Mixed Pasture Research Articles

Impact of seasonal nitrogen fertilisation on production characteristics of a mixed grass pasture in the Western Cape province of South Africa

Pasture production in the Western Cape has traditionally been based on temperate species producing the majority of fodder during spring and autumn after which dry matter production decreases in winter. To investigate seasonal fertiliser nitrogen (N) management strategies to optimise seasonal dry matter production, a mixed grass pasture consisting of perennial ryegrass (Lolium perenne), tall fescue (Festuca arundinacea) and cocksfoot (Dactylis glomerata) was established. The effect of fertiliser N (0, 20, 40, 60 and 80 kg N ha−1) and season of application (spring, summer, autumn and winter) were evaluated. Dry matter production was significantly (p = 0.05) the highest in spring (year 1) and in spring and summer (year 2) with application of 60–80 kg N ha−1. Botanical composition was mainly determined by season of application, whereas crude protein content was characterised by a strong interaction between season of N application and application rate. It is concluded that, excluding winter, seasonal application of N can be used as a management tool to increase dry matter production. It is recommended that 40 kg N ha−1 during autumn and spring and 60 kg N ha−1 during summer should be applied to grass pastures under irrigation in the Winelands subregion of the Western Cape.

Endometrial gene expression in primiparous dairy cows at the end of the voluntary waiting period is affected by nutrition: Total mixed ration vs increasing levels of herbage allowance.

The study postulated that differential nutritional management during the early lactation period would be reflected in endometrial expression of genes related to embryo growth at the end of the voluntary waiting period. Thus, the effect of the combined use of total mixed ration (TMR) and grazing under different herbage allowances during the first 75days post-partum (DPP) on endometrial gene expression was evaluated in primiparous dairy cows. Cows were blocked by body weight, age and body condition score and randomly assigned to three grazing treatments: high (HA, 30kg DM per cow per day), medium (MA, 15kg DM per cow per day) and low (LA, 7.5kg DM per cow per day) herbage allowance (mixed pasture, 2,600kg DM per ha) plus 8kg DM of supplement or TMR (55% forage, 45% concentrate) fed ad libitum (TMR) from calving to 75 DPP. At 57 DPP, cows were synchronized for oestrus (day 0, 68 DPP) and at day 7, endometrial biopsies were obtained. The nutritional treatment did not affect insulin, IGF-1 and leptin concentrations on days 0, 4 or 7. Expression of IGF1, IGFBP3, IGFBP4, ADIPOR1 and ADIPOR2 mRNA was significantly affected by the nutritional treatment. Endometrial IGF1 and IGFBP4 mRNA were twofold greater in TMR and HA than MA and LA cows. Expression of IGFBP3 and ADIPOR1 mRNAs was greater in TMR and HA than MA cows, but did not differ from LA cows. All groups had greater expression of ADIPOR2 mRNA than MA cows. This study provided solid evidence of the importance of nutritional management during early lactation on uterine environment at the end of the voluntary waiting period. The greater expression of genes related to embryo growth and uterine function (IGF system, progesterone and adiponectin receptors) in cows fed diets maximizing energy intake suggests a favourable environment for embryonic growth, which may explain the improved reproductive performance of cows in good energy balance.

A Research on Yield Prediction of Mixed Pastures in Korea via Model Construction in Stages

A Research on Yield Prediction of Mixed Pastures in Korea via Model Construction in Stages

Defoliation management affects morphogenetic and structural characteristics of mixed pastures of brachiaria grass and forage peanut

A sound understanding of the effects of defoliation management in a grass–legume pasture is key in balancing populations between species. The aim of this study was to quantify the morphogenetic and structural characteristics and forage production of brachiaria grass and forage peanut mixtures under four defoliation strategies. A two-year experiment was carried out in Brazil (Cwa climate), where the following treatments were studied: rest period interruption by cattle grazing when the canopy attained light interception (LI) of 90%, 95% and 100%, and grazing performed every 42 d. Morphogenetic and structural characteristics of both species were measured. The forage and leaf accumulation rates were also quantified. The design was randomised blocks, with three replications, and repeated measurements over time. The 100% LI had greater stem and stolon elongation rates and a lower leaf appearance rate in both species and fewer tillers or stolons when compared with the other strategies. Conversely, rest periods of 90–95% LI promoted an increase of about 30% on forage and leaf accumulation rates of both grass and legume. Therefore, to enhance productivity and stability when these species are associated we recommend defoliating at 90–95% LI, which represents a canopy height ranging from 26 to 32 cm.

