Increasing Stocking Rate Research Articles

Multi-year performance of white clover oversown into eastern North Island hill country

Animal performance on summer-dry North Island hill country pastures is limited by soil fertility and the challenge of establishing and retaining a strong legume base in swards on steeper slopes. However, this can be overcome by 1. selecting legume species adapted to the various slope, aspect and soil type combinations; and 2. following well-recognised establishment and management techniques developed in the 1980s. We broadcast white clover in two large southerly aspect paddocks on Tangihanga Station, Gisborne, in the autumn of 2019. Establishment methods involved resident pasture control by hard grazing and selective herbicide to supress dominant low-fertility grasses, broadcasting at high sowing rates and trampling of seed with sheep. We followed white clover persistence and animal performance over the subsequent 5 seasons of rotational cattle grazing with heifers and steers, in comparison with adjacent unsown paddocks. The cost of establishment was c. $220/ha. White clover abundance remained high throughout the 5 years, between 25-40% of cover, compared with 7-17% in unsown paddocks. This increase in clover content of the pastures translated into both increased stocking rates and per head growth rates, with overall annual LWG increasing by 67-169% depending on season. The investment was paid back within the first year.

PSXIII-7 Effects of whole corn on gain and subsequent feedlot and carcass traits of Brahman steers stocked on Tifton 85 bermudagrass

Abstract Supplementation (SUP) of stocker calves is used to enhance gain and/or adjust for stocking rates (SR). Our objective was to determine the influence of whole corn on performance of steers stocked on Tifton 85 bermudagrass [Cynodon dactylon (L.) Pers. X Cynodon nlemfuensis Vanderyst] (T85) that has documented forage crude protein ranging from 18.5% in June to 13.5% in September. For a 3-yr period, Brahman (Bos indicus) steers, 15 mo old and 275 kg body weight (BW), were stocked on T85 and received daily whole corn at 0 (PAS), 0.3% BW (SUP3), or 0.6% BW (SUP6). A fourth treatment included SUP6 at an increased stocking rate (SUP6SR). The 3-yr average SR of 275 kg steers was 11 steersּ ha-1 on PAS, SUP3, and SUP6, and 15 steersּ ha-1 on SUP6SR. Average daily gain (ADG) was similar for SUP steers at 0.98 kgּ d-1 (SUP6), 0.92 kgּ d-1 (SUP3), and 0.92 kgּ d-1 (SUP6SR), but greater (P = 0.002) than PAS steers at 0.84 kgּ d-1. Steer gainּ ha-1 was greatest (P = 0.001) for SUP6SR at 1230 kgּ ha-1. Gain ha-1 was similar for SUP6 and SUP3 at 1,010 kgּ ha-1 and 941 kgּ ha-1, respectively, and similar for SUP3 and PAS (860 kg-1). Body weights off pasture tended to be greater (P = 0.083) for all SUP steers at 370 kg than PAS steers at 354 kg. Body condition score off pasture was similar for all SUP steers at 5.7 and different (P = 0.001) from PAS steers at 5.2. At termination of stocking, steers were shipped 700 km to a commercial feedlot in South Texas. Each year, steers were fed in the same pen until a visual assessment of about 1.25 cm backfat was attained. Days on feed were similar for all steers at 190 d. Feedlot ADG was similar for steers on SUP3 (1.36 kgּ d-1), PAS (1.34 kgּ d-1), and SUP6SR (1.29 kgּ d-1), but greater (P = 0.045) than steers on SUP6 (1.24 kg d-1). These feedlot ADG exhibited some compensatory gain effects from pasture treatments. Off feedlot weights were similar at 620 kg. Steers were transported 60 km to an abattoir for harvest and carcass trait evaluations. There were no differences across treatments for steer hot carcass weight, 367 kg; 12th rib fat thickness, 1.13 cm; marbling score, 395; calculated yield grade, 3.10; longissimus dorsi area, 85.02 cm2; or internal fat (kidney-pelvic-heart), 1.92%. With SUP:extra gain at 12.5:1 for SUP3 and 13.8:1 for SUP6, supplementation of whole corn for Brahman steers stocked on T85 was not as efficient as previous T85 x SUP experiments with DDGS, but may offer management options for specific cattle classes and ownership-stocking strategies.

