Grass and Forage Science最新文献

Reduced reliance on inputs such as fertilizer is fundamental to sustainable grazing systems. This two-year study compared four sward types, including multispecies swards (MSS), for herbage dry matter (DM) production, species contribution to DM, and herbage nutritive value under grazing. The systems were: (1) Lolium perenne L. monoculture (PRG; 170 kg N ha⁻¹ year⁻¹); (2) permanent pasture (PP; 135 kg N ha⁻¹ year⁻¹), (3) six species sward consisting of two grasses, two legumes and two herbs (6S; 70 kg N ha⁻¹ year⁻¹), (4) twelve species sward consisting of three grasses, four legumes and five herbs (12S; 70 kg N ha⁻¹ year⁻¹). Herbage samples were collected for DM yield, botanical composition, and nutritive value. Mean annual DM production for PRG, PP, 6S, and 12S was 11,374, 8526, 13,783, and 13,338 kg DM ha⁻¹ respectively. Herb proportions decreased in 6S and 12S from 2020 to 2021 while grass proportions increased. Mean crude protein levels were similar across all systems (p > 0.05), with higher ash content in 6S and 12S compared to PRG (p < 0.001). Organic matter digestibility was lowest in PP compared to PRG (p < 0.001) while neutral detergent fibre content of PP and PRG were greater than 6S and 12S (p < 0.001). Water soluble carbohydrate content was highest in PRG (p < 0.0001). Over 2 years, MSS delivered increased herbage DM yield and nutritive quality relative to PRG and PP swards, from reduced N inputs. However, maintenance of the herb component of MSS is a challenge.

Integrating forage legumes into grasslands offers numerous ecosystem services. However, the management of grass-legume pastures is challenging because the interaction between the defoliation frequency and severity may affect the legume persistence and forage intake by grazing animals. This 2-year study evaluated the most effective grazing intensity to increase forage intake while maintaining a balanced legume proportion in tropical pastures consisting of Brachiaria brizantha and Arachis pintoi. Three treatments (grazing intensities) were assessed: severe, moderate, and low, corresponding to stubble heights of 10, 15, and 20 cm, respectively, and a pre-grazing height of 25 cm. Two purebred Tabapua heifers were used for each treatment, and additional put-and-take animals were introduced, as required. Canopy structure, grazing behaviour, nutritive value, and forage intake were evaluated. The legume proportion in herbage mass remained consistent across all intensities, averaging 35% pre- and 32% post-grazing. The grazing duration remained consistent across treatments on the first and third days, with an average grazing time of 390 and 440 min, respectively. Under post-grazing conditions, low-intensity grazing had a 52% greater intake rate than severe-intensity grazing, which was attributed to a greater biting rate (37.9 bites/min) and bite weight (0.9 g DM/bite). Moderate grazing intensity (stubble height of ~15 cm associated with a pre-grazing height of ~25 cm) is recommended to manage a mixture of B. brizantha and A. pintoi when the objective is to couple high forage intake with a balanced legume proportion in the pasture.

Understanding how forage can be utilized in the rumen is important for optimizing system efficiency. We aimed to evaluate the ruminal fermentation parameters and methane (CH₄) production of Marandu palisadegrass [Brachiaria (syn. Urochloa) brizantha (Hochst. ex A. Rich.) R. D. Webster] growing in monoculture or in integrated systems. The experiment was conducted over 3 years to evaluate four systems [livestock (L), livestock-forestry (LF), crop-livestock (CL), and crop-livestock-forestry (CLF)] during the dry and rainy seasons. In the dry season, palisadegrass in CLF presented the greater crude protein (CP) and the lesser neutral detergent fibre (NDF) concentrations. The greatest gas volume was produced in L, while LF and CL reduced CH₄ production compared to L. The greatest ammoniacal-nitrogen concentration, propionate and valeric acid proportions, and degradability of NDF were in CLF. In the rainy season, palisadegrass in LF and CLF presented the greater CP concentration and the lesser CH₄ production. Integration of crop and forestry components in a forage-based livestock system affected ruminal fermentation parameters of Marandu palisadegrass, consequently, reducing CH₄ production. In addition, the inclusion of a forestry component enhanced forage CP concentration. Integrated systems can improve ruminal fermentation, supporting sustainable livestock production and optimizing forage utilization.