CHARACTERIZATION OF BIOGENIC, INTERMEDIATE AND PHYSICOGENIC SOIL AGGREGATES OF AREAS IN THE BRAZILIAN ATLANTIC FOREST

ABSTRACT Aggregate formation and stability are related to soil quality, contributing significantly to the carbon storage and nutrient maintenance capacities of the soil. Soil aggregates are formed by two different process: physicogenic, related to moistening and drying cycles and input of organic matter; and biogenic, related to the action of macrofauna organisms and roots. The objective this work was to classify aggregates according to their formation process, quantify and compare organic carbon contents in humic substances and assess the stability of aggregates formed by different processes, in areas with different coverage in the Mid Paraiba Valley, Pinheiral, State of Rio de Janeiro, Brazil. Aggregated soil samples were collected at a depth of 0-10 cm, in a Cambisol (Cambissolo Háplico Tb Distrófico) under four plant covers: secondary forest in advanced (SFAS), medium (SFMS) and initial (SFIS) successional stages and managed mixed pasture (MMP). Aggregates were classified and identified into three morphological classes (physicogenic, biogenic and intermediate). The variables evaluated were mean weight diameter (MWD) and geometric mean diameter (GMD) of aggregates, chemical fractions of organic matter, total organic carbon (TOC) and humic substances: humin (C-HUM) humic acid (C-FAH) and fulvic acid (C-FAF). Biogenic aggregates were found in smaller quantities and showed higher TOC, C-HUM and C-FAH, compared to intermediate and physicogenic aggregates. Thus, biogenic aggregates have potential to be used as soil quality indicators for structured environments, which are able to maintain its intrinsic formation processes.

Tall fescue forage mass in a grass-legume mixture: predicted efficiency of indirect selection

High fertilizer prices and improved environmental stewardship have increased interest in grass-legume mixed pastures. It has been hypothesized, but not validated, that the ecological combining ability between grasses and legumes can be improved by breeding specifically for mixture performance. This experiment examined the predicted efficiency of selection in a grass monoculture environment to indirectly improve tall fescue (Lolium arundinaceum (Schreb.) Darbysh.) forage mass in a grass-legume mixture. Heritability, genetic and rank correlations, and selection efficiencies were estimated for forage mass in a tall fescue half-sib population grown as spaced-plants overseeded with either turf-type tall fescue (monoculture) or alfalfa (mixture). Heritability for tall fescue forage mass in monoculture ranged from 0.32 to 0.70 and were always similar or greater than those in mixture (range 0.27–0.55) for four successive harvests and annual total. Genetic correlations between monoculture and mixture tall fescue forage mass varied with values of 0.48, 0.92, −0.31, 0.70, and 0.25 in June, July, August, October, and annual total, respectively. Indirect selection efficiencies exceeded or approached direct selection for mixtures only in July and October (1.29, and 0.73, respectively). Whereas, indirect selection efficiencies were low in June, August, and annual forage mass (0.58, −0.31, and 0.28, respectively). Moreover, low Spearman’s rank correlations (−0.03 to 0.35) indicated differing half-sib family performance between the monoculture and mixture environments. Results indicate that direct selection should be used to improve tall fescue forage mass in a grass-legume mixture, and support the hypothesis of increasing ecological combining ability by breeding for mixtures per se.

