Normally, I am of the opinion that buying organic is generally better because 1) you can be sure that what you are buying is free from chemicals, additives, hormones, antibiotics, etc, 2) you are reducing your environmental footprint, and 3) you vote with your dollar and increase the demand for better quality food. However, the cost of organic milk has been rising over the past few years and is at least double (sometimes triple) the cost of non-organic milk. So it begs the question of if it is worth the extra price?
Should you buy organic dairy?
Before I delve into the topic further, I will say that the key principle of buying organic is it is more beneficial to buy organic with the items that make up the majority of your diet. For example, I eat tons of kale and berries, but I rarely consume dairy. So for me buying organic kale and berries would make more sense than buying organic dairy.
There are really two ways to look at this topic.
1) Organic milk from industrial-scale producers (i.e Horizon) vs. conventional milk
From an animal treatment perspective, industrial scale producers of organic milk still keep their cows in CAFOs (concentrated animal feeding operations), very rarely let them feed on a pasture, and subject them to the same stressful conditions as factory farms. In essence, these dairy cows are diseased and depressed just like their conventionally farmed counter parts, but are just not loaded up with antibiotics. Environmentally, industrial scale producers of organic milk are still creating the same amount of waste and pollution, even if they are marginally better by eliminating antibiotic/hormone use.
From a health perspective, all milk, conventional or organic, is tested for antibiotics before being sold to the consumer. Many people are concerned about traces of the growth hormone (rbST) in conventionally farmed milk, but there are conventional producers of milk that do not administer the growth hormone to their cows. Of course, the cost of non-rBST treated dairy is typically higher, but the premium is not as high as organic dairy. Also, organic milk is ultrapasturized to increase shelf life. There has been some evidence to suggest that the high heating temperatures of ultrapasturization actually reduces the quality of the milk and removes some of the nutrients.
If given the choice between organic milk from industrial scale producers and conventionally farmed milk, I would say that the premium of organic milk is not worth the benefits.
2) Organic milk from small-scale family farms or co-ops of family farms vs. conventional milk
Small-scale family farms generally have better practices, as a result of having the means to allow the cows space and land for pasture. Small-scale farmers tend to the land better, produce less waste, and have a human connection to the farm. However, being certified organic is a huge expense and takes time.
If you find a small scale farm that is producing quality milk, but isn't certified organic don't rule it out. The cows on that farm might have even more grazing time than those on the farms that are certified, but the farmer might not have been able to chalk up the expense to get certified. This is why I think buying dairy from farms where the cows are grass fed is the best option. Although it may or may not be organic, you can ensure the cow was at least a happier cow than the cows that were unable to graze. In addition, grass-fed has it's own health benefits (higher amounts of omega-3 fatty acids and CLAs).
If given the choice between organic milk from small scale farms and conventionally farmed milk, I would purchase the milk from the small scale farm.
In my opinion, the order basically goes like this:
Buy grass fed over organic and conventional.
If you can't buy that or it's too expensive, buy organic from a family farm over conventional.
If you can't find that or it's too expensive, buy conventional non-rBST treated milk.
If you want a quick resource to see if the organic milk you are buying is worth it, The Cornucopia Institute has a great scorecard of organic dairy producers which you can find here. If you are interested in more information, they also have a great paper on Maintaining the Integrity of Organic Milk.