Grazing Management Strategies Research Articles

Identification of SSTR5 Gene Polymorphisms and Their Association With Growth Traits in Hulun Buir Sheep.

The aim of this study was to locate SSTR5 polymorphisms and evaluate their association with growth traits in Hulun Buir sheep. The study followed up 884 Hulun Buir sheep from birth to 16 months of age, which were born in the same pasture and the same year, and a consistent grazing management strategy was maintained. The birth weight (BRW) was recorded at birth, and body weight (BW), body height (BH), body length (BL), chest circumference (ChC), chest depth (ChD), chest width (ChW), hip width (HW), and cannon circumference (CaC) were measured at 4 and 9 months of age. BW, BH, BL, ChD, HW, and CaC were also recorded at 16 months of age. Based on the growth traits, 233 sheep were selected as experimental animals. Sanger sequencing was performed, and seven single-nucleotide polymorphisms (SNPs) were identified. Association analyses of the SNPs and the growth traits were then conducted. Seven SNPs of the SSTR5 exhibited moderate polymorphism (0.25<PIC<0.5) and were consistent with the Hardy–Weinberg equilibrium. SNP7 (T989C, rs601836309) caused a change in amino acid sequences, while others did not cause any change. The genotypes of SNP1 (C186T, s400914340) were significantly associated with BW, ChW, and ChC at 4 months of age and with HW at 9 months of age (p<0.05). These genotypes also showed extremely significant association with CaC at 4 months of age (p<0.01). The genotypes of SNP7 exhibited a significant association with ChW and CaC at 4 and 9 months of age, respectively. Moreover, the genotypes of SNP3 (T384C, rs413380618)) and SNP4 (T537C, rs605867745) were significantly associated with CaC at 9 months of age (p<0.05). Linkage disequilibrium was observed among the seven SNPs with five haplotypes. However, these haplotypes were not associated with growth traits at different ages. In conclusion, SNP1, SNP3, SNP4, and SNP7 may serve as molecular markers for the growth traits of Hulun Buir sheep.

Evaluating Several Vegetation Indices Derived from Sentinel-2 Imagery for Quantifying Localized Overgrazing in a Semi-Arid Region of South Africa

Rangeland monitoring aims to determine whether grazing management strategies meet the goals of sustainable resource utilization. The development of sustainable grazing management strategies requires an understanding of the manner in which grazing animals utilize available vegetation. In this study, we made use of livestock tracking, in situ observations and Sentinel-2 imagery to make rangeland scale observations of vegetation conditions in a semi-arid environment, to better understand the spatial relationships between vegetation conditions and sheep movement patterns. We hypothesized that sheep graze more selectively under low stocking rates—resulting in localized overgrazing. We also assessed the importance of image spatial resolution, as it was assumed localized effects of grazing will be best explained by higher resolution imagery. The results showed that livestock tend to congregate along drainage lines where soils are deeper. The findings demonstrate how the spatial analysis of remotely sensed data can provide a landscape-scale overview of livestock movement patterns. This study illustrates that high-resolution normalized difference vegetation index (NDVI) data can be used as a grazing management tool to determine the spatial variability of productive areas across the semi-arid Upper Karoo rangelands and identify preferred grazing areas.

Evaluation of the APEX cattle weight gain component for grazing decision-support in the Western Great Plains

Rotational grazing studies have produced mixed results related to animal performance (weight gain), which has contributed to producer uncertainty regarding grazing management decisions. To enhance decision-support for producers, we improved algorithms in the Agricultural Policy/Environmental eXtender (APEX) model to better represent cattle weight gain in real-world rangeland conditions under two grazing management strategies. Simulated weight gain and related forage effects were evaluated with experimental data from 2014 to 2018 under two grazing strategies. The traditional rangeland management strategy used continuous season-long grazing stocked at a moderate level. The collaborative adaptive rangeland management strategy employed grazing with one large herd rotated using a sequence developed by a stakeholder group with movement between pastures driven by predetermined decision triggers. For each grazing strategy, yearling steers grazed from mid-May to October on ten 130-ha pastures. With the APEX modifications, daily weight gain was adequately simulated for both continuous (traditional rangeland management) grazing and management intensive rotational (collaborative adaptive rangeland management) grazing. Dry matter intake, total digestible nutrients, and temporal distribution of dry matter intake were the primary influencers of cattle performance (weight gain). Once shown to be accurate, we used APEX to evaluate several management alternatives (i.e., stocking rate, rotation interval, and rotation decision criteria) to showcase its decision support capabilities. These important enhancements increase the utility of APEX in semiarid environments, such as the western Great Plains, in providing science-based rangeland decision support to ranchers, agency land managers, and policy makers.