Quantification of dead vegetation fraction in mixed pastures using AisaFENIX imaging spectroscopy data

New Zealand farming relies heavily on grazed pasture for feeding livestock; therefore it is important to provide high quality palatable grass in order to maintain profitable and sustainable grassland management. The presence of non-photosynthetic vegetation (NPV) such as dead vegetation in pastures severely limits the quality and productivity of pastures. Quantifying the fraction of dead vegetation in mixed pastures is a great challenge even with remote sensing approaches. In this study, a high spatial resolution with pixel resolution of 1m and spectral resolution of 3.5–5.6nm imaging spectroscopy data from AisaFENIX (380–2500nm) was used to assess the fraction of dead vegetation component in mixed pastures on a hill country farm in New Zealand. We used different methods to retrieve dead vegetation fraction from the spectra; narrow band vegetation indices, full spectrum based partial least squares (PLS) regression and feature selection based PLS regression. Among all approaches, feature selection based PLS model exhibited better performance in terms of prediction accuracy (R2CV=0.73, RMSECV=6.05, RPDCV=2.25). The results were consistent with validation data, and also performed well on the external test data (R2=0.62, RMSE=8.06, RPD=2.06). In addition, statistical tests were conducted to ascertain the effect of topographical variables such as slope and aspect on the accumulation of the dead vegetation fraction. Steep slopes (>25°) had a significantly (p<0.05) higher amount of dead vegetation. In contrast, aspect showed non-significant impact on dead vegetation accumulation. The results from the study indicate that AisaFENIX imaging spectroscopy data could be a useful tool for mapping the dead vegetation fraction accurately.

English

Sustainable models of animal production constantly seek for ways to pasture production with inputs reduction. In this context, the introduction of forage legumes in the pasture system is fundamental to fix nitrogen from the atmosphere and supply it to grasses, increasing its production and persistence, enhancing animal nutrition as it grazes, at the same time. Still, the use of plant mixes in the system brings further benefits to it, such as better utilization of fertilizers as well as enhances the nutrient cycle and soil coverage. However, there are still many gaps in our knowledge regarding intercropping legumes and grasses, especially the use of tropical legumes. The purpose of this review is compiles data about forage legumes as well as analyses them to find new tendencies and gaps on the knowledge to shed some lights on researches in this area. We also expect that this review will help researchers and producers to understand the role of forage legumes in a pasture system and that there will be an increase in its utilization worldwide, especially in the tropics, where nitrogen is easily leached and lost from the pastures. With emphasis on description of promising tropical legumes but still little used Arachis pintoi, Macrotyloma and Neonotonia whightii. Key words: Arachis pintoi, grass, Macrotyloma axillare, mixed pasture, Neonotonia wightii.

The value of legumes to a Whanganui hill country farm

There is interest in the sheep and beef sector in lifting the legume content of hill pastures. This interest is tempered by the uncertainty of the benefits and how much farmers can afford to spend to achieve them. The objective of this study was to quantify the value to a hill country farm of differing proportions of legumes in a mixed species pasture using AgInform® (Integrated Farm Optimisation and Resource Allocation Model). AgInform® is a multi-year farm systems model, adapted so that the legume proportion of pasture as it influences pasture growth and animal performance through its influence on diet could be included as variables in the model. Three levels of legume (Low, Base and High) in a mixed pasture were modelled. The model predicts that increasing the legume proportion increases farm profitability although not in a linear manner with increasing legume proportion. This analysis provides an indication of the investment that hill country farmers can afford to increase the legume proportion in mixed pastures. Keywords: farm systems, legume, variability, AgInform®, multi-year

Fatty Acids Profile and Quality Attributes of Beef from Steers Finished on Legume and Grass Pasture

