Herbage Crude Protein Research Articles

Quality of Red Clover Forage in Different Organic Production Systems

The aim of this study was to determine the quality of organically grown red clover herbage and silage after being influenced by supplementary mineral fertilization. The experimental treatments were as follows: control treatment without fertilization (group C), treatment where kalimagnesia (Patentkali) was applied (group P), and treatment where potassium sulfate (SOP) was applied (group S). In each year of the experiment, first-cut herbage was harvested at the beginning of flowering and ensiled. The year of the study had a significant (p ≤ 0.05) influence on the analyzed parameters of herbage and silage, excluding the content of calcium (Ca), acetic acid (AA), and ammonia nitrogen (N-NH3). The organic production system exerted a significant (p ≤ 0.05) effect on the concentrations of crude protein (CP), acid detergent lignin (ADL), water-soluble carbohydrates (WSC), minerals (P, K, Ca, Na), lactic acid (LA), ethanol, and N-NH3. The pattern of fermentation was affected by both experimental factors. True protein (TP) content was determined at 70–84% CP in herbage and 53–65% CP in silages. The energy value and the protein value of herbage varied significantly across years of the study and in response to the combined effects of both experimental factors (p ≤ 0.05). Red clover grown in organic production systems supplied high-quality forage.

An inventory of grassland use on horse farms

Horses can contribute to the maintenance of grassland. To determine the potential contribution of grassland to horse nutrition, we investigated the seasonal variation of herbage on offer and its nutritional quality in an inventory on six practical horse farms in Central Germany during 2019. On all horse-grazed pastures compressed sward height (CSH) was measured monthly and converted into aboveground herbage (AGH) to allocated short and tall grass sward areas (area-specific) via calibration cuts. In addition, four focus pastures were selected for monthly obtained area-specific herbage quality samples. The farm-specific management was monitored using questionnaires and grazing diaries to determine underlying factors influencing herbage biomass and quality. The proportion of short grass sward areas increased during the grazing season (p=0.0010), which was related to high stocking intensity in terms of livestock unit grazing days (LUGD, p <.0001). On most farms, LUGD were constant throughout the growing season and not adjusted to changing grass growth. Herbage crude protein (CP, p=0.0038), metabolizable energy (ME, p <.0001) concentrations and acid detergent fibre in the organic matter (ADF, p <.0001) differed among the grass sward areas. The results suggest that sufficient ME (4.2 ± 0.32 – 8.4 ± 0.15 MJ ME kg−1 DM) for maintenance and pre-caecal digestible CP (pcdCP) (37.0 ± 3.86 – 77.4 ± 4.44 g kg−1 DM) could be provided during the grazing season. The study highlights the need to incentivise grassland management for herbage provision among horse owners to exploit the potential of grassland during the grazing season.

Methane emissions and milk yields from zebu cows under integrated systems

Integrated systems are technologies that potentially increase animal production and environmental preservation, but the effect of these systems on the efficiency and methane emissions of dairy cows is still unknown. This study aimed to compare enteric methane emissions, dry matter intake and performance of grazing dairy cows in integrated systems in the Brazilian Cerrado biome, i.e., crop-livestock integration (CLI) or crop-livestock-forest integration (CLFI). Eighteen Holstein-Zebu cows were randomly assigned to the two production systems (n = 9 for each system) based on Monbasa pasture (Megathyrsus maximus cv. Mombaça; Syn. Panicum maximum) under rotational stocking management. Herbage allowance ranged from 12 to 14% body weight, and cows were supplemented with concentrated feed according to milk yield. Herbage samples were collected by simulated grazing to determine nutritional value. Milk yield was determined weekly. Herbage intake was estimated from fecal output and indigestibility of the pasture dry matter. Fecal output was estimated by the external indicator LIPE®, and dry matter digestibility was estimated by the internal indicator NDFi. Enteric methane emissions were estimated by the SF6 tracer gas technique. Data were collected in three sampling periods to characterize the rainy season, the transition from the rainy season to the dry season and the dry season. Data were analyzed in split plots, with animals within the system as the plot and seasons as the subplot. Statistical significance was considered at P < 0.05. The herbage crude protein content was 35.9% higher on average in the CLFI than in the CLI. In vitro dry matter digestibility was 16.7% lower in the CLI than in the CLFI in the rainy season. Milk yield and feed efficiency were similar between systems and seasons. The total dry matter intake in the rainy season was 34.6% higher in the CLFI than in the CLI. The energy loss, production and yield of methane were 29.8%, 35.0% and 31.3%, respectively, lower in the rainy season than in the other seasons. Enteric methane emissions, milk yield and feed efficiency were similar between the integrated CLI and CLFI systems in the Brazilian Cerrado region.

