista, município localizado em região tropical de altitude no estado da Bahia. Utilizou-se o delineamento experimental em blocos casualizados, com três repetições e nove tratamentos, constituídos pelos genótipos São Carlos, UPF 86081, FAPA 2, FAPA 43, UPF 15, IAPAR 61, UPF 19, IPR 126, UFRGS 16. A semeadura foi realizada manualmente, após aração e gradagem do solo, em maio de 2006. A adubação nitrogenada variou de 80 a 120 kg ha-1 de N, divididos em aplicações no momento do plantio, 20 dias após o plantio e após cada corte. Nos períodos de baixa disponibilidade hídrica foi utilizada irrigação suplementar via aspersão. O primeiro corte foi realizado no início de emborrachamento e os cortes seguintes, quando as plantas atingiram altura entre 35 e 40 cm. Foram avaliados o número de dias da emergência ao florescimento e o número de dias da emergência ao amadurecimento dos grãos para determinação do ciclo de crescimento dos genótipos. Ao longo do ensaio, foram avaliadas as produtividades de massa verde e massa seca e a composição bromatológica, determinando-se os teores de proteína bruta, fibra em detergente neutro, fibra em detergente ácido e digestibilidade in vitro da matéria seca. Os genótipos UPF 86081, UPF 19 e UFRGS 16 apresentaram potencial de utilização na região, no período de inverno, com maior produtividade de biomassa verde, enquanto que os genótipos FAPA 43, FAPA 2, IPR 126, IAPAR 61, UPF 15 e São Carlos apresentam melhor desempenho bromatológico com reduzido conteúdo de fibras e maior digestibilidade da matéria seca.

Characterization of ash in algae and other materials by determination of wet acid indigestible ash and microscopic examination

Algae are known for high ash content. It is important to properly characterize their ash for value added utilization of algae as food, feed, and feedstock for biofuels. In this study, 12 algae of different sources were measured for proximate composition and mineral profile. Results showed that the relative difference between ash content by dry ashing and total minerals content by wet digestion increased with ash content. A major cause was soon identified: when using a common procedure of strong attacks for sample digestion before mineral analysis, incomplete digestion existed for most algae samples due to the presence of siliceous materials. It was proposed that algae consist of wet acid indigestible ash (WAIA) and wet acid digestible ash, whereas WAIA is siliceous. Methods to measure WAIA content in the 12 algae, along with oat grain, oat forage, defatted soymeal and fine sand, were then developed based on digestion with nitric acid or sulfuric acid-hydrogen peroxide. For the 12 algae, ash ranged 1.9 to 37.4% dry matter while WAIA by nitric acid digestion varied 0.1% to 25.6%. High correlation between WAIA and ash contents indicates WAIA as an important contributor for algae ash. For identifying what constituted the siliceous materials, all samples in three matrixes (original, ash by dry ashing, and WAIA) were microscopically examined. Because wet acid digestion had an ability to concentrate siliceous materials and maintain their original shape and size, WAIA was the best matrix for microscopic examination. Micrographs of WAIA show three types of siliceous materials in algae: non-diatom cellular structures, diatom cell walls, and sandy particles. It was concluded that high ash content of algae resulted partly from contamination of diatoms and/or sandy particles of geologic origin and that WAIA should be an important quality parameter for algae. Subsequently, several measures are proposed to produce algae with low ash content.

Effects of feeding practices on milk yield and composition in peri-urban and rural smallholder dairy cow and pastoral camel herds in Kenya

Associations between feeding practices, milk yield, and composition were assessed in smallholder rural and peri-urban dairy cow (n=97) and pastoral camel (n=15) herds. A cross-sectional survey supplemented by follow-up collection of feed and milk samples for laboratory analyses was conducted. Data was analyzed using descriptive, correlation, and analysis of variance statistics. Feeding practices in rural smallholder dairy cows' herds were pastured based (87.7%) with napier grass (89.4%) and concentrates (93.9%) as forage and concentrate supplements. In smallholder peri-urban dairy cows' herds, it was napier grass based (68.4%) with concentrates (100%), oat forages (42.9%), and crop residues (28.6%). Pastoral camel herds were shrub browsing (53%), rangeland pasture grazing (20%), or Euphorbia tirucalli feeding (27%). Smallholder rural farmers offered more feeds (16.1 vs 15.3kg/day) than peri-urban farmers, hence net energy for lactation (1.4 vs 1.3Mcal/kg), crude protein (CP) (10 vs 12%), and milk yields (12 vs 9kg/herd/day) was higher. Milk fat was higher in smallholder peri-urban (4.3%) than that of rural (3.9%). In pastoral camels, E. tirucalli feeding had higher daily milk yield/herd, fat, and CP (63kg, 4.5 and 3.6%) than shrub browsing (35kg, 4.2 and 3.0%) and grazing (23kg yield, 2.6 and 2.7%). Five feeding practices out of 14 in smallholder dairy cattle herds resulted in more than 10kg milk/cow/day because of low forage-to-concentrate ratio (2.5), inclusion of legume crop residue, or processing forages. They present opportunities for improved production in smallholder herds. In pastoral camel, E. tirucalli feeding showed the highest potential.