ObjectivesFeeding legume and grass can alter fatty acids profile and quality characteristics of pasture-finished beef. Therefore, the objective of this study was to compare finishing beef steers on mixed legume-grass pastures to feeding a high-energy supplement to grazing steers and feeding a high-concentrate diet on fat content, fatty acids profile, lipid oxidation, objective color, texture, and WBSF of beef.Materials and MethodsBritish × zebu-cross steers (n = 18) were assigned randomly to 1 of 3 dietary treatments: 1) grazing pastures comprised of oats, ryegrass, white and red clover (PAST); 2) grazing the mixed legume-grass pastures and supplementing steers (1.4% BW) with whole corn (SUPP); or 3) limit-feeding (2.8% BW) an 85% whole corn finishing diet (GRAIN). All steers were slaughtered after the 91-d feeding trial, and boneless ribeye rolls were removed from left sides 24 h of chilling, and subsequently cut into 2.54-cm-thick steaks that were individually vacuum packaged and frozen at –20°C for 20d. Analyses included proximate composition (g/100g), cholesterol (g/100g), fatty acids profile (g/100g FAME), cooking loss (%), and shear force (N), and texture profile. Five steaks were thawed and displayed at 4°C for 13 d to evaluate objective color (L*, a*, b*). TBARS (mg MDA/kg meat) were quantified on d 1, 4, 7, 10, and 13 d. Data were analyzed as a CRD. Days of display and oxidation were analyzed as repeated measures. MIXED and GLM procedures of SAS (SAS Inst. Inc., Cary, NC) were used and when significance (P ≤ 0.05) was identified by ANOVA.ResultsFinishing steers on GRAIN led to higher fat content (P = 0.002) and lower moisture values (P 0.05) among dietary treatments.No treatment effect was observed for L*, cooking loss, WBSF, and texture profile attributes, except for cohesiveness (higher from PAST and SUPP samples than for GRAIN samples, P = 0.002). Lipid oxidation was significant higher on beef from steers fed GRAIN than beef from SUPP and PAST (P < 0.001). Steaks from steers fed PAST and SUPP were redder after 10 and 13d of display than steaks from GRAIN-fed steers, and steaks from PAST and SUPP differed after 13d of display (P < 0.001). Although yellowness decreased during retail display (P < 0.001), dietary treatments did not influence b* values (P = 0.051).ConclusionBeef finished on GRAIN had higher values of n-6/n-3 ratio and increased lipid oxidation. Higher proportions of PUFA found in beef from steers finished on mixed pasture (PAST) and supplemented with corn (SUPP) did not affect lipid and color stability of beef, possibly due to natural antioxidants found in legume-grass mixtures. Dietary treatments did not influence texture, tenderness, and cholesterol values. Beef from steers finished on legume and grass pasture (PAST) showed similar attributes when compared to beef from steers finished with corn supplementation (SUPP).

Fatty Acids Profile and Quality Attributes of Beef from Steers Finished on Legume and Grass Pasture

