Grazing Strategies Research Articles

Targeted Grazing of an Invasive Grass Improves Outcomes for Native Plant Communities and Wildlife Habitat

Rangelands provide ecosystem services that are economically and ecologically critical for humans. Globally, invasion of exotic grasses drives loss of biodiversity and resilience of rangelands. In South Texas, buffelgrass (Cenchrus ciliaris syn. Pennisetum ciliare [L.] Link), a C4 perennial grass, was brought from Africa for range improvement as early as the 1930s. Buffelgrass generally increases forage biomass for livestock yet reduces habitat suitability for wildlife. Interest in controlling buffelgrass has increased due to its negative impacts on iconic wildlife, such as whitetailed deer (Odocoileus virginianus, Zimmermann 1780) and northern bobwhite (Colinus virginianus, Linnaeus 1758). The objective of this study was to evaluate the effect of a targeted grazing strategy that used buffelgrass and plant community phenology as indicators to determine the timing of cattle movement. On two private ranches in different ecoregions, we tracked targeted grazing versus light grazing in native-dominated and buffelgrass-dominated plant communities across variable precipitation through five growing seasons. We measured the effects of grazing type, plant community type, and precipitation on buffelgrass cover, native plant species richness, foliar cover, and Shannon diversity. Targeted grazing had a strong impact on diversity, increasing 0.37 ± 0.07 from a mean of H = 1.29 under the targeted grazing management. Conversely, buffelgrass cover was negatively correlated with Shannon diversity, decreasing it by 0.075 ± 0.03 for every 10% increase in buffelgrass cover from a mean of H = 1.29. Despite a variability in precipitation across seasons and years (93−455 mm), targeted grazing improved species richness and cover of native plants throughout the study. Our findings suggest that targeted grazing shows promise as an adaptive grazing strategy that reduces the impact of buffelgrass across highly variable precipitation. In unpredictable environments, management techniques that improve the resilience of plant communities through preserving biodiversity are critical.

PSX-15 Fall grazing of annual forages with fall born lambs may improve animal growth and total protein concentrations when compared to stockpiled pastures

Abstract There is a consistent demand for grass-fed livestock products in the domestic market. Alternative grazing strategies should be considered to sustain the year-round production of grass-fed products that meet consumer demand and support animal health and performance. The objective of this study was to evaluate the effect of annual forages on the growth and parasite resilience of growing lambs. We hypothesized that lambs grazing annual forages would increase their body weight at a greater rate when compared to lambs grazing stockpiled pasture. A total of 54, 60-day-old lambs (24 kg ± 4.9 kg) were stratified by weight, sex, and randomly assigned to one of three grazing treatments: 1) oats (O); 2) turnips (T); and 3) stockpiled tall fescue pasture (F). Lamb body weight and indices of parasitism were measured every 14 days. Data were analyzed using PROC MIXED in SAS. There was a treatment × day effect for body weight such that T lambs were heavier on days 42 and 56 than O and F lambs (P < 0.03). Furthermore, there was a treatment × day effect for average daily gain (ADG) whereas T lambs had a greater ADG on days 28 and 42 than O and F lambs (P < 0.0001). In addition, on day 42, F lambs had a greater ADG when compared to O lambs (P < 0.003). For the indices of parasitism, T lambs demonstrated lesser total plasma protein concentration on days 28 and 42 when compared with O lambs (P < 0.05). Forage type plays a critical role in lamb resilience to gastrointestinal parasites and body weight gain whereas T lambs showed a greater liveweight gain. However, T lambs also demonstrated lesser concentrations of total plasma protein when compared to O lambs. Under these conditions, annual forages adequately sustained the growth of fall grazing lambs.

