As of right now, I have seven goals that I am hoping to accomplish, but in reality there is no way that I can map out exactly where this experience is going to take me. I might stumble upon things that I wasn't anticipating that could create new goals and a shift in my focus—who knows! Some of my goals are exclusively focused on the wild horses and others on the domestic animals, but several of them offer a combination of the two to create a bigger picture of what this experience is about:
1) To learn general science-based research skills through lab work and data analysis that will be beneficial to any area of science, not just veterinary science
2) To develop an idea of what working as a veterinarian would be like and ascertain whether it would be something to pursue as a career
3) To determine the level of internal parasite infestation in feral horses versus domestic animals through lab work and data analysis
4) To evaluate the relationship between body condition score and fecal parasite egg count in feral horses
5) To understand the resistance of bugs, such as Heartworm in dogs, as a result of dewormers and medications
6) To apply animal-related research to medicine in humans, such as how resistance and superbugs are being built up in response to misuse and overuse of medications
7) To gain a greater understanding of how the population of feral horses is controlled and how birth control plays a role in this management
Today's focus was mainly on the last goal, learning about how the overpopulated wild herds are now being managed through a birth control vaccine. First, though, I read about the history of the wild Corolla mustangs.
These horses have been proven through DNA testing to be descendants of Spanish mustangs brought to the United States by explorers and colonists as long ago as the 1500s. However, they no longer roam the village of Corolla as they did for hundreds of years, as highway NC12 was completed in the mid 1980s and excessive development closed in on the the wild animals' space. The Corolla Wild Horse Fund then moved the wild horses north of Corolla to the last remote and mostly undeveloped land on the northern-most reaches of Currituck Banks, but these banks won't stay remote and undeveloped forever; the wild horses' future is still threatened by the pressures of incessant development. Because of this constant pressure and the decrease in the horses' amount of land, the population growth in the herds began to outstrip the capacity of their ranges to support them.
Today I watched a series of six videos by Dr. John Turner, who is a professor at the University of Toledo and has designated much of his career to finding a way to manage wild herds all over the country. (Here is the link to the videos: https://itunes.apple.com/us/itunes-u/wild-horse-population-management/id559317069?mt=10.) Previously, the only non-lethal way to limit population growth was to remove horses from the range, but that is not a viable long-term solution for several reasons. First, there is no way to keep up with the reproduction rate of the horses while trying to reduce the size of the herd. Second, once the horses are removed, there is the burden of trying to figure out what to do with them. Usually the older horses go to warehouses and the younger ones go for adoption, but again, there is no way to stay ahead of the population when it is rapidly growing. In addition, warehousing horses is currently costing about 30 million dollars a year.
Therefore, as Dr. Turner said, the only non-lethal way to control population is to reduce the rate of production, which would completely eliminate the need for warehousing. To be implemented, this fertility control agent had to meet many criteria: it had to be reversible; highly effective; completely biodegradable and unable to pass through the food chain; cost effective; have a multi-year duration; no disruption of social and sexual behavior; no effect on existing pregnancy; and no toxicity to the recipient or applicator. The first contraceptive that was tried was a steroid hormone and was effective but impractical, as it caused behavioral side effects and contaminated the environment. The second contraceptive tried, called Porcine Zona Pellucida (PZP), was extremely successful and is still used today to manage herds. PZP meets all of the above criteria and, unlike the steroid hormones, has no behavioral side effects and does not release any byproducts into the environment, in addition to the fact that it is reversible and lasts 3-5 years.
This vaccine quickly proved that it worked as well as it seemed it would! It was first implemented in 1994 (the horses are coraled into chutes and given an injection with the vaccine), and population growth immediately leveled off. Within a few years it began to decline, as mortality rates began to show, because of fewer foals being produced. This graph shows a 38.5% reduction of population in the herd from 2001 to 2011.