Chlorophyll (Chl) concentration is one of the factors that affects crop productivity. This study investigated the prediction of chlorophyll concentrations in Mombaça grass' leaves using hyperspectral data and machine learning techniques. Chlorophyll variations were induced by different levels of nitrogen fertilization (104, 208, 312, and 416 kg ha⁻¹). Spectral signatures (400–2500 nm) and chlorophyll contents of the leaves were obtained in October, November, and December 2017, and January 2018. Models were generated using Partial Least Square Regression (PLSR), Random Forest (RF), and Support Vector Regression (SVR). Two validation techniques were employed: holdout, dividing the data into training (75%) and testing (25%) sets; and leave-one-date-out cross-validation (LOOCV), in which one date was omitted during model training and used to predict the omitted date's value. Chlorophyll concentrations varied according to N doses, with the highest concentrations observed in October and December. In these months, there were greater variations in spectral reflectance in the green and red bands (530–680 nm). December was identified as the ideal period for chlorophyll quantification, for both holdout and LOOCV validation techniques. The SVR technique performed best (R² = 0.71, RMSE = 0.23 mg g⁻¹, dr = 0.72) compared to RF (R² = 0.63, RMSE = 0.27 mg g⁻¹, dr = 0.66) and PLSR (R² = 0.60, RMSE = 0.27 mg g⁻¹, dr = 0.67). Therefore, the prediction of chlorophyll in Mombaça grass using spectroradiometry is promising and applicable across different cultivation periods.

The incorporation of dual-purpose alfalfa (Medicago sativa L.) cultivars into bermudagrass (Cynodon spp.) is a viable option to extend the grazing season in Southern forage systems. However, data are limited on which harvest management strategy (HMS) optimizes the use of alfalfa-bermudagrass (ABG) mixtures in the Southern US. A two-year study evaluated ABG mixtures under three HMS [cut only (CO), graze only (GO), or cut and graze (CG)].in Headland, AL and Tifton, GA. Alfalfa-bermudagrass mixtures utilized in this evaluation were ‘Bulldog 805’ alfalfa that was interseeded into ‘Tifton 85’ bermudagrass. Treatments were evaluated for forage, animal, and total system performance. Herbage accumulation varied by year and location (p < .01), but the number of harvests ultimately determined the total forage produced. Forage allowance was never limiting but did differ among treatments at Tifton, GA (p = .02). The CG HMS allowed for similar daily (p > .06) and liveweight gains (p > .56) on fewer days of grazing as compared to the GO treatments. The greater alfalfa percentage in the CG HMS translated to greater total digestible nutrients (TDN) and crude protein (CP), though not always statistically different. The CO HMS maximized system performance when evaluated for total gain (actual gains + predicted gains). However, the CG management allowed for more production opportunities across the season, thereby reducing economic risk. Future research should focus on evaluating the economic implications of introducing each HMS into ABG systems.

Failure of perennial ryegrass-based pastures to persist beyond 3 years post-sowing is an increasing threat to the sustainability of livestock industries in the north of New Zealand. Little is known of the long-term responses of plants and populations to the environmental stresses responsible for persistence failure, or the effects of ryegrass genetics on those responses. Plants were collected from 10-year-old pastures sown in two environments (Waikato, North Island: warm-temperate, summer/autumn dry; Canterbury, South Island: cool temperate, irrigated) to four ryegrass functional types and grazed by dairy cattle. Surviving plants in Canterbury pastures were almost all true-to-type for the original genotype, whereas there was substantial ingress of volunteer plants in the diploid cultivars in Waikato. Plants confirmed as true-to-type were compared to reference plants grown from the original seed lines. Leaf mass was lower in survivor plants than in reference plants for all functional types. This effect was reversed by recruitment of new plants from seed in a grazing deferment treatment applied at the Waikato site 18 months before plant collection, in a manner consistent with epigenetic control. Reproductive development was delayed by 4–6 days in survivors of mid- and late flowering diploid cultivars: this effect appeared to be the result of true genetic differentiation. There was less aftermath heading in the Canterbury survivors, but not Waikato survivors, compared with the reference plants. The relevance of these findings for ryegrass survival strategies and targeted selection of traits for improved persistence is discussed.

The primary objective of haymaking is to dry forage adequately to inhibit the growth of undesirable microbes and halt residual plant enzymatic activity that causes nutrient losses. During the field and storage phases of haymaking, the environment, management practices, and other factors influence the extent of dry matter losses. This review discusses these factors and the strategies that have been developed to mitigate nutrient losses. A major emphasis was placed on hay microbiome dynamics, as it has been scarcely studied despite its importance on nutrient losses during storage and harvest, especially under humid conditions. The effects of cutting height, mower type, and swath manipulation on soil contamination were discussed. Also, the impact of environmental conditions and swath manipulation on wilting time was analysed for humid and arid conditions. Special attention was given to design improvements in harvesting equipment to reduce wilting time and field losses. Furthermore, we assessed the nutrient losses during storage caused by microbial and residual plant enzymatic activity resulting from excessive moisture at baling or re-introduced moisture during storage. The spoilage extent during storage depends on bale moisture, size, density, shape, wrapping, forage type, and storage facilities. A Venn diagram analysis showed that each phase of haymaking process has a unique microbiome and that certain fungal and bacterial genera could be shared across more than one hay production phase. To take corrective actions, hay producers need to be aware of the increased susceptibility to nutrient losses associated with particular field and storage practices, environmental conditions, and forage types.