187 Utilizing Working Groups to Provide Hands-On Learning Opportunities for Experienced Beef Cattle Producers

Abstract The Systems 360° Working Group program was created for experienced beef cattle producers who desired to learn more about timely topics related to beef cattle production than could be covered in a single night meeting. To aid in developing these working groups, the Alabama Extension Animal Science and Forages Team developed curriculum regarding grazing management, watering systems, marketing, handling facilities, and animal management. Regional animal science and forages agents then coordinated planned visits to producer farms and Auburn University research centers that highlighted specific management practices surrounding these topics, and facilitated group discussion at those sites to encourage peer-to-peer learning experiences. A working group consisted of beef cattle producers (n = 10–25 participants per group) sharing a common interest in learning more in-depth about strategies to improve their respective operations. Four working groups were organized in different regions of Alabama and met five times throughout 2018–2019. The closing survey (n = 50 responses) for the working groups indicated that 100% of participants felt this program met expectations, and given the opportunity they would join another working group. Overall, 94% of respondents indicated that they planned to adopt one of more of the management practices discussed in the group in the next 12 months. Top practices that producers planned to implement included improved winter grazing strategies, rotational stocking, water resource management and testing, and facilities design/animal handling. Producers indicated that they learned the most from farm-visits and speakers/discussion leaders as part of the program. Participants reported that knowledge gained from this program could potentially lead to a total farm economic impact averaging $6,095 per operation. These data indicate that Systems Working Groups are an effective means to disseminate knowledge, engage producers in peer-based learning opportunities and improve herd profitability among experienced beef cattle producers.

Effects of long-term removal of sheep-grazing in a series of British upland plant communities: Insights from plant species composition and traits

Environmental and management pressures are considered a threat for preserving plant communities worldwide. Identification of long-term impacts of changing management practices on plant community composition must, therefore, be a major priority to ensure improvement in conservation value. Land abandonment/wilding is one topical area where there is little available information on long-term impacts. To address this, here, we describe plant species compositional change over relatively long-time scales in a range of four British upland communities (high-level grasslands, intermediate grasslands, blanket bogs and high-level bogs) and its relationships with a series of life-history and plant trait variables. Our aims were to determine whether the business-as-usual sheep grazing practice was maintaining these communities, and if grazing was to be removed as part of abandonment/wilding strategies, would there be a conservation benefit. We used a series of long-term experimental grazing-exclosure studies at twelve sites (>40 years) on the Moor House National Nature Reserve in northern England. Each site consisted of paired plots; i.e. sheep-grazed versus ungrazed. Our results showed that there was relatively little change in dominant plant species with most change occurring within sub-dominant species. Similarly, different temporal responses in plant species richness were detected between the experiments (richness was reduced in three experiments, only one increased). In any case, the vegetation temporal trajectories were moving in similar direction in grazed and ungrazed plots at most sites. Interestingly, blanket bog experiments showed a clear compositional convergence for both grazed and ungrazed plots, although, the between-site differences related to a combination of elevation and past burning testament. Finally, the bryophytes (especially liverworts) and lichens were the groups that contributed most to the reductions in species richness. Moreover, implementation of a no-stock grazing strategy under a land abandonment/wilding approach will not bring about much plant change in the short-term in the plant communities studied here.

Continuous grazing of mixed native warm‐season grass in the fescue belt

AbstractContinuous, season‐long (May–August) grazing is the most commonly used grazing strategy among tall fescue [Lolium arundinaceum (Schreb.) Darbysh.] belt beef (Bos taurus) producers. However, little information is available regarding the feasibility of managing native warm‐season grass (NWSG) pastures in this region with continuous, season‐long grazing. We compared stand sustainability, beef cattle performance, and pasture production between continuous (CONT), season‐long grazing and heavy‐early (HEAVY), a modified continuous grazing strategy, on mixed‐NWSG pastures. Heavy‐early was designed to match the growth curve of NWSG, with an initial stocking target of 1.25 times the CONT density until 25 June, at which time stocking was reduced to 0.75 times the CONT density. Pastures were mixed big bluestem (Andropogon gerardii Vitman), indiangrass [Sorghastrum nutans (L.) Nash], and little bluestem [Schizachyrium scoparium (Michx.)]. The plant population (plants m−2) was similar between treatments, but years differed (P < .001), with a 35% reduction from 2017, the third and final year of grazing, to 2018. Despite the decline in plant density, overall tiller density (tillers m−2) increased 14%, indicating that the grazing strategies were likely sustainable. The grazing strategies had similar (P > .05) average daily gain (ADG; kg d−1), animal‐days ha−1, and total gain (kg ha−1). Weaned steer ADG was 0.98 kg d−1 for CONT and 0.89 kg d−1 for HEAVY. Total gain was 379 kg ha−1 for CONT and 334 kg ha−1 for HEAVY. Continuous grazing appears to be an appropriate strategy for managing NWSG pastures in the Fescue Belt.