ObjectivesFeeding legume and grass can alter fatty acids profile and quality characteristics of pasture-finished beef. Therefore, the objective of this study was to compare finishing beef steers on mixed legume-grass pastures to feeding a high-energy supplement to grazing steers and feeding a high-concentrate diet on fat content, fatty acids profile, lipid oxidation, objective color, texture, and WBSF of beef.Materials and MethodsBritish × zebu-cross steers (n = 18) were assigned randomly to 1 of 3 dietary treatments: 1) grazing pastures comprised of oats, ryegrass, white and red clover (PAST); 2) grazing the mixed legume-grass pastures and supplementing steers (1.4% BW) with whole corn (SUPP); or 3) limit-feeding (2.8% BW) an 85% whole corn finishing diet (GRAIN). All steers were slaughtered after the 91-d feeding trial, and boneless ribeye rolls were removed from left sides 24 h of chilling, and subsequently cut into 2.54-cm-thick steaks that were individually vacuum packaged and frozen at –20°C for 20d. Analyses included proximate composition (g/100g), cholesterol (g/100g), fatty acids profile (g/100g FAME), cooking loss (%), and shear force (N), and texture profile. Five steaks were thawed and displayed at 4°C for 13 d to evaluate objective color (L*, a*, b*). TBARS (mg MDA/kg meat) were quantified on d 1, 4, 7, 10, and 13 d. Data were analyzed as a CRD. Days of display and oxidation were analyzed as repeated measures. MIXED and GLM procedures of SAS (SAS Inst. Inc., Cary, NC) were used and when significance (P ≤ 0.05) was identified by ANOVA.ResultsFinishing steers on GRAIN led to higher fat content (P = 0.002) and lower moisture values (P < 0.001) when compared to PAST. Dietary treatments did not affect crude protein (P = 0.99) and cholesterol values (P = 0.13). The LT from PAST- and SUPP-fed steers had greater proportions of n-3 PUFA and 18:2cis-9, trans-11 CLA than the LT from GRAIN-fed steers; however, LT of GRAIN steers had greater (P < 0.001) n-6/n-3 ratio (8.86%) than the LT from either SUPP-fed (2.65%) or PAST-fed steers (1.91%). Although steers fed GRAIN had greater (P = 0.002) proportions of MUFA than PAST, proportions of PUFA and SFA were similar (P > 0.05) among dietary treatments.No treatment effect was observed for L*, cooking loss, WBSF, and texture profile attributes, except for cohesiveness (higher from PAST and SUPP samples than for GRAIN samples, P = 0.002). Lipid oxidation was significant higher on beef from steers fed GRAIN than beef from SUPP and PAST (P < 0.001). Steaks from steers fed PAST and SUPP were redder after 10 and 13d of display than steaks from GRAIN-fed steers, and steaks from PAST and SUPP differed after 13d of display (P < 0.001). Although yellowness decreased during retail display (P < 0.001), dietary treatments did not influence b* values (P = 0.051).ConclusionBeef finished on GRAIN had higher values of n-6/n-3 ratio and increased lipid oxidation. Higher proportions of PUFA found in beef from steers finished on mixed pasture (PAST) and supplemented with corn (SUPP) did not affect lipid and color stability of beef, possibly due to natural antioxidants found in legume-grass mixtures. Dietary treatments did not influence texture, tenderness, and cholesterol values. Beef from steers finished on legume and grass pasture (PAST) showed similar attributes when compared to beef from steers finished with corn supplementation (SUPP).

Release from Streambed to Water Column during Baseflow Periods: A Modeling Study.

Streambed sediments can harbor large populations that are released into the water column during high-flow events. Few studies have been conducted on the rates of transfer from streambed sediment to water column in low-flow conditions in natural streams. The aim of this work was to apply the watershed-scale model SWAT (Soil and Water Assessment Tool) to a natural stream to evaluate the need to account for the release from streambed sediments during baseflow periods and to compare the results of simulating such a release by assuming predominantly passive transport, driven by groundwater influx, against simulations assuming predominantly active transport of random or chemotaxis-driven bacteria movement. concentrations in water during baseflow periods were substantially underestimated when release from the streambed was attributed only to streambed sediment resuspension. When considered in addition to the release due to sediment resuspension at high flows, the active and passive release assumptions provided 42 and 4% improvement, respectively, in the RMSE of logarithms of concentrations. Estimated fluxes to water column during the baseflow periods from June to November ranged from 3.3 × 10 colony-forming units (CFU) m d in the game land area to 1.4 × 10 CFU m d in the mixed pasture and cropland. Results demonstrate that release of from streambed sediments during baseflow periods is substantial and that water column concentrations are dependent on not only land management practices but also on in-stream processes.