Spatial distribution of shrubs and perennial plants under grazing disturbance in the desert steppe of Inner Mongolia

The desert steppe is unique as a transition zone from the steppe to the desert of the Eurasian Steppe. The spatial distribution of shrubs and perennial plants has changed due to long-term disturbance caused by overgrazing in the ecosystem. This study aimed to determine the degree of patchiness of shrubs and perennial plants under grazing disturbance, which is of great significance to better understand the succession mechanism of plant community in the desert steppe. This study investigated the spatial distribution of shrubs and perennial plants under four stocking rates (no grazing, CK, 0 sheep·hm−2·half year−1; light grazing, LG, 0.93 sheep·hm−2·half year−1; moderate grazing, MG, 1.82 sheep·hm−2·half year−1; heavy grazing, HG, 2.71 sheep·hm−2·half year−1) in the desert steppe of Inner Mongolia, primarily using geostatistical methods. The density of perennial grasses increased with increasing stocking rate, while its height decreased (except for HG). The density and height of the shrubs and the perennial forbs showed an exponential or gradual decline. The spatial distribution of shrubs and perennial plants is mainly affected by structural factors such as topography, soil parent material, and climate, and the density of shrubs and perennial plants is most sensitive to changes in stocking rate. An appropriate stocking rate increases the spatial heterogeneity of shrubs and perennial plants, but heavy grazing reduces the spatial heterogeneity of shrubs and perennial plants.

Produtividade vs. área

The objective of this study was to analyze the development dynamic of the Uruguayan dairy farms in the last decade integrating country, experimental and commercial databases. A large commercial dairy farm database was segmented into four groups according to productivity and growth rate (PGR) during the fiscal years 2015/2016 to 2021/2022. Productivity growth rate was calculated as: PGR = (P2122/P1516)1/6-1, where: P2122 = productivity fiscal year 2021/22, and P1516 = productivity fiscal year 2015/2016. The PGR groups were defined as: negative (NPGR; PGR < 0% per year), low (LPGR; 0 ≤ PGR < 3%), medium (MPGR; 3 ≤ PGR ≤ 6%) and high productivity growth rate (HPGR; PGR ≥ 6%). A mixed model was used to evaluate productivity slope heterogeneity with fiscal year as a continuous variable, PGR group as categorical and their interaction. Farms that were able to increase productivity (M and H PGR) had higher mean productivity, pasture DMI and margin over feed cost vs. the less dynamic systems (N and L PGR). Larger changes in productivity (+64 and +27% for H and M PGR, respectively) were likely primarily due to changes in stocking rate (+20 to 30%) and in individual cow milk production (+10 to 20%). Production systems that increased productivity relied on increasing stocking rate and individual milk production based on more home-grown forage consumption. However, higher PGR was linked to lower initial values of productivity, which suggests decreasing returns as the dairy farms reached higher milk yields and forage DMI.

An Approach to the Key Soil Physical Properties for Assessing Soil Compaction Due to Livestock Grazing in Mediterranean Mountain Areas

The selection of key soil physical properties (SPPs) for studying the impact of livestock treading is an unexplored research topic, especially in studies that analyze the influence of livestock management on the degradation process. The objective of this work was to demonstrate that the key SPPs for studying the impact of livestock treading depend on the objectives of the research and the environmental characteristics of the study site. This work used discriminant analysis to establish the most significant SPPs among the following: bulk density (BD), total porosity (P), field capacity (FC), infiltration capacity (IC), and aggregate stability (AS). Results showed that (1) IC and BD are the key properties for identifying the areas affected (bare patch) and unaffected (vegetated patch) by livestock treading, (2) none of the SPPs are significant under increasing stocking rates, and (3) BD is the key property for analyzing livestock impact with increasing stocking rate, using soil calcium carbonate content, slope exposure, and grass cover. We concluded that the relationship between physical soil degradation and stocking rate is not linear because it depends on environmental factors; therefore, to establish the key SPPs, it is necessary to take this fact into account.

