Research: Effects of Bovine Somatotropin Treatment on Performance, Reproductive, and Physiological Responses of Replacement Beef Heifers

Oh yes, rBST (or BST, rBGH, “hormone injections”, “chemicals”, or any lay term the media can come up with), clearly the reason we are all getting cancer with every steak we eat and glass of milk we drink (second only to cell phone radiation and airport scanners). Animal science faces many of the same problems as food science. If the media can report on it and with scary images, all the while promoting ignorance of the processes of food production, then they will gladly jump on any and all practices in food production. This is super effective because everyone eats, and so we are sensitive to news that what we eat may harm us. I’ll discuss a little more about rBST use in Oregon, but fist I want to examine this proposal we’ll be examining at the EOARC.

The premise of the proposal is that in cow-calf operations, replacement heifers become less and less financially viable if they take longer to reach puberty, or miss their first breeding season. Previous research done at the EOARC has shown that higher IGF-1 (insulin like growth factor 1) concentrations are found in heifers that reach puberty by 12 months compared to non-pubertal heifers of the same age (Cooke et al., 2007). These levels are usually encouraged by using a high plane of nutrition; however, in eastern Oregon we generally run our cow-calf operations on poor forage because it’s economical, it’s what we have, and what we can take advantage of. The idea of the study then, is to see if rBST administration will result in higher IGF-1 levels which will hasten puberty compared to untreated cattle. Additionally, because the normal high plane of nutrition would also raise levels of insulin, blood glucose, and leptin which could also affect onset of puberty, this study will single out IGF-1 levels and determine if the absence of those other factors plays a role in puberty onset.

The procedures are pretty standard, so I won’t rewrite them all here, I’ll post the proposal below so you can read them yourself if you want to examine the methods. One thing I’m impressed by is the rotation of bulls between the treatment and control groups to account for bull effects. I’ve learned about estrus synchronization and other pheromone effects in repro, but the effects a specific bull might have are even more interesting. I wrote about one of these effects when looking at stallions kept on home pasture with pregnant mares a while ago, and was fascinated by the idea of spontaneous (or conscious!) abortion in the presence of specific stallions.

One thing I was a little concerned about is the sample size of the proposal. I’m told anything over 20 is considered viable, but you can’t really lock in any trends you may find with a sample size that small. This particular study will use 40 cattle, which makes the control and treatment groups composed of 20 animals. I think that we’ll still get good data, but that more research with more animals will be necessary to fortify the conclusions that come out of this study.

So that’s pretty much all I have for this one, it’s pretty straightforward. The only problem I have is that, while I support the use of rBST, the current trend is to abandon its use, which may end up making this research obsolete.

This needs to be said in any discussion about the hormone, and it isn’t said enough: the FDA has not found any significant effects resulting from the ingestion of milk from rBST treated cattle. It’s clever advertizing! And we as consumers have to start making the harder choices. We either have to start paying more for our food, or allow our farmers to use safe treatments to increase yields. We can’t have it both ways. I admire people who buy organic items because by purchasing them at a higher price they acknowledge that our agriculture industry needs to make money, and that the margins for small farms are incredibly slim. It’s the ones who want to limit the industry by preventing the use of tools that increase production, but still want to pay 2 dollars for a gallon of milk that make it harder and