Enhancing composition and persistence of mixed pasture swards in southern New South Wales through alternative spatial configurations and improved legume performance

This study examined whether the productivity and persistence of mixed pastures that included subterranean clover (Trifolium subterraneum L.), lucerne (Medicago sativa L.), and/or phalaris (Phalaris aquatica L.) were improved if species were spatially separated rather than being sown together in each drill row. The study also compared the productivity and persistence of subterranean clover with alternative annual legume species biserrula (Biserrula pelecinus L.) and strand medic (Medicago littoralis Rhode ex Loisel). Twelve pasture treatments were sown in replicated field experiments at five locations across the medium-rainfall region of south-western New South Wales in 2012 and monitored for 3 years. Pastures that included lucerne, phalaris and subterranean clover were generally more productive than pastures with only one or two of those species, regardless of sowing configuration. Averaged across sites, subterranean clover regeneration in year 3 was 29% higher and total cumulative biomass 13% higher where subterranean clover was sown in a 1 : 1 configuration with lucerne than where the species were mixed together in every drill row. There were fewer consistent benefits of alternative spatial configurations on swards containing phalaris with subterranean clover or with lucerne. Results of the present study appeared to be highly site-specific, or season-dependent, and therefore alternative spatial configurations cannot be recommended as a universal strategy at this time. More research is required to understand the factors driving the responses to alternative spatial configurations observed in the present study. Neither biserrula nor strand medic was superior to subterranean clover in a 3-year pasture phase with lucerne, despite abundant rhizobia compatible with all species at all sites. The density of subterranean clover in year 3 was 29% and 41% higher than of biserrula and strand medic, respectively. A narrow choice of adapted cultivars as well as excessive levels of hard seed for the legumes used in phased pastures with lucerne are suggested as contributing to the inferior performance of the alternative legumes species tested in the study.

Triticale–annual ryegrass mixture effects on forage characteristics and performance of early-weaned beef calves

ABSTRACT Mixing small grains with annual ryegrass (Lolium multiflorum) may be a feasible management practice to improve forage production for early-weaned beef calves in the southeastern United States. The objective of this experiment was to evaluate forage characteristics and animal performance of early-weaned beef calves grazing annual ryegrass or annual ryegrass–triticale (X Triticosecale) mixed pastures. The experiment was conducted at Ona, Florida, from February to April 2011 (yr 1) and 2012 (yr 2). Treatments were annual ryegrass or triticale–annual ryegrass pastures distributed in a completely randomized design with 4 replicates. Four calves (mean initial BW = 100 ± 13 kg) were allocated to each pasture (0.3 ha) using a continuous and fixed stocking rate. Calves were supplemented daily with concentrate (16% CP and 78% TDN) at 1% BW. Herbage mass was greater (P = 0.01) for the triticale–annual ryegrass than annual ryegrass treatment in yr 1 (2,730 vs. 2,080 ± 100 kg/ha), but there was no difference (P = 0.87) between treatments in yr 2 (1,750 ± 120 kg/ha). The annual ryegrass treatment had greater CP (19.5 vs. 15.0 ± 0.7%) and in vitro OM disappearance (80.6 vs. 76.2 ± 1.7%) than the triticale–annual ryegrass in yr 2. Calf ADG decreased from February to April (P = 0.04) and was greater (P

Evaluation of refractive index for measuring urinary nitrogen concentration in a sensor worn by grazing female cattle

ABSTRACTA urine sensor has been developed to measure the volume and nitrogen (N) concentration of individual urination events from female cattle in the field. The objective of this paper was to establish that the sensor’s refractive index (RI) value could be used to accurately estimate urinary-N concentration. Individual urine samples (168 in total) were collected from 18 cows that were fed monocultures (ryegrass, clover or turnips) or from cattle that grazed conventional mixed pasture (ryegrass/white clover) in the field. Regression analysis of urine sensor RI values with either urinary-N or potassium (K) concentrations yielded strong linear relationships (P < 0.001) for all feed types. However, individual regression lines varied between feed types, particularly for turnips. We conclude the use of RI in the sensor provides an accurate estimate of urinary-N but site-specific calibration of the sensor is warranted due to different feed types affecting urine K:N ratio and, by inference, other aspects of composition.

White clover: the forgotten component of high-producing pastures?