Shade and nitrogen fertilization affect forage accumulation and nutritive value of C4 grasses differing in growth habit

AbstractLight reduction in silvopastoral systems and self‐shading in treeless grasslands can lead to shade‐avoidance responses by tropical grasses. Light environment in association with nitrogen (N) supply influence the growth and nutritive value of forage grasses. This study aimed to quantify forage accumulation (FA) and forage nutritive value of tropical grasses differing in growth habit in environments with contrasting light and N resources. A field study was conducted using ‘Jiggs’ bermudagrass [Cynodon dactylon (L.) Pers.] and ‘Mulato II’ hybrid brachiariagrass (Urochloa spp). Full‐sun environments were compared with shaded environments where shade cloth limited incident radiation to 45% of ambient. Low and high N treatments were imposed (30 and 120 kg N ha−1 after each harvest), resulting in a 2 × 2 × 2 factorial arrangement of treatments in four replicates of a randomized complete block design. Forage was harvested every 28 d from May to September in 2014 and 2015 to determine FA. Herbage crude protein (CP) concentration and in vitro digestible organic matter (IVDOM) were assessed. Annual FA was greater for Mulato II than Jiggs and for high‐N and full‐sun treatments. Species showed similar CP concentrations, but Mulato II had greater IVDOM than Jiggs, likely due to a greater leaf percentage. Shade increased CP concentration of the forages whereas effects on IVDOM were not consistent. Although more productive with greater leaf percentage and nutritive value than decumbent, stoloniferous Jiggs, upright‐growing, bunchgrass Mulato II was not persistent when multiple freeze events occurred during winter, limiting its adoption in cooler subtropical environments.

Effect of fertilizer inputs on productivity and herbage quality of native pasture in degraded tropical grasslands

AbstractThe practice of applying fertilizer inputs on an unimproved natural pasture is limited in tropical grasslands. A study was conducted to evaluate the response of degraded natural pasturelands in terms of species composition, forage yield, and quality to the application of different types of fertilizer. The study was conducted in two districts in the central Rift Valley of Ethiopia with contrasting agroecologies. The treatments were control (no application of fertilizer), commercial fertilizer (50 kg urea ha–1 and 100 kg diammonium phosphate [DAP] ha–1), cattle manure (7.5 t ha–1), wood ash (3 t ha–1), and lime (7.5 t ha–1). Soil physical properties were not altered following application of the treatments, but chemical properties, including soil pH (P &lt; .01), electroconductivity (EC) (P &lt; .001), total nitrogen (TN), and P (P &lt; .001) were affected. Soil TN increased from 0.11 to 0.32% following the application of cattle manure. The pH increased from 5.9 to 7.3 with wood ash application. Herbage dry matter (DM) yield increased (P &lt; .001) from 1.88 to 6.65 t ha–1 with chemical fertilizer. The herbage crude protein content increased (P &lt; .01) from 96 to 157 g kg–1 with manure application. On the other hand, the neutral detergent fiber tended to decrease (P &lt; .05) following manure application. Partial cost‐benefit analysis indicated a positive economic gain from the direct sale of pasture hay for all treatments except for lime. The results indicated that fertilizer inputs offer feasible options to improve pasture productivity and enable rural farmers to benefit from their land resources.

The Relative Importance of Herbage Nutritive Value and Climate in Determining Daily Performance per Cow in a Pasture-Based Dairy Farm

The objective of this study was to assess the relative importance of herbage nutritive value (NV), herbage quantity and climate-related factors in determining daily performance per cow in a pasture-based dairy farm. Data on milk production, live weight, body condition score, weather, herbage NV and herbage quantity were regularly collected from August 2016 to April 2017 and from July 2017 to April 2018 at Dairy 1, Massey University, Palmerston North, New Zealand. Data were analyzed using multiple linear regression. Results indicated herbage NV was of higher relative importance in explaining the variation in performance per cow than herbage quantity and climate factors. The relative importance of the interaction between herbage metabolizable energy (ME) and crude protein (CP) on explaining variation in yields of milk, fat and protein was high (0.11 ≤ R2 ≤ 0.15). Herbage ME was of high relative importance in determining milk urea and body condition score, while neutral detergent fiber was a key driver of milk urea and liveweight (0.12 ≤ R2 ≤ 0.16). The quantity of herbage supplied at Dairy 1 might have been high enough to not limit cow performance. Developing feeding strategies aimed at improving the efficiency of cow feeding by exploiting the daily variation in herbage NV to better match supply and demand of nutrients may be useful to improve the overall performance per cow of pasture-based dairy farms.

