How much manure does a pig produce




















The proxy variable for the amount of manure produced w was then computed by subtracting y from x 2. Over 90 continuous and dichotomous variables previously listed, Losinger, were initially considered for inclusion in a production function with w as the dependent variable. Spearman correlation coefficients, which are based on ranks, were computed rather than Pearson correlation coefficients because many of the variables were dichotomous and took values of zero or one.

Logarithms were computed for continuous variables. A significance level of 0. Variables in this model were deemed "screened," and were considered for inclusion in the final production function. Interaction terms between logarithms of screened continuous variables and screened dichotomous variables were created by multiplying the value of the logarithm of the continuous variable by the value of the dichotomous variable for all of the screened variables.

To allow for the eventuality of a translog or transcendental production function Christensen et al. To permit the development of a generalized power production function de Janvry, , the values of screened continuous variables were multiplied by the logarithm of all other screened continuous variables. Since a Cobb-Douglas type of production function resulted, the determination of returns to scale was straightforward.

In the presence of dichotomous variables which interact with the continuous variables, the returns-to-scale parameter may be computed thus:.

If such interaction terms are present, returns to scale may vary depending on the values of l ij. In addition, the returns-to-scale parameter may vary depending upon whether one believes particular inputs to be variable if an input is believed to be fixed, then it should not be used in the computation of the returns-to-scale parameter. For each of the operations used in the development of the production function, marginal physical products and average physical products were calculated for all continuous explanatory variables in the production function.

Of operations that participated in the second stage of data collection for the National Swine Study, Table 1 summarizes descriptive statistics for manure production computed assuming that all pigs produced a fixed 8.

Most of the manure was produced by pigs marketed at slaughter weight. On average, this was Therefore, as the number of pigs increased, the value of the proxy variable w fell relative to the estimate of manure production which would have been obtained under the assumption that all pigs produced the same percentage of manure relative to their body weights. Table 3 provides the coefficients for the production function. The difference between feed fed and weight gained was reduced on operations that restricted entry to employees only.

Feeding food waste garbage to pigs was associated with an increase in the difference between feed fed and body weight gained, which increased as the number of pigs increased. Table 4 lists the Spearman rank correlation coefficients for the model variables.

As one would expect, x 1 number of pigs was highly correlated with x 2 amount of feed. If x 3 is considered a fully variable input, R is significantly below one regardless of the practice of feeding food waste to pigs. Table 6 presents summary statistics on marginal physical products and average physical products for the continuous explanatory variables in the production function. On average, an extra pig would have resulted in a reduction of A rather large number of participants In addition, many of the producers gave figures for average daily gain and feed efficiency that were estimated or guessed rather than calculated accurately USDA, Quality of reported average daily gain and reported feed efficiency were offered for multivariable modelling for the production function, but never entered the model.

Thus, one probably does not need to be overly concerned about potential biases presented. Still, producers can undeniably receive benefits from maintaining an accurate record-keeping system Muirhead, ; Edwards et al.

Producers who knew the average daily gain and feed-conversion ratios of their pigs most likely computed these figures from the quantity of pork produced and amount of feed fed over a particular time frame for a particular number of pigs. In this study, the figures which the producers gave for average daily gain and feed-conversion ratio were used to compute estimates of the amount of pork produced and amount of feed fed for the pigs included in the study period.

Literature on animal growth generally assumes that growth of animals follows a sigmoidal shape rather than the linear projection used here to estimate manure production. However, the model which they used did not allow for differences in average daily gain of pigs. Average daily gain certainly varies depending on the age of the pig.

In epidemiologic and socio-economic analyses, to use a proxy variable as a surrogate for a variable of interest when the variable of interest cannot be measured directly is a fairly common practice Maddala, For example, Frisbie et al. Nerrie et al. Certainly not all of the feed fed to pigs is turned into pork or manure. Some is used in metabolic processes including respiration and transpiration. Some feeds result in greater feed efficiency than other feeds Muirhead, Unconsumed feeds may be disposed of together with the manure.

Although little is known about actual quantities of manure and other waste produced from feed not converted into pig flesh on farms in the United States, the quantity and characteristics of swine manure are known to be affected by the diet, environmental conditions including ambient temperature , and body weight of the pigs Clanton et al. However, to examine the economics of swine waste production on the national level, one would need to move beyond this assumption.

Further research is required to determine how well this variable applies as a proxy for swine-manure production. Although the relationship between manure production and the difference between feed fed and body weight gained is unknown, it seems reasonable to postulate that the amount of manure produced increases as the difference between the kg of feed fed and the kg of body weight gained increases.

However, Maddala argues that high intercorrelations among explanatory variables do not necessarily create a problem, and that many suggested remedies may do more harm than good. An important criterion for selecting from among possible functional forms to describe an economic relationship is that the model should be useful in predicting outcomes Lau, One well-known limitation of the Cobb-Douglas type of production function is that elasticities of substitution between all pairs of inputs are one Lau, Variable transformations that would have turned the model into a transcendental or power production function did not enter the model.

Many larger operations are highly specialized in pork production, do not raise crops, and thus have little use for the manure. A cookie is small text file that is stored in your web browser after your visit a website.

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Advertising — these third party advertising cookies are placed by advertising platforms or networks to show you relevant advertising both on and off wikifarmer. Third party companies, such as analytics or advertising companies, typically use cookies to collect user information anonymously. Livestock activities have an environmental impact when manure is improperly handled due to the pollution from various nutrients and organic compounds nitrogen, phosphorous, organic matter… , from the emission of ammonia to water soil and air and greenhouse gas emission GG.

The gases emitted NH 3 , CH 4 , N 2 O result from the breakdown of animal manure containing carbon and nitrogen and are released in the buildings, during subsequent storage and during land spreading Chadwick et al. Water pollution by nitrates NO 3 - or by phosphorous P in certain intensive livestock production areas arise from spreading manure rich in N and P beyond the capacity of the land. The surplus nitrogen and phosphorous is not used by the crop or soil and is washed out by surface run-off or seepage leading to eutrophication of water sources Velthof et al.

As a result, the livestock sector is considered as one of the principal sources of pollution leading to global warming in the case of GG emission water and soil contamination and the loss of biodiversity Steinfeld et al. The scale of these impacts are thus closely linked to amongst other factors the management and composition of animal manure Menzi et al.

As a consequence, the management of livestock manure is a central issue in a series of international protocols, of European directives and national regulations. Effectively, the practical aspects of the methods chosen by farmers can influence the scale of diffuse emissions and the possibility to reduce these losses Chadwick et al. The signatory countries of international conventions or those targeted by European Directives must measure the existing level of water pollution and make an inventory of current emissions of the listed gases.

These measurements and inventories are thus the reference base for reduction objectives that imply the enactment of action programs.

Various published works relating to gas emission inventories or the movement of N and P, underline the need for detailed data due to the large variability of management methods in livestock production. In general terms, inventories and environmental analysis of livestock farms need data on animals, the operation of the farm, the level of manure production, the methods of handling of the manure whether solid manure—FYM or slurry and their composition concentration of nitrogen, phosphorous, and organic matter.

It is the acquisition of such data that is often considered the most demanding step in carrying out an inventory or an analysis of the farm. Furthermore, the quality of such data is central as this can improve the accuracy of the material balance and provide a reliable basis for subsequent actions Milne et al.

Finally, the availability of data reflecting different manure management practices and its application in different countries remains limited or somewhat artificial or inconsistent thus rendering comparisons difficult between methods used in different countries affected by air and water pollution Menzi et al. France is one of the major livestock nations in Europe and the farming systems vary widely. In fact, the country makes the biggest contribution to the 1, million tons of animal manure estimated for the European Union Foged et al.

Thus, the purpose of this paper is to bring together, as far as possible, available data on the management of animal manure in France, especially information used in the different inventory tools or in the evaluation of technologies used for the reduction of water and air pollutants. This paper is not set out to provide new data but to assemble, standardize, and complete existing data sets.

All livestock farms in France fall under French and European regulations that seek to protect both the environment and local inhabitants. Basic nationally prescribed measures set out in specific decrees MEDDE, a , b , c that relate to the installation and management of farm buildings, effluent storage, and land spreading may be reinforced by local rules depending on the local climate and the vulnerability of the local environment.

These obligatory reglementations can affect the management of farm manure both directly and indirectly. Livestock manure raw or treated come under several legal categories waste, by-product, product depending on their use and each with different land spreading constraints Houot et al. Raw livestock manure managed on the farm are considered as by-products from animal production and must respect the environmental rules set out by the RSD, ICPE, and IED with respect to collection, storage, and land spreading.

The outputs from treatment composting, anaerobic digestion, separation, drying,… that are carried out on the farm or at an external site composting center, joint AD facilities, and others , are still considered as farm manure and must be applied to the field following an approved scheme of land spreading.

However, these same outputs composts, digestates, solids from separators, dried material, etc. These fertilizer products are thus used according to the recommendations of the supplier without the need of a land spreading plan. Digestates from AD must be approved a long and costly procedure limiting approvals to just 3 products in or more recently, they can be used by following a set of procedures detailed under a decree published in MAA, A farmer is allowed to give away, sell, or exchange for straw raw or treated effluents that are neither standardized nor authorized under a specific contract where the recipient undertakes to spread these effluents on land in full compliance with the rules in place.

In the case of exported composts and AD digestate, a sanitary certificate is required. Livestock buildings, storage tanks and the spreading of effluent must observe minimal distances from residences or aquatic resources which vary depending on the effluent being spread compost, raw manure, digestates from AD units… , on the specific regulation RSD, ICPE, water protection… and the specific region rules governing vulnerable areas.

The minimal distance is set at m for buildings and storage facilities for all effluents. On the other hand, the minimal distances for land spreading depend on the effluent type slurry, FYM, treated effluent and the method of land spreading: thus 10 m for composts, 15 m for injected livestock slurry or that incorporated immediately, but up to m for other products.

In vulnerable areas, the spreading of slurry and solid manures is forbidden closer than 35 m from the banks of rivers and streams unless there is a permanent vegetative zone where the minimal distance is reduced to 10 m. Livestock farmers must have available adequate storage capacity measured in cubic meters for slurries or square meters for FYM , sufficient to enable compliance with the minimal storage periods before land spreading.

Legal exceptions are possible if the existing capacity is enough to enable the good agronomic use of applied manure. Field storage is allowed in the case of stable FYM i. Land spreading is forbidden during certain periods or on certain land that would otherwise lead to environmental impact via run off or by leaching of the applied nitrogen and phosphorous e.

In vulnerable areas, spreading periods are determined with respect to the effluent type in terms of the level of mineralization of the organic nitrogen content, local climatic conditions, and technical limitations soil firmness, access to the field, etc. Under the ICPE rules, incorporation after land spreading on bare soil is obligatory within 24 h for cattle FYM and solid pig manure raw or treated previous held for at least 2 months in storage for stabilizing with respect to drainage liquids and 12 h for all other effluents from the farm, whether raw or treated.

Effluent treatment is also obligatory under the Water Framework Directive in the Loire-Brittany catchment area with the purpose of ensuring an agronomic phosphorous balance. Treatment also becomes obligatory when using effluents or digestates in the case of AD as a soil improver or organic fertilizer defined by French standards AFNOR, France is one of the main producers of meat in Europe being the largest in the case of cattle production, second for poultry and fourth for pig production Eurostat, Cattle rearing covered farm units and numbered in total More recent data from indicates that livestock numbers are unchanged but spread across fewer farms Agreste, a : , 17 , and 67 farms in the case of cattle, pig, and poultry respectively.

Livestock numbers are not evenly spread across the country. More than half Cattle is more evenly spread accross the French countryside but with nonetheless different regional concentrations of dairy cows found predominantly in the north of the country and beef animals found mostly in the center of the country.

Agricultural land dedicated to the three livestock sectors, pig, cattle, and poultry, amounts to In the case of poultry production, the mean area of farmland was in 63 ha per broiler farms, 56 ha for egg laying farms and 46 ha for pullets Itavi, a. More generally, these averages hide large regional differences. The conditions have an impact on the quantity and composition of the animal manure produced.

The organic production concerns mostly broiler and egg production, representing 1. In , the pig sector covered by the regulations of Red Label code accounted for less than 3. The number of livestock farms covered by one or other quality codes is projected to increase for all types and especially for dairy and beef cattle farms FranceAgrimer, On average, the typical cattle farm had animals in rising to in Agreste, b , but the variation of the mean size from region to region was much greater ranging from 58 to animals in Agreste, b.

Dairy farms with more than 20 cows are predominantly for breeding The bulk of pig numbers are thus held in livestock farms with more than pigs or 20 sows and the mean size for this sector is 1, pigs, but with large regional differences ranging from a mean of 1, pigs per farm in Champagne-Ardenne, down to pigs per farm in Corsica. The size of farms varies widely depending on the type of production and the methods used whether standard practice or following specific codes relating to quality.

In the case of both standard broiler production and egg laying systems in cages , the farms are especially large scale Agreste, c. Those poultry farms governed by specific codes relating to quality are generally smaller Itavi, As an example, the average size of a poultry house following standard practice is m2 whereas the average for a farm applying a quality code is m2. Livestock farms for cattle, pig, and poultry had together in Agreste, a , b , c around slurry stores mostly away from the animal house in the case of cattle and pig farms and with a combined storage volume of 47 million m 3 Table 1.

Thirty-nine percentage of poultry farms had covers on their external stores. The storage of solid manure was in carried out at stores representing a combined area of 25 million m 2 ha. A large part of the solid manure 55 million tons , mostly from the cattle sector 52 million tons , was stored in field heaps. Table 1. Storage capacities of French livestock according to the survey Agreste, a , b , c.

Manure treatment for the three main farm animal types accounted for The main processes, predominantly used at the farm, were composting 8. Other treatments of solid manure including physical-chemical methods, were less common 0. In addition, a large part of poultry droppings is dried in or out of the rearing house.

The application of livestock manure whether raw or treated is mainly done on farmer's land or other land generally close to the farm Quideau, Fields available for taking the applications of manure are linked to the crop rotation in practice at the farm Ramonet et al.

Based on the data given in Table 2 , of the total nitrogen in the manure from livestock farms destined for land spreading [estimated as around kt N: Citepa, , and personal communication] Nitrogen from cattle manure is more often spread on grassland than that from piggery manure because of differences in the crop cycle between the farm types whereas nitrogen from poultry manure is mostly spread on cereal land.

In certain regions Brittany, Pays de la Loire, Limousin , livestock manure make up the main source of nitrogen and are spread essentially on maize ground, of which the area included in crop rotation is greater than elsewhere Agreste, a. Table 2. This difference between the animal types is explained by the large proportion of the slurry form produced by pig farms and the related obligation to reduce the odor nuisance with respect to nearby people by using the method of incorporation.

Table 3. Table 4. Manure type slurry, FYM, or dropping and the quantities produced at a farm depend on the housing type slatted floor or bedding and the stage of animal rearing. Manure management in the building drying belt, scrapping, flushing, storage pit, etc. Generally, solid manure FYM is stored in field heaps or in manure stores and slurries stored in pits. Deep litter barns without an exercise yard is predominant in the case of cows with followers and other cattle but less so for dairy cows where straw bedding or cubicles are also common.

Slurry-based systems are rarely used except for veal calf production and for dairy cows kept in cubicles with slatted floors. Table 5.



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