Grazing altered soil aggregates, nutrients and enzyme activities in a Stipa kirschnii steppe of Inner Mongolia

Grasslands are a major biome on Earth, and their soils play a dominant role in the overall ecosystem functions and dynamics. Though the majority of global grasslands are used for grazing, the impact of grazing on soil structure and soil quality remains unclear due to large variations among grasslands. In this study, we assessed soil nutrient content, enzyme activities and soil aggregates at 0–30 cm depth under different grazing intensities, including a treatment of grazing exclusion. Heavy grazing reduced content of soil nitrogen, potassium, and soil urease and sucrase activities. While grazing increased the mechanical stability of soil aggregates, it reduced the water stability of soil aggregates. With increasing grazing intensity, water stability of the aggregates was correspondingly weakened, as was the erosion resistance of the soil. The soil urease activity, available soil nutrients, mean weight diameter by wet sieving (w-MWD), and geometric mean diameter by wet sieving (w-GMD) showed significant high sensitivity to grazing intensity in this Stipa kirschnii dominated grassland in Inner Mongolia. Overall, the soil quality at the heavy grazing site appeared poor compared with that at the light grazing site. For developing grazing management strategies, it is clear that heavy grazing should be avoided in this type of grasslands, albeit continued monitoring of soil structure is needed to explore the potential long-term consequences of the grazing.

Sward structure and forage intake rate of elephant grass cv. Napier subjected to strategies of intermittent stocking management

Context Grazing management strategies affect sward structure, changing patterns of foraging and intake, and consequently animal performance. Aims The objective of this study was to evaluate the relationship between sward structure and forage intake rate by cattle grazing elephant grass (Pennisetum purpureum Schumach) cv. Napier subjected to strategies of rotational stocking management. Methods The experiment was conducted in Piracicaba, SP, Brazil, from January 2011 to April 2012. Treatments corresponded to all combinations between two post-grazing conditions (post-grazing heights of 35 and 45 cm) and two pre-grazing conditions (95% and maximum canopy light interception during regrowth; LI). The response variables evaluated at both pre- and post-grazing conditions were: (1) vertical distribution of morphological components; (2) bite rate; (3) bite mass; (4) intake rate; and (5) forage nutritive value (morphological and chemical composition of oesophageal extrusa samples). Key results Bite mass was smaller and bite rate was greater for LI95% swards at pre- and post-grazing, resulting in greater rate of forage intake. The post-grazing height targets affected the morphological and the chemical composition of the forage consumed. Conclusions In general, pastures managed with targets LI95% (pre-grazing) and 45 cm (post-grazing height) resulted in greater leaf percentage and nutritive value of the consumed forage. Implications Adequate grazing management strategies allow for high residual leaf area in pastures, ensuring rapid recovery after grazing. For grazing elephant grass cv. Napier, this corresponded to the combination between the LI95% pre-grazing target and the 45 cm post-grazing height.

Low-Intensity, High-Frequency Grazing Strategy Increases Herbage Production and Beef Cattle Performance on Sorghum Pastures.

