High Stocking Rates Research Articles

Effects of stocking rate, forage management, and grazing management on performance and economics of cow-calf production in Southwest Arkansas.

The objective this research was to determine the effect of application of multiple grazing management practices at 2 stocking rates (SR) on the productivity and economics of the cow-calf enterprise in the Southeastern United States over a 4-yr period. Pasture management systems included: continuous grazing management at a moderate SR (0.8 ha/cow; CG) without additional forage management, rotational grazing management at a moderate SR (0.8 ha/cow (MR) with addition of stockpiled bermudagrass [ (L.) Pers.] and complementary cool season annuals, and rotational grazing management similar to MR but with a high SR (0.4 ha/cow; HR). Stockpiling in MR and HR was managed by fertilization of 0.2 ha/cow of bermudagrass in early August with 168 kg ammonium nitrate and deferring grazing until November. Wheat (; 112 kg/ha) and annual ryegrass ( Lam.; 28 kg/ha) were interseeded (0.2 ha/cow) in HR and MR with a no-till drill in the fall. Cow and calf performance and economics data were analyzed by ANOVA using the MIXED procedure of SAS (SAS Inst. Inc., Cary, NC) and pregnancy percentage was analyzed using the GLIMMIX procedure of SAS; pasture was the experimental unit and year was the random block. Hay feeding days decreased ( < 0.01) from 107 ± 10.9 d for CG to 37 ± 10.9 d for HR, which was further reduced ( = 0.01) to 15 ± 10.9 d for MR. Pregnancy percentage did not differ ( = 0.20) among treatments. Weaning BW in CG (237 ± 7.3 kg) tended ( = 0.09) to be greater than in MR (227 ± 7.3 kg) and were greater ( < 0.01) than in HR (219 ± 7.3 kg). However, total weaning BW per hectare was 89% greater ( < 0.01) for HR compared with CG and MR, which did not differ ( = 0.31). With rotational stocking, there was the opportunity to harvest excess forage as hay in both MR and HR with a net value of US$52.90/ha ± 25.73 and $15.50/ha ± 25.73, respectively. Net returns per hectare did not differ ( = 0.30) between CG ($429 ± 63.0/ha) and MR ($479 ± 63.0/ha) but were increased ( < 0.01) by 107% by HR ($1,024 ± 63.0/ha). Using rotational grazing, stockpiled bermudagrass, and complementary cool-season annual grasses can drastically reduce winter feed requirements and simultaneously increase carrying capacity and net return.

Blame it on the goats? Desertification in the Near East during the Holocene

The degree to which desertification during the Holocene resulted from climatic deterioration or alternatively from overgrazing has puzzled Quaternary scientists in many arid regions of the world. In the research reported upon here, a multi-disciplinary investigation of a 5-m deep, ~11,000-year-old sediment column excavated in a dry lake bed in southern Jordan revealed an early interval in which proxies of plant cover and sheep/goat stocking rates co-varied directly with climatic cycles. Beginning ~5.6 kcal BP, however, this pattern changed with fecal spherulite and phytolith densities failing to co-vary and with spherulites often greatly exceeding phytolith densities, which we suggest is indicative of overgrazing. Moreover, the lack of agreement between the high phytolith densities and other indicators of a desert landscape (i.e. geomorphic and palynologic) suggests that phytolith densities were inflated by fodder subsidies and as such are not entirely reflective of plant cover for this later interval. Given the co-incidental emergence of overgrazing with archaeological evidence for a marked rise in regional population, emergence of widespread trade, and expansion of the Timnian pastoral complex during Chalcolithic–early Bronze times, we argue that desertification was a consequence of socio-economic factors (e.g. higher stocking rates) associated with a shift from a subsistence to a market economy. In addition, we contend that the signature lithic artifact variety (tabular scraper) that appeared in great abundance during this period was directly tied to the emergent market economy and its secondary products (wool) in having been used to shear sheep. Moreover, in that these changes took place largely concurrent with local and regionally recognized evidence of a moist interval, we conclude that the mid- to late-Holocene desertification of the southern Levant was induced more by anthropogenic than climatic factors.

