The environmental impact of dairy cattle continue to be in the news as global warming concerns are raised due to methane production and carbon dioxide relationships. Dairy cows produce methane when digesting feed in the rumen which has 25 times more impact compared to carbon dioxide. While a wide range of claims have been made, 6 percent of the total carbon footprint is from agriculture with dairy responsible for 11 percent of the total 6 percent or 0.7% of the total is related to dairy production. The real story is the huge reducing in the dairy carbon foot print due to the improved efficiency in producing milk. Using 1944 as the base year of comparison (largest number of dairy cows in the U.S.), the number of dairy cows have dropped from 25.6 million cows to 9.2 million cows while milk production increased from 117 billion pounds of milk to 186 billion pounds of milk. Using pounds of carbon dioxide per gallon of milk as the carbon footprint value, it dropped from 31 lb in 1944 to 12 pounds per gallon in 2007. Thus, the dairy industry has become very "green". The National Academy of Science published a peer reviewed paper in 2008 reflecting two strategies in dairy production; the improving of milk production efficiency and impact of organic dairy production to convention production. One challenge is when technology is being denied that improved dairy efficiency (not using GMO application such as crop or rBST). For example if one million U.S. cows produce 10 lb more milk per day due to technology adoption, the following impacts could be expected.

• Reduce 157,000 cows needed to produce the same level of milk
• Reduce 219 fewer hectare of land for feed production
• Reduce methane emission by 41 million kg annually
• Reduce manure excretion by 2.8 million tons annually

Another application was comparing organic milk production to conventional milk production results in needing 25 percent more cows, 30 percent more land for feed production, 39 percent more nitrogen excretion, and 13 percent increase in global warming potential. What does the National Academy of Sciences peer reviewed research results mean to consumers, producers, and the environment.

• For consumers, it requires careful analysis to determine if carbon foot print and global warning applications are more important than denying technology applications, especially when that technology does not change nutrient content of food or impact animal health.
• For dairy managers, increasing milk production efficiency will reduce carbon foot print, nitrogen efficiency, and reduce global warming; these dairy managers are increasingly more "green".

For the environment, using fewer resources to produce food will improve the carbon footprint.

China is back in the news with the recall of milk products due to the addition of melamine, an industrial chemical used plastics and fertilizer production. The appearance of this product has created to crisis in China leading to the death of babies (contained in infant formula) and 340 children hospitalized with kidney disorders, and 54,000 infants exposed to the compound. Initially, Sanfu Group was the only milk company involved due to their relationship with Fonterra, New Zealand's largest export of milk and now has expanded two several more China milk processors. Milk has been pulled from stores and formal apologies extended by government and company officials.

Melamine contains nitrogen which increases the protein content in milk when tested. By adding this compound, milk appears to be higher in protein content and nutrient value. Part of the reason this occurred is limited quality control and higher feed prices resulting in cows receiving lower quality rations, especially in small family dairy farms. Chinese also want to increase their intake of milk from 15 grams to 150 grams a day with over 2 billion consumers increasing the demand for higher quality nutrients. The large industrial dairy herds have not added the compound to their milk supply. Currently, inspectors are located on farms monitoring milk quality.

The concern has spread around the world as Chinese milk products can be found in numerous food products such as candies, cakes, and bakery leading to recalls in the U.S. Earlier in the U.S. this product appeared in dog food leading to health problems and product recall.

The take home message for U.S, consumers is that the U.S. dairy supply is safe due to the constant testing and regulation for food safety. No antibiotics, pesticide, herbicides, or other chemicals can be added and are monitors regardless of type of milk (organic, natural, and wholesome milk sources).

The dairy managers also know the important of safe guarding milk quality and safety when feeding and managing dairy cows. The knowledge base is key for dairy farmers.

Finally, consumers will continue to ask where their food sources are coming from as these problems continue to occur in the food chain including vegetables, spinach, and lettuce.