234 Can We Use Moderate Quality Round Bale Bermudagrass Silage to Stretch Wheat pasture?

Abstract Grazing wheat pasture with growing calves is an economically important enterprise in the Southern Great Plains and Southeastern U.S. Wheat forage is available when there are few other high quality forage options, and a offers a favorable seasonality of net returns for the stocker cattle enterprise. Our objective was to determine if a moderate quality wrapped round bale silage can be used to profitably increase stocking rates during the fall and winter. This research was conducted at the University of Arkansas System Division of Agriculture Livestock & Forestry Research Station near Batesville, AR (35°50′N, 91°48′W; elevation 150 m) over 3-yr from fall 2018 to spring 2021. Treatments were: HCON, where steers were stocked at 2.47 steers/ha in the fall without bermudagrass baleage or were stocked at 1× (H1.0), 1.5× (H1.5), or 2× (H2.0) the HCON stocking rate with ad libitum access to bermudagrass round bale wrapped silage during the fall. In the spring all pastures were stocked at 5.56 steers/ha without baleage (HCON) or with access to baleage (H1.0, H1.5, H2.0). Steer performance, forage mass and nutritive quality were analyzed as a randomized complete block design with SAS 9.4 (SAS Inst. Inc. Cary, NC). The bermudagrass baleage was analyzed to be 48.8% DM in yr 1, 40.2% DM in yr 2, and 46.8% DM in yr 3; and ranged from 13 to 14% CP and 55 to 56% TDN across the 3-yr (Table 1). Baleage intake based on estimated disappearance from feeders increased (P < 0.01) with increasing stocking rate in the fall and tended (P = 0.07) to increase during the spring with increased fall stocking rate. Steer ADG showed a positive associative effect of baleage feeding in the fall with greater (P = 0.01) ADG for H1.0 than HCON, while HCON and H1.5 did not differ (P = 0.71), but were greater (P ≤ 0.03) than H2.0. Gain per hectare in the fall tended (P = 0.06) to be greater for H1.0 than HCON, H1.5 and H2.0 were greater (P < 0.01) than H1.0 but did not differ from each other. Performance and BW did not differ (P ≥ 0.73) during the spring, but steer grazing days/ha and BW gain/ha were greater when baleage was offered in the spring compared with HCON. Supplemental efficiency of feeding silage did not differ (P ≥ 0.47) among treatments, on the average gains were increased by 0.22 kg/kg baleage DM fed in the fall and 0.11 kg/kg baleage DM in the spring. Offering moderate quality warm-season grass baleage to steers on wheat pasture enabled increased stocking rates in the fall while maintaining acceptable levels of performance and extending the length of the grazing season in the spring.

Grazing decreased soil organic carbon by decreasing aboveground biomass in a desert steppe in Inner Mongolia

The mechanisms through which stocking rates affect soil organic carbon in desert steppe landscapes are not fully understood. To address this research gap, we investigated changes in the biomass of Stipa breviflora plant communities and soils in a desert steppe. Through our research findings, we can establish an appropriate stocking rate for Stipa breviflora desert steppe. The establishment serves as a theoretical foundation for effectively maintaining elevated productivity levels and increasing the carbon sink, thereby offering a valuable contribution towards mitigate climate change.This study examined the effects of different stocking rates on soil organic carbon input, sequestration, and output and found: (1) For soil organic carbon input, the aboveground and litter biomass of plant communities decreased with increasing stocking rate. (2) Grazing treatments did not affect soil organic carbon retention. (3) Regarding soil organic carbon output, the grazing treatments exhibited no significant alteration in soil respiration when compared to the no grazing. In summary, the primary mechanisms through which increasing stocking rates affect the soil organic carbon pool are decreased inputs from plants and increased output through wind erosion. Therefore, decreasing grazing intensity is key to improving soil organic carbon retention in the desert steppe.

Mason bees and honey bees synergistically enhance fruit set in sweet cherry orchards

AbstractMason bees (Osmia spp.) are efficient fruit tree pollinators that can be encouraged to occupy and breed in artificial nesting material. In sweet cherry orchards, they are occasionally used as an alternative managed pollinator as a replacement for or in addition to honey bees (Apis mellifera). Yet, the lack of practical guidelines on management practices, for example optimal stocking rates, for both mason bee nesting material and honey bees might compromise pollination service provision. In this study, we assessed the relationship between stocking rates (honey bee hives and mason bee nesting material) and the abundance of honey bees and mason bees in 17 sweet cherry (Prunus avium) orchards in Central Germany. We furthermore performed a pollination experiment to explore the interactive effect of mason bees and honey bees on sweet cherry fruit set. In the orchards, both honey bee and mason bee abundance increased with increasing stocking rates of hives or nesting material, respectively. Honey bee abundance increased linearly with stocking rates. In contrast, mason bee abundance asymptoted at 2–3 nesting boxes per ha, beyond which more boxes resulted in little increase in visitation rate. Our pollination experiment demonstrated that orchards were pollen limited, with only 28% of insect‐pollinated flowers setting fruit versus 39% of optimally hand‐pollinated flowers. Honey bees and mason bees enhanced sweet cherry fruit set, but only when both were present and not when either was present alone in an orchard. Our findings demonstrate that offering nesting material for mason bees and employing honey bee hives can enhance bee abundance in sweet cherry orchards. By increasing honey bee abundance in combination with enhanced mason bee abundance, farmers can substantially boost fruit set and potentially sweet cherry yield. To enhance pollination services, farmers should consider the benefits of increasing pollinator biodiversity as an immediate benefit to improve crop yields.

