The weather dynamic: the challenge of winter grazing and the parameters of sustainability

Authors: Barnes, A.P.*1, Rees, R.M.1, Morgan, C.,3 Vosough Ahmadi, B.1, Stott, A.W5, Marley, C.L.4, McGechan, M.2, Topp, C.F.E.2, Hyslop, J.J3.

1: Department of Land Economy, Environment and Society, SRUC, West Mains Road, Edinburgh, EH9 3JG2: Department of Crop and Soil Science, SRUC, West Mains Road, Edinburgh, EH9 3JG3: Farm Rural Business Services, SRUC, 2 Technopole Centre, Bush Estate, Penicuik, EH26 0PJ4: Animal Systems Research Group, Institute of Biological, Environmental & Rural Sciences (IBERS), Aberystwyth University, Penglais, Aberystwyth, Ceredigion, SY23 3DA5: Future Farming Systems Group, SRUC, West Mains Road, Edinburgh, EH9 3JG

* Corresponding Author: Dr Andrew Barnes, Department of Land Economy, Environment and Society, SRUC, Edinburgh, EH9 3JG. E: Andrew.Barnes@sruc.ac.uk

Abstract: Livestock production has significant impacts on the environment as a consequence of greenhouse gas production, nutrient and pathogen release to stream water and impacts on soil and plant communities. The way in which livestock are managed within a farming system can have important implications for the magnitude of these impacts. A management strategy that has grown in popularity recently in temperate regions of Europe, is wintering cattle on grassland. This infers managing cattle for part or whole of the winter season on designated grassland areas.

Outwintering is mostly driven by the desire to maintain financial sustainability under increasing economic and policy pressures, as it obviates the need for high capital investment in housing. Assessment of the outwintering system must therefore be on economic, social and environmental parameters. We present a classification schema for different types of outwintering system and assess the impact on sustainability of adoption of these systems.

The literature reveals large gaps in our understanding towards outwintering on grasslands and work partially related to outwintering has to be used to infer impact of this system. Whilst we find that outwintering tends to improve both the gross and net margins within a farm, and, if managed correctly, has benefits for animal welfare when compared to indoor systems. The main pressures are on environmental criteria, concentrated on damage to grassland both during and post-grazing period in periods of increased precipitation. However, correct management of these factors, dictated by site choice, management of cattle in extreme events and post-treatment of the field will, we argue, serve to temper the negative environmental effects.

Outwintering on grasslands entwines farm system research with future government ambitions related to sustainability of the farming sector and targets on greenhouse gas emissions. It is clear that these impacts have been understudied for a management system which is proving increasingly popular in the UK and elsewhere. We conclude that the dimensions for sustainability assessment need to be widened to encompass outwintering cattle, as there is a strong temporal element which will negate some of the environmental damage, and also a spatial element, with respect to site choice and proximity of outwintered cattle to fragile ecosystems. In addition, we show how modelling frameworks are needed to combine these impacts to fully understand the synergies and trade-offs within the outwintering system and so satisfy the needs of policy.

1.0 IntroductionGrasslands occupy 60% of the UK’s agricultural land area (DEFRA, June

Agricultural and Horticultural Census 2008), and provide a wide variety of

ecosystem services. These include the provision of human and animal food

materials, the buffering of pollutant transfers to water, the provision of a

habitat for plant, animal and soil microbial biodiversity, carbon storage, and

landscape and recreational value.

Livestock production has significant impacts on the environment as a

consequence of greenhouse gas production, nutrient and pathogen release to

stream water and impacts on soil and plant communities (Steinfeld et al.,

2006). The way in which livestock are managed can have important

implications for the magnitude of these impacts. A range of technologies

have been suggested for these farming systems which mitigate greenhouse

gases and also maintain or extend production output goals (Macleod et al.,

2010; Moran et al., 2011; Shortall and Barnes, 2013).