The contribution of white clover (Trifolium repens L.) to nitrogen fixation and feed quality in mixed pastures is indisputable, but the benefits of clover inclusion to total herbage accumulation (HA) are less clear. Results from four experiments comparing mixed pastures of white clover–perennial ryegrass (Lolium perenne L.) with perennial ryegrass monocultures are presented. These experiments covered a range of environments (dryland northern New Zealand and irrigated southern New Zealand), management inputs (nitrogen (N) fertiliser rates and defoliation management), and genotypes of ryegrass and white clover. Mixtures resulted in a significantly greater HA than did monocultures in 7 of the 8 years for which data were available; the interaction between pasture type (monoculture or mixture) and N rate was significant in six of those years, with a greater advantage in HA for mixtures under low N rates (mean = 3.08 t DM/ha.year) than under high N rates (mean = 1.54 t DM/ha.year). Two-thirds to four-fifths of the yield advantage under grazing was due to the direct effect of clover contribution (which ranged between 10% and 30% of total annual yield) to HA, most of which accrued in summer. The remainder was due to the capture of additional clover-derived N by the grass component of the mixture, estimated to equate to 50–60 kg N/ha under low N-fertiliser rates and 15–35 kg N/ha under high N rates. The magnitude and consistency of the yield advantages observed here indicates that there are unrealised yield and other benefits not currently being captured in New Zealand dairy production systems, largely because they are negated by the use of high N-fertiliser rates. The agronomic practices required to support clover-rich mixed pastures receiving moderate rates of N fertiliser are well documented and can be applied to help deal with nutrient loss limits required by environmental regulations plus volatility in farm-gate milk prices.

Animal and Pasture Responses to Grazing Management of Chemically Suppressed Tall Fescue in Mixed Pastures

Treatment of toxic endophyte‐infected tall fescue [Lolium arundinaceum (Schreb.) Darbysh] with metsulfuran‐methyl {Methyl 2‐[[[[(4‐methoxyl‐6‐methyl‐1,3,5‐triazin‐2‐yl)‐amino]carbonyl]amino]sulfonyl] benzoate}, as delivered by Chaparral herbicide (Dow AgroSciences, Indianapolis, IN) can mitigate fescue toxicosis and enhance forage nutritive value by suppressing seedhead emergence. A grazing experiment was conducted with steers (2013) and heifers (2014) to evaluate animal and plant responses to grazing management of mixed cool‐season grass pastures treated with Chaparral. Continuous and rotational stocking treatments were assigned to six, 3.0‐ha pastures in a randomized complete block design with three replications in 2013 and two replications in 2014. Each pasture had six tester animals, and stocking rates were varied using put‐and‐take animals. Pastures were grazed from 16 April to 8 July 2013 and 20 May to 12 Aug. 2014. Pasture carrying capacity was 20% greater for rotational than continuous stocking. Calves on rotationally stocked pastures also had 26% greater average daily gain (ADG) and body weight (BW) gain per hectare than those on the continuous treatment. Pre‐grazed herbage had less neutral detergent fiber (NDF) and acid detergent fiber (ADF) than post‐grazed herbage and herbage from continuously stocked pastures in 2013, but they did not differ in 2014. Crude protein (CP) was lower in post‐graze rotational pasture than in continuous or pre‐graze rotational pasture. Fescue roots in rotationally stocked pastures had greater water soluble carbohydrates (WSC) and N concentrations than continuously stocked pastures following the second year of grazing. Results indicated that rotational stocking of Chaparral treated mixed pastures can improve animal performance and pasture productivity.

Grazing winter and spring wheat crops improves the profitability of prime lamb production in mixed farming systems of Western Australia