Ecosystem services under different grazing intensities in typical grasslands in Inner Mongolia and their relationships

Grazing, as the main land use of grasslands, is a key factor affecting the supply of ecosystem services11ES, ecosystem service; GI, grazing intensity; CK, control check; LG, light grazing; MG, moderate grazing; HG, heavy grazing; BI, biodiversity; HI, herbage intake; CP, crude protein content; SOCD, soil organic carbon density; SMN, soil mineralization nitrogen; AB, aboveground biomass; BB, belowground biomass; LB, litter biomass; TES, total ecosystem services; SSU, standard sheep units. (ESs) as well as the relationships between ESs. Using four grazing intensities, including control check, light grazing, moderate grazing, and heavy grazing, this paper quantified eight key ESs, including biodiversity, herbage intake, herbage quality (herbage crude protein content), climate regulation (soil organic carbon density), soil mineralization nitrogen, soil conservation (aboveground biomass), wind prevention and sand fixation (belowground biomass), and soil erosion prevention(litter biomass), in typical grassland areas of Inner Mongolia. Structural equation models were used to illustrate the impact of grazing on ESs through biodiversity, and the root mean square error was used to quantify the level of trade-offs for ES pairs. The results of this study indicated that grazing intensity (GI) significantly affected all ESs (p < 0.05), except for soil organic carbon density and soil mineralization nitrogen. As GI increased, provisioning services increased, while most regulating services decreased, and there was a general trade-off relationship between regulating services and other ones. In order to realize the maximum ESs benefit and the minimum trade-offs for ES pairs, the optimal grazing intensity for typical grasslands of Inner Mongolia should be between 170 (standard sheep units) SSU · d · hm−2 · y−1 and 340 SSU · d · hm−2 · y−1. The results of this study provide a decision-making foundation for grassland grazing management policies for the sustainable development of Inner Mongolian grasslands.

NITROGEN RETENTION IN RAPIDLY-GROWING STEERS GIVEN UREA SUPPLEMENTED DIETS

"Shika" (indigenous, V,) and "Ngala" (introduction, V2) varieties of elephant grass (Pennisetum purpureum Schum.) field planted at 60 x 90, 60 x 60 or 60 x 30 cm spacing and fertilized at 0, 100, 200 or 400kg N/ha/yr, were examined for dry matTer (DM) yield, crude protein (CP) content, CP yield, nitrogen (N) recovery and stand persistence at Shika during the 1975 and 1976 growing seasons. The highest DM yield resulted from 60 x 30 cm spacing/400kg N combination but the 60 x 60 cm spacing (27,800 plants/ha) with 200kg N appeared optimum for yield. V produced 4.3 to 21.0t DM and V2 2.8 to 17.41 DM/ha/yr over the range of population densities and fertilizer levels investigated. DM yield per kg N applied rose with increasing population density (V, only) and decreasing N rate, the highest value of 49kg being recorded for V t. Mean herbage CP content varied from 7.0% without N to 9.7% with 400kg N/ha but the highest value of 11.0% was obtained from V2 planted at 60 x 90cm. For both grasses, N increased annual CP yield 1.2— 4.5—Fold. The highest apparent fertilizer N recovery of 76.3% occurred at 200kg N/ha while plants survived best at 60 x 60cm spacing.