Does the recoupling of dairy and crop production via cooperation between farms generate environmental benefits? A case-study approach in Europe

The intensification of agriculture in Europe has contributed significantly to the decline of mixed crop-livestock farms in favour of specialised farms. Specialisation, when accompanied by intensive farming practices, leaves farms poorly equipped to sustainably manage by-products of production, capture beneficial ecological interactions, and adapt in a volatile economic climate. An often proposed solution to overcome these environmental and economic constraints is to recouple crop and livestock production via cooperation between specialised farms. If well-managed, synergies between crop and livestock production beyond farm level have the potential to improve feed and fertiliser autonomy, and pest regulation. However, strategies currently used by farmers to recouple dairy livestock and crop production are poorly documented; there is a need to better assess these strategies using empirical farm data. In this paper, we employed farm surveys to describe, analyse and assess the following strategies: (1) Local exchange of materials among dairy and arable farms; (2) Land renting between dairy and arable farms; (3) Animal exchanges between lowland and mountainous areas; and (4) Industrially mediated transfers of dehydrated fodder. For each strategy, cooperating farm groups were compared to non-cooperating farm groups using indicators of metabolic performance (input autonomy, nutrient cycling and use efficiency), and ecosystem services provision. The results indicate that recoupling of crop and dairy production through farm cooperation gives farmers access to otherwise inaccessible or underutilised local resources such as land, labour, livestock feed or organic nutrients. This in turn leads to additional outlets for by-products (e.g. animal manure). Farmers’ decisions about how to allocate the additional resources accessed via cooperation essentially determine if the farm diversifies, intensifies or expands operations. The key finding is that in three of the four crop-livestock integration strategies assessed, these newly accessed resources facilitated more intensive farming practices (e.g. higher stocking rate or number of milking cows per hectare) on cooperating dairy farms relative to non-cooperating, specialised dairy farms. As a consequence, cooperation was accompanied by limited environmental benefits but helped to improve resource use efficiency per unit of agricultural product produced. This article provides a critical step toward understanding real-world results of crop-livestock cooperation beyond the farm level relative to within-farm crop-livestock integration. As such, it brings practical knowledge of vital importance for policy making to promote sustainable farming.

Description and validation of the Teagasc Lamb Production Model

A stochastic budgetary simulation model of a sheep farm was developed to investigate the effects of changes in lamb production systems on farm profitability. Model inputs included: land, labour, capital, animal numbers, as well as, input and output prices. Model outputs were simulated on a monthly basis and included: flock sales and purchases, net energy demand, grass supply and demand, lamb growth and slaughtering pattern, as well as, land and labour utilization. Grass growth, ewe and lamb mortality, fertiliser and concentrate price along with lamb and mutton price were all included in the model as stochastic variables. Farm earnings before interest and tax and net profit, both including and excluding owner/operator labour, were calculated from total receipts from lamb, culled animals and wool less variable and fixed costs. Validation of the model was undertaken by comparing the model outputs to real farm data recorded on 20 Irish commercial sheep farms as well as comparing the model outputs to those of three individual Irish commercial sheep farms. The model outputs were similar to the real farm data indicating that the model provides a realistic representation of actual farm performance, output and profit. To demonstrate potential application of the model, two lambing date scenarios were investigated; a mid-season lambing flock, with a mean lambing date of March 1st and an early lambing flock, with a mean lambing date of January 1st. Both lambing date scenarios had the same farm area, overall herbage utilization, pregnancy scanning rate and number of lambs weaned per ewe joined to the ram, but the early lambing flock had a higher stocking rate (13.23ewes/ha versus 9.46ewes/ha for March 1st lambing) which increased due to the higher proportion of concentrate in the total flock diet compared with March 1st lambing. The annual return on investment (ROI) of the mid-season lambing flock was 0.95% with a net profit of €11,045 excluding owner/operator labour and management. The early lambing system produced a ROI of −0.70% and a net profit of −€4862. When owner/operator labour and management cost were included the ROI was −0.38% with net profits of −€5462 for March 1st lambing and a ROI of −2.46% and net profits of −€26,735 for January 1st lambing.