Simple SummaryFinding smart management targets to improve livestock production and make it sustainable are very important for livestock in the tropics. We assessed the effects of high-intensity and low-frequency (HILF) vs. low-intensity and high-frequency (LIHF) grazing on herbage production and performance of beef cattle grazing sorghum pastures. The LIHF resulted in shorter rest periods when compared with the HILF. The greater leaf lamina mass in LIHF allowed greater sward light interception at post-grazing, resulting in greater total herbage production than HILF. The average daily gain (ADG) was greater for the LIHF than for the HILF treatment; however, even with a greater stocking rate in the HILF, there was no difference for LW gain per ha. Our findings demonstrated that the LIHF strategy that is based on offering to the animals an optimal sward structure to favor the herbage intake rate fosters greater herbage production, harvesting efficiency, and ADG without compromising LW gain per area, despite the lower herbage harvested per stocking cycle. Therefore, we conclude that the classic trade-off between animal performance and forage production could be offset on tropical grasses grazed by beef cattle only by adjusting grazing management according to a LIHF grazing management strategy.We assessed the effects of high-intensity and low-frequency (HILF) vs. low-intensity and high-frequency (LIHF) grazing on herbage production and performance of beef cattle grazing sorghum pastures. The experimental design was a complete randomized block with two treatments and four replicates (paddocks), carried out in 2014/15. The management target of 50 and 30 cm for pre- and post-grazing, respectively, a LIHF grazing management strategy oriented to maximize beef cattle herbage intake per unit time, was compared with a HILF grazing management strategy of 80 and 20 cm for pre- and post-grazing, respectively, aiming to maximize herbage accumulation and harvest efficiency. Sixteen Brangus steers of 15-month-old and 265 ± 21 kg of live weight (LW) were randomly distributed to paddocks (experimental units). The LIHF resulted in shorter rest periods when compared with the HILF. The greater leaf lamina mass in LIHF allowed greater sward light interception at post-grazing, resulting in greater total herbage production than HILF (7581 and 4154 kg DM/ha, respectively). The average daily gain (ADG) of steers was greater for the LIHF than for the HILF treatment (0.950 and 0.702 kg/animal, respectively); however, even with a greater stocking rate in the HILF, there was no difference for LW gain per ha, with an average of 4 kg LW/ha/day. Our findings demonstrated that the LIHF strategy that is based on offering to the animals an optimal sward structure to favor the maximum herbage intake rate fosters greater herbage production, harvesting efficiency, and ADG without compromising LW gain per area of beef steers, despite the lower herbage harvested per stocking cycle.

Vernal pool wetlands respond to livestock grazing, exclusion and reintroduction

AbstractIn disturbance‐adapted ecosystems, the removal of disturbance can lead to losses of diversity and sometimes irreversible changes in community composition. It is important to identify the thresholds at which these changes can occur, and to understand the reversibility of these shifts. We examined this question in a vernal pool ecosystem that evolved with low to moderate levels of grazing disturbance. In this system, it is not clear whether the negative effects of long‐term grazing exclusion are reversible through grazing reintroduction.We compared adjacent vernal pool wetlands in annual Mediterranean grasslands under three grazing management strategies: continuously grazed (100+ years), long‐term excluded (40+ years) and 2 years of reintroduced grazing. We also asked whether grazing treatments altered pool characteristics that are likely to influence plant community composition, and how these relationships changed with environmental conditions.Reintroducing grazing to vernal pools led to both increased diversity and native cover, but the effects on native cover were more immediate than on diversity. We identified several biotic and abiotic mechanisms related to this pattern, including changes to competitive dynamics that favour small statured native annuals and increases in hoofprint microdepressions that make soil moisture more available to plants.Synthesis and applications. Our results show that reintroduced grazing at moderate stocking rates can have significant effects on plant communities after just 2 years and can increase native cover more quickly than overall diversity. Our findings suggest that the negative effects of long‐term grazing exclusion in vernal pools may be reversible, but that land managers interested in restoring diversity should plan to monitor beyond the first two years of grazing reintroduction.

Evaluating the APEX model for alternative cow-calf grazing management strategies in Central Texas

