Search Results (7)

The pasture–animal interface of warm-season perennial grass–legume mixed pastures has never been investigated in forage-based equine systems. Therefore, this 2-year study investigated the herbage and animal responses under 84-day continuous stocking in mixed pastures of rhizoma peanut (RP, Arachis glabrata Benth) and bahiagrass (BG, Paspalum notatum Flüggé) with 30 kg nitrogen (N) ha⁻¹ (BG-RP) compared to BG pastures fertilized with 120 kg N ha⁻¹ (BG-N₁₂₀) and no N (BG-N₀). Measurements were taken every 14 days, except for intake and in vivo digestibility, which were measured every 28 days. BG-N₁₂₀ had the highest stocking rate (p = 0.01; 3.7 AU ha⁻¹) in 2019, while BG-N₀ had the lowest (p = 0.01; 2.6 AU ha⁻¹) in 2020. Crude protein and digestible energy were greatest (p < 0.05) for BG-N₁₂₀ and BG-RP in some of the evaluation days in 2019 but similar across pastures in 2020. Crude protein digestibility was greatest (p < 0.05) for BG-RP in the late season. Intake was less (p = 0.03) for horses grazing BG-RP (3.2%BW) compared to BG-N₀ (5.0%BW). Nonetheless, no differences (p > 0.05) were observed among pastures for body measurements. The results indicate that BG-RP pastures can improve forage nutritive value and maintain horse body condition while maintaining similar stocking rate to monoculture bahiagrass with high N fertilizer rates. Full article

The demand for dairy products is ever increasing across the world. The livestock sector is a significant source of greenhouse gas (GHG) emissions globally. The availability of high-quality pasture is a key requirement to increase the productivity of dairy cows as well as manage enteric methane emissions. Warm-season perennial grasses are the dominant forages in tropical and subtropical regions, and thus exploring their nutritive characteristics is imperative in the effort to improve dairy productivity. Therefore, we have collated a database containing a total of 4750 records, with 1277 measurements of nutritive values representing 56 tropical pasture species and hybrid cultivars grown in 26 different locations in 16 countries; this was done in order to compare the nutritive values and GHG production across different forage species, climatic zones, and defoliation management regimes. Average edaphoclimatic (with minimum and maximum values) conditions for tropical pasture species growing environments were characterized as 22.5 °C temperature (range 17.5–29.30 °C), 1253.9 mm rainfall (range 104.5–3390.0 mm), 582.6 m elevation (range 15–2393 m), and a soil pH of 5.6 (range 4.6–7.0). The data revealed spatial variability in nutritive metrics across bioclimatic zones and between and within species. The ranges of these nutrients were as follows: neutral detergent fibre (NDF) 50.9–79.8%, acid detergent fibre (ADF) 24.7–57.4%, crude protein (CP) 2.1–21.1%, dry matter (DM) digestibility 30.2–70.1%, metabolisable energy (ME)3.4–9.7 MJ kg⁻¹ DM, with methane (CH₄) production at 132.9–133.3 g animal⁻¹ day⁻¹. The arid/dry zone recorded the highest DM yield, with decreased CP and high fibre components and minerals. Furthermore, the data revealed that climate, defoliation frequency and intensity, in addition to their interactions, have a significant effect on tropical pasture nutritive values and CH₄ production. Overall, hybrid and newer tropical cultivars performed well across different climates, with small variations in herbage quality. The current study revealed important factors that affect pasture nutritive values and CH₄ emissions, with the potential for improving tropical forage through the selection and management of pasture species. Full article

Sward architecture mediates ruminant grazing behavior in temperate grazing lands. Temperate grasses differ in their sward structure, which may influence the grazing behavior of cattle. We determined relationships between the grazing behavior of dairy heifers and the sward structure of the following temperate grasses: meadow fescue (Schedonorus pratensis (Huds.) P. Beauv.), orchardgrass (Dactylis glomerata L.), quackgrass (Elymus repens (L.) Gould), and reed canarygrass (Phalaris arundinacea L.). Vegetative-stage grasses were rotationally grazed by Holstein heifers (average initial body weight of 460 kg) during 5 day periods in the spring, summer, and fall of 2007 and 2008. The herbage dry matter (DM) allowance was twice the expected daily intake (11 kg DM animal⁻¹ d⁻¹). The sward characteristics were measured before grazing (e.g., the herbage height and mass, vertical distribution of leaf and stem fraction, and nutritive value). The grazing behavior of the heifers was quantified using automatic jaw movement recorders. In this study, the grass species had little effect on the grazing behavior. However, the bite rate was negatively correlated with the herbage mass, while the number of bites was positively correlated with the sward height and herbage mass. These results suggest that when herbage availability is not limited, grazing dairy heifers exhibit similar ingestive and rumination behavior across grass species and seasons, yet jaw movement dynamics may respond to the different characteristics of the swards. The results of this study provide the following benefits: (1) they inform managers about the jaw movement mechanics that can be expected of dairy heifers in temperate forage systems, showing that they are not limited by herbage allowance, and (2) they provide insight for future studies that employ on-animal sensors to evaluate foraging dynamics and animal performance outcomes in temperate forage pasture systems. Full article

