Estimation of the virtual water content of some livestock products (milk and meat) in Khorasan Razavi province

Virtual water in Tony Allen's definition is the amount of water that consumes during agricultural or industrial products and services (Sadek, 2011; Mousavi et al., 2009; Mohammadi, 2012; Agahi et al., 2011; Mehdi Zadeh, 2014; Mokhtari, 2013). The population growth, water crisis, global warming increases the challenges of food security. Therefore, it is essential to consider enhancing water productivity as well as reducing virtual water. Livestock is a kind of activities that consume a considerable amount of water. Some previous studies have been done to the estimation of virtual water in the livestock industry in India (Brindha 2017) and in Saudi Arabia (Shakhawat Chowdhury et al., 2017) in recent years. Moreover, Ibidhi and Salem (2020) reported the water footprint of livestock products strongly related to the water footprint of forage and other kinds of livestock nutrition. Although Iran located in an arid region and the Khorasan Razavi province has an active livestock industry, there were not any surveys in the virtual water trend of live stocks in Khorasan Razavi province. Accordingly, in this study, the virtual water of the purebred, hybrid and native cows has estimated in each city of Khorasan Razavi province.

The virtual water content of livestock products was calculated based on Chapagin and Hokestra (2003). At first, the water requirement of purebred, native and hybrid cows was calculated with CROPWAT software for three consecutive years from 2015 to 2017in 28 cities of Khorasan Razavi province. Then the virtual water content of live cows was calculated. Finally, the virtual water of milk and meat was calculated separately for each city.

The results showed that the highest values of milk’s virtual water, related to hybrid dairy cows with 1590 cubic meters per ton (m3 ton-1) in in Gonabad and Bajestan cities and the lowest one related to native dairy cows with 309 m3 ton-1 in Mashhad. Moreover, the highest amount of virtual water of meat production belonged to hybrid dairy cows with 52350 m3 ton-1 in Gonabad and lowest was for purebred 9232 m3 ton-1 in Mashhad. Therefore, it would be recommended to produce milk from native cows and meat from purebred. Compared to world average values, virtual water of native cow’s milk in Mashhad was 68.8% lower while in Gonabad it was 60.6% higher. Therefore, it could be recommended to produce milk from native cows and meat from purebred.

Livestock feed compositions are one of the most influential factors on the total amount of virtual water in livestock products. In accordance with the previous studies, it could be suggested, the most milk should be produced in industrial conditions as well as should produce in cities which have advantages in producing fodder, based on virtual water aspects. It also might suggest changing the cultivation patterns of the province with less water consumption such as clover, fodder peas, fodder beet and sorghum. Other influential factors in the total amount of virtual water are cattle breeds and the value of milking. Virtual water for milk and meat productions in Gonabad city had the highest values in all three types of livestock and was the lowest for Mashhad and Quchan cities, so it might be better to grow more dairy cattle in Mashhad as well as to decrease the livestock productions and development in Gonabad and similar areas. Calculating the virtual water trends for the whole country also are deeply recommended in order to achieve a better vision for water resource management. Keywords: Virtual water, Khorasan Razavi province, Animal feed, Milk and meat, CROPWAT.