Also, before PZP, many horses had to be taken out of the herds because of overpopulation and the risk of destroying the land. However, as this graph shows, by 2011 PZP had done such a good job of managing the population that none of the horses had to be removed from the herds.
After watching Dr. Turner's videos today, I decided to email him with a few questions, and I already got a reply! I told him about my upcoming experience and asked if PZP was used to control the Corolla herds where I will be going. He replied that yes, it is used to control the wild Corolla horses in addition to many other wild animals, such as deer! Because he mainly deals with horses in the west, he referred me to his colleague, Dr. Allen Rutberg, who handles population control of the herds on the east coast.
Tomorrow I will be researching and reading about several different parasites that I will be examining in the wild horses. Dr. Paul Siciliano, my mentor, also sent me a video to watch on how to examine fecal examples so that I'll have an idea of what to do when I get there.
Hi Grace-- great first blog entry! I have a very clear idea of your very ambitious goals. I applaud your willingness to be open to your goals being transformed as you learn more but also encourage you to identify two or three main (global) goals that you will be dedicated to achieving (your first two goals seem to me to be such goals). Next, I encourage you to think about how we'll know whether you've achieved those goals? What kinds of evidence will you produce?
ReplyDeleteYou are off to a great start. I look forward to following your journey. It looks like you've got lots of resources and too many goals to add anything, but one thing came to mind as I read your blog and that is, what about the ethics of the entire situation? What damage do these horses (non-native species) do to the environment and how are they forcing out other (native) species-- flora and fauna? I know there is some controversy in the scientific community about whether these horses should be supported at all or if they should simply be eliminated. What do you think about that?
Hi Mr. Boehm!
DeleteWhen I was designing this winterim, the very first goals that came to mind were the first two goals that I have on my list. I agree with you in the fact that those will not be likely to change, and they are the ones that I will be most dedicated to achieving. I am keeping a notebook with all of my notes from articles and experiences, which could be one way of providing evidence for achieving my goals. I will also be doing a lot of research in the lab, which pertains to my first goal, so I was thinking that I would do some sort of lab report after my time in North Carolina, which would also cover several of my other goals.
You're right--there is some controversy when dealing with the issue of population management and the use of birth control. Some people say that the horses are wild and human interference should be avoided, but at the same time, the herds would get wildly out of hand and destroy the land if their population was not being managed. In addition, many argue that using birth control is a much more ethical solution to this problem than packing horses into warehouses for much of their life.
Although the wild horses do cause some damage to the land, they help it in ways, too. Negative impacts include that they trample vegetation, pack the soil down, and overgraze the land. Also, it has been shown that inhabited areas tend to have fewer plant species, less plant cover, and more invasive grasses, which then affects smaller reptiles and mammals that depend on burrows and brush cover to survive and breed. However, like I said, there are also many positive impacts. For example, in comparison to cattle, horses actually do very little damage to the land. This is because cattle do not have top teeth and in order to graze, they wrap their tongue around the grass and rip it out. This often causes the grass to be pulled up by the roots and then cannot grow back. Horses, however, have top and bottom teeth, which allows them to cut grass much like a lawn mower without ripping it out by the roots, allowing it to then grow back. An article that I read said that when looking at a boundary fence where horses range on one side and cattle range on the other, the horses' side typically reveals about 30% more native grasses. In addition, horses' digestive systems do not thouroughly degrade the vegetation they eat; this allows the seeds to pass through the system undegraded and are then able to fertilize the land. Enriching the soil also helps it absorb and retain water upon which many diverse plants and animals depend. Also, because of this water retention, less fires occur in fire-prone areas. Another benefit of the wild horses in an ecosystem is that during the winter, they are able to break open water sources with their hooves, which then allows smaller animals to drink.
I think that these wild horses should not be eliminated, as they have been around for hundreds of years, especially since this method of birth control has proven to be successful. As long as their population can be moderated and they are not destroying the land, they should definitely be supported and protected.