Intermediate wheatgrass [IWG; Thinopyrum intermedium (Host) Barkworth & D.R. Dewey] is a perennial grass, dual-purpose crop that can provide environmental services. In addition to the grain production, assessing its forage potential is crucial. We developed models for near-infrared (NIR) spectrometry prediction of the chemical composition and digestibility of IWG across various experimental sites. Among these, a Belgian field was used to compare its dual production in pure stands or in mixture with legumes. Good quality NIR predictions were observed, offering an efficient tool to characterize the forage composition of IWG. Its forage parameters were mainly influenced by the phenological stage with an increase of fiber and a decrease of protein, digestibility, and energy content (NE_L) during the growing season. IWG forage at vegetative stages could be used to feed lactating dairy cattle with a NE_L of 1625 kcal kg⁻¹ of DM but, its biomass was low averaging 1.8 t of DM ha⁻¹. At grain maturity, biomass was higher (i.e., 5.3 t of DM ha⁻¹), representing 73%–92% of the total biomass production, and could replace straw in high-starch dairy diets with a NE_L averaging 849 kcal kg⁻¹ of DM. Although the mixture of IWG with legumes enhanced some forage parameters, its value as animal feed was not improved. In mixture, we observed a tradeoff between the increase of the forage yield and the reproductive potential of IWG. These insights can inform the on-going process of breeding and help farmers to design relevant systems to experiment this new crop.

This study hypothesized that urea fertilization could optimize animal performance in an agroforestry system. This study evaluated how increasing rates of N fertilization (0, 100, 200, and 400 kg N ha⁻¹ year⁻¹) using urea (CH₄N₂O) affected forage mass, nutritive value, and beef cattle (Bos indicus) performance in an agroforestry system with Massai grass (Megathyrsus maximus Jacq. cv. Massai) and legume tree (Mimosa caesalpiniifolia Benth.), in the humid tropic region of Brazil, over 2-year period. The experiment was carried out in a randomized complete block design with four treatments (N fertilizer rates) and three replications. Forage mass was positive and linearly affected by N fertilization (p = .0236, R² = 0.92), ranging from 1297 to 1583 kg DM ha⁻¹ under 0 and 400 kg N ha⁻¹ year⁻¹, respectively. There was greater average forage mass during the rainy period (1826 kg ha⁻¹) (p < .05). Crude protein in green forage mass increased linearly (p = .0041, R² = 0.91) in function of the N applied. Cattle average daily gain showed a positive quadratic response to the rates of N applied (p = .0298, R² = 0.97), ranging from 0.46 kg to 0.68 kg animal day⁻¹; and the gain per area increased linearly from 1.84 to 2.68 kg LW ha⁻¹ day⁻¹ (p = .0640, R² = 0.96). The findings indicate that applying 200 kg N ha⁻¹ year⁻¹, split-applied during the rainy season, would yield acceptable outcomes in terms of forage mass, nutritive value, and animal performance for this type of agroforestry system.

Biorefining is seen as a potential method to produce protein-rich feed for monogastric farm animals from grassland, which does not compete with human nutrition. Therefore, a new biorefinery facility was constructed and tested in this experiment by using silages from grass clover mixture and red clover. After biorefining, press juice was stored for further use while press cake was re-ensiled. Samples from silage, press juice, fresh press cake and re-ensiled press cake were analysed for nutrient composition, fermentation parameters, amino acids (AA) and biogenic amines (BA) concentrations. Furthermore, digestibility of silage and re-ensiled press cake was tested in wethers. We found that press juice contained about 205 g crude protein (CP), more than 180 g crude ash and more than 130 g volatile organic compounds (VOC, all values per kg dry matter [DM]). Furthermore, press juice had an unfavourable AA ratio for use as a monogastric feed (methionine and cysteine were reduced). Forage type hardly affected nutritive value of press juice. Re-ensiling of press cake was successful as a sufficient decrease of pH and VOC concentration was observed. Press cake had 26–36 g/kg DM lower CP content and 0.77–1.12 MJ/kg DM lower metabolisable energy content than silage with greater differences in red clover than in grass clover mixture. Press juice can be used as feed in monogastric animals, but its use is limited due to its low CP content and unfavourable AA profile. Press cake could be an appropriate feed for ruminants, especially dry cows or heifers.