Microbiological assessment of sheep lymph nodes with lymphadenitis found during post-mortem examination of slaughtered sheep: implications for veterinary-sanitary meat control

BackgroundMicrobiological examination of lesions found in slaughtered animals during meat inspection is an important part of public health protection as such lesions may be due to zoonotic agents that can be transmitted by meat. Examination of inflamed lymph nodes also plays a particular important role, as lymphadenitis may reflect a more widespread infection. Such lesions in sheep are mainly caused by pyogenic bacteria but also mycobacteria are occasionally found. Meat inspection data from 2017 to 2018 from southern Poland, especially from the Małopolska region, indicate that purulent or caseous lymphadenitis involving the mediastinal and tracheobronchial lymph nodes (MTLNs) is a common finding. The primary aim of the current study was to determine the aetiology of these lesions. Furthermore, it was investigated how presence of lesions was correlated with age and grazing strategy of affected sheep.ResultsPost-mortem examination revealed purulent or caseous lymphadenitis in the MTLNs of 49 out of 284 animals (17.3%). Subsequent microbiological examination revealed the presence of Corynebacterium pseudotuberculosis (34.7%), Streptococcus dysgalactiae subsp. equisimilis (34.7%), Staphylococcus aureus (8.2%), Enterococcus spp. (2.0%), Trueperella pyogenes (2.0%), and β-haemolytic strains of Escherichia coli (2.0%). Mycobacterium spp. and Rhodococcus equi were not detected. In older sheep, the probability of the presence of purulent or caseous lymphadenitis was higher than in younger, and the risk was increasing by 1.5% with each month of life. Sheep grazing locally had 4.5-times greater risk of having purulent or caseous lymphadenitis than individuals summer grazing in the mountains.ConclusionThe most common aetiological agents of purulent or caseous lymphadenitis in the MTLNs of sheep in the Małopolska region were C. pseudotuberculosis and S. dysgalactiae subsp. equisimilis. Particular attention during post-mortem examination should be paid to the carcasses of older sheep and sheep grazing on permanent pastures, as they seem more prone to develop purulent or caseous lymphadenitis.

Comparative genomics of the sheep Tas2r repertoire to cattle, goat, human, dog, and mice

Type two taste receptors (Tas2r) are the only taste receptors that distinguish bitter-tasting compounds. Human Tas2r genes have been extensively studied and have been associated with dietary preferences, health, substance dependence, and other diseases. Sheep are an important livestock species known for grazing vast rangelands with variable ecology and plant communities. However, the limited work related to Tas2r gene repertoires in the reference genomes of grazing animals creates a challenge for understanding how these genes influence diet selection preferences. Tas2r genes typically cluster on two regions of the genome. In the second cluster of the sheep (OAR_rambouillet_1.0), goat (ARS1), and cattle (ARS-UCD1.2) reference genomes, there are six, nine, and two Tas2r genes that were not annotated, respectively. Comparative genomic strategies were used to cross-reference sheep Tas2r genes in cattle, goat, human, dog, and mice for the proposed annotations. A nucleotide similarity comparison of the whole Tas2r repertoires for the three grazing species suggested that goat and cattle are similar to sheep (≥ 95.5% and ≥ 91.9% similarity, respectively). Several Tas2r genes found in sheep, cattle, and goat are likely not found in human, dog, or mice and may be reserved to ruminants or animals of similar feeding ecology. Using a comparative genomics approach, this paper proposes annotations for sheep, cattle, and goat Tas2r genes. Further research is needed to better understand how Tas2r genes may influence diet selection in grazing ruminant species, which could provide more insight into management of western rangelands through grazing strategies.

