Water productivity in meat and milk production in the US (Part II)
This article is Part 2 of a two-part discussion on water productivity in livestock production. Part one focuses on improvements in the sector over the past 50 years.
Growth in the livestock sector has a lot of potential to benefit Nebraska economically, however it can also have negative impacts on our natural resources. To address some of these environmental impacts, the sector has been working hard to improve livestock water productivity. Recently, scientists at the Daugherty Water for Food Global Institute and the Department of Animal Science of the University of Nebraska, together with colleagues from the University of Twente, and the National University of Singapore worked together to estimate the changes in water productivity of animal products from 1960 to 2016. Their work gives insight to the following questions:
- How much water is the livestock sector using today?
- What still needs to be done to continue to improve water use in the livestock sector?
How much water is the livestock sector using today?
The yearly average of total water consumed by the livestock sector in the US between 2014 and 2016 was 72,650 billion gallons/y. Out of this total, 99% of this water was used to produce animal feed (Table 1). During the period of 1960 to 2016, water consumption decreased by 36% due to an increase in animal productivity (output per head) and the increase in yields of feed crops. This shows the vital importance of optimizing water use in the production of feeds such as alfalfa, corn, soybeans, and pasture and other forages, in order to improve the overall sustainability of livestock production.
|Animal category||Grains||Oilseeds meal||Other by-products||Forage||Pasture||Drinking and service water||Total|
Since the water demands for crop production could be utilized for other purposes, animals that are fed grain-based diets could be competing for freshwater sources with human’s domestic and industrial uses (Mekonnen & Hoekstra, 2012). Beef cattle are responsible of almost half of the water consumption of livestock production, but the 84% of the water used in beef production was used to produce forages, pastures, and crop byproducts. It is important to emphasize that pastures and forages are non-human edible products and are produced on land that is not suitable for grain production or are included in rotations that include crop production for soil health improvements. Also, water used in pasture production is mainly supplied by rainfall, whereas food crops are more likely to be irrigated with groundwater or rerouted surface water sources. Next to beef cattle, poultry and swine production have the highest water demand, most of which occurs in the production of grain or grain byproduct feeds.
What still needs to be done to continue to improve water use in the livestock sector?
Livestock producers have steadily improved the water productivity of their products over the past 50 years. However, the sector still has the opportunity to identify and implement methods to reduce its water use further. Some possibilities include: better animal management to reduce water requirements at livestock facilities, increased use of crop residues and crop byproducts for feeds and forage, and the substitution of alternative feed crops that have smaller water footprints.
The use of cereal byproducts as feed is a promising opportunity to increase the water productivity for animal production. For example, distillers’ grains are a byproduct of the ethanol industry, and during 2016 about 41.25 million US tons of distillers’ grains were produced in the US. The use of distillers’ grains as a feed supplement has improved the water productivity in all livestock animals. Milk production can see improvements of more than 21% in water use efficiency by replacing grains with distilled grain products; while pork, beef, and poultry can improve 13%, 7% and 4%, respectively (Figure 1). This reduction is due to the significantly lower water requirements allocated to the byproducts within a grain production system compared to the primary products (i.e. ethanol, corn syrup). Other by-products being used as feed in the animal production are derivatives of the wheat, cotton, soybeans, peanut, meat and rice industries (Bernard, 2017).
Other incremental improvements can build on previous gains in livestock productivity, feed efficiency, and crop water use. These include important actions, such as: making appropriate decisions while selecting breeds, feed components and sourcing, and using best practices and management strategies for crop production.
Continuing the improvements of the last 50 years in water productivity will challenge the livestock sector. However, with focus across the value chain, from crop and livestock farmers to end consumers, improvements can continue to be made to rise to the challenge.
Mekonnen, M., & Hoekstra, A. (2012). A Global Assessment of the Water Footprint of Farm Animal Products. Ecosystems, 401-415.
Bernard, J. (2017). Considerations for Using By-Product Feeds. UGA Extension Bulletin 862. University of Georgia.
Mekonnen, M., Neale, C., Ray, C., & Hoekstra, A. (2019). Water productivity in meat and milk production in the US from 1960 to 2016. Environment International, 132.
This article was reviewed by Mara Zelt, Crystal Powers and Dr. Rick Stowell