How does stocking rate influence horse behaviour, performances and pasture biodiversity in mesophile grasslands?

Reducing grazing intensity is widely recommended as a strategy to increase grassland biodiversity through greater sward heterogeneity. Horses are playing an increasing role in the management of permanent grasslands across Europe, but the effects of horse grazing under contrasting stocking rates have been poorly studied. Here we describe the effects of two contrasted stocking rates (“High” 1.8LUha−1vs. “Moderate” 1.1LUha−1) on sward structure, horse foraging behaviour and performances, and pasture biodiversity in a mesophile grassland of central France. Horses selectively grazed vegetative patches of high nutritive value, especially at the moderate stocking rate (p<0.01). This enabled them to maintain diet quality (diet dry matter digestibility: 59% DM) and performances (daily liveweight gain>270ganimal−1d−1) at the same level in highly and moderately grazed plots despite contrasted herbage biomass and quality. Horses, with their two sets of incisors, created and maintained patches of short grass in a matrix of tall vegetation in both treatments. Consequently, sward structural heterogeneity did not significantly differ between highly and moderately grazed plots, and there was no detectable effect of grazing intensity on floristic and arthropod diversity over the four-year study. The two stocking rates did however result in a divergent evolution of legumes for which abundance increased at the high stocking rate (p<0.05). Abundance of Carabidae and grasshoppers from tall grasslands was higher at the moderate stocking rate (p<0.05). We conclude that decreasing stocking rate would only have a marginal effect on grassland biodiversity, while farm performance will be strongly affected by the decrease in the number of horses per unit area.

Carbon balance of an intensively grazed permanent grassland in southern Belgium

Grasslands are an important component of the global carbon balance, but their carbon storage potential is still highly uncertain. In particular, the impact of weather variability and management practices on grassland carbon budgets need to be assessed. This study investigated the carbon balance of an intensively managed permanent grassland and its uncertainties by drawing together 5 years of eddy covariance measurements and other organic carbon exchanges estimates. The results showed that, despite the high stocking rate and the old age of the pasture, the site acted as a relatively stable carbon sink from year to year, with a 5-year average net biome productivity of −161 [−134 −180]gCm−2yr−1. Lateral organic carbon fluxes were found to increase the carbon sink because of high carbon imports (organic fertilization, feed complements) and low carbon exports in form of meat compared to dairy pastures. The cattle stocking density was adapted to grass production, which itself depends on weather conditions and photosynthesizing area, in order to maintain a steady meat production. This resulted in a coupling between grazing management and weather conditions. As a consequence, both weather and grazing impacts on net ecosystem exchange were difficult to distinguish. Indeed, no correlation was found between weather variables anomalies and net ecosystem exchange anomalies. This coupling could also partly explain the low C budget inter-annual variability. The findings in this study are in agreement with those reported by other studies that have shown that well-managed grasslands could act as carbon sinks.

Cattle stocking rates estimated in temperate intensive grasslands with a spring growth model derived from MODIS NDVI time-series

There is an identified need for high resolution animal stocking rate data in temperate grassland systems. Here is presented a 250m scale characterization of early spring vegetation growth (DOY 32–DOY 120) from 2003 to 2012 based on MODIS NDVI products for this period for Ireland. The average rate of grass growth is determined locally as a simple linear model for each pixel, using only the highest quality data for the period. These decadal spring growth model coefficients, start of season cover and growth rate, are regressed against log of stocking rate (r2=0.75). This model stocking rate is used to map grassland use intensity in Ireland, which, when tested against an independent set of stocking rate data, is shown to be successful with an RMSE error of 0.13 for a range of stocking densities from 0.1 to 3.0 LSU/Ha. This model provides the first validated high resolution approach to mapping stocking rates in intensively managed European grassland systems.