Grazing immature cereal crops, particularly different varieties of wheat, has become widely adopted in the high rainfall areas of southern Australia. Recently, there has been growing interest in applying this technology in drier parts of the mixed farming zones of Western Australia. A modelling study was conducted to examine farm business returns with or without the grazing of immature wheat (winter and spring varieties) in different locations of Western Australia (Merredin, Wickepin and Kojonup), representing the low to high rainfall (319–528 mm) cropping regions, respectively. A combination of APSIM (crop simulation model) and GrassGro (pasture and livestock simulation model), were used to evaluate the changes in farm gross margins with the grazing of cereal crops at three locations of Western Australia. The results of the study showed that grazing the two wheat varieties (dual-purpose winter and spring) at the high rainfall location increased the profitability of the livestock enterprise by 2.5 times more than grazing crops at both low rainfall locations (P &lt; 0.05). Across all years and sites, the average supplementary feeding costs were reduced by the inclusion of grazed winter (12%) and spring (2%) wheat crops in the lamb production system. The comparative reduction in the cost of supplementary feeding varied between locations and by crop variety within locations, due to both the frequency and average duration of the grazing of wheat crops in these regions, and the farm-stocking rate that was chosen. Both wheat varieties were grazed frequently at the lowest rainfall site (68% and 30% of years for winter and spring wheat varieties respectively), whereas grazing spring wheat was less frequent at the higher rainfall location and averaged 16% of years due to a greater difference in the relative availability of wheat crops versus pasture for grazing among regions. The grazing model assumed that there were abundant productive mixed ryegrass and subterranean clover pasture in the farming system. Overall, this study suggests that both winter and spring wheat crops are likely to supply green feed during the winter feed shortage (April–July) and reduce supplementary feed requirements for a short period of time in some seasons. The value of grazing crops is likely to be higher on farms with poorer soils and less productive pastures.

Soil moisture and soybean physiology affected by drought in an integrated crop-livestock system

Abstract: The objective of this work was to evaluate the impact of grazing intensities after 11 years of an integrated crop-livestock system, under no-tillage, on soil moisture and soybean physiological parameters during a summer season affected by drought. The experiment was established in 2001 on a Rhodic Hapludox. Treatments consisted in the succession of soybean (summer) and a mixed pasture of black oat + Italian ryegrass (winter), under different beef-cattle grazing intensities: intensive grazing, with 0.10-m pasture height; moderate grazing, with 0.20-m pasture height; and no grazing. During the soybean cycle, in the 2011/2012 crop season, rainfall was 40% of the climatological normal. The soil moisture was within the limits of available water both under moderate grazing and no grazing, at 0.00-0.50-m soil depth, but, under intensive grazing, it was below the permanent wilting point, especially up to the grazing height of 0.20 m. Intensive grazing affected negatively the plant physiology parameters, reaching peaks of -2.5 MPa and +6°C for leaf water potential and leaf-air temperature difference, respectively. Moderate grazing or the absence of grazing, during the winter season, results in similar physiological responses, contributing to soybean plant homeostasis.

Effects of including forage herbs in grass–legume mixtures on persistence of intensively managed pastures sampled across three age categories and five regions

ABSTRACTTo test the hypothesis that the inclusion of the forage herbs chicory (Cichorium intybus L.) or plantain (Plantago lanceolata L.) or both in a grass–legume pasture mix improves persistence of sown vegetation and reduces weed and invertebrate pest ingress, a study was undertaken in 31–44 intensively managed pastures in each of five regions in New Zealand (Northland, Waikato, Bay of Plenty, Taranaki and Canterbury). The regions were stratified according to farm type (dairy or sheep and beef), pasture type (sown with grasses, legumes and herbs or grasses and legumes) and pasture age (young: 1–2 years old; medium: 3–4 years old; and old: 5+ years since sowing, n = 171). Sown species ground cover and emergence from the soil seed bank was greater, and unsown species ground cover and emergence lower, in sheep and beef pastures sown with herbs than without herbs (78% vs 68% ground cover, respectively, averaged over all pasture ages), but there was no difference between pasture types on dairy farms. Invertebrate predator and parasitoid abundance was 65% greater under pastures sown with herbs than without herbs. The number and % dry matter contribution of sown species decreased, and that of unsown species increased, as pastures aged. Unsown species comprised 90% (sheep and beef) and 98% (dairy) of total seedling emergence. The inclusion of forage herbs increased persistence of sown species and reduced weed ingress, but only on sheep and beef farms.