Rhizoma peanut herbage and root–rhizome responses to extended regrowth periods

AbstractRhizoma peanut (RP; Arachis glabrata Benth.) is an important species for hay production in the U.S. Gulf Coast region; however, frequent summer rains and high humidity often preclude optimal harvest intervals. Extended regrowth periods are common on‐farm but data are limited assessing their impact on plant responses. The objective was to compare above‐ and belowground responses of 14 RP entries to defoliation frequency during 3 yr. Frequencies were one (1×) and two (2×) harvests per year, reflecting common producer practice. Annual herbage accumulation (HA) was approximately twice as great for 2× than 1× (10.5 vs. 5.4 Mg ha−1 yr−1, respectively). An exception was experimental line Beta for which HA did not differ between frequencies, perhaps because of Beta's greater disease tolerance that minimized leaf shedding. The 2× frequency also had greater herbage crude protein concentration than 1× (150 and 125 g kg−1, respectively). Reductions in HA and nutritive value for 1× vs. 2× were generally greatest for upright‐growing entries. Plots cut once per year had 54% more root–rhizome mass than those cut twice (8.5 vs 5.5 Mg ha−1, respectively) but defoliation frequency did not affect root–rhizome total nonstructural carbohydrate (TNC) concentration. Results indicated RP hay producers should harvest both summer and fall (2×) at minimum. If rhizomes are to be dug for subsequent vegetative propagation, defoliation should be limited to once annually to avoid reduction in root–rhizome mass.

Season‐long, mixed stocking of a cool‐temperate pasture

AbstractMixed‐species grazing offers a means to diversify livestock production systems for cool‐temperate regions typified by the Appalachian plateau of the USA. Our objective was to determine how mixed grazing influenced herbage and animal production, and sward botanical composition of three grazing systems including cattle and sheep. Three replicated systems were as follows: (A) cattle only with winter grazing; (B) cattle and sheep with winter grazing; and (C) cattle and sheep without winter grazing. Herbage mass and growth rate differed by grazing period; system C had the lowest growth rate and showed an interaction of system and grazing period. The proportion of grass in the sward differed by period, and the legume component was influenced by an interaction of system and period. Forbs and dead were influenced by period and sampling location. Herbage crude protein was not influenced by treatment. Herbage fiber components and lignin were consistently higher during the second grazing period. Steers performed similarly in all systems, but total gains varied with year. Lambs in the system without a winter grazing component were heavier than lambs in the system with a winter grazing component. Live weight gains were modest. Lamb fecal egg count was higher in the system with a winter grazing component; however, the fecal egg count per gram was relatively low throughout the experiment. Animal productivity differed with year and tended to be slightly greater for the system without a winter grazing component. Our findings suggest that livestock production systems that included mixed‐species grazing and extended‐season grazing practices contributed to desirable changes in botanical composition and improved herbage productivity patterns, especially in years with ample precipitation. The practices could be used to drive pasture composition by modifying relative abundance of various plant functional groups.

In situ dry matter and crude protein disappearance dynamics in stockpiled limpograss

AbstractStockpiling warm‐season perennial grasses for winter grazing is an important management practice for beef cattle production systems in tropical and subtropical regions. Limpograss [Hemarthria altissima (Poir.) Stapf et C.E. Hubb.] has greater digestibility at late maturity than other commonly used warm‐season perennial grasses; however, decreased crude protein (CP) concentration may limit livestock performance. The objective of this study was to evaluate the in situ dry matter (DM) and CP ruminal disappearance kinetics of stockpiled limpograss herbage. Forage for the in situ study derived from a 2‐yr field experiment in which treatments were the factorial combinations of three cultivars (‘Kenhy’, ‘Gibtuck’, or ‘Floralta’) and three stockpiling periods (8, 12, or 16 wk) distributed in three replicates of a randomized complete block design. Effective degradability of DM was greater for Kenhy and Gibtuck compared with Floralta (614 and 611 vs. 575 g kg−1), and it declined linearly as stockpiling period increased from 8 to 16 wk (623 vs. 586 g kg−1). Herbage CP concentration (48–32 g kg−1 DM) also declined linearly from 8 to 16 wk, but rumen‐unavailable CP increased during stockpiling (257–438 g kg−1 CP), causing effective CP degradability to decrease (637–489 g kg−1 CP). Limpograss is a good option for stockpiled forage, and both new releases outperformed Floralta; however, concentration and availability of CP must be considered when defining a supplementation strategy.