CONTEXTSimulation tools are increasingly used to inform grazing management decisions by assessing livestock performance, as well as environmental and economic impacts. Ability to represent the grazing of multiple pastures (i.e., paddocks) that differ in soil, hydrology, vegetation, and management is critical for reliable grazing management decision support. OBJECTIVEThe main objectives of this study were to: 1) modify APEX (Agricultural Policy/Environmental eXtender) for sub-daily grazing, cow-calf weight gain, and supplemental hay, and 2) evaluate the APEX modifications in terms of simulating biomass, calf weight gain, economic impacts of alternative cow-calf grazing management strategies. METHODSAPEX was modified to enhance its ability to simulate alternative grazing management strategies by including sub-daily grazing among multiple paddocks, supplemental hay estimation, and optional simulation of cow-calf weight gain based either on energy or total digestible nutrients (TDN). Simulation results were evaluated against a 5-year experimental data set from Central Texas comparing multi-paddock rotational grazing and conventional continuous grazing. RESULTS AND CONCLUSIONThe modified APEX model adequately simulated the responses of vegetation biomass (coefficient of determination, R2 = 0.60–0.70), hay consumption (R2 = 0.94–0.95), calf weaning weight (R2 = 0.52–0.65), costs (R2 = 0.98), and profits (R2 = 0.89) to the two grazing treatments across years. Simulations with the energy-based weight gain algorithm showed more pronounced effects on above-ground biomass, whereas the TDN-based algorithm had a more pronounced weight gain response to forage intake and hay quality. No significant differences (p > 0.05) in biomass and calf weaning weight were observed between treatments across the years for measured data and for energy-based APEX simulation; however, the TDN-based algorithm simulated lower calf weaning weight in multi-paddock rotational grazing than in continuous grazing. Measured and simulated data also showed similar profits between the two grazing treatments, but total cost and gross return per ha were greater for continuous grazing. SIGNIFICANCEThe model enhancements for sub-daily grazing, cow-calf weight gain, and supplemental hay improved the potential utility of APEX for assessing environmental and economic impacts of alternative grazing strategies at ranch scale.

Grazing impacts on ground beetle (Coleoptera: Carabidae) abundance and diversity on semi‐natural grassland

Abstract Semi‐natural grasslands are commonly managed as a grazing resource for domestic livestock but, due to their unique biodiversity, they are also of conservation interest. Numerous drivers have impacted on the status of these grasslands in recent decades, most importantly changing grazing management strategies. These changes have the potential to affect the biodiversity associated with these habitats, including on some rich invertebrate assemblages. Responses, however, are often dissimilar between different invertebrate taxa. We investigated the responses of ground beetles to different grazing regimes within a replicated, controlled, long‐term grazing experiment on upland semi‐natural grassland in Scotland. Although there was substantial overlap of species composition of ground beetle assemblages in different grazing treatments, species richness, abundance and Shannon diversity of ground beetles were significantly lower in ungrazed plots than in plots subject to high‐ or low‐intensity sheep grazing. Ground beetle abundance (but not species richness or diversity) was lower in ungrazed plots compared to those with low‐intensity mixed grazing by sheep and cattle. However, no differences were identified in abundance, species richness or diversity between the three grazed treatments. Our results suggest that ground beetles may show different responses to grazing compared to responses of some other invertebrate groups and demonstrate the difficulty of attempting to manage grazing to optimise conditions for a wide range of invertebrates.

Effect of grazing management strategies on alpine grassland on the northeastern Qinghai-Tibet Plateau

In recent decades, alpine grassland has been seriously degraded owing to overgrazing across the Qinghai Tibetan Plateau (QTP), although grazing exclusion has been widely adopted to restore degraded QTP grassland. It remains unknown whether such management approach is effective for all degraded alpine grasslands, and the effect of different grazing management strategies on grassland at varying levels of degradation needs to be assessed. In this study, plots with three grazing management treatments (free grazing, FG; reduced grazing, RG; grazing exclusion, GE) and four degradation stages (non-degradation, ND; light degradation, LD; moderate degradation, MD; heavy degradation, HD) were compared. Our results showed that the total aboveground biomass (AGB) and species richness (SR) under free grazing treatment were reduced with increasing degradation, whereas total belowground biomass (BGB) under free grazing treatment increased with increasing degradation. Furthermore, the responses of SR, AGB and BGB to grazing management varied with the degree of degradation. The total AGB in the LD, MD and HD stages increased significantly following RG and GE treatments, but there was no significant change of AGB in the ND stage. Meanwhile, SR reduced significantly following RG and GE treatments under all degradation stages except for HD. After RG and GE treatments, the total BGB increased significantly in the ND stage but decreased significantly under GE treatment in the MD and HD stages. Furthermore, the responses of plant functional groups to grazing management were varied. The Gramineae AGB increased significantly across all degradation levels under RG and GE treatments, whereas the sedges AGB decreased (except in the MD stage under GE management). Our results suggested that the effect of grazing management on alpine grassland depended on the degree of degradation.