Evaluation of Grazing Options During Summer for Growing Heifers – Year 3

Developing methods to provide high quality forage through most of the year is important for cattle operations. The purpose of this study was to determine forage management options to offset the summer “slump” with fescue. Four grass pasture treatments (10 pastures total; 4 acres each) were used in a completely randomized design and stocked with growing heifers (n = 49; initial wt 461 ± 65 lb). Pasture treatments consisted of novel fescue (FES), crabgrass (CRAB), bermudagrass (BERM), and sorghum-sudan interseeded into novel fescue (SS-FES). Heifers were weighed and they grazed pastures from May to September. Heifers on FES were continuously grazed. All other pastures were rotationally grazed. Sorghum-sudan was interseeded into fescue pastures in May. Average daily gain (ADG) for the entire grazing period was not different between pasture systems. Heifers on BERM and SS-FES had greater gain per acre than those FES pastures, with CRAB being intermediate. This result was primarily based on the increased stocking rates for those pastures. The extreme drought during the summer of 2022 resulted in little to no production of the sorghum-sudan and these pastures had the lowest biomass through the grazing period. Moisture is essential for success of interseeding sorghum-sudan into fescue pastures. Weather patterns impact animal performance as it impacts forage production. The best management practice may involve operations that have a variety of cool and warm-season grasses that producers can use to optimize forage production through varying weather events.

Grazing season length and stocking rate affect milk production and supplementary feed requirements of spring-calving dairy cows on marginal soils

The objective of this study was to investigate the effect of increasing stocking rate (SR) and extending grazing season (GS) length on pasture and animal productivity on a marginal, poorly draining soil type. The study was a multiyear (2017 to 2020, inclusive) whole farm systems evaluation with a 2 × 2 factorial experimental arrangement of treatments. The systems evaluated comprised 2 GS lengths, average (AGS; 205 d) and extended (EGS; 270 d), and the 2 whole farm stocking rates were medium (2.5 cows/ha) and high (2.9 cows/ha). We used this study design to create 4 grazing system intensities (500, 600, 700, and 800 cow grazing days per hectare per year). In 2017, cows were randomly allocated to 1 of the 4 whole farm systems precalving and remained on the same treatments for the duration of the study. We found no significant differences in total average annual pasture production [14,133 ± 538 kg of dry matter (DM) per hectare] or sward chemical composition between GS and SR treatments over the 4-yr period, with the exception of average crude protein content, which was lower for EGS (211 g/kg DM) compared with AGS (218 g/kg DM). Grazed pasture production was significantly increased in EGS treatments (+758 kg of DM/ha) compared with AGS (9,917 kg of DM/ha), whereas conserved silage DM production was greater for AGS (+716 kg of DM/ha) compared with EGS (3,583 kg of DM/ha). Neither GS nor SR had a significant effect on daily or cumulative lactation milk and fat plus protein production per cow (5,039 and ±440 kg, respectively). Increasing SR resulted in increased milk fat plus protein yield per hectare based on increased grazed pasture utilization. These results add further credence to the important additive contributions of both extended grazing and SR intensification to achieve high levels of grazed pasture utilization and milk production per hectare while reducing supplementary feed requirements within spring-calving grazing systems.

Direct and indirect nutritional factors that determine reproductive performance of heifer and primiparous cows.

Pregnancy rate is a major determinant of population dynamics of wild ungulates and of productivity of livestock systems. Allocation of feeding resources, including stocking rates, prior to and during the breeding season is a crucial determinant of this vital rate. Thus, quantification of effects and interaction among multiple factors that affect pregnancy rate is essential for management and conservation of pasture-based systems. Pregnancy rate of 2982 heifers and primiparous cows was studied as a function of animal category, average daily gain during the breeding season, stocking rate, pasture type and body weight at the beginning of the breeding season. Data were obtained from 43 experiments conducted in commercial ranches and research stations in the Pampas region between 1976 and 2015. Stocking rate ranged from 200 to 464 kg live weight ha-1, which brackets values for most of the grazinglands in similar regions. Age at breeding was 14-36 months (24.6±7.5 months); initial breeding weights were 129-506 kg and 194-570 kg for heifers and primiparous cows. Pregnancy rate was modeled with an apriori set of explanatory variables where proximate variables (breed, body weight at start of breeding, weight gain during breeding and category) were included first and subsequently modeled as functions of other variables (pasture type, supplementation and stocking rate). This modeling approach allowed detection of direct and indirect effects (through nutrition and body weight) of factors that affect pregnancy rate. Bos taurus breeds (N = 1058) had higher pregnancy rate than B. Taurus x B. indicus crossbreed (N = 1924) females. Pregnancy rate of heifers and primiparous cows grazing in natural grasslands decreased with increasing stocking rate, but no effect of stocking rate was detected in cultivated and improved pastures. Pregnancy rate increased with increasing average daily gain during the breeding season. Use of cultivated or improved natural pastures promotes higher pregnancy rate, as well as allows an increase in stocking rate at the regional level. Body weight at the start of the breeding season is the primary determinant of pregnancy rates in heifer and primiparous cows.