Benefits Are Limited with High Nitrogen Fertiliser Rates in Kikuyu-Ryegrass Pasture Systems

Nitrogen (N) fertiliser is applied to pastures in dairy farming systems to ensure productivity, but it is an expensive input that could be damaging to the environment if used excessively. In the southern Cape region of South Africa, N fertilisation guidelines for pastures were developed under conditions different to current management practices, yet dairy producers still base fertiliser programmes on these outdated guidelines. This study aimed to determine the efficiencies of N fertilisation. Various N fertiliser rates (0, 20, 40, 60 and 80 kg ha−1 applied after grazing), as well as a variable rate according to the nitrate concentration in the soil water solution, were assessed on a grazed pasture. Dairy cows returned to a pasture approximately 11 times per year. Pasture production showed a minimal response to fertilisation within each season. The most responsive parameters to fertilisation were the herbage crude protein content, soil mineral N content and urease activity. Reduced microbial activity was observed when more than 40 kg N ha−1 was applied. When considering the soil total mineral N content, N is used inefficiently at rates above 40 kg N ha−1. The results are indicative of an N saturated system that provides a rationale for reducing N fertiliser rates.

Herbage Accumulation, Nutritive Value, and Organic Reserves of Continuously Stocked ‘Ipyporã’ and ‘Mulato II’ Brachiariagrasses

ABSTRACTAlthough Brachiaria spp. grasses are important components of sustainable forage–livestock systems in the Amazon biome, cultivar diversification is needed to reduce risk from pests and diseases. Brachiaria hybrid ‘BRS RB331 Ipyporã’ [B. ruziziensis Germ. &amp; Evrard × B. brizantha (Hochst. ex A. Rich.) Stapf] was released in 2017 as an alternative for intensively managed forage–livestock systems. Our objective was to compare herbage accumulation (HA), nutritive value, and organic reserves of Ipyporã and standard hybrid ‘Mulato II’ (B. ruziziensis × B. brizantha × B. decumbens Stapf) under continuous stocking during 2 yr in the Amazon biome. Treatments were the two cultivars replicated four times in a randomized complete block design, and each experimental unit was 1.5 ha. Pastures of Mulato II presented ∼15% greater HA than Ipyporã (17,360 vs. 14,930 kg dry matter ha−1 yr−1) across the 2 yr, and Mulato II leaf mass was greater than Ipyporã (1440 vs. 1900 kg dry matter ha−1) in the dry season. Both cultivars had greater herbage mass, HA, and herbage bulk density during the rainy season of 2016–2017 compared with 2017–2018 due to a shorter period of water deficit (30 d) and greater rainfall (2147 vs. 1762 mm) in the first than second year. Mulato II herbage crude protein was 10 g kg−1 greater than Ipyporã. In this severe risk region for spittlebug, Mulato II required spittlebug monitoring and control due to occurrence of foliar damage. Although Ipyporã had lesser HA, no spittlebug damage was evident. Thus, Ipyporã is an attractive alternative for diversification of forage‐based livestock systems in the Amazon biome.

Temporal variations of herbage production and nutritive value of three grasslands at different elevation zones regarding grazing needs and welfare of ruminants.

Interannual and monthly variations of herbage production and nutritive value regarding grazing ruminants' needs and welfare were evaluated in three grasslands (semi-mountainous, mountainous and sub-alpine) located at different altitudes (480–900, 901–1500 and 1501–2334 m, respectively) in northern Greece during 2015–2016. Herbage biomass was collected from 30 experimental cages (10 per grassland), weighed, dried at 65 C, milled and analyzed for crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), lignin, calcium (Ca) and phosphorus (P) content and in vitro dry matter digestibility (IVDMD). The sub-alpine grassland was the most productive (1031 and 1231 kg DM ha) with the highest mean annual herbage CP content (93 and 87 g kg dry matter; DM) for 2015 and 2016, respectively. CP content was sufficient to meet small ruminants' and beef cattle maintenance requirements until April and May in the semi-mountainous and mountainous grasslands, respectively, while it could cover the above requirements in the sub-alpine grassland until June and August, respectively. The herbage Ca concentration was higher than the grazing ruminants' needs, while the phosphorus concentration was insufficient. Protein and phosphorus supplementation should be provided to animals to cover their maintenance requirements during the whole period and to reach high levels of welfare. Even though grazing is considered as a welfare-friendly procedure, it is uncertain whether all the welfare principals are satisfied in extensive production systems due to variations of forage availability and nutritive value as well as the lack of infrastructure in grasslands.