Variation in prescribed fire and bison grazing supports multiple bee nesting groups in tallgrass prairie

Fire and grazing are historic ecosystem drivers of tallgrass prairie and both are used for restoration management today. The effects of these drivers on animal taxa are still incompletely resolved, especially for wild bees, a growing conservation and restoration priority. Fire and grazing could affect wild bee communities through structural changes to nest site availability via changes to soil conditions, vegetative cover, and availability of plant stems. Here, we sought to determine how different bee nesting groups are affected by the combination of fire and bison grazing management strategies. We grouped bee species by nesting substrate (ground, stem/hole, large cavity) because we expect the availability of these substrates to vary with the application of prescribed fire and grazing. We collected bees in restored and remnant high‐quality tallgrass prairie and analyzed whether the proportion of each nesting group within the total bee community was predicted by fire and/or grazing. Ground‐nesting bees reached their greatest proportion in bee communities immediately after prescribed fire, but declined proportionally over time since the last burn. Stem‐/hole‐nesting bees reached their highest proportion in the bee community with infrequent fire (6‐year interval) and differed in their response to fire depending on the presence/absence of bison. Sampling year affected bee nesting groups and we found that nesting groups did not change in concert (i.e. different nesting groups had different good and bad years from each other). Our results show that spatiotemporal variation of prescribed fire and bison grazing is essential for conservation of multiple bee nesting groups.

Descriptive analysis of nematode management practices and Nematodirus battus control strategies on UK sheep farms.

Farm management practices have a major impact on nematode population dynamics. The presented study aimed to understand current nematode management practices on UK sheep farms; with a particular focus on Nematodirus battus because of the changing epidemiology, and emerging anthelmintic resistance observed in this species. A 42 question online survey covering grazing management, farm demographics and parasite control strategies was developed and distributed to the farming community in 2016. Analysis of the 187 completed questionnaires explored regional variations in practices. Uptake of recommendations was variable, particularly quarantine practices and monitoring tools. Results also highlighted variation in the epidemiology of N. battus; respondents in the north (Scotland, north-west and north-east England) typically reported N. battus in spring with a perception of more severe clinical symptoms than those from the south (Midlands, Wales, south-east and south-west England; p=0.03). Farms in the south observed greater changes in the timing of disease (p=0.006) with N. battus being reported throughout the year on some holdings and more frequent use of faecal egg count monitoring (p=0.006). Control of N. battus infection is challenging and 'one-size-fits-all' advice is not applicable; however, the information gathered will enable the development of effective, adaptable control strategies.

Herbage accumulation dynamics in mixed pastures composed of kikuyugrass and tall fescue as affected by grazing management

AbstractA less‐explored alternative to animal production in the subtropics is a mixture of perennial cool‐ and warm‐season forage grasses. This study aimed to determine a grazing management strategy to enhance forage production and attenuate the seasonality of a mixed pasture composed of kikuyugrass (Pennisetum clandestinum) and tall fescue (Festuca arundinacea). Four treatments were implemented in a completely randomized block design using a factorial scheme (2 × 2) with three replicates. The factorial arrangement consisted of two canopy heights (12 and 17 cm) associated with or without a single autumn grazing of 7 cm. Evaluations were conducted over 2 years. Nitrogen fertilization was performed only during the winter and spring seasons. Regardless of grazing height targets (12 or 17 cm), severe defoliation in autumn increased forage accumulation by 10% in mixed pastures composed of kikuyugrass and tall fescue; however, such management strategy should not be recommended because it delayed canopy recovery by 90–120 days, restrained winter grazing, and, paradoxically, increased forage production seasonality. Tall fescue was the dominant species in all treatments in the second year of evaluation, and we hypothesized that the lack of N fertilization during the summer impaired the persistence of kikuyugrass and was the main reason for this dominance effect. Therefore, we suggest evaluating summer N fertilization strategies, which could benefit both species and ensure the persistence of kikuyugrass in the mixture.