Holistic perspectives—Understanding rancher experiences with holistic resource management to bridge the gap between rancher and researcher perspectives

On the Ground • Holistic Resource Management (HRM) is a ranch management strategy plagued by controversy; experimental evidence from ecological studies has consistently failed to support that HRM provides ecological benefits, yet many ranchers staunchly support the method. • Using a qualitative approach, we found that the HRM processes used on four case study ranches in eastern Colorado provided a systematic framework for key ranch stakeholders to improve long-term, adaptive approaches to managing ranches as complex socioecological systems. • Notably, the ranchers emphasized the planning benefits of HRM over the grazing benefits, suggesting the value of the system is not in how the cattle are grazed but in how it changes the way ranchers make decisions about how to graze their cattle and manage the many other complexities of operating a ranch. • Approaching HRM as a planning framework versus as a grazing strategy may be a key factor in the difference in claims between ranchers practicing HRM and researchers studying grazing systems.

A global meta-analysis of grazing effects on plant richness

A major challenge in rangeland ecology is understanding diverse responses of diversity to grazing, what factors determine these responses and what their relative importance is. Numerous site-level studies have explored grazing-diversity relations, but meta-analyses of these empirical results at a global scale are scarce. Our goals were to estimate the mean effect of grazing on plant richness and to assess the relative importance of different variables at a global scale. We conducted a global meta-analysis of 259 comparisons of plant richness in grazed vs. ungrazed sites from 96 published studies. Then, we performed analyses of subgroup, meta-regression and correlation for testing the relative roles of regional and local variables (e.g. evolutionary history of grazing, aridity, stocking rate, etc.).Globally, grazing significantly increased plant richness compared to grazing exclusion, especially in wet grasslands. The effect of evolutionary history of grazing was insignificant, which cannot support the major perception behind Milchunas-Sala-Lauenroth (MSL) model. Aridity, vegetation type, and stocking rate were three important variables that together explained 41 % of the global variation in plant richness. The roles of stocking rate and duration of grazing exclusion were revealed only when aridity and vegetation type were added to the analyses, which showed a stronger effect of stocking rate in wet areas but a stronger effect of the duration of grazing exclusion in dry areas. Changes in plant richness were significantly correlated with changes in soil carbon and nitrogen, both showing hump-shaped patterns.Our findings substantiate that scholars may improve existing theories (e.g. the MSL model, the intermediate disturbance hypothesis) through further expounding the interactions between grazing variables and aridity and vegetation type. Rangeland managers need to devise local-scale grazing strategies for conserving plant diversity according to site-specific conditions, rather than adopting a one-size-fits-all solution.

Rangeland Grazing Strategies to Lower the Dependency on Imported Concentrates in Norwegian Sheep Meat Production

Norway has vast rangeland resources (292,361 km2) with an estimated carrying capacity of nearly four million sheep and lambs, twice the current number. However, the intensive production system currently applied has led to more concentrate dependency, resulting in heavier animals in addition to poorer utilization of rangelands and homegrown feed. Intensive feeding systems indirectly influence the sustainability of ecosystems by promoting intensive cropping that can deplete soil fertility and threaten landscape preservation and biodiversity. By contrast, extensive grazing systems can produce environmentally and animal-friendly food products and contribute to regulating soil health, water and nutrient cycling, soil carbon sequestration, and recreational environments. In this paper, the economics of current sheep feeding practices in Norway, using a linear programming model, were compared with more extensive systems which allow for higher usage of on-farm feed resources. Changes in current sheep farming practices have the potential to increase lamb meat production relative to mutton production, in addition to improving the year-round supply of fresh meat. The investigated alternatives, using the Norwegian White Sheep (NWS) breed, suggest that delayed lambing is useful only on farms with abundant pastures available for autumn feeding. Lambs achieve a better market price than hoggets and mature sheep. Therefore, based on the current Norwegian meat market and price offered per kilogram of meat for lamb, an increase in NWS lamb production improves farm profits. On the other hand, when the aim is on greater use of homegrown feed and rangelands, this can be achieved through hogget production, and the quantity of concentrates required can be reduced substantially.