In addition, a raised food security agenda emphasises the role of increasing

productivity on scarce land (Royal Society, 2011). From a farming

perspective the management of livestock incur financial burdens which may

not, without the aid of subsidy, prove to be economically worthwhile (SAC,

2008, Acs et al., 2010). In managing cattle the high capital investment costs

for housing and slurry storage facilities, as well as increasing pressures on

market prices has led farmers, in temperate areas, to consider the merits of

keeping cattle outside for a greater proportion of the year, or out-wintering

non-lactating cattle for the whole winter period. Whilst these grazing systems

offer benefits by reducing production costs, there will be implications for the

environment as wetter weather coupled with stocking activity on grassland,

will lead to a degradation of soil and water quality. In addition, some issues

may arise for the health and welfare of the cattle, particularly with regard to

the hardiness and suitability of certain dairy breeds. These systems may also

require additional labour input to ensure grazing areas are managed

according to the requirements of policy (e.g. cross-compliance) and to ensure

that animal health and welfare, and thus performance, are not compromised.

Sustainability indicators, however, tend to focus on 1-point estimates, given

constraints in data collection, which usually do not accommodate the

dynamics of a livestock grazing system over a whole year period. The

influence of extreme weather events will increase pressure on a system to

remain sustainable, both environmentally and economically throughout the

year. This is further complicated by the requirement to design management

strategies that promote pollution swapping (i.e. the substitution of one form of

pollution by another), as would be the case if reduced nitrate leaching was

replaced by increased emissions of nitrous oxide.

The only record of outwintering activity seems to be the farm practices survey

(Defra, 2008) which surveys livestock farms in England and Wales. High

numbers of farmers were conducting some form of cattle outwintering, the

most prevalent being grazing farms in Less Favoured Areas (88%), and in

lowland areas (70%). This survey also found that the smaller farms are the

most likely to outwinter, possibly because it obviates the need for high capital

investment.

A number of outwintering strategies are available to farmers, these either rely

on providing brassicas to support nutrition through part of the winter period,

offering temporary grazing, or at the most extreme, sacrificing a field over the

winter period and providing feed when grazing quality degrades. The majority

of UK farmers were found to use temporary grazing or sacrifice fields (Defra,

2008). A sacrifice field can be defined as a field or part of a field that is

allowed to deteriorate as a result of winter grazing. Consequently, it seems

to present an extreme form of management which may have severe

environmental consequences. Specific grassland issues revolve around soil

damage from cattle movement, subsequent water and air pollution effects, as

well as impacts on the underlying biodiversity in and around the grazing area.

Despite the popularity of outwintering, little is known about the implications of

grazing over an extended winter period, especially under a strategy of

sacrificing a field. Though damage is expected due to the degradation of the

field, there may also be benefits compared to other strategies which house

cattle, e.g. through reduced energy costs and the impact on greenhouse gas

emissions.

The purpose of this paper is to review the current literature available related to

the practice of outwintering cattle, in order to present a framework and

typology of these impacts and, thus, provide a basis for future study within this

research area. The next section presents a schema for outlining the types of

cattle that may be managed under a sacrifice field system.

2.0. A typology of cattle outwintering management on sacrifice fieldsTable 1 presents a typology of outwintering strategies for the cattle sector.

For the dairy sector it is unlikely that dairy cows that are lactating will be

outwintered, as cold weather tends to adversely affect lactation. However, in

each herd there are a number of non-lactating animals which could potentially

be managed in this way. These animals fall into three categories:

Dairy Cows

Dry pregnant cows [Table 1, category 1] : these are cows in the late stages of

pregnancy that have been dried off in preparation for the birth of the calf and

the new lactation. Young heifers pre-mating [Table 1, category 2] : these are

the animals selected to form replacements and are between 3 and 15 months

of age for herds that are calving at two years of age. Yearling heifers post-

mating [Table 1, category 3] : these are the replacement stock that have been

served and are between 15 months and 2 years of age.

Dairy beef animals

These two categories [Table 1, category 4] and [Table 1, category 5] refer to

steers and heifers that are produced by the dairy cow and are being reared for

beef production. Depending on the season of calving and finishing system

there will be varying proportions of these two classes of stock.