Effect of Stocking Rate on Forage Availability and Growth Performance of Goat Kids in Mediterranean Kermes Oak Shrublands

This study aims to investigate the effect of stocking rate on vegetation cover (VC) and forage mass (FM) of Mediterranean Kermes oak shrublands, and the growth performance of pure hair goat kids ( Capra hircus L.). Two villages that had the same ecological conditions but where the presence of pure hair goats did or did not exceed the grazing capacity were selected specifically within this scope. The birth weight (BW) and the daily live weight gain at 90 days (DLWG at 90 days) of pure hair goat kids in these villages were identified and compared in order to monitor their growth. As a result, there is a very strong positive correlation between the growth performance of goat kids, and VC and FM in these villages (P<0.01). Results indicated that high stocking rate effect forage availability and this situation cause decrease in the growth performance of goat kids. It was concluded that forage availability and stocking rate in grazing plans are points to consider providing sustainable goat farming.

English

This work aimed to evaluate dry matter intake (DMI) and performance of F1 Nellore x Guzera with live weight (LW) of 180±15 kg (5 months) on pastures of Brachiaria brizantha cv. Marandu in silvo-pastoral systems composed of babassu palm (Attalea speciosa) and monoculture systems in Pre-Amazonic region of Maranhao state, Brazil. Animals were evaluated in four systems: 0, 80, 131 and 160 adult palms ha-1, characterizing monoculture (MC), low density (LD), average density (AD) and high density palm trees (HD), respectively, during the rainy (RS) and dry season (DS). Comparing seasons, only DMI in MC and AD were affected. DMI was between 2.6% LW for the RS and 2.8% LW for the DS, These values are very close as suggested by NRC, which is 2.7% LW for animals in this category. Higher average daily gain per ha was observed in animals kept in pastures with LD (0.750 g.day-1 and 84.37 kg.ha-1, respectively). It was observed that animal performance was influenced by density of palm trees and the DMI by season, probably by the sward structure. Animal performance and production forage biomass were higher in 0 and 80 palm systems. This greater forage biomass allow higher stocking rate and, consequently higher animal production per ha. Key words: Silvo-pastoral systems, pasture, season, Guzera, Nelore, matter intake, daily gain.

Grazing intensity effects on soil quality: A spatial analysis of a Mediterranean grassland

Intensive grazing, such as that occurring in the vicinity of animals' shaded concentration points (CPs), causes the degradation of many soil properties, creating patterns as a function of distance from the CPs. The aim of this research is to characterize the spatial patterns of land degradation as a function of grazing intensity, in terms of soil quality, with respect to (1) the distance from CPs; (2) grazing density; and (3) additional environmental variables, in typical Mediterranean grassland, in the eastern Galilee region of Israel. To fulfill this aim, a soil quality index (SQI) was developed based on the integration of 12 physical, biological, and chemical soil properties. Soil properties and quality surface maps were developed by using the spline interpolation technique as a geostatistical analysis on a small spatial scale. In addition, a spatial statistics technique, namely the geographically weighted regression (GWR), was used to measure the effect of different explanatory variables (grazing density, distance from CPs, vegetation cover, aspect, slope, and landscape cover classification) on the SQI. The results show that near the CPs, there is a clear effect of grazing activity on all soil properties and nutrients that can be attributed to a low SQI. Significantly lower soil quality was found around the CPs with moderate and high stocking rates than in the pasture and the control area, where grazing was excluded. Applying the GWR model, using the landscape-cover classification as the explanatory variable for the SQI, provided the best results in the spatial analysis with R2adjusted=0.97. The second and third most influential explanatory variables for the SQI were the distance from the CPs and grazing density, with R2adjusted=0.94 and R2adjusted=0.93, respectively. This outcome demonstrates grazing intensity effects on SQ and its complexity, mainly due to the impact of landscape cover and grazing density. In conclusion, the presented framework was found adequate and could potentially be made operational for assessing SQ under different grazing intensities and degradation stages in a spatial scale.