Warm- and cold- season grazing affect plant diversity and soil carbon and nitrogen sequestration differently in Tibetan alpine swamp meadows

Seasonal grazing is a traditional grassland management practice in alpine swamp meadows on the Tibetan Plateau, but little information is available on the interactions between plant diversity and soil carbon and nitrogen sequestration in warm- and cold- season grazed alpine swamp meadows. A multisite survey was conducted to investigate the plant characteristics and soil properties of Tibetan alpine swamp meadows under warm-season grazing (WG) and cold-season grazing (CG). Our study showed that plant biomass, litter mass, soil water content (SW), soil available nitrogen, soil microbial biomass carbon and nitrogen were significantly lower in the WG meadows than in the CG meadows (P < 0.05). However, plant diversity, species richness and the evenness index tended to increase in the WG meadows. Soil C and N storage were significantly lower in the WG meadows than in the CG meadows (P < 0.01). Grazing-induced changes in SW, plant diversity, plant biomass and litter mass were the major factors resulting in the decrease in soil C and N storage. Our results indicate that warm-season grazing is beneficial for species diversity conservation, whereas cold-season grazing is suitable for soil C and N sequestration in alpine swamp meadows. Grazing-induced changes in litter mass greatly contributed to variations in plant diversity and soil C and N storage. In view of the accelerated vegetation and soil degradation in alpine grasslands, periodic warm- and cold-season grazing strategies should be considered to maintain alpine swamp meadow sustainability.

Modeling rangelands as spatially-explicit complex adaptive systems

Rangelands cover one third of the earth's land area, provide livelihoods for one billion persons, and most have been degraded by overgrazing of domestic livestock. Recent debate about best management practices often has centered on comparison of continuous grazing and rotational grazing. Resolution to this debate may lie in viewing rangelands as complex adaptive systems. We describe a spatially-structured, individual-based model of rangelands that embodies this perspective, and simulate forage dynamics and cattle production under semi-arid rangeland conditions typical of the southern Great Plains of the USA employing both continuous and rotational grazing. Relative “success” of simulated grazing schemes depended primarily on the evaluation metric used (e.g., rangeland ecological condition, sale weight of cattle, secondary production efficiency) and the particular manage scheme employed, and neither continuous nor rotational grazing schemes were uniformly more successful. Our results demonstrate that solution of the grazing systems debate is unlikely to be found in a single group of grazing schemes, but, rather, in adaptive management of feedbacks among system components. The present work provides an example of how modeling rangelands as complex adaptive systems can aid in the evaluation of management schemes.

Maximizing Lucerne (Medicago sativa) Pasture Intake of Dairy Cows: 1-the Effect of Pre-Grazing Pasture Height and Mixed Ration Level.

The effect of lucerne (Medicago sativa L.) pre-grazing pasture height on pasture intake and milk production was investigated in a sub-tropical partial mixed ration (PMR) dairy system in south-east Queensland, Australia. The experiment involved a 26-day adaptation period followed by an eight-day measurement period during April and May 2018. Twenty-four multiparous Holstein-Friesian dairy cows were offered a mixed ration at either 7 (low) or 14 (high) kg dry matter (DM)/cow/day and allocated pastures at pre-grazing heights ranging from 23 to 39 cm. The targeted pasture intake was 14 and 7 kg DM/cow/day for cows offered the low and high mixed ration allowances respectively, with a total intake target of 21 kg DM/cow/day. Pasture structure did not limit pasture intake as the all groups left at least 12% of the allocated area ungrazed, and therefore could selectively graze pasture. There was no significant difference in intake between mixed ration levels, however intake had a positive linear relationship with pre-grazing pasture height. For every one cm increase in pasture height, intake increased by 0.3 kg DM/cow/day. Using a grazing strategy that ensures the some pasture remains ungrazed and the pre-grazing height of lucerne is approximately 39 cm above ground level will maximise pasture intake in sub-tropical PMR dairy systems.

Mob and rotational grazing influence pasture biomass, nutritive value, and species composition