Suckler beef animals

In Britain outwintering management is most commonly applied to pregnant,

non-lactating spring calving cows [Table 1, category 6]. The nutrient

requirements of these cows are relatively low and can be easily met by

appropriate supplementation of the natural grass cover. It is less common to

outwinter lactating autumn calving suckler cows [Table 1, category 7] as their

nutrient requirements are higher and they have a young calf which is

susceptible to adverse effects of the weather. Recently there has been

renewed interest in outwintering young 6 month old spring born [Table 1,

category 8] and yearling autumn born [Table 1, category 9] steers and heifers

being raised for beef production.

Criteria for measuring impacts

Given the range of systems which can be outwintered, the next section

provides a review of the possible impacts from these systems. This must be

assessed against specific criteria for assessing sustainability, which follows

the standard criteria set out by the Brundtland Commission (WCED, 1987)

and we take the prime indicators of livestock management as proxies for

environmental, economic and social sustainability.

Within the UK, the policy focus is now on sustainable production and

consumption, with more targeted goals centred on a sustainable food and

farming system (Defra, 2012) . This translates into a suite of regulatory and

voluntary interventions, including research funding, that promotes best

practice within the food supply chain, provides information for consumers and

enhances the range of ecosystems services emerging from agricultural

activity and food production and consumption. Accordingly, what follows is an

attempt to translate these goals and concepts to the practice of outwintering,

which represent an activity driven by the need for financial sustainability, but

which adds significant pressure on a fragile set of ecosystems. These are

categorised as grassland management, reflective of environmental

dimensions, farm level finance, reflective of economic dimensions, and animal

welfare impacts, reflective of social impacts.

3.0. Results

3.1. Grassland Management

Grassland plays an important role in the management of air and water

pollution. The role of grasslands in terms of interaction with the environment

is becoming increasingly apparent (Hooda et al. 2000; ADAS, 2007). This

interaction includes both beneficial and detrimental effects. Grasslands act as

a medium that exchange both energy and nutrients, but are also managed

through human activity in a way that can result in major changes in nutrient

and energy exchange.

3.1.1. Gaseous Exchange

Grasslands play an important role in the exchange of radiatively active gases

(greenhouse gases) between the land surface and our atmosphere (Hynst et

al., 2007; Soussana et al. 2007). Our understanding of this role has

developed rapidly in recent years with the development of advanced

micrometeorological techniques allowing continuous measurement of C

exchange and measurements of other greenhouse gases (Sutton et al.,

2007). Many grassland systems offer the opportunity to remove large

amounts of CO2 from the atmosphere on an annual basis by photosynthesis

(Rees et al., 2005). Grasslands exchange CO2 in two directions with the

atmosphere, but the difference between net ecosystem loss (by respiration)

and net C uptake (by photosynthesis) is defined as net ecosystem exchange

(NEE), and provides a measure C sequestration potential by a particular

system. Uptake of CO2 ranges from 0.07-to 4.5 t C ha-1 yr-1 in a range of

studies recently reviewed (Rees et al. 130-54). There is however significant

annual variability between uptake rates with studies indicating a fourfold

variation as a result of climatic variability (Emmerich, 2004).

Grassland systems also play an important role in the exchange of other

greenhouse gases. Thus in the UK grassland ecosystems are the single most

important source of nitrous oxide, and where grazing animals are present,

they also contribute to significant amounts of methane emissions. Nitrous

oxide emissions can be particularly large where there are large inputs of

fertiliser nitrogen, although emissions tend not to be evenly distributed across

the country. Grasslands in wetter parts of the country in southwest England

and West of Scotland tend to be particularly prone to large emissions (Jarvis

et al., 2001; Jones et al., 2007). There is considerable uncertainty regarding

the magnitude of N2O release from grasslands, however, we know that

emissions tend to be geographically variable and unevenly distributed

throughout the year. Particularly high emissions are associated with periods

when there are high levels of available nitrogen in the soil to coincide with

periods of soil wetness.

Grasslands can also act as a small source of methane (Yamulki and Jarvis,

2002), however, the major source is derived from ruminant livestock. Annual

emissions from this source in Europe are variable, with a recent study

reporting emissions from cut and grazed grasslands of between 11-140 kg

CH4 y-1. Diet is known to be one of the factors influencing methane

emissions (Vlaming et al., 2008). The amount of digestible nutrients contained

in the diet appears to be directly linked to methane emissions (Jentsch et al.,

2007), thus animals fed on lower quality feed that may be present in low input

systems may have a higher CH4 emission per unit of intake, although

emissions per unit area may be less than those in more intensively managed

systems (Pinares-Patino et al., 2007).