Intermittent stocking strategies for the management of Marandu palisade grass in the Brazilian Cerrado biome

AbstractThe objective of the study was to evaluate the effect of pre‐ and post‐grazing targets on the forage accumulation and canopy characteristics of Marandu palisade grass (Brachiaria brizantha [Hochst. ex A. Rich.] Stapf. syn. Urochloa brizantha) to define grazing management strategies in Brazil's Cerrado biome. The experimental design comprised a randomized complete block with four replicates in a 2 × 2 factorial arrangement of treatments: two grazing frequencies (95% of light interception (LI95%) and maximum (LIMax) light interception of the forage canopy) and two grazing intensities (10 and 15 cm of post‐grazing canopy height). Pastures were sampled to quantify forage mass and morphological components at pre‐ and post‐grazing. The tillers population density and forage nutritive value were estimated at pre‐grazing. Pastures managed with the LI95% target demonstrated greater basal (1,341 versus 1,193 tillers/m2) and aerial tillers (101 versus 53 tillers/m2) population densities, a greater leaf:stem ratio (3.8 versus 2.0), and a lower canopy height (33 versus 55 cm), forage mass (3,225 versus 4,320 kg/ha), stem proportion (30.6% versus 44.5%), and leaf (2.5% versus 2.8%) and stem (3.4% versus 3.8%) acid detergent lignin content than those managed with the LIMax target. In the Cerrado, Marandu palisade grass must be grazed when the canopy height reaches 33 cm. Furthermore, animals must be removed from the paddocks when the canopy height reaches 15 cm.

Low-Intensity, High-Frequency Grazing Positively Affects Defoliating Behavior, Nutrient Intake and Blood Indicators of Nutrition and Stress in Sheep.

The intensity and frequency of grazing affect the defoliating strategy of ruminants, their daily nutrient intake, thus nutrition and physiological status. Italian ryegrass (Lolium multiflorum Lam.) pastures were grazed by sheep either under a low-intensity/high-frequency grazing strategy (Rotatinuous stocking; RN) with nominal pre- and post-grazing sward heights of 18 and 11 cm, respectively, or under a high-intensity/low-frequency strategy (traditional rotational stocking; RT) with nominal pre- and post-grazing sward heights of 25 and 5 cm, respectively. Treatments were arranged under a complete randomized design and evaluated over two periods, in different years. In 2017, the aim was to depict the type of bites that sheep perform during the grazing-down and associate them to the grazing management strategy according to their relative contribution to the diet ingested. In 2018 we estimated the total nutrient intake and evaluated blood indicators of the nutritional status and immune response to stress of sheep. The bite types accounting the most for the diet ingested by RN sheep were those performed on the “top stratum” of plants with around 20, 15, and 25 cm, whereas the type of bites accounting the most for the diet of RT sheep were those performed on “grazed plants” with around 10, 5, and ≤ 3 cm. In 2018, the RN sheep increased by 18% the total organic matter (OM) intake and by 20–25% the intake of soluble nutrients (i.e., crude protein, total soluble sugars, crude fat), digestible OM and of metabolizable energy, and had 17.5, 18, and 6.1% greater blood concentration of glucose, urea nitrogen (BUN) and albumin, respectively, but 17% lower blood neutrophil-to-lymphocyte (N:L) ratio. Sheep grazing vegetative Italian ryegrass pastures under the low-intensity/high-frequency grazing strategy (RN) ingested a diet of better quality from bites allocated on the top stratum of plants, had greater intake of soluble nutrients and blood parameters positively associated with nutritional status and immune response to stress.

Effect of grazing management strategies on the yield and nutritional value of Marandu grass in the semiarid of Brazil

The objective of this study was to evaluate the effects of two grazing management strategies on structural, productive and nutritional parameters of Marandu grass (Urochloa brizantha cv. Marandu). A completely randomized block design with two pasture management strategies and eight replications (blocks) was used. The grazing management strategies were: (1) low intensity rotational grazing (LI), with a pre-grazing sward height of 40 cm and a post-grazing sward height of 24 cm, i.e., a defoliation intensity of 50%; (2) High intensity rotational grazing (HI), with a pre-grazing sward height of 40 cm and a post-grazing sward height of 10 cm (±70% defoliation intensity). Pastures were sampled before and after grazing for estimation of forage mass, forage accumulation rate, structural characteristics, nutritional value and dry matter intake.The LI strategy resulted in higher dry matter production than HI before (18.33%) and after grazing (49.06%), increasing pre-grazing forage density by 13.21% (P &lt; 0.05). The production of potentially digestible dry matter was highest (P &lt; 0.05) in LI strategy (21.3% before and 39.6% after grazing, respectively). Higher post-grazing green forage mass (45%) increased the residual crude protein in LI. The LI management strategy increased forage mass production and can be used in Marandu grass pastures.