PSXIII-19 Snaplage Residue as a Strategy to Finish Beef Cattle Under Different Stocking Rates

Abstract The objective of this study was to evaluate different stocking rates of heifers on corn snaplage residue as an exclusive source of fiber on finishing phase performance. Immediately after the corn snaplage harvest, the area was divided into sixteen paddocks, and treatments were randomly assigned. The treatments were two stocking rates (SR): 1) low stocking rate (LSR; 3.5 AU/ha), and 2) high stocking rate (HSR; 7.0 AU/ha). The treatments were obtained by modifying the size of the paddocks. Crossbred beef heifers (n = 48, initial body weight = 275 ± 23 kg) were randomly allotted to 16 paddocks (3 heifers/paddock). Concentrate was fed ad libitum daily at 0600h. Data were analyzed using the MIXED procedure of SAS. Means were estimated using the LSMEANS statement and compared using the Tukey test. Initial residual mass was similar for all treatments (11,000 kg DM/ha). There was no stocking rate × time effect (P = 0.88) on total mass. There was less total mass for HSR (P < 0.01) than LSR and total mass decreased over time (P < 0.01). There was no difference between HSR and LSR for average residue intake (P = 0.34; 0.434 vs 0.478 kg/day, respectively), concentrate intake (P = 0.84; 7.72 vs 7.78 kg/day, respectively), and daily gain (ADG; P = 0.94; 0.952 vs 0.956 kg/day, respectively), The HSR treatment increased (P < 0.01) gain per area (618 vs 309 kg/ha) compared to LSR. In conclusion, the stocking rate did not affect finishing phase performance of beef heifers but increasing stocking rate did increase gain per area of land.

Heavy grazing reduced the spatial heterogeneity of Artemisia frigida in desert steppe

BackgroundGrazing disturbance plays an important role in the desert steppe ecosystem in Inner Mongolia, China. Previous studies found that grazing affected the spatial distribution of species in a community, and showed patchiness characteristics of species under different grazing treatments. Artemisia frigida is the dominant species and semi-shrub in desert steppe, and whether grazing interference will affect the spatial distribution of A. frigida is studied. In this study, geo-statistical methods were mainly used to study the spatial distribution characteristics of A. frigida population in desert steppe of Inner Mongolia at two scales (quadrat size 2.5 m × 2.5 m, 5 m × 5 m) and four stocking rates (control, CK, 0 sheep·ha–1·month–1; light grazing, LG, 0.15 sheep·ha–1·month–1, moderate grazing, MG, 0.30 sheep·ha–1·month–1, heavy grazing, HG, 0.45 sheep·ha–1·month–1).ResultsThe results showed that the spatial distribution of A. frigida tended to be simplified with the increase of stocking rate, and tended to be banded with increased spatial scale. The density and height of A. frigida increased with increasing scale. With increased stocking rate, the density of A. frigida population decreased linearly, while its height decreased in a step-wise fashion. The spatial distribution of A. frigida was mainly affected by structural factors at different scales and stocking rate. The density of A. frigida was more sensitive to change in stocking rate, and the patchiness distribution of A. frigida was more obvious with increase in scale.ConclusionsStocking rate has a strong regulatory effect on the spatial pattern of A. frigida population in the desert steppe. Heavy grazing reduced the spatial heterogeneity of A. frigida in the desert steppe. The smaller dominant populations are unfavourable for its survival in heavy grazing condition, and affects the stability and productivity of the grassland ecosystem.

Feeding Strategies to Mitigate Enteric Methane Emission from Ruminants in Grassland Systems.