Sward structure and herbage intake of Brachiaria brizantha cv. Piatã in a crop-livestock-forestry integration area

Forage species tolerate varying degrees of shading. In agrosilvopastoral systems, forage plants are able to adjust and partially compensate growth reduction under light stress. These adjustments change morphological proportions and composition along the vertical profile of the sward. Sward morphological composition is directly related to animal intake behavior and performance. One objective of this study was to evaluate the effects of different tree shading levels on sward vertical structure of Piatã palisadegrass cultivated in a crop-livestock-forestry integration area. Another objective was to identify the relationship between sward vertical structure and herbage intake by cattle (Boss pp.). Three experiments were conducted simultaneously to evaluate three shading levels: 1. Full sunlight (FS); 2. Moderate shade (MS; 338 trees.ha−1); and Intense shade (IS; 714 trees.ha−1). Evaluation was performed during three periods in which total rainfall during the experimental period corresponded to 86, 12 and 2% (periods 1, 2 and 3, respectively). Pastures were rotationally stocked and grazed at 95% canopy light interception (LI) during regrowth (95% LI). Two strategies for taking the reference readings of LI were tested in IS paddocks: LI reading inside (under the tree canopy) and outside (under full natural light) the experimental area. The IS had greatest forage height and proportion of stems, both pre- grazing and post-grazing. Consequently, animals under IS had decreased bite mass and intake rate, pre- and post-grazing except for period 3. There was an effect of shading level on herbage crude protein (CP) concentration. Greatest CP concentrations were observed on IS areas. Neutral detergent fiber (NDF) and acid detergent fiber (ADF) did not vary with shading levels. Herbage dry matter digestibility varied with evaluation period, and lowest values were recorded during period 3. Greater herbage intake was observed on FS and MS relative to IS, due to greater leaf proportion in sward herbage mass. Moderate shading is not so detrimental to system's productivity, highlighting the importance of adequate choice of tree species, plant density and arrangement.

Performance of Limpograss Breeding Lines under Various Grazing Management Strategies

Limpograss [Hemarthria altissima (Poir.) Stapf et C.E. Hubb.] is a C4, perennial, stoloniferous grass that is well adapted to poorly drained soils and grows throughout frost‐free periods during winter in southern Florida. Its use has increased rapidly in recent decades, but nearly all area in cultivation is planted with one cultivar, ‘Floralta’. A breeding program was initiated to develop improved alternatives to Floralta, resulting in a group of breeding lines requiring evaluation under grazing. The objective of this research was to evaluate the performance of five limpograss breeding lines (1, 4F, 10, 32, and 34) under combinations of grazing frequency and intensity. During the 2012 and 2013 growing seasons, those lines, plus Floralta, were tested at two pre‐grazing canopy light interception levels (80 and 95%), that triggered the initiation of each grazing event, and two post‐grazing stubble heights (20 and 30 cm). Lines 4F and 10 had greater herbage accumulation, apparent herbage harvested, and persistence than Floralta. Initiation of grazing at 80% canopy light interception resulted in more frequent grazing events, a longer grazing season, shorter pre‐grazing canopy height, greater leaf percentage, less herbage bulk density, and greater herbage crude protein concentration compared with 95% canopy light interception. These data support cultivar release of breeding lines 4F and 10 and suggest that persistence and efficient utilization of limpograss under rotational stocking can likely be achieved by initiating grazing at a pre‐grazing canopy height of ∼60 cm, well before 95% canopy light interception, and by ending grazing at a post‐grazing canopy height of ∼30 cm.

Comparative effects of food processing liquid slurry and inorganic fertilizers on tanner grass (Brachiaria arrecta) pasture: grass yield, crude protein and P levels and residual soil N and P

AbstractThis small‐plot field study evaluated food processing liquid slurry (FPLS) as a potential fertilizer for tanner grass (Brachiaria arrecta) production on an acidic loam soil. The treatments, arranged in a randomized complete block design with three replicates, consisted of an unfertilized control, inorganic fertilizer applied at 50 and 200 kg nitrogen (N) ha−1 with and without phosphorus (P) at 50 kg P ha−1, and FPLS applied at 50 and 200 kg N ha−1. Compared to the unfertilized control, the FPLS applied at 200 kg N ha−1 significantly increased grass dry‐matter yield (DMY), herbage crude protein (CP) and P content, and N and P uptake in the second of two trials and P uptake in both trials. However, DMY and contents, of CP and P were generally lower for the FPLS treatments compared to the inorganic fertilizers. Apparent N recovery was higher for the inorganic fertilizer treatments than FPLS treatments in trial 1, while apparent P recovery was similar among all treatments in both trials. The FPLS treatments did not significantly increase soil NO3‐N and P concentrations, but increased NH4‐N in the 0–15 cm layer. The results suggest that application of FPLS to tanner grass pastures is an alternative to its disposal in landfill.