Increased stocking rate and associated strategic dry-off decision rules reduced the amount of nitrate-N leached under grazing

The effect of intensive agricultural systems on the environment is of increasing global concern, and recent review articles have highlighted the need for sustainable intensification of food production. In grazing dairy systems, the leaching of nitrate-N (NO3-N) to groundwater is a primary environmental concern. A herd-level factor considered by many to be a key contributor to the amount of NO3-N leached from dairy pastures is stocking rate (SR), and some countries have imposed limits to reduce the risk of NO3-N loss to groundwater. The objective of the current experiment was to determine the effect of dairy cow SR on NO3-N leached in a grazing system that did not import feed from off-farm and had the same N fertilizer input. Five SR were evaluated (2.2, 2.7, 3.1, 3.7, and 4.3 cows/ha) in a completely randomized design (i.e., 2 replicates of each SR as independent farmlets) over 2 y. Pasture utilization, milk production/hectare, and days in milk/hectare increased with SR, but days in milk/cow and milk production/cow declined. The concentration of NO3-N in drainage water and the quantity of NO3-N leached/ha per year declined linearly with increasing SR, and the operating profit/kg NO3-N leached per ha increased. Higher SR was associated with fewer days in milk/cow, resulting in a reduction in estimated urine N excretion/cow (the main source of N leaching) during the climatically sensitive period for NO3-N leaching (i.e., late summer to winter). We hypothesized that the reduction in estimated urine N excretion per cow led to an increase in urinary N spread and reduced losses from urine patches. The results presented indicate that lowering SR may not reduce nitrate leaching and highlight the need for a full farm system-level analysis of any management change to determine its effect on productivity and environmental outcomes.

Preliminary observations on effects of using different stocking rates of meat goats to control understory vegetation in longleaf pine stands

The use of goats for clearing longleaf pine (Pinus palustris Mill.) stand undergrowths has potential as an alternative tool to prescribed burning. Objectives of the experiment were to determine the effects of using different stocking rates of meat goats on understory plant biomass height and quantity, understory crown cover density, animal productivity, soil characteristics and damage to pine trees. A 4.86 ha of 8–9 years old longleaf pine stands with 1112 trees/ha was divided into twelve 0.40 ha at Tuskegee, AL. The understudy vegetation contained many volunteer tree species with Broomsedge (Andropogon virginicus L.) being the predominant grass cover. Fifty-four mature Kiko wether goats (initial BW = 48.5 ± 2.5 kg) were allocated randomly to four treatments (0, 3, 6, 9 goats/0.4 ha) with three replications per treatment for 83 days in 2013 according to a completely randomized block design. The data was analyzed using the GLM procedure of SAS. The tree damage was monitored. Results showed that both initial and the final soil bulk density and soil compaction, plant biomass heights and quantity were not significantly different (P > 0.05) among treatments. Average daily BW gains were not significantly different (P = 0.76) but daily gains were close to zero. The combined final crown cover density percent at 2.0 m decreased linearly (P < 0.05) with increasing stocking rates. The tree damage was minimal even at the highest stocking rates. The results suggest that goats have potential to manage understory vegetation under longleaf pines.

Livestock grazing impact on soil wettability and erosion risk in post-fire agricultural lands

Fires in agricultural areas are common, modifying the functioning of agro-ecosystems. Such fires have been extensively studied, and reported to considerably affect soil properties. Yet, understanding of the impact of livestock grazing, or more precisely, trampling, in fire-affected lands is limited. The objective of this study was to assess the impact of low- to moderate-fire severity and livestock trampling (hoof action) on the solid soil's wettability and related properties, and on soil detachment, in burnt vs. non-burnt croplands. The study was implemented by allowing livestock to access plots under high, medium, and low stocking rates in (unintentionally) burnt and non-burnt lands. Also, livestock exclusion plots were assigned as a control treatment. Results showed that fire slightly decreased the soil wettability. At the same time, water drop penetration time (WDPT) was negatively related to the stocking rate, and critical surface tension (CST) was ~13% smaller in the control plots than in the livestock-presence treatments. Also, the results showed that following burning, the resistance of soil to shear decreased by ~70%. Mass of detached material was similar in the control plots of the burnt and non-burnt plots. At the same time, it was three-, eight-, and nine-fold greater in the plots of the burnt×low, burnt×medium, and burnt×high stocking rates, respectively, than in the corresponding non-burnt ones. This study shows that livestock trampling in low- to moderate-intensity fire-affected lands increased the shearing of the ground surface layer. On the one hand, this slightly increased soil wettability. On the other hand, this impact considerably increased risks of soil erosion and land degradation.