Simple SummaryRuminants under grazing conditions play an important role, especially in developing countries. Enteric methane emissions from ruminants are greater with pasture-based diets; however, it is not clear which abatement practices are effective to reduce methane emissions under grazing conditions. The objective of this review was to identify and describe enteric methane abatement practices for ruminants that are applicable under grazing conditions. Decreasing the pre-grazing herbage mass reduced methane emissions per unit of product. Other grazing management practices such as increased stocking rate, decreased forage maturity, rotational stocking, and incorporating tannin-containing or non-tannin-containing legumes showed inconsistent results. Nitrogen fertilization or silvopastoral systems did not modify methane emissions, although they may alter carbon sequestration in a system. Supplementation in grazing conditions shows inconsistent responses on methane emissions. However, lipid supplementation showed promising results. Identifying and implementing grazing strategies and supplementation practices under grazing conditions is required to increase efficiency and reduce the environmental impact of these systems.Ruminants produce approximately 30% of total anthropogenic methane emissions globally. The objective of this manuscript was to review nutritional enteric methane abatement practices for ruminants that are applicable under grazing conditions. A total of 1548 peer-reviewed research articles related to the abatement of enteric methane emissions were retrieved and classified into four categories: non-experimental, in vitro, in vivo confined, and in vivo grazing. The methane abatement strategies for grazing systems were arranged into grazing management and supplementation practices. Only 9% of the retrieved papers have been conducted under grazing conditions. Eight grazing management practices have been evaluated to reduce methane emissions. Decreasing the pre-grazing herbage mass reduced the methane emission per unit of product. Other grazing management practices such as increased stocking rate, decreased forage maturity, rotational stocking, and incorporating tannin-containing or non-tannin-containing feeds showed contradictory results. Nitrogen fertilization or silvopastoral systems did not modify methane emissions. Conversely, supplementation practices in grazing conditions showed contradictory responses on methane emissions. Lipid supplementation showed promising results and suggests applicability under grazing conditions. Identifying and implementing grazing strategies and supplementation practices under grazing conditions is required to increase efficiency and reduce the environmental impact of these systems.

Yield gaps of lucerne (Medicago sativa L.) in livestock systems of Argentina

AbstractArgentina grows the second‐largest area of lucerne in the world. Despite its importance, a yield gap exists between potential and measured yields, but factors contributing to it are still unclear. This study aimed to identify management factors and research needs to reduce the lucerne yield gap to improve the livestock systems in this region. We used meteorological data coupled with lucerne crop modelling and measured yields from the National Lucerne Cultivar Evaluation Network (NLCEN) to quantify the lucerne yield gap in nine sites located within the Argentinian Pampas (between parallels 30–45°S and meridians 58–65°W) and three sites outside the Pampas. Specifically, we used the model developed by McCall & Bishop‐Hurley (2003), adapted and calibrated for lucerne in Argentina by Berone et al. (2017) to estimate the potential yield (PY) for 12 locations (three irrigated and nine rainfed), and compared those results with measured yields from the NLCEN to calculate yield gaps. We found the average available photosynthetic active radiation (PAR) and temperatures were sufficient to achieve 21.5 ± 3.7 t dry matter (DM) ha−1 yr−1 under rainfed conditions (environments with mean annual rainfall from 400 to 1,200 mm). However, the average measured yield from the NLCEN was 16.8 ± 2.4 t DM ha−1 yr−1 (a 22% gap). Potential yields ranged between 10 and 25 t DM ha−1 yr−1 under rainfed conditions and between 25 and 39 t DM ha−1 yr−1 for irrigated crops. As latitude increased rainfed locations had lower yields, while irrigated locations had higher yields. Adding irrigation was predicted to increase yields to 35.4 ± 2.0 t DM ha−1 yr−1 (a 53% gap) in rainfed sites. For irrigated locations, the gap was smaller (27.3 ± 3.5 vs 32.4 ± 2.2 t DM ha−1 yr−1 for measured vs potential yield, respectively), and most likely linked to nutrient deficits. Also, current grazing management was estimated to achieve approximately 50% less grazing efficiency than optimal grazing management. Our results demonstrated that the livestock industry can potentially increase animal production under current environmental conditions. The four main adjustments to achieve this are increased use of irrigation, increased use of fertilisers, earlier commencement of grazing in spring and increased stocking rates. The costs of irrigation, fertilisers and grazing management are envisaged to be small compared with potential increases in incomes and thus profitability available to beef and dairy farmers using lucerne as a major feed source in Argentina.

Intensification strategies for temperate hot-summer grazing dairy systems in South America: Effects of feeding strategy and cow genotype