The combined emissions of methane and nitrous oxide effectively offset the

uptake of carbon through carbon sequestration. This is most clearly

illustrated when the greenhouse gas budget of a grassland system is

expressed on the basis of global warming potential (GWP) which expresses

the warming potential of CO2, N2O and CH4 in units of CO2. A study of

seven grassland systems across Europe showed that net ecosystem

exchange varied between -13 – 419 g C m-1 y-1 (Soussana et al., 2007).

However, when the emissions of N2O and CH4 were taken into account the

carbon sink strength reduced by an average of 19%. The UK is known to have

relatively high emissions of nitrous oxide on an European basis (Flechard et

al., 2007), and mitigation options that can reduce these emissions are likely to

make an important contribution to mitigation of UK greenhouse gas

emissions.

Ammonia is an important pollutant in the UK, contributing to acidification and

nutrient enrichment (Erisman et al., 2008). In 2007 there was a deposition of

289 tons of ammonia 91% of which originated from Agriculture (NAEI, 2007).

Livestock farming is a particularly important source, with dairy farming

becoming more important (Jarvis and Ledgard, 2002). Manure is the source of

much of the ammonia emissions associated with livestock farming and

therefore mitigation opportunities centre around improved manure

management (Misselbrook et al., 2000).

3.1.2. Nutrient exchange

Many intensively managed grasslands receive large inputs of synthetic

fertilisers, containing the elements nitrogen and phosphorus. Additional

nutrients are added in the form of slurries and manures leading to higher total

nutrient loadings. Although these nutrient inputs are controlled by the

statutory regulations associated with NVZ regulations, and advisory

recommendations, there remains a potential for significant nutrient loss to

drainage water. These losses are most likely to occur in circumstances where

the supply of nutrient inputs exceeds the demand by plants for nutrient uptake

(Jarvis, 2000). This is most likely to occur during winter periods and plant

growth is reduced, and excess rainfall will contributed to the leaching of

nutrient elements from the soil. A study of slurry applications to grasslands in

the autumn and winter has shown that N leaching losses over 4 years could

vary between 0-50% of the N applied (Smith et al., 2002) In circumstances

where heavy rainfall falls on already saturated ground, overland flow can

contribute to nutrient inputs to river water systems are from sources that have

bypass the normal drain flow (Petry et al., 2002). In such a circumstances the

loss of surface applied slurries and manures poses a particular hazard to

streams and rivers (McGechan, Lewis, and Provolo, 1998), and codes of good

practice have been designed in order to try to minimise this risk.

The transfer of N to adjacent water bodies can be reduced by the use of grass

buffer strips to which no applications of slurries or fertilisers are made,

however these need to be at least 10 m in width and take account of local

slope and drainage characteristics.

Grazed grasslands can represent a significant non-point source of P to river

systems (Hawkins and Scholefield, 1996). Because soils can store large

amounts of P, inputs from grazing livestock can sometimes be buffered, but,

applications of livestock manures have been shown over the long term to

increase losses (Sentran and Ndayegamiye, 1995).

Livestock systems pose a particular risk to the contamination of water by

pathogens (Hooda et al., 2000) Overland flow associated with heavy rainfall

events has been shown to be particularly important in contributing to the

transfer of pathogens to surface water bodies (Vinten et al., 2004). The risk is

more acute where grazing animals are depositing dung directly on fields than

in circumstances where fields are treated with applications of slurry (Vinten et

al. 2004). This appears to be a consequence of the decline in pathogen

numbers with time in slurry stores, and their adsorption onto soil particles

once applied to the field. Previous studies do however highlight the risk that

is posed by grazing animals in an overwintering situation in circumstances

where winter rainfall events could contribute to significant episodes of

pollution.

3.1.3. Soil quality

The preservation of soil quality is recognized as a critically important aspect of

the management of farming systems. Good soil quality is important not only

for the continued productivity but also for the provision of a range of other

ecosystem goods and services, including improved environmental benefits.