English

Desmodium incanum DC., popularly known as pega-pega, is a wide spread leguminous plant in fields in the state of Rio Grande do Sul in Southern Brazil and is well accepted by the cattle as forage. However, its forage potential is currently threatened, due to the replacement of natural grasslands by agricultural crop and grazing lands and because of the poor pasture management associated with high stocking rate, making it necessary to search for alternatives for the preservation of this genetic resource. The aim of this study was to test variations in the composition of culture media in order to optimize the development of in vitro plantlets of D. incanum. The study was divided into three stages: the first test, evaluated different compositions of MS medium, varying concentrations of nutrients, especially macronutrients (MS 50%; MS 50% and macronutrients at 25%; MS 100% and macronutrients at 50%; MS 100% and macronutrients 25%); the 2nd test evaluated different concentrations of MS medium nutrients, especially micronutrients (MS 50%; MS 100% and micronutrient at 50%; MS 50% and micronutrients at 25%); and the 3rd test, in which varying concentrations of IBA (0, 0.5, 1.0 and 1.5 mgL-1) were evaluated. In Test 1, the culture media with components diluted to 50% provided better development for D. incanum in relation to the media with 100% of the components, and MS 50% was the best treatment. In Test 2, the MS medium with 25% of micronutrients and 50% of other components provided the best growth. In Test 3, the species D. incanum responded positively to the addition of IBA with an increase in root development. Key words: In vitro, forage, pampa biome, leguminous plant, mineral nutrition.

Goat pasturing—A biological solution to counteract shrub encroachment on abandoned dry grasslands in Central Europe?

Shrub encroachment is one of the main causes of dry grassland loss in Central Europe. Abandoned semi-natural grasslands are often overgrown by thorny or spiny shrubs. Such unpalatable shrubs have frequently established by selective foraging during periods with low grazing pressure, particularly if sheep herding was performed. Feeding behaviour and diet selection vary between different livestock species and especially browsing goats are increasingly recognized for preventing woody encroachment. However, little is known about the appropriate timing of the grazing regime and the selection of woody species on abandoned dry grasslands already dominated by thorny and spiny shrubs.We quantified the foraging behaviour of Boer goats by direct observation on three encroached paddocks in the lower Saale River valley (Central Germany), which were grazed yearly from spring to autumn with a high stocking rate (0.6–0.8 LU/ha/yr). Feeding activities, the proportion of browsed woody species and identity of the browsed species were recorded in five minute intervals during a total of 30days in spring and 30days in summer/autumn. Dry grassland vegetation and woody coverage were observed on grazed and ungrazed 25-m2 plots for seven years.Contrary to other studies on grazing animals, we found that goats frequently browsed on spiny or thorny shrub species, if these species exhibited a high share of the shrub coverage. Altogether we detected a significant relationship between the abundance of woody species and browsing time on the respective species. The goats tended to spend more time browsing in spring than in summer/autumn. As a result of the browsing activity, we observed a significant decrease of woody coverage within pastures from 69.8% to 37.4% over seven years, which was positively related to the frequency of typical and endangered dry grassland species. An opposite trend was recorded on ungrazed plots.Therefore, goat pasturing with high-stocking rates and an early start in spring can be an efficient method for improving shrub-encroached dry grasslands during the restoration phase.

Sward structure and nutritive value of Alexandergrass fertilized with nitrogen.