The thermal time, expressed in accumulated growing degree-days (AGDD), was used as a predictor to describe and simulate the independent growth of two pasture crops, Lolium perenne L. and Bromus valdivianus Phil. Two sinusoidal models (four-parameter Logistic and Gompertz) were applied to the growth variables (total leaf blade length per tiller—LBL, and accumulated herbage mass—AHM). The nutritive value of pastures was predicted and modeled using regression equations (linear and quadratic), depending on each nutrient. Data for modeling were collected from a two-year study, in which LBL, AHM, and nutritive value variables for L. perenne and B. valdivianus pastures were measured at three-day intervals. Defoliation was determined according to the AGDD, such that the swards were defoliated at 90, 180, 270, 360, and 450 AGDD. The Logistic and Gompertz models presented similar values for the growth rate (GR) parameters, superior asymptote (A_sup), inferior asymptote (A_inf), and point of maximum growth (P_max). In both species, the maximum growth was 260 AGDD. The GR was similar for both species in different seasons of the year, but the maximum AHM varied, with B. valdivianus presenting a higher value (+1500 kg DM ha⁻¹) than L. perenne during the spring. The regressions accurately described the nutritive value, demonstrating a positive linear relationship between the AGDD and concentrations of neutral and acid detergent fiber (NDF, ADF), an inverse linear relationship with crude protein (CP), and a quadratic relationship with metabolizable energy (ME) and water-soluble carbohydrate (WSC) concentration. Full article

Cropping among trees with perennial legumes is one option for increasing agro-ecosystem services, such as improving the nitrogen supply and increasing soil protection by herbaceous vegetation. Moreover, cropping under the canopy of olive trees should diversify the farm production, compared to the traditional fallow management. Among perennial legumes, alfalfa (Medicago sativa L.) produces abundant biomass under Mediterranean rainfed condition. Based on this, a two-year field experiment was implemented in southern Tuscany in a rainfed olive orchard to test the competition for light effects on alfalfa biomass production and nutritive value. Light availability under the tree canopy was measured by hemispherical photos. In both years, the alfalfa yield of under-canopy varied according to the tree presence. A significant relationship between biomass production and light availability was recorded. The nutritive value of under-canopy alfalfa was similar to that of the open-grown alfalfa. However, same significant differences did however occur, between shaded and sole crop. When differences were found, under-canopy herbage was characterised by a higher content of crude protein and a lower content of fibre with respect to open-grown. In a hilly silvoarable olive orchard, alfalfa biomass accumulation was reduced mainly due to scarce light availability, therefore tree management such as pruning and plantation layout can enhance the herbage productivity. Studying shade tolerant forage legumes in order to enhance the yield and nutritive value of herbage production in rainfed agroforestry systems is essential. Full article

This study focuses on calibrating and validating models for hyperspectral canopy reflectance data that are useful to predict the nutritive value of ryegrass-white clover mixed herbage available to the grazing cow. Hyperspectral measurements and herbage cuts were collected from 286 sampling plots from a dairy farm from July 2017 to May 2018. Hyperspectral data were pre-treated by applying a Savitzky-Golay filter followed by a Gap-segment derivative algorithm. Herbage samples were analyzed for determination of herbage nutritive value traits, digestible organic matter in dry matter (DOMD), metabolizable energy (ME), crude protein (CP), neutral detergent fiber (NDF) and acid detergent fiber (ADF). Partial least squares regression was performed to calibrate the spectra against the five nutritive value traits. Results indicate that accuracy was moderately high for the CP model (R² = 0.78) and moderate for the DOMD, ME, NDF and ADF models (0.54 < R² < 0.67). The possibility of being able to use proximal sensing for the estimation of herbage nutritive value in the field could potentially contribute to more efficient grazing management with potential economic benefits for the farm business. Full article

The herbage mass and nutritional value of harvested forage are fundamental determinants of the production potential of pastoral systems. The objective of this study was to evaluate the growth dynamics and accumulated herbage mass expressed in dry matter (DM) of perennial ryegrass (Lolium perenne L.) and pasture brome (Bromus valdivianus Phil.) pastures, using thermal time (TT) as a defoliation criterion. Thirty plots (15 of L. perenne and 15 of B. valdivianus) were distributed in three field blocks and subjected to five defoliation frequencies (DF) determined by TT, expressed as the accumulated growing degree-days (AGDD; DF1 = 90, DF2 = 180, DF3 = 270, DF4 = 360, and DF5 = 450 AGDD) for one year (2016), at the Austral Agricultural Experimental Station of the Universidad Austral de Chile. Every three days, the total leaf length (TLL) was measured, and the leaf elongation rate (LER, cm L⁻¹), leaf growth rate (LGR, cm L⁻¹), leaf appearance rate (LAR, d L⁻¹), phyllochron (AGDD L−1), and accumulated herbage mass per hectare (kg DM ha⁻¹) were calculated. Defoliations were scheduled according to AGDD, and a sample was taken from each cutting to determine (dry matter ‘DM’, crude protein ‘CP’, neutral detergent fiber ‘NDF’, acid detergent fiber ‘ADF’, water-soluble carbohydrates ‘WSC’ and metabolizable energy ‘ME’). The pastures that were allocated to DF5 presented higher DM yields (12,600 kg DM ha⁻¹ year⁻¹), TLL (54.6 cm), and LER (0.63 cm d⁻¹) compared to pastures with high DF (90 and 180 ADGG). B. valdivianus presented a lower phyllochron than L. perenne (74.4 vs 87.9 AGDD L⁻¹, respectively). Concentrations of CP and ME decreased from the shortest DF (90 AGDD) to the largest DF (450 AGDD), dropping from 221 to 138 g kg⁻¹ CP and from 2.6 to 2.4 Mcal kg⁻¹ DM of ME. All variables were affected by the season (Ssn) (p < 0.001). The AGDD can be used as a defoliation criterion and a tool to balance yield with nutritive value according to the farmer’s needs. Full article