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

ABSTRACTSupplements 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 &amp; 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.

Evaluation of 3 bromegrass species as pasture: Herbage nutritive value, estimated grass dry matter intake and steer performance

A 2 year grazing study was conducted to evaluate the effects of grazing meadow bromegrass (Bromus riparius Rehm.; cv. Paddock), smooth bromegrass (B. inermis Leyss.; cv. Carlton), and hybrid bromegrass (B. riparius×B. inermis.; cv. AC Knowles) on herbage nutritive value, dry matter (DM) intake and grazing beef steer performance. Each year, 36 crossbred beef steers (297±6kgBW) (15 month initial age) were randomly allocated to 1 of 3 replicated (n=2) paddocks of each bromegrass species in a “put and take” stocking system from May to July. Herbage samples were collected at start, middle, and end of each grazing period and analyzed for DM, crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), in vitro dry matter digestibility (IVDMD) and in situ rumen degradation kinetics. Herbage DM intake was estimated by combining fecal output with herbage in vitro dry matter digestibility. Fecal output was estimated using chromium sesquioxide (Cr2O3) as an external marker. Herbage CP (138±4.2g/kg), NDF (574±5.3g/kg), ADF (340±5.3g/kg), IVDMD (628±3.5g/kg), and effective degradation of herbage DM (35.87±1.07% of DM) did not differ (P>0.05) among the bromegrasses. In all 3 bromegrasses, CP and IVOMD decreased (P<0.05) and NDF and ADF increased (P<0.05) as the grazing season progressed. Over the 60d grazing season, DM intake (10.0±1.7kg/d), ADG (1.0±0.24kg/d), and final BW (329.0±9.2kg) were similar (P>0.05) among steers grazing either bromegrass pasture. The results of this study suggest that meadow bromegrass, smooth bromegrass and hybrid bromegrass are suitable species for grazing providing suitable nutritive value and steer performance for pasture in western Canada.

Effect of nitrogen fertilization rate and regrowth interval of grass herbage on methane emission of zero-grazing lactating dairy cows

Dairy cattle farming in temperate regions often relies on grass herbage (GH)-based diets but the effect of several grass management options on enteric CH4 emission has not been fully investigated yet. We investigated the combined effect of N fertilization rate and length of regrowth period of GH (predominantly ryegrass) on CH4 emission from lactating dairy cows. In a randomized block design, 28 lactating Holstein-Friesian dairy cows received a basal diet of GH and compound feed [85:15; dry matter (DM) basis]. Treatments consisted of GH cut after 3 or 5 weeks of regrowth, after receiving either a low (20kg of N/ha) or a high (90kg of N/ha) fertilization rate after initial cut. Feed intake, digestibility, milk production and composition, N and energy balance, and CH4 emission were measured during a 5-d period in climate respiration chambers after an adaptation to the diet for 12d. Cows were restricted-fed during measurements and mean DM intake was 15.0±0.16kg/d. Herbage crude protein content varied between 76 and 161g/kg of DM, and sugar content between 186 and 303g/kg of DM. Fat- and protein-corrected milk (FPCM) and feed digestibility increased with increased N fertilization rates and a shorter regrowth interval. Increasing the N fertilization rate increased daily CH4 emission per cow (+10%) and per unit of DM intake (+9%), tended to increase the fraction of gross energy intake emitted as CH4 (+7%), and (partly because of the low crude protein content for the low fertilized GH) only numerically reduced CH4 per unit of FPCM. The longer regrowth interval increased CH4 emission per unit of FPCM (+14%) compared with the shorter regrowth interval, but did not affect CH4 emission expressed in any other unit. With increasing N fertilization CH4 emission decreased per unit of digestible neutral detergent fiber intake (−13%) but not per unit of digestible organic matter intake. There was no interaction of the effect of N fertilization rate and regrowth interval on CH4 emission, but effects of N fertilization were generally most distinct with GH of 5 wk regrowth. The present results suggest that altering grass quality through an increase of N fertilization and a shorter regrowth interval can reduce CH4 emission in zero-grazing dairy cows, depending on the unit in which it is expressed. The larger amount of CH4 produced per day and cow with the more intensively managed GH is compensated by a higher feed digestibility and FPCM yield.