This experiment evaluated forage production, sward structure, stocking rate, weight gain per area and nutritive value of forage as grazed by beef heifers on Alexandergrass (Urochloa plantaginea (Link) Hitch) pasture fertilized with nitrogen (N): 0; 100; 200 or 300 kg of N/ha. The experiment was a completely randomized design following a repeated measurement arrangement. The experimental animals were Angus heifers with initial age and weight of 15 months and 241.5±5 kg, respectively. The grazing method was continuous, with put-and-take stocking. N utilization, regardless of the level, increase by 25% the daily forage accumulation rate and the weight gain per area by 23%. The level of 97.2 kg N/ha leads to a higher leaf blade mass and increases by 20% the leaf:stem ratio. Alterations in sward structure changes the nutritive value of forage as grazed. The utilization of 112.7 kg of N/ha allows the highest stocking rate (2049.8 kg of BW/ha), equivalent to 7.5 heifers per hectare.

Productive responses of breeding Cashmere goats and their kids to different stocking rates on improved upland pastures.

Although goat meat production could be an option for diversification in improved upland pastures in northern Spain, precise information on the optimal grazing management to enhance goat performance and maximize production per unit land area is lacking. The objective of this study was to compare the effects of 3 stocking rates, high stocking rate (HSR; 20 goats/ha), medium stocking rate (MSR; 15 goats/ha), and low stocking rate (LSR; 10 goats/ha), on gastrointestinal (GI) nematode infections and productive responses of Cashmere goats grazing such pastures. Treatments were replicated twice on 6 paddocks sown with and and with a high presence of the native grass . The experiment lasted 3 grazing seasons (from spring to autumn). Pastures were sampled for sward height and botanical and proximate composition. Body weight and BCS changes of goats were monitored and GI nematode infections were assessed by fecal egg counts (FEC). The established treatments resulted in lower mean sward height in the HSR than in the MSR and LSR (9.6, 11.5, and 14.4 cm, respectively; < 0.001). Pasture botanical composition and nutritive quality did not differ between treatments. The mean FEC of does across the 3 grazing seasons were greater ( < 0.05) in the HSR than in the LSR. spp., , and were the most prevalent nematode species identified in coprocultures. Does showed more favorable ( < 0.001) BW and BCS changes in the LSR than in the MSR and HSR (-14, -30, and -52 g/d and -0.1, -0.3, and -0.7 BCS units [scale 1 to 5], respectively). Greater ( < 0.001) kids' BW gains were observed in the LSR and MSR (average 94 g/d) compared with the HSR (70 g/d). Inversely, kid output per unit land area was greater in the HSR than in the MSR and LSR (320, 258, and 192 kg∙ha∙yr, respectively; < 0.001), whereas daily kids' BW gains per hectare were greater ( < 0.001) in the HSR and MSR (average 1.37 kg∙d∙ha) compared with the LSR (0.98 kg∙d∙ha). A medium stocking rate of 15 goats/ha could represent the best compromise between animal health, performance, and productivity per unit land area in this type of upland pastures, but stricter controls of parasite levels during the grazing season would be necessary to avoid production losses, unless alternative nutraceuticals are provided.

Animal performance and sward characteristics of two cultivars of Brachiaria brizantha (BRS Paiaguás and BRS Piatã)

The objective of the present study was to evaluate live weight gain per animal and per area and its relationship with the characteristics of pastures of Brachiaria brizantha cv. Paiaguas and Piata. A randomized blocks experimental design was used, with two treatments and six replicates. The experimental area was 8.0 ha, divided into twelve paddocks of 0.67 ha. The grazing method used was continuous stocking, with variable stocking rate. Three tester steers were used per paddock. Sward heights were measured once a week, and the stocking rate (SR) was adjusted using regulator steers to maintain the sward height at 30 cm. Pasture samples were collected once a month, and herbage accumulation rate (HAR), percentage of leaves (PL), leaf:stem ratio (LSR), and nutritive value (NV) were determined. Animals were weighed every 28 days. No differences between the two cultivars were observed during the wet season for any of the evaluated parameters. However, cv. Paiaguas presented higher HAR and, consequently, higher SR than cv. Piata during the dry season. As a result of its higher regrowth, cv. Paiaguas pastures presented significantly higher PL, LSR, and NV and, consequently, significantly higher average daily live weight gain. These differences resulted in higher live weight gain per area for Paiaguas grass (695 kg/ha per year) than for Piata grass (645 kg/ha per year). Thus, Brachiaria brizantha cv. Paiaguas is a good alternative to decrease the temporary forage shortage and for the diversification of pastures in the Cerrado biome region.

