How do severity and frequency of grazing affect sward characteristics and the choices of sheep during the grazing season?

International audience1. Dry matter digestibility is a critical component of herbage nutritive value, a major service delivered by grasslands. The aim of this study was to test whether the dominance hypothesis applies to assess the impacts of environmental gradients and management regimes on thiscomponent of herbage nutritive value in permanent grasslands. 2. At the plant level, digestibility has been related to a number of functional traits, but whether this can be scaled up to the community level in species-rich grasslands and how such relationships are modulated by environmental conditions and management regimes remainunknown. Our primary objective was to test whether community-weighted means – species trait values weighted by the species abundance – of morphological, phenological and chemical traits could be used to explain variations in digestibility over a large range of climatic contexts,soil resource levels and management regimes. Our second objective was to explain variations in community digestibility within and among nine contrasting sites along large natural and man-induced environmental gradients.3. Over the whole data set, digestibility and most community-weighted means of traits responded to climatic factors and management regimes, but relations were not always significant when each site was considered separately. Community digestibility was significantly related to one or more plant traits within each site and to all of the measured traits when considering all the sites. Leaf dry matter content (LDMC) had the most consistent effects on digestibility, with a strikingly similar negative effect within each site. Potential evapotranspiration was negatively related to digestibility and contributed to explain a large part of the among-site variance. In addition, a low return interval of disturbance and a high disturbance intensity (biomass removal) were both associated with a high digestibility.4. Synthesis and applications. Disturbance regime, plant traits and local climate impacted dry matter digestibility roughly equally in grasslands. The effects of community composition on digestibility and its response to abiotic factors could be successfully captured by community weightedmeans of leaf dry matter content. This functional marker can be used to develop indicators and grassland management rules to support farmers in the refinement of their practices towards specific needs, such as target production outputs

show abstract

“…In addition to the indirect long‐term effects, frequent herbage removal maintains swards at high digestibility levels (Garcia et al . ).…”

Section: Introductionmentioning

confidence: 97%

Plant trait–digestibility relationships across management and climate gradients in permanent grasslands

Gardarin

Garnier

Carrère³

et al. 2014

Journal of Applied Ecology

View full text Add to dashboard Cite

show abstract

“…Hirata et al (2006a) investigated patch choice by cattle grazing on tropical grass swards, under experimental conditions where the animals were offered alternative patches differing in availability and quality. The preference of these animals for the patches was explained largely (R 2 = 0.76) by the relative crude protein (CP) concentration of the patches; a quality measure that has not been widely identified in previous studies on temperate forages Ganskopp et al 1997;Bergman et al 2001;Garcia et al 2003;.…”

Section: Introductionmentioning

confidence: 97%

Selection of feeding areas by cattle in a spatially heterogeneous environment: selection between two tropical grasses

Hirata

Sakou

Terayama

et al. 2007

J Ethol

View full text Add to dashboard Cite

A herd of 28-33 Japanese Black cows (Bos taurus) were allowed to graze on an experimental plot comprising monoculture swards of centipedegrass (Eremochloa ophiuroides) and bahiagrass (Paspalum notatum) (0.39 and 0.61 ha, respectively) for 3-5 days each month (from 0850 to 1600 hours) between May (late spring) and October (mid-autumn). On a monthly basis, the animals showed an increasing trend to select centipedegrass in preference to bahiagrass as the relative crude protein (CP) concentration of the former increased relative to the latter. On a daily basis, the animals showed a decreased selectivity for centipedegrass with the progression of grazing days, as centipedegrass sward lost both quantity and quality faster than bahiagrass sward under higher degrees of defoliation. Animals maintained similar bite rates on the two swards by modifying feeding station behavior as soon as they switched between the swards, i.e., they increased the number of bites per feeding station and decreased the number of feeding stations selected per unit grazing time soon after switching to centipedegrass, with the reverse process occurring soon after the switch to bahiagrass. The results show CP concentration to be a partial forage factor influencing animals' choice between tropical grasses growing as patches. The results also demonstrate that animals have an ability to adapt their foraging behavior flexibly and rapidly to varying types of vegetation.

show abstract

“…The ability of herbivores to selectively graze better quality components of the sward or favoured plant species has been widely documented in many studies (Heady 1964;Coleman 1992;Dumont et al 1995;Mayland & Shrewmaker 1999;Dumont et al 2002;Garcia et al 2003). In practice, various methods were used to study the diet selection and they can be generally divided into two broad types: 1) methods directly connected with animals such as the analysis of fecal and rumen contents (Homolka & Heroldová 1992;Heroldová 1996;Mellado et al 2004), esophageal fistulation (Henley et al 2001;Woji & Iji 1996) and direct observations of grazing animals (Dumont & Boissy 2000); or, alternatively, 2) methods based on vegetation such as the measurement of sward height (Correl et al 2003;Barthram et al 2005), biomass sampling of grazed plots and ungrazed control (Lepš et al 1995) or direct estimation of grazing damage caused by bites upon individual plant species on the pasture (Bílek et al 2000;Stroh et al 2002).…”

Section: Introductionmentioning

confidence: 99%

Sward structure and diet selection after sheep introduction on abandoned grassland in the Giant Mts, Czech Republic

et al. 2008

View full text Add to dashboard Cite

The effect of rotational grazing on the sward structure of long-term abandoned grassland and the sheep diet selection were investigated in the Giant Mts (Krkonoše/Karkonosze). The aim of the study was to answer the following questions: (1) Does sheep grazing affect the sward structure of previously abandoned mountain grassland? (2) How does sheep diet selection develop within and among grazing seasons? (3) Which section of a pasture do sheep prefer to graze? Data was collected three times during each grazing season in spring, summer and in autumn in the years 2001, 2002 and 2003. Fifty 1 × 1 m plots were used where the plant species occurrence and damage of plants by grazing for all species were repeatedly recorded. 1) Nonsignificant changes in plant species occurrences were recorded in spite of obvious visual changes in sward structure due to grazing e.g. the retreat of tall dominant species characteristic of long-term unmanaged grasslands. 2) Seasonal as well as inter-annual changes in sheep diet selection were detected. In spring 2001, sheep grazed over a wide variety of plant species in low quantities. In subsequent springs, they preferred species favoured during previous autumns (Veratrum album subsp. lobelianum; Ranunculus platanifolius; Senecio ovatus) and changed the diet only as a result of the elimination of favoured plants. 3) Sheep preferred to graze at the highest elevated part of the pasture probably as a consequence of anti-predator behaviour not due to higher occurrence of favoured plant species or the presence of a drinking place or salt licks. Changes in the sward structure were mostly of a quantitative not qualitative character, thus the presence-absence data collection is not a suitable method for monitoring the effects of management restoration. The diet selection changed probably due to the animals' experience; sheep had no experience with montane species in spring 2001. The sheep were able to recognize favoured plant species after 6 months of wintering in lowland.

show abstract

How do severity and frequency of grazing affect sward characteristics and the choices of sheep during the grazing season?

Cited by 32 publications

References 24 publications

Plant trait–digestibility relationships across management and climate gradients in permanent grasslands

Plant trait–digestibility relationships across management and climate gradients in permanent grasslands

Selection of feeding areas by cattle in a spatially heterogeneous environment: selection between two tropical grasses

Sward structure and diet selection after sheep introduction on abandoned grassland in the Giant Mts, Czech Republic

Contact Info

Product

Resources

About