Temporal Variations in Chemical Composition, In Vitro Digestibility, and Metabolizable Energy of Plant Species Browsed by Goats in Southern Mediterranean Forest Rangeland.

Simple SummaryMediterranean forest rangelands constitute essential feed resources for grazing goats. The objective of this study was to evaluate the temporal variations in chemical composition, in vitro digestibility, and metabolizable energy of browsed plant species by goats on forest rangelands of the Southern Mediterranean of northern Morocco. Overall, the nutritive value of the selected plant species was highest in spring and then steadily decreased through the summer and autumn. Most of the selected plant species present high levels of crude protein than the minimum required level for maintenance. This study provides a valuable and useful database to elaborate the seasonal grazing and feeding management plan for goat herds.Forest rangelands contribute largely to goat diets in the Mediterranean area. Information about browsed plant quality is essential for adequate feeding management. The purpose of this study was to evaluate the temporal changes in chemical composition and in vitro digestibility of the main plant species selected by goats in the Southern Mediterranean forest rangeland during two consecutive years; these were very contrasted (dry and wet). The browsed species were composed of herbaceous, eleven shrubs, and four tree species. Overall, large variability in chemical composition, in vitro organic matter digestibility (IVOMD), and metabolizable energy (ME) was observed among species, grazing season (spring, summer, and autumn), and years within each species. Crude protein (CP) content varied from 60 to 240 g/kg dry matter (DM). The fiber fractions, except for Quercus suber, increased significantly by advancing maturity. Due to the water stress, the lignin level presented a higher value during the spring of the dry year. Condensed tannin (CT) content varied from 2 to 184 g/kg DM. CP, IVOMD, and ME showed a negative correlation with lignin and CT. Based on the results presented herein, it is concluded that the nutritive value of the browsed plant species was highest in the spring and lowest during the summer and autumn of both studied years. With a good grazing management strategy, the selected plant species by goats could guarantee high-quality feeding resources throughout the year.

Palisadegrass pastures with or without nitrogen or mixed with forage peanut grazed to a similar target canopy height. 1. Effects on herbage mass, canopy structure and forage nutritive value

AbstractNitrogen (N) inputs to pasture systems coupled with grazing management strategies based on monitoring and control of canopy structure may provide conditions for greater productivity and enhanced forage nutritive value. This 2‐year study assessed canopy structure and nutritive value responses of three pasture treatments, namely, (1) mixed Marandu palisadegrass (Brachiaria brizantha [Hochst. ex A. Rich.] R.D. Webster [syn. Urochloa brizantha Stapf]) cv. Marandu and forage peanut (Arachis pintoi Krapov. &amp; W.C. Greg.) cv. BRS Mandobi pastures without N fertilizer (GRASS + LEGUME); (2) monoculture Marandu palisadegrass pastures fertilized with 150 kg N/ha (GRASS + N); and (3) monoculture Marandu palisadegrass without N fertilizer (GRASS). Grazing management was similar across pasture treatments, using continuous stocking and a target canopy height of 20–25 cm. Herbage mass was greater in GRASS + N and GRASS + LEGUME pastures than in GRASS in summer and spring (p = .014). The leaf:stem ratio in the grass mass (p = .731) was similar between treatments. Grass crude protein (CP) and in vitro digestible dry matter (IVDDM) were greatest in the GRASS + N pasture (p &lt; .001). Grass neutral detergent fibre (NDF) concentration was greater at GRASS and GRASS + LEGUME pastures than in GRASS + N (p &lt; .001). Forage peanut had a greater IVDDM and CP concentration and a lower NDF concentration than Marandu palisadegrass. Nitrogen application or the presence of the legume increased green herbage mass and improved forage nutritive value in canopies with similar height.