Impact of stocking rate on species diversity and composition of a subtropical grassland in Argentina

AbstractQuestionsWhat is the effect of a range of controlled stocking rates on plant species richness and diversity?LocationSubtropical grasslands of Corrientes, Argentina, South America.MethodsWe studied the effect of three controlled stocking rates (0.6, 0.8 and 1.0 cow equivalents·ha−1) on species diversity and composition during 8 yr. We calculated species diversity using the antilog of the Shannon‐Wiener index, and considered its two components, richness and evenness. We also assessed the proportion of prostrate and erect species. Species abundance was based on biomass estimations.ResultsSpecies diversity under high stocking rates gradually decreased throughout the experiment and became nearly 50% lower than under low stocking rate. This decline was largely accounted for by changes of evenness because species richness was not affected by stocking rates. Species composition clearly diverged among the three treatments over time. Low stocking rate maintained a fairly constant relative cover of erect and prostrate grasses throughout the experiment, whereas intermediate and high stocking rate treatments were gradually and consistently enriched in prostrate grasses and forbs. These effects occurred simultaneously with drastic inter‐annual changes likely driven by annual precipitation.ConclusionsThe range of stocking rates had no effect on species richness, but reduced diversity through the effect on evenness. High stocking rate progressively increased the proportion of prostrate species in the biomass.

052 Effects of stocking rate, forage management, and grazing management on performance and economics of cow-calf production in Southwest Arkansas

The objectives of this research were to determine the impacts of grazing management practices, including rotational grazing, stockpiling bermudagrass, and cool-season annual grasses on productivity and economics of spring calving cows (n = 72/yr, BW = 547 ± 33.2 kg) grazing bermudagrass pastures (n = 9, 4.7 ha). Treatments included: CG - low intensity management with continuous grazing at a moderate stocking rate (SR, 0.8 ha/cow); MR - intensive management at moderate SR (0.8 ha/cow); HR – intensive management with high stocking rates (0.4 ha/cow). Stockpiling in MR and HR was managed by fertilization of 0.2 ha/cow of bermudagrass in early August with 168 kg ammonium nitrate and deferring grazing until November. Wheat (112 kg/ha) and annual ryegrass (28 kg/ha) were established (0.2 ha/cow) in HR and MR by interseeding with a no-till drill in the fall. Cow and calf performance and economics data were analyzed by ANOVA using the mixed procedure of SAS (SAS Inst. Inc., Cary, NC) and pregnancy percentage was analyzed using GLIMMIX, pasture was the experimental unit and year the random block. Hay feeding days decreased (P < 0.01) from 106 ± 10.9 d for CG to 37 ± 10.9 d for HR which was further reduced (P = 0.01) to 15 ± 10.9 d for MR. Pregnancy percentage tended (P = 0.08) to be greater for HR (88 ± 3.5%) than MR (80 ± 4.6%) and CG (78 ± 4.7%) which did not differ (P = 0.74). Weaning weights in CG (238 ± 7.4 kg) tended (P = 0.09) to be greater than MR (228 ± 7.4 kg) and were greater (P < 0.01) than HR (220 ± 6.8 kg). However, total weaning weight per hectare was 89% greater (P < 0.01) for HR compared with CG and MR, which did not differ (P = 0.31). With rotational stocking there was the opportunity to harvest excess forage as hay in both MR and HR with a net value of $52.90/ha and $15.50/ha ± 6.99, respectively. Net returns per hectare did not differ (P = 0.39) between CG ($536 ± 65.82/ha) and MR (641.70 ± 65.82/ha), but were increased (P< 0.01) by 107% by HR ($1,221.29 ± 65.82/ha). Using rotational grazing, stockpiled bermudagrass, and complementary cool-season annual grasses can drastically reduce winter feed requirements and simultaneously increase carrying capacity and net return.