Grassland ecosystems are generally associated with the development of

relatively good soil quality. This can be linked to the input of carbon

associated with the systems, and the prevalence of plant roots which

encourage the formation of good soil structure (Ball et al., 2005). However, in

circumstances where systems are managed intensively and in particular

where there are high densities of livestock overwintering on areas of

grassland, there is a potential for soil damage. This is associated with a the

formation of compacted areas associated with trampling by cattle, a problem

which is made worse with wet soil conditions, because in these circumstances

soil strength is reduced, and damage can occur. Work in Irish grasslands has

shown that grazing animals can contribute to significant increases in bulk

density and penetration resistance, alongside reductions in macroporosity

(Kurz, O'Reilly, and Tunney, 2006). Such changes can lead to alterations in

site hydrology and in increase in overland flow(McDowell et al., 2003),

accelerating the transfer of nutrients and pathogens to local water courses.

Compaction occurring as a consequence of overwintering livestock can lead

to long-lasting problems which are difficult or expensive to rectify. Excessive

to deposition of nutrients are in areas used for overwintering cattle can also

lead to a degradation in soil quality (Novak and Slamka, 2003) resulting in

high levels of nutrient loss through gaseous leeching pathways as discussed

above.

3.2. Economic ImpactsA number of applied studies have been conducted on the economic impact of

outwintering. These have tended to focus on headline indicators of economic

performance, predominantly due to the advisory nature of outwintering, in

comparison to indoor systems. The bulk of these studies provide case by

case estimates of gross output and gross margins of various outwintering

systems. The ‘Outwintering Blueprint’ (SAC and QMS, 2009) outlines the

costings for a variety of systems operated within a Scottish context for

deferred grazing it was estimated that this could save £0.28 per cow per day,

but this is only for a two month period as, after the new year grass quality

reduces to the extent that extra nutrition has to be introduced, either through

feeding blocks or supplementary forage.

Bio-economic models using operational research techniques such as dynamic

programming (DP) and linear programming (LP) have been widely used in

solving agricultural and environmental management problems. Some studies

have used LP as a tool to compare conventional farming systems against

changes to examine the effect of policies (Acs et al, 2010). However, to date

this has not been specifically applied to understand the whole impact of

outwintering strategies, though some examples exist which attempt to

combine both economic and epidemiological concepts to understand the

interaction between production and animal health (Stott et al. 2003).

Dynamic programming (DP) determines the sequence of decisions, best

expressed as a decision tree, which maximises overall effectiveness

(Bellman, 1957). DP models have been used to investigate the economic and

epidemiological impacts of prevention/control strategies on a series of animal

health and management problems: mastitis, paratuberculosis, infertility,

optimal feeding policies, optimal culling/replacement policies, etc. (Kennedy et

al. 1976; van Arendonk 1988; Kennedy and Stott 1993; Yalcin and Stott 2000;

Stott and Kennedy 1993; Stott et al 2002; Stott et al., 2005).

The most relevant is Vosough Ahmadi et al. (2009) who explored a range of

trade-offs between animal welfare indicators and farm profitability in

extensively managed outwintering suckler cow systems. They identified

possible conflicts between policy on animal welfare and on the environment.

This was mainly due to the fact that herds with high levels of feeding, which

implies higher welfare, required more replacements leading to a higher

number of animals on farm. This may adversely affect the environment,

through increased pollutants and feeding requirements.

3.3 Animal WelfareThe main factors affecting the health and welfare status of out-wintered cattle

include the genetics of the animal, the social structure within which the animal

is kept, the nutritional quality of any feed offered and the overall management

regime on the individual farm. These factors are inter-related and important in

all cattle systems, irrespective of their winter management practice.

Incidences of individual clinical and sub-clinical diseases that are recorded in

housed cattle systems also occur in out-wintering systems, although the

magnitude of the incidence of many of these diseases may be either lower or

higher in out-wintering systems due to different management practices. For

example, there are a multitude of causes that can contribute to the incidence

of lameness, with large individual variations in severity occurring between

farms due to differences in environment and the standards of husbandry

applied but, the use of extended grazing has been shown to be a major factor

reducing the incidence of lameness in organic dairy systems (Rutherford et

al., 2009). However, contrary to a common assumption, good welfare does

not necessarily occur with more extensive systems.