‘Rotatinuous’ stocking: An innovation in grazing management to foster both herbage and animal production

‘Rotatinuous’ stocking is a grazing management strategy based on animal behavioural responses to sward structure which is designed to maximize herbage intake per unit of grazing time. It is an alternative to traditional grazing management practices focusing on pasture use efficiency and maximizing herbage accumulation and harvesting. To investigate this approach, Italian ryegrass (Lolium multiflorum) pastures grazed by sheep were evaluated in 2014 and 2015 under two contrasting grazing management strategies. Paddocks were distributed under a complete randomized block design with four replicates. Grazing management strategies were: traditional rotational stocking (RT), with pre- and post-grazing sward heights of 25 and 5 cm, respectively, and ‘Rotatinuous’ stocking (RN), with pre- and post-grazing sward heights of 18 and 11 cm, respectively. Thirty-two castrated Texel × Polwarth crossbred lambs were randomly allocated to treatments. As a consequence of grazing strategies, the stocking cycles were 12 and 4, with resting periods of 13 and 35 days, respectively, for RN and RT treatments. Herbage production, total herbage harvested, and feed conversion efficiency were 28%, 20%, and 40%, respectively, greater for RN than for RT treatment. Although the stocking rate was lower, the average daily gain per animal and live weigh gain per hectare were 153% and 43%, respectively, greater for the RN treatment. Despite the RN treatment being orientated to maximize herbage intake per unit of grazing time, it results in greater total herbage production and harvesting. We conclude that the ‘Rotatinuous’ stocking strategy is not necessarily reversed by low herbage harvesting efficiency. This innovation in grazing management conciliates high herbage and animal production at the same time.

Using Grazing to Manage Herbaceous Structure for a Heterogeneity‐Dependent Bird

ABSTRACTGrazing management recommendations often sacrifice the intrinsic heterogeneity of grasslands by prescribing uniform grazing distributions through smaller pastures, increased stocking densities, and reduced grazing periods. The lack of patch‐burn grazing in semi‐arid landscapes of the western Great Plains in North America requires alternative grazing management strategies to create and maintain heterogeneity of habitat structure (e.g., animal unit distribution, pasture configuration), but knowledge of their effects on grassland fauna is limited. The lesser prairie‐chicken (Tympanuchus pallidicinctus), an imperiled, grassland‐obligate, native to the southern Great Plains, is an excellent candidate for investigating effects of heterogeneity‐based grazing management strategies because it requires diverse microhabitats among life‐history stages in a semi‐arid landscape. We evaluated influences of heterogeneity‐based grazing management strategies on vegetation structure, habitat selection, and nest and adult survival of lesser prairie‐chickens in western Kansas, USA. We captured and monitored 116 female lesser prairie‐chickens marked with very high frequency (VHF) or global positioning system (GPS) transmitters and collected landscape‐scale vegetation and grazing data during 2013–2015. Vegetation structure heterogeneity increased at stocking densities ≤0.26 animal units/ha, where use by nonbreeding female lesser prairie‐chickens also increased. Probability of use for nonbreeding lesser prairie‐chickens peaked at values of cattle forage use values near 37% and steadily decreased with use ≥40%. Probability of use was positively affected by increasing pasture area. A quadratic relationship existed between growing season deferment and probability of use. We found that 70% of nests were located in grazing units in which grazing pressure was &lt;0.8 animal unit months/ha. Daily nest survival was negatively correlated with grazing pressure. We found no relationship between adult survival and grazing management strategies. Conservation in grasslands expressing flora community composition appropriate for lesser prairie‐chickens can maintain appropriate habitat structure heterogeneity through the use of low to moderate stocking densities (&lt;0.26 animal units/ha), greater pasture areas, and site‐appropriate deferment periods. Alternative grazing management strategies (e.g., rest‐rotation, season‐long rest) may be appropriate in grasslands requiring greater heterogeneity or during intensive drought. Grazing management favoring habitat heterogeneity instead of uniform grazing distributions will likely be more conducive for preserving lesser prairie‐chicken populations and grassland biodiversity. © 2021 The Wildlife Society.