Wednesday, March 30, 2011

Links post

As usual, may of these are old, because I don’t have time to keep up to date on my blog reading.

Tuesday, March 29, 2011

The Dairy Welfare Farm Tour, part 2: growing calves

(Continued from The Dairy Welfare Farm Tour, part 1.)

We pulled up at the farm where Dr. Mulain performs a weekly herd check every Tuesday morning, checking a bunch of potentially pregnant cows to determine if they are in fact knocked up. Lots of rectals! While we were sticking our arms inside of cows, Dr. Mulain pointed out that we can tell a lot about how cows are handled by how they respond to us. When you are in the middle of a herd of cows, do they panic and run away? They have probably not had great experiences with humans in the past. Do they come up to you, sniff you, lick you, follow you around, and generally make pains of themselves? It is likely they have had good experiences with humans in the past. These cows were like mosquitoes; I was literally batting them away. When I yelled “Shoo!” and waved my arms at them, they stared at me blankly. They had clearly been handled gently by the farm workers.

After the herd check was over, we visited the calves in their hutches. This farm used the conventional method of raising calves: separate them from their mothers immediately and raise them in tiny hutches that look like plastic igloos. The hutches are typically clustered together in a little village, but must be far enough apart that the calves can't touch each other. Calves typically live in individual hutches like this from birth until shortly after weaning.

Although the little village of hutches is adorable, something in me rebels at the idea of raising social animals in isolation like this, where they cannot touch another member of their species. Why do we do it? We raise them separately to keep them cleaner. Calves inevitably have diarrhea, and if you raise them together, that will be the method of transmission of all sorts of (sometimes fatal) diseases. So it is safer for them to keep them separate until their immune systems mature. Also, taking them away from their mothers leaves more milk for sale (they are most often raised on milk replacer, which costs less than the real stuff).

This method of raising calves is the conventionally accepted one in the industry, and is what we were taught about in our large animal medicine class. But Dr. Mulain told us about a new method that some farmers are trying, and took us to see it in practice on other farms. You can apparently raise healthy calves in groups if you free feed them, in other words, let them consume as much milk, or replacer, as they want. With the extra nutrition, their immune systems are more robust. The calves grow faster, too.

Dr. Mulain said wryly, “Remember, this isn't abnormally fast growth. This is normal growth.” His perspective is that the dairy industry has been feeding calves smaller amounts to cut costs, but this has resulted in weakened immune systems and smaller calves. With time, we have come to see these weakened immune systems as normal, but they are not.

We saw one farm in which calves had access to a big bucket of milk replacer. They were living in a group of just a few calves. Another farm had turned about ten calves in with three lactating cows. Cows chosen for nanny duty were the low producing cows — the ones later in their lactation cycles who produce less milk. It is amazing that we have bred cows to produce so much milk that a low producing cow can easily support three calves! The calves didn’t bond with a particular cow, but just partook of the nearest milk bar. Because these were low producing cows, they were by definition late in their lactation cycle, so it is unlikely that any of the calves were actually theirs.

This approach to raising calves feels emotionally better to me. I don’t like to see babies of social species raised out of physical contact with other social animals. So the approach to raising calves in groups is appealing. Time will tell if it works well, producing healthy calves and saving farmers money.

Saturday, March 26, 2011

Why do veterinarians call them “necropsies”?

When you dissect a human cadaver to investigate the cause of death, you are performing an autopsy. But when you dissect a non-human cadaver to investigate the cause of death, you are performing a necropsy. Why are the terms different?

I’ve always wondered this but never took the time to find out. (Look, I learn 98,347,824 new things every day in vet school. There isn’t room in my head for more.) But you guys wanted to know, so I embarked on some investigation.

Wikipedia doesn’t have an answer. (Wikipedia, you have been disappointing me lately!) Random googling did get me an answer, at, where a veterinarian gives us some definitions. According to this site, the common root of both words is the Greek opsis, or to see. Auto means self, and nekro means corpse. So autopsy means “to see with one’s own eyes,” and necropsy means “to see a corpse.” Under this interpretation, necropsy is just a more specific term, and may be used by veterinarians to differentiate the practice of examination of an animal cadaver from the practice of examination of a human cadaver.

Then I asked some of my rotation mates. They opined that autopsy means not “to see with one’s own eyes,” but “to see one’s self,” in other words, to investigate something which is the same as you — a member of your own species. Under this interpretation, necropsy (seeing a corpse) is more general than autopsy, rather than the other way around.

I also asked The Boy for his assistance. He is usually excellent at finding histories of word usage. His sources failed him this time, though.