The practice of out-wintering cattle, whilst it does allow the animal to be kept

in what is deemed as a more natural environment, has potential implications

on health, in addition to the welfare considerations. Health and welfare status

may be influenced by the climatic conditions and geographical location on the

individual farm and consideration needs to include the provision of suitable

shelter to ensure that livestock are protected from exposure to wind and

extremes of temperature and avoidance of over-poaching of the ground. The

latter can increase dirtiness around the udder and cause subsequent

infections (Christiansson et al., 1996). Cattle will acclimatise to colder weather

by growing longer, thicker coats with reduced hair shedding to provide better

insulation against lower temperatures, but the coat must be clean and dry to

allow protection to the cow (Tarr, 2006). While UK winters have not normally

been associated with extreme cold this risk is increasing as a result of climate

change. In general, temperature per se is not a true measurement in relation

to the response and hardiness of cattle out-wintered, as the accumulated

effect of the wind chill factor, rainfall and state of the ground all increase the

loss of body heat from the cow. Beef cattle are frequently out-wintered and

are more adaptable to changes in climatic conditions compared with dairy

breeds, due to their higher body condition scores and thermal insulation

(Wright and Russell, 1984). In two reviews, Johnson and Vanjonack (1976)

and Sharma et al. (1988) reported that to maintain good health the 'comfort

zone' for dairy cows was temperatures between 2 and 22oC. Furthermore, the

use of extended grazing over the winter period may increase the exposure of

livestock to gastro-intestinal parasites, which may increase the incidence of

parasitic infections (Ruest, 2002) unless a successful rotational grazing

system is employed (Larsson et al., 2006).

However, general evidence suggests that outwintering, compared to indoor

systems, has a positive effect on welfare of the cows. In some cases welfare

is improved (SAC, 2009; Boyle et al, 2008). Wassmuth (2003) found that the

fertility of cows was not affected by out-wintering and their health was

positively influenced owing to the lack of respiratory diseases and infection

with ectoparasites.

The effective husbandry of cattle requires regular assessment of productivity

and welfare and this is generally achieved by monitoring live weight and body

condition score changes. There are target growth rates for replacement

heifers to ensure that they achieve the appropriate live weight at calving. Any

deviations from the target must be addressed by adjusting the feed allowance.

Similarly for suckler cows there are target body condition scores at each stage

of the reproductive cycle through the year (calving, mating, weaning). The

condition score targets enable the producer to ensure optimum fertility and

milk production with minimum calving difficulties, all within a controlled cost of

feeding during the winter.

3.3.1. Specific welfare concerns

Out-wintered animals face a broad range of challenges that potentially

endanger their welfare. The Five Freedoms (Farm Animal Welfare Council,

2005) provide one approach to assessing these challenges. Depending on the

region, freedom from hunger and discomfort are particularly pertinent to the

extensive management of beef cows in winter since they are often allowed to

lose body condition and weather conditions (cold, wind and rain) may present

a challenge to thermoregulation.

Morgan et al (2009) reported that a moderate loss of body condition over the

winter with cows in good condition initially was not detrimental to cow

productivity and welfare. Thus, providing condition score is managed

effectively through supplementary feeding, the remaining challenges are

concerned with cold stress and lying deprivation.

3.3.2. Cold stress

The rate of loss of heat from the body depends on several factors related to

the cow (energy intake, live weight, body condition and coat depth) and the

environment (rainfall (coat wetness), ambient temperature and wind speed)

