CONTRARY to the negative image often associated with "factory farms", the United States population's requirements for dairy products are best fulfilled and most sustainable through the application of modern agricultural techniques, a just-released study has found.
The study, conducted by Drs Jude Capper and Dale Bauman of Cornell University, and Roger Cady, formerly of Monsanto and now with Elanco Animal Health, compared the environmental impact of modern (2007) US dairy production with dairy systems in 1944.
For the comparison, the researchers used a deterministic model based on the metabolism and nutrient requirements of the dairy herd.
The model estimated resource inputs and waste outputs per billion kilograms of milk.
Both the modern and historical production systems were modeled using characteristic management practices, herd population dynamics and production data from US dairy farms.
Among the findings were that modern dairy practices require considerably fewer resources than dairying did in 1944 - 21 per cent of animals, 23pc of feedstuffs, 35pc of water and only 10pc of the land required to produce the same 1 billion kilograms of milk.
Waste outputs were similarly reduced, with modern dairy systems producing 24pc of manure, 43pc of methane and 56pc of nitrous oxide per billion kilograms of milk compared with what was produced in 1944 for the equivalent milk output.
In 1944, the US dairy population totaled 25.6 million cows that produced a total of 53.0 billion kg of milk annually.
It was characterised by pasture-based systems and rations reliant on home-grown forages with few purchased concentrate feeds.
Draft horses powered the majority of agronomical operations, with only 1.2 tractors employed per farm.
Inorganic fertiliser use was not yet widespread; instead, animal manure was used to fulfill crop nutrient requirements.
The researchers noted that many characteristics of 1944 dairy farming - low yielding, pasture based, no antibiotics, inorganic fertilisers or chemical pesticides - are similar to those of today's organic systems.
In contrast, the researchers said, the 2007 US dairy herd was comprised of only 9.2 million cows with an annual milk production of 84.2 billion kg.
Typical modern dairy production systems are characterised by the use of total mixed rations formulated to fulfill nutrient requirements, together with herd health and management programs and facilities designed to minimise stress and maximise production.
Furthermore, feedstuffs used in modern systems are harvested from high-intensity row-crop farming practices, they said.
The carbon footprint per billion kilograms of milk produced in 2007 was found to be 37pc of equivalent milk production in 1944.
"The 2007 dairy industry produced 59pc more milk (186 billion pounds versus 117 billion lb.) using 64pc fewer cows (9.2 million versus 25.6 million)," said Dr Capper.
She noted that this major improvement in efficiency reduced the carbon footprint per gallon of milk by 63pc.
Furthermore, Dr Capper said the total dairy industry carbon footprint was 114 million tonnes in 2007, just 59pc of the 194mt produced in 1944.
The researchers' work was recently published in the Journal of Animal Science.
Dr Capper is now an assistant professor of dairy science at Washington State University.
A copy of the complete research, as well as a video interview with the researchers, can be found on FeedstuffsFoodlink.com.
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