What I did not do was ask veterinary faculty. I didn’t get a chance to do so yesterday, and anyways in my experience they don’t tend to be very word-oriented people. One exception to this rule was my favorite pathologist faculty member, who unfortunately is no longer working at my school. Dr. Simmons would rant during lecture about how silly some of the veterinary-specific terminology is. I remember him being particularly amused by the insistence of veterinarians on using the term adhese instead of the more generally used adhere (as in, “the two organs have adhesed,” when you mean that they are unfortunately stuck together in one spot). He also gave a brief lecture about the use of dirigibles during World War II when he was supposed to be telling us about the pancreas, which was so interesting and hilarious that I copied it into my notes word for word. He is missed.

So in the end, I still don’t have much more than conjecture about why veterinarians do necropsies while doctors do autopsies. I confess to liking my rotation mates’ explanation better than the one I found on the web, but I am still curious as to when the two terms divided, and if there was an inciting cause for the division. If you know, tell us!

Thursday, March 24, 2011

A week in the life: pathology rotation

I am in my first week (of three) of my pathology rotation. This is known as the laid back rotation: only 8am to 5pm five days a week, with some on-call time. Mornings are clinical pathology. We read slides, learn to make blood smears, discuss lab test result interpretation. At least so far, none of these have been real cases, but it has been interesting, and I’ve learned a lot.

Afternoons are anatomic pathology. We are learning to do necropsies, on real patients when they are available. So far I have seen: a massive hemangiosarcoma tumor on a dog’s heart; a kidney completely lost inside a mass half a foot long (probably also hemangiosarcoma); a pacemaker inside a dog (not the cause of death, but very cool — and before you ask, it was indeed in the heart, not, say, inside the stomach); several yards of horse intestine that was dead due to a strangulating tumor that had cut off blood supply to it. I have a guilty feeling that I should be enjoying this part of the rotation more, but I am  having trouble getting past being disturbed by the necropsies themselves.

Tuesday, March 15, 2011

The Dairy Welfare Farm Tour, part 1: humane handling certification

I woke up at 6 am, and it felt luxuriously late after my 5:30 am wake up the previous morning. This was the morning of the second of my two electives during third year elective week. The day before I had spent the day in a small animal emergency room. Today, I would ride with a cow vet and some other students, seeing different farms and comparing how they care for their cows. It was chilly, but warmer than it had been, and the weather site I checked suggested a warm afternoon. I dithered between my insulated coveralls and the regular ones, before opting for the regular ones.

Two other students met me at my house, and we made the hour’s drive to the Ambulatory clinic together, where we met the fourth member of our little group. At the clinic, we hovered somewhat aimlessly in the break room and made small talk with the fourth year students there who were on a week of Ambulatory rotation. After a few minutes, Dr. Maolain, who was running the farm tour, walked through and asked us if we all had our boots. We were scornful. Did he really think we would have shown up for a day on farm without boots? (The boots are of course much appreciated when you are walking through a soup of cow manure. They are also more scrubbable than street shoes — easier to hose off and soap before leaving a farm, so that you do not carry infectious disease to the next farm you visit.)

We piled into Dr. Maolain’s truck, a tight fit, and headed out. We had a forty minute drive to our first stop, during which time Dr. Maolain taught us, via a mixture of the Socratic method and long rambles, about the state of third party certification for humane handling of dairy cows.
I have written about this before, but here is the situation in a nutshell: consumers want to buy milk from producers who treat their cows well. Some consumers purchase organic milk for this reason. However, organic certification in no way guarantees cow welfare. Currently, the only way to be sure you’re supporting a producer who treats his cows well is to buy the milk directly from an individual farmer whose practices you know. This is impractical, to say the least, especially for the average consumer who may not know enough about dairy practices to be able to identify those which result in good cow welfare.

One solution to this problem could be third party certification. An organization like American Humane offers certification to farmers for a fee. Consumers then buy milk from producers who are certified by this third party.

Unfortunately, this doesn’t work either! There is no system in place to allow individual producers to have their milk pasteurized and marketed separately. The milk truck collects milk from multiple farms before delivery to the processing plant: if one farmer is certified and another is not, the milk nevertheless mixes together on the truck and in the plant. There is no way to process certified milk separately so that it can be marketed separately.

What’s the solution to that? More processing plants? Maybe, but they are expensive to build, and I don’t know all the relevant issues involved in their funding and construction. It is an interesting problem. I know the public has an interest in milk from humanely raised cows, and it frustrates me that the market systems are not in place to deliver it to them.

(More to come...)