(Blaxter, 1977; National Research Council, 2000). Estimates of the lower

critical temperature (LCT: the temperature below which heat production

increases in response to a fall in ambient temperature) of pregnant beef cows

indoors are very low (e.g -25oC, National Research Council, 1981) and may

be low for out-wintered cows in dry, still conditions. However, the calculated

LCT can be considerably higher for cows out-wintered in wet and windy

conditions and the models of climatic energy demand are very sensitive to

these factors (Blaxter, 1997; National Research Council, 2000; Olson and

Wallander, 2002). Morgan et al (2009) reported that in unsheltered locations

the calculated LCT of cows could be as high as 13oC but that the cows chose

locations (by trees or the feeder) where the wind speed was reduced and their

calculated LCT was below ambient temperature. The correlation coefficient

between the time cows spent in sheltered conditions and the average wind

speed was 0.67 (P<0.001). In addition to choosing sheltered locations cows

alter their standing and lying behaviour so as to minimise energy

requirements and orient their bodies to derive maximum solar radiation (Keren

and Olson, 2006). Even un-roofed shelters are sufficient to enable cows to

maintain their body temperature (Wassmuth et al, 1999) so a shelter belt of

trees providing protection from the prevailing wind will be beneficial (Bruce,

1984). Provision of such shelter can incur problems if it is not free-draining

since it will not be exposed to the wind to dry out and may become

excessively poached and the cows will be reluctant to lie down (SAC, 2009).

3.3.4. Lying deprivation

Large ruminants spend 40% or more of their time lying during the winter

(Olson and Wallander, 2002). Lying behaviour provides rest and with dry lying

conditions heat loss is reduced since wind speed is lower closer to the

ground. There is an inverse relationship between lying time and moisture

content of the lying surface (Keys et al, 1976; Fregonesi et al, 2007) and at

high moisture contents cows may not achieve sufficient lying time to meet

their demand (Jensen et al, 2005) and can show evidence of stress (e.g

elevated plasma cortisol concentrations (Tucker et al, 2007)). Morgan et al

(2009) reported that lying times were reduced in conditions of high rainfall.

Thus a lack of a dry lying area has an adverse effect on the cow’s welfare

(Wassmuth et al, 1999).

4.0. DiscussionFood production from land is recognised as providing multiple benefits, and

grassland is becoming increasingly valued as an important societal resource

(Nábrádi, 2007;Lindborg et al., 2008). Management of grassland for livestock

production creates a complex set of issues for research and policy agendas.

Adequate management of grassland is necessary to either engender benefits

or mitigate the more negative impacts of livestock production. In addition

consumer awareness towards the methods of food production complicates the

development of, sometimes conflicting, multiobjective land use. This is all

framed against an underlying policy goal which aims to maintain the

sustainability of farming communities.

Clearly the growing popularity of outwintering cattle has been driven by

pressures on the economic health of farming. This, therefore, provides a

clear example of a system driven by the needs for economic sustainability

which incurs pressure on environmental sustainability parameters.

Furthermore, the risk of wetter weather will lead to greater pressure on

environmental sustainability parameters. This is in contrast to our proxy for

social sustainability, namely animal welfare, in which it could argued there is

minimal damage. It is important to note that in any herd, the failure to

maintain both a good heath status and high welfare standards has the

potential to affect the financial margins that can be achieved and increases

the risk of the enterprise becoming financially non-viable. Given this

assumption, outwintering probably requires more intensive and specialised

labour inputs to ensure that suffering is not prolonged in the herd compared to

indoor systems where health can be better regulated. If no adequate dry

shelter is provided then welfare deteriorates from reduced ability to shelter

from the wind and avoid cold stress and reduced lying down opportunities.

Thus, the assumption of good management pervades this assessment of

impacts.

In addition, Barnes et al. (2013) examined the perceptions of farmers with

respect to outwintering practices and found that they preferred to see animals

outside which was considered to be the natural environment. This may reflect

a further social dimension with respect to farmer ease towards management

of the livestock system.

Accordingly, the focus should be on reducing the environmental impact of

outwintering, as there may be gains across the other two dimensions of

sustainability which match Government requirements for a sustainable

industry. A range of best management practice guidelines have been

proposed for managing outwintering cattle and relate to site choice (SAC,

2008) , management of extreme events, e.g. persistent rainfall (Barnes et al.,

forthcoming), and land improvement options (McGeechan and Barnes, 2014).

Sousanna et al (2010) argue for cautious management of pastures to retain

the benefits of grassland as a C sink and outwintering may not be the best

option for maintaining a resource which may mitigate some of the damaging

climate related effects of livestock production.