AbstractMob grazing, which uses very high stocking densities for short durations followed by a relatively long rest period, was designed to mimic bison (Bison bison) grazing in western U.S. grassland. This project assessed the suitability of mob grazing for livestock production in the Northeast. Objectives were to compare the effects of mob and rotational grazing on dry matter (DM) mass, nutritive value, and botanical composition across four grazing seasons. Eight, 0.10‐ha paddocks were established in 2014 as a randomized complete block with four replications, and seeded with alfalfa (Medicago sativa L.), white clover (Trifolium repens L.), orchardgrass (Dactylis glomerata L.), narrowleaf plantain (Plantago lanceolata L.), and tall fescue [Schedonorus arundinaceus (Schreb.) Dumort]. Mob‐grazed (MOB) paddocks were grazed by yearling beef cattle twice each year, (70–90–day interval), and rotationally grazed (ROT) paddocks were grazed four to six times each year (when sward height reached 25 cm). Cumulative pre‐grazing forage biomass (PGFM) of ROT was greater than MOB in three of four years. At the final grazing, the PGFM of ROT exceeded MOB by 2,500 kg ha−1. Within year, PGFM of ROT was more consistent, varying by only 1,000–1,400 kg DM ha−1 compared with 1,800–2,800 kg DM ha−1 for MOB. Grazing strategy altered botanical composition; ROT favored grasses while MOB favored alfalfa. Forage fiber content was consistently lower in ROT than MOB paddocks, indicating superior nutritive value. Results suggest rotational grazing is likely suitable for more consistent forage production of greater nutritive value in temperate, cool‐season grass‐legume pastures of the northeastern United States.

Animal performance and sward characteristics of Mombaça guineagrass pastures subjected to two grazing frequencies

The aim of this work was to compare grazing management practices of Mombaça guineagrass (Megathyrsus maximus syn. Panicum maximum cv. Mombaça) based on the sward incident light interception (LI) concept. We tested, when the regrowth period in rotationally stocked Mombaça guineagrass ended, if LI (90 or 95%) affected forage accumulation, sward characteristics and animal performance. Both treatments had a common post-grazing canopy height of 50 cm and were replicated 4 times in a randomized complete block design. Pastures were sampled pre- and post-grazing to determine forage mass, morphological composition and forage accumulation rate (FAR). Nutritive value (NV) was estimated in pre-grazing samples. Stocking rate was adjusted twice a week, and animals were weighed every 28 days. Pre-grazing conditions of 90 and 95% LI were reached at pasture heights of approximately 80 and 90 cm, respectively. FAR, sward structure and NV were similar for pastures grazed at 90 and 95% LI. Consequently, stocking rate, average daily gain and liveweight gain/ha were similar for both LI treatments. Data suggest that Mombaça guineagrass can be grazed at pre-grazing heights of 80–90 cm (90–95% LI) without compromising pasture structure and animal performance provided moderate defoliation severity is employed. Further testing of this grazing strategy over longer periods should be carried out with this species as well as other tropical grasses.

Foraging Behavior of Goats Browsing in Southern Mediterranean Forest Rangeland.

Simple SummaryGrazing goats in forests is an ancestral practice in the Mediterranean region. This study aims to assess the seasonal variations in the feeding behavior of goats browsing in the Mediterranean forest rangeland of Northern Morocco for two years. The goats’ diet was largely composed of woody species. Overall, the smaller the bite mass, the higher the biting rate, leading to an increased instantaneous intake rate. During the dry season, goats tend to compensate for the low intake rate by extending daily grazing time, thus reducing the sensitivity of intake rates to forage availability. A particular high selection of cork oak was observed over seasons. The higher diet diversity was recorded during summer and fall compared to the spring. Nevertheless, it should be remembered that the diet selection of goats is ultimately influenced by the herder’s decisions. Results confirm the high adaptability of goats to the seasonality of complex Moroccan forest rangelands.Mediterranean forest rangelands offer an important feed source for goats. Concerns about grazing strategies and management schemes in order to ensure the rangeland sustainability of Southern Mediterranean forest have revived interest in the foraging behavior of goats. This study was conducted to investigate the seasonal changes of feeding behavior of grazing goats in the Southern Mediterranean forest rangeland of Northern Morocco during two consecutive years beginning in 2016. The direct observation method was used to compare diet composition, intake rate, and diet selectivity of goats during three seasons (spring, summer, and fall). Bite mass of each plant species selected by goats was estimated using hand-plucked simulation. The optimal foraging theory was used as a tool to explain the goats foraging decisions. Bite mass range was extremely wide and varied seasonally. The goats’ diet was largely composed of Cistus spp., Lavandula stoechas, Quercus spp., and Myrtus communis. The result shows that the smaller the bite mass, the higher the biting rate, leading to increased short term intake rates. The selection of various plant species during fall and summer enlarged the diet diversity of goats. As expected, goats preferred trees and some shrubs despite their low availability. Consequently, the most available species is not necessarily the most positively selected. Particular high and positive selection of Quercus suber was observed over seasons. The outcomes confirm the high adaptability and ability of goats to select a woody species across seasons. Knowledge about forage availability and the feeding behavior of goats could be used as the first guide for rangeland managers to ensure herd and forest sustainability.