Pasture-based dairy systems present the opportunity to increase productivity per hectare through increasing stocking rate and forage utilization. However, in the temperate hot-summer region of South America, different productive strategies are being adopted by farmers. The aim of this study was to quantify the effect of feeding strategy (FS) and cow genotype (G) on individual animal and whole-farm biophysical performance. A design with 2 × 2 levels of intensification aiming to increase home-grown forage utilization and milk output per hectare was evaluated. The experiment was a randomized complete block design with a 2 × 2 factorial arrangement of treatments, combining 2 feeding strategies with varying proportions of grazing in the annual feeding budget [grass fixed (GFix) and grass maximum (GMax)] and 2 Holstein Friesian cow genotypes [New Zealand (NZHF) or North American Holstein Friesian (NAHF)]. The effects of FS, G, and their interaction were analyzed using mixed models. New Zealand Holstein Friesian cows presented lower individual milk yield and higher milk component concentrations, maintained higher average body condition score, and increased body weight (BW) throughout the experiment, while presenting a better reproductive performance compared with the NAHF cows. Although all farmlets were planned at the same stocking rate on a per kilogram of BW basis, the current stocking rate changed as a result of animal performance and grass utilization resulting in NZHF cows achieving greater BW per hectare. The superior stocking rate led to greater milk solids production and feed consumption per hectare for the systems with NZHF cows. The GFix feeding strategy resulted in greater total home-grown forage harvest and conserved forage surplus than GMax. Overall, it was feasible to increase stocking rate and increase milk production per hectare from home-grown forage with differing feeding strategies and Holstein Friesian cow genotypes within grazing systems located in the temperate hot-summer climate region of South America. The interactions reported between FS × G highlight the superior productivity per hectare of NZHF cows within the GMax feeding strategy based on maximizing grazed pasture, which could represent a competitive intensification strategy in terms of cost of production for this region.

Effect of 3 autumn pasture management strategies applied to 2 farm system intensities on the productivity of spring-calving, pasture-based dairy systems

The objective of this study was to investigate the effect of altering autumn pasture availability and farm system intensity on the productivity of spring-calving dairy cows during autumn. A total of 144 Holstein-Friesian and Holstein-Friesian × Jersey crossbred dairy cows were randomly assigned to 2 whole farm system (FS) intensities and 3 autumn pasture availability (PA; measured above 3.5 cm) treatments in a 2 × 3 factorial arrangement. The 2 farm systems consisted of a medium intensity (MI: 2.75 cows/ha, target postgrazing sward height of 4.0-4.5 cm) and high intensity system (HI: 3.25 cows/ha, target postgrazing sward height of 3.5-4.0 cm, + 1.8 kg of concentrate dry matter [(DM)/cow per day]. Within each farm system treatment, cows were further subdivided into 3 different PA management strategies: high PA (HPA), medium PA (MPA), and low PA (LPA). The experimental period lasted for 11 wk from September 1 to housing of all animals on November 20 (±2 d) over 3 yr (2017-2019, inclusive). To establish the different average pasture covers for each PA treatment during autumn and in particular at the end of the grazing season, grazing rotation length was extended by +13 and +7 d for HPA and MPA, respectively, beyond that required by LPA (37 d). There were no significant FS × PA interactions for any of the pasture, dry matter intake, or milk production and composition variables analyzed. There were also no differences in pregrazing sward characteristics or sward nutritive value between FS with the exception of daily herbage allowance, which was reduced for HI system (12.2 vs. 14.2 kg of DM/cow). Milk and milk solid yield were greater for HI groups (15.9 and 1.55 kg/cow per day, respectively) compared with MI (15.4 and 1.50 kg/cow per day, respectively). Mean paddock pregrazing herbage mass was significantly higher with increased PA ranging from a mean of 1,297 kg of DM/ha for LPA to 1,718 and 2,111 kg of DM/ha of available pasture for MPA and HPA, respectively. Despite large differences in pregrazing herbage mass, there was no difference in cumulative pasture production and only modest differences in grazing efficiency and sward nutritive value between PA treatments. On average, closing pasture covers were 420, 650, and 870 kg of DM/ha for LPA, MPA, and HPA, respectively, on December 1. In addition to maintaining similar grazing season lengths and achieving big differences in availability of pasture on farm into late autumn, PA treatment had no significant effect on dry matter intake, milk production, and body condition score during the study period. The results of this study indicate that greater cow performance and pasture utilization can be achieved through a greater daily concentrate allocation along with an increased stocking rate. Moreover, the potential to adapt grazing management practices to increase the average autumn pasture cover in intensive grazing systems is highlighted. In addition, a high dependence on high-quality grazed pasture during late autumn can be ensured without compromising grazing season length while also allowing additional pasture to be available for the subsequent spring.