Finally, whilst we focus on three dimensions of sustainability, there is a

growing literature which has attempted to provide wider definitions of

sustainability. Seghezzo (2009) extended the definition to include time and

space to the rubrick of sustainability assessments. These aspects are highly

relevant to the activity of outwintering. Specifically, the dynamic weather

effects of winter periods can significantly affect environmental sustainability,

and longer-term effects concerning spring treatment of the damaged field, or

the outwintered field within the rotation define some of the parameters of

damage (McGechan and Barnes, 2014). Outwintering cattle itself has been

driven by external financial pressures caused by depressed market prices and

subsidy change, which may inhibit capital investment. Accordingly, farmers

may revert to in-housed systems if a growing confidence, led by higher prices,

pervades the industry. Nevertheless, outwintering is the most popular

management strategy for grazing livestock and prices may remain depressed

for some time in the meat sector before any large-scale switches in production

could occur. In addition, spatial effects are also highly relevant as site choice

will impact water and air pollution vectors, but also proximity effects with

respect to managing wildlife within the spatial unit of a farm (Guillam et al.,

2012).

5.0. ConclusionsThe main driver for outwintering has been financial necessity. Outwintering

strategies, when combined with changes in feeding regimes has been

observed to reduce variable and fixed costs on several case study farms.

Economic modelling is shifting from conventional utilitarian management

problem-solving tools, i.e. maximising gross margins, toward becoming a

more holistic decision-support tool (Newell-Price et al., 2011). The capacity of

mathematical modelling frameworks to capture this increased complexity is

proving valuable to decision-makers and should be explored further for

providing an integrated approach to understanding the impacts of outwintering

cattle.

It is notable that upland, generally lower income farms are the most likely to

adopt outwintering, due to lack of access to capital investment. To counteract

the fall in economic returns, farmers may increase stocking rates which would,

of course, potentially increase damage through intensive grazing. Similarly,

an alternative not considered in the literature is a possible movement towards

more centralised and industrial methods of livestock production. Large scale

housing facilities could be a more resource efficient and pollution saving

technology compared to the strategies considered here. However, the wider

social effects of public opinion, perhaps mitigate the possibility of this

approach.

The temporal effect of policy and economics on outwintering practices seems

a significant finding. A significant proportion of farmer incomes emerges

through support payments, through the Common Agricultural Policy. Recent

reforms have focused on maintaining grasslands as a condition of support.

This imposes restrictions through cross-compliance and therefore makes

outwintering a possibly riskier management strategy (Barnes et al., 2013).

This raises the issue of whether outwintering is a response to a lack of policy

intervention in this area, and change will emerge if there were a more

strategic adjustment towards a more ecosystems service orientated policy.

Rural Development Plans do support mitigation measures and relate to

conditions on grazing management. Creating more voluntary support

schemes focused on outwintering measures, may target environmental

damage and thus meet stated Government aims of ensuring true economic,

social and environmental sustainability over time for the livestock sector.

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Table 1. Identification of farming systems adopted for management of outwintering cattle on grasslandOutwintering Animal type Grassland farming system

Typology numberSemi-natural grazing Reseeded grassNaturalregeneration

Natural regeneration

Sacrifice/reseed

Dairy animalsDry pregnant dairy cows [1] [1.1] [1.2] [1.3]Young growing dairy heifers (pre-mating) [2] [2.1] [2.2] [2.3]Older growing dairy heifers (post-mating) [3] [3.1] [3.2] [3.3]

Dairy beef animalsYoung growing weaned calves (Strs & hfrs) [4] [4.1] [4.2] [4.3]Yearling growing weaned calves (Strs & hfrs) [5] [5.1] [5.2] [5.3]

Suckler beef animalsDry suckler cows (spring calving) [6] [6.1] [6.2] [6.3]Lactating suckler cows (autumn calving) [7] [7.1] [7.2] [7.3]Young growing weaned calves (Strs & hfrs) [8] [8.1] [8.2] [8.3]Yearling growing weaned calves (Strs & hfrs) [9] [9.1] [9.2] [9.3]