Estratégias de manejo do pastejo para capim-xaraés (Brachiaria brizantha cv. Xaraés)

Objetivou-se com este estudo, avaliar os efeitos de duas estratégias de pastejo intermitente, com 24 dias fixos de descanso e com 95% de interceptação luminosa em capim-xaraés. Para a avaliação das características produtivas, estruturais e bromatológicas foi utilizado o delineamento inteiramente casualizado com medidas repetidas no tempo, com quatro ciclos de pastejo e duas estratégias de pastejo. Para o consumo dos animais foi utilizado o delineamento inteiramente casualizado em arranjo fatorial 2 x 3, sendo duas estratégias de pastejo e três dias de ocupação, e para a taxa de lotação utilizou-se o arranjo 2 x 4 (duas estratégias e quatro ciclos de pastejo). Não houve efeito para as variáveis: disponibilidade, estrutura e composição bromatológica da forragem, com exceção para interceptação luminosa e proteína bruta, onde o tratamento com IL obteve maior valor de interceptação luminosa (2,73% superior que o DF) e menor teor de PB (1,08% inferior ao tratamento DF). Para o consumo de matéria seca houve efeito (P

Dairy farming system markers: The correlation of forage and milk fatty acid profiles from organic, pasture and conventional systems in the Netherlands

The relationships between the fatty acid (FA) composition in forage and milk (F&M) from different dairy systems were investigated. Eighty milk samples and 91 forage samples were collected from 40 farms (19 organic, 11 pasture and 10 conventional) in the Netherlands, during winter and summer. The FA profiles of F&M samples were measured with gas chromatography. The results showed that the F&M of organic farms were significantly differentiated from the F&M of other farms, both in summer and winter. The differences are likely due to the different grazing strategies in summer and different forage composition in winter. The Pearson’s correlation results showed the specific relationship between individual FAs in forages and related milk. A PLS-DA model was applied to classify all milks samples, resulting in 87.5% and 83.3% correct classifications of training set and validation set.

放牧管理模式对高寒草甸鼢鼠鼠丘群落演替的影响

放牧管理模式对高寒草甸鼢鼠鼠丘群落演替的影响

Understanding breeding preferences among small-scale cattle producers: implications for livestock improvement programmes

Livestock production provides a pathway for improving livelihoods and reducing poverty in semi-arid tropical regions. However, this contribution has been affected by low livestock productivity. Most livestock programmes have also failed due to, among other things, the inability to understand the dynamics in smallholder breeding preferences. Using data from the sub-humid region in Zimbabwe, this paper sought to provide evidence on smallholder cattle breeding preferences and the implication on livestock improvement programmes. It applies the choice experiment approach to model farmer preferences for selected cattle breeding attributes. The results show three attributes that significantly affect breeding preferences. The attributes ‘cow body condition score’ and the ‘useful life of a bull/semen’ have a positive influence while ‘artificial insemination/bull maintenance cost’ negatively affects farmer preferences. This means farmers prefer breeding strategies which improve the nutrition of their cows, have a longer lifespan for the bull/semen and whose cost of breeding services is low. However, access to education and income affected these preferences. Education made farmers to make informed choices while higher incomes increased the propensity of investing in livestock breeding technologies. The findings also show that existing institutional arrangements in animal management and community grazing do not promote investment in livestock improvement. Thus, more attention should be given to improving animal nutritional management which includes promoting sustainable grazing schemes. There is also a need to provide affordable livestock breeding services through recruiting and training more artificial insemination service providers. Strong and effective institutions that provide incentives for collective participation are integral to any community-based livestock breeding programme. There is also a need to promote access to information and enhance farmers’ knowledge and capacity in improved livestock management practices.