Together we stand, divided we fall: Effects of livestock grazing on vegetation patches in a desert community

AbstractQuestionsVegetation patches formed by interacting xeric species are the main drivers of dryland structure and function. Plant aggregation enhances microclimatic conditions and triggers abiotic and biotic processes, such as nutrient cycling and accumulation, and species interactions. However, vegetation patches may be modified by disturbances in unpredictable ways. We tested whether livestock grazing affects vegetation structure and plant spatial associations in a desert community, by considering the role of plant species in ecological succession.LocationPatagonian Monte Desert, Argentina.MethodsWe used high‐quality standardized photographs along transects to characterize plant community structure (i.e., cover, abundance, richness), spatial patterns (i.e. plant‐plant associations), and classified species based on their successional role (i.e. early, intermediate and late species). We used regression models and network analysis to evaluate the effect of grazing on vegetation.ResultsIn general, grazing modified community structure, reducing total cover, abundance and richness. Grazing modulated community spatial patterns, simplifying and removing vegetation patches. The impact of grazing depended on the species successional role. The abundance and cover of early species were less affected by grazing than intermediate and late species, the latter being the most affected. However, species richness significantly decreased with increasing stocking rates, regardless of their successional role. Late species were present in most plant spatial associations, indicating a major contribution to multi‐specific vegetation patches formation.ConclusionsThe reduction in species richness and low abundance of late species highlights the need to prevent irreversible degradation caused by overgrazing. Late species emerge as key structures of vegetation in desert rangelands facilitating the establishment and protecting other plant species. Due to the critical role of vegetation patches in maintaining desert ecosystem functioning, conservation and management practices should focus on late species, while early species, responsible for vegetation patch formation in overgrazed situations, should be preferred for restoration practices.

Performance and economics of backgrounding yearling beef steers on smooth bromegrass pastures

This experiment was conducted to evaluate performance (using 5 yr of data reported here, and the additional 5 yr of results previously) and economic return (10 yr) of steers grazing smooth bromegrass pastures over 10 consecutive years to determine profitability and pasture longevity under 3 management strategies. Treatments consisted of cattle (n = 450; 45/yr) grazing smooth bromegrass pastures (n = 9/yr) fertilized with 90 kg of N/ha (FERT), unfertilized pastures stocked with cattle that received distillers grains plus solubles (DGS) daily at 0.6% of BW (SUPP), and unfertilized pastures stocked with cattle that received no supplement (control, CON). A randomized complete block design was used each year with 3 treatments present in each of 3 pasture blocks and treatments maintained in the same areas for all 10 yr. Cattle supplemented daily with DGS had greater ADG (1.19 kg/d; P < 0.01) than those on the CON and FERT treatments (0.83 and 0.86 kg/d, respectively; P = 0.44). Stocking rates for SUPP [10.95 animal unit months (AUM)/ha] and FERT (10.73 AUM/ha) cattle were similar to one another ( P = 0.75) and greater than those for CON (6.72 AUM/ha; P < 0.01). Net returns were greatest ( P < 0.01) for SUPP cattle ($146.56), with FERT ($130.04) and CON ($127.17) cattle being similar ( P = 0.62). In the current analysis, SUPP was the most profitable treatment in 7 of the 10 yr, with FERT being the most profitable 2 yr and CON 1 yr. Fluctuating market conditions and changes of input costs affect the overall profitability of treatments and relative differences. In this scenario, holding all prices constant except DGS, price of DGS would have to increase by 20% (increase of $43.29/908 kg) in order for applying N fertilizer to pastures (FERT) or increasing stocking rate (CON) to be more profitable than supplementing cattle with distillers grains (SUPP).

Northern temperate pastures exhibit divergent plant community responses to management and disturbance legacies identified through a producer survey

AbstractQuestionsDoes plant composition differ among grasslands having divergent disturbance and management histories? Which vegetation attributes and disturbances specifically influence rangeland health?LocationNorthern temperate pastures in the Central Parkland and adjacent Boreal natural regions of central Alberta, Canada.MethodsPlant composition and rangeland health data from 102 pastures were related to disturbance history acquired from retrospective producer surveys. Health assessments evaluated indicators such as vegetation composition, hydrologic function, and site stability. Producers were asked to identify pasture history (e.g., last cultivation date, whether fire had occurred), contemporary grazing actions (timing of use, grazing systems, type of livestock), and other management activities (i.e. herbicide application, manure spreading).ResultsCultivation and burn history were the primary drivers of vegetation differences, where previously cultivated pastures were dominated by introduced, naturalized grasses, eliminating most native species. Remnant non‐cultivated grasslands were occupied by a mix of native and invasive plant species. Grazing system had limited impact on vegetation composition due to uniformly high livestock stocking. Plant composition corresponded with gradients in rangeland health, where the latter declined with increased stocking rate and supplemental feeding on pasture. Greater health was characterized by increased cover of graminoids (primarily introduced forages), abundant litter, low plant richness, and reduced stocking rates. Other land management activities had comparatively less impact on the composition and health of these grasslands.ConclusionsConversion of native grassland and forest in this region has a strong legacy effect on vegetation. Management actions associated with high stocking rates and supplemental feeding lowered rangeland health.