Sorghum and black oat forage production and its nutritive value under phosphate levels

Phosphorus (P) is one of the most limiting mineral elements for biomass and grain production in tropical soils. This study was undertaken to assess the influence of P on herbage accumulation (DM) and the nutritive value of forage sorghum (Sorghum bicolor) and black oat (Avena strigosa) in succession. Evaluated treatments were P fertilization levels of 0, 50, 100, 150 and 200 kg of P2O5 ha-1 distributed in a randomized complete block design with three replicates. The treatments were applied at sorghum seeding in the summer 2010/2011 and 2011/2012. Black oat was seeded following sorghum in 2011 with no additional P fertilization. Herbage production and its nutritive value were assessed by successive cuts. The greatest sorghum DM yields were obtained at the highest phosphate level tested (200 kg P2O5 ha-1), with residual response in subsequent black oat. There was no effect of P fertilization levels on the nutritive values of both crops, considering crude protein (CP) levels, in vitro dry matter digestibility (IVDMD), neutral detergent fiber (NDF) and acid detergent fiber (ADF), what demonstrates that P addition has no effect in forage nutritive value, especially when the soil P levels are classified as medium or high. The plant P recovery efficiency decreased when increasing P fertilization levels for both sorghum and black oat. The level of 50 kg P2O5 ha-1 year-1 presented the greatest P recovery by plants, which supports the idea of less fertilizer use with more efficiency.

Effects of the frequency of forage allocation and harvest maturity of whole-crop oat forage on dry matter intake and ruminal fermentation for beef heifers

The objective of this experiment was to determine whether feeding frequency of whole-crop oat forage harvested at 2 maturities affects forage intake and ruminal fermentation. Whole-crop oat forage (c.v. Weaver, Crop Development Centre, Saskatoon, SK, Canada) harvested at the hard dough and ripe stages were offered ad libitum either daily (1-D) or once every 3 d (3-D) to 4 ruminally cannulated heifers. Treatments were arranged in a 2 × 2 factorial within a 4 × 4 Latin square design. Because of low forage availability, one period was omitted, resulting in an incomplete Latin square. Diets were supplemented to ensure CP was balanced across treatments. Data were analyzed using the mixed model of SAS. Total DMI and forage intake were not affected by harvest maturity, feeding frequency, or the interaction (P ≥ 0.41). Minimum ruminal pH averaged over 3 d was less for heifers fed 3-D (5.53) compared with 1-D (5.89; P < 0.001). Mean pH increased from 5.81 to 5.99 and then 6.35 for d 1, 2, and 3, respectively, for heifers fed 3-D (frequency × day; P = 0.002). However, mean ruminal pH did not differ among days for heifers fed 1-D (average of 6.32). There was a frequency × day interaction for the total ruminal short-chain fatty acid concentration (P = 0.046), with the concentration being less for heifers on d 3 relative to d 1 when fed 3-D; however, no differences among days were detected for heifers fed daily. These data suggest that feeding 3-D may not affect forage intake but increases the risk for low ruminal pH, and transiently reduces ruminal short chain fatty acid concentrations.

Net effects of nitrogen fertilization on the nutritive value and digestibility of oat forages

Applications of soil amendments containing N are part of routine forage-management strategies for grasses, with a primary goal of increasing forage yield. However, the effects of N fertilization on forage nutritive value, estimates of energy density, and in vitro dry matter or neutral detergent fiber disappearance sometimes have been erratic or inconsistent. Our objectives were to evaluate the effects of N fertilization on the nutritive value of a single cultivar (ForagePlus, Kratz Farms, Slinger, WI) of fall-grown oat fertilized at planting with 20, 40, 60, 80, or 100 kg of N/ha of urea or 2 rates of dairy slurry (42,300 or 84,600 L/ha). Nitrogen fertilization exhibited consistent effects on fiber components; forages fertilized with urea or dairy slurry had greater concentrations of fiber components compared with those harvested from unfertilized check plots (0 kg of N/ha), and fiber concentrations increased linearly with urea fertilization rate. In contrast, concentrations of water-soluble carbohydrates were greatest for unfertilized forages (21.2%), but declined linearly with urea fertilization, exhibiting a minimum of 13.5% at the 80 kg of N/ha urea application rate. Similarly, nonfiber carbohydrates also declined linearly, from 34.8% for unfertilized check plots to a minimum of 24.6% at the 80 kg of N/ha urea application rate. Fertilization with urea resulted in consistent linear increases in crude protein (CP), neutral detergent soluble CP, neutral detergent insoluble CP, and acid detergent insoluble CP; however, the partitioning of CP on the basis of association with specific fiber fractions could not be related to N fertilization when concentrations were expressed on a percentage of CP basis. The summative calculation of energy, expressed as total digestible nutrients was closely related to N fertilization rate during both the 2013 (y = -0.038x + 72.2; R2 = 0.961) and 2014 (y = -0.040x + 69.2; R2 = 0.771) production years. Following 30- or 48-h incubations in buffered rumen fluid, in vitro dry matter disappearance was greater for unfertilized forages compared with those fertilized with either urea or dairy slurry, and disappearance declined linearly with urea fertilization rate; however, these responses were not detected for neutral detergent fiber disappearance. Overall, the forage nutritive value of fall-grown oat declined mildly in response to N fertilization, but these responses were not nearly strong enough to offset the advantages obtained by improved forage yields.