Life cycle assessment towards optimization of water use in an industrial cattle farming complex by focusing on virtual water approach, Case study of Foka complex

Introduction
Isfahan province covers an area of 107045 square kilometers and a population of about four million with an average annual rainfall of 120 mm. In the event of successive droughts over the past six years, the water resources were affected both from the viewpoint of quantity and quality. Due to successive droughts in the province and the uncontrolled consumption of water table, water resources has got into a dangerous situation and must be economized in different domains. The issue of virtual water trade is of great and particular importance in sustainable development planning of the future of many countries located in arid and semi-arid areas to save and maintain parts of water needed for domestic production of goods. The consideration that the consumption of meat and dairy products has an extraordinary effect on the dearth of water globally has been widely published and proclaimed. The consumption of animal products in large quantities has an extra effect on fresh water resources. About one third out of the worlds total agricultural water footprint is related to animal products while their water- footprint is extremely higher than that of farm products with an equal nutritional value.
Poor food efficiency in the process of production for livestock products is largely responsible for the relatively high water footprint and virtual water content. Life cycle assessment may help save water, return water to cycle and reduce energy costs. According to the statistics provided by the statistical center of Iran in 2013 the number of active cattle farming complexes in the province is around180. If the consumption of livestock per capita is considered 100-150 liters daily for drinking and services (different in summer and winter), around 2086 cubic meters will suffice only for drinking needs in this part.

Materials and Methods
This study was conducted with two main objectives: To determine the amount of virtual water content of one Kg of beef (calf) and also to optimize water use in the life cycle of a livestock breeding. So in this boundary, cycle input is a farm for producing animal feed and cycle output is the slaughter- house.
The method used in this study was presented by Chapagain and Hoekstra (2003) that determines the virtual water content and also estimates the grey virtual water used by Hoekstra et al. (2011). Also, The amount of water needed to irrigate the product is obtained in order to calculate the amount of water needed for the production of any agricultural product (animal feed).
This is affected by the amount of evaporation from the soil surface . Blue virtual water, including water resources (surface and subsoil) is along with the supply chain of a product. Blue water used in this research includes water used in irrigating crops, drinking and washing services. Green virtual water content refers to the use of green water resources. Water used in dry farming (products for animal feed) is located in this category. However Rain-fed crops are not included in this study. As a result, blue-green water is sent together. Gray virtual water content refers to the volume of pollution and is defined as the volume of freshwater used to absorb pollutants to reach normal levels and current standards required for water quality. To calculate the virtual water derived from animal products such as "pure meat" it is necessary to acquire virtual water in living animals and then distribution of water in the products. Every living animal (cattle) has three components of virtual water. Virtual water content of an animal at the end of his life is the total volume of its virtual water content. This amount includes the amount needed for food, service, and drink. As mentioned above, for calculating the virtual water content of livestock and livestock products it is needed to have a virtual water content of the plant (used in animal feed) that is obtained by method of Hoekstra & Hung,( 2002). To calculate the amount of water needed to produce each product, the amount of water needed to irrigate the product should be considered. Furthermore, the evaporation and transpiration from the Earth's surface, soil and plant should also be included. As a result, information such as crop water needs throughout the growth period, evaporation and transpiration rate, annual performance product and product returns are required. Virtual water of crops (cubic meters per ton) is obtained by dividing the total amount of water needed to produce the entire product. Penman- Muntit equation is usually used to calculate the reference plant evapotranspiration. In the original Penman -Muntit equation water requirement of the plant is determined in one step by plant resistance coefficient, reflection coefficients and air resistance. Due to the lack of FAO data, regarding the constants in this equation, it has been calibrated to estimate the reference plant evapotranspiration. In this method water requirement is calculated by using the coefficients occur in two stages. In this study NETWAT software is also used.

Results
The amount of feed consumed by cattle depends on many factors like weather conditions in the region, season, race, diets and also whether the cattle is raised for meat production or not. Animal feed and diet composition are different although the same nutritional value as follows. Weight gain in beef cattle by nutrition is related to race. The amount of feed for cattle is calculated according to data from the case study. In this cycle, the virtual water content will be studied that includes blue-green water used for farm irrigation and gray water from the fertilizers and pesticides that are used on the farm. In this respect, the required information includes: area under crops fodder, expertise, the crop water requirements (used for animal feed) and the content of plants virtual water. After the assignment of feed intake of animal by each cattle breeding, feed virtual water content is achieved and then by using formulas we calculate the virtual water content of the drink as well as the service. Value of virtual water in cubic meters per ton of bone and boneless meat from the original product (living cattle) can be obtained. Information and data relating to the calculation of value fraction are taken from the Foka's slaughterhouse. The cow virtual water content when slaughtering is 11055 cubic meters per ton. Virtual water content of meat with bone is 19485 cubic meters per ton and the virtual water content of boneless meat is 22,800 cubic meters per ton.

Conclusions
It is clear that animal products need a lot of water. As a result, different methods of water management in animal product chains should be proposed, evaluated and implemented. What can be a good happening in Iran and also at the global level is to apply changes in diet and to consume meat products as economically as possible. This can play a big role in saving water content of the food at the national and international level. Minimum and maximum values of water recovery on farms (within Isfahan Province) have been measured to be 17.6 and 59.1 percent, respectively. Therefore increased efficiency in the agricultural sector is an effective step to reduce water consumption. Alternatively, it is also possible to reduce water consumption by changing agricultural products. Using organic matters and agricultural biotechnology can help to increase agricultural productivity and thus reduce the virtual water content. Storage and transport of water, the two process that will have their own virtual water content. Due to different water requirements of plant performance in different regions, the virtual water contents in different provinces are not the same. Accordingly, the required feed may be supplied from provinces where lowest amounts of water are consumed to yield crops.
Keywords: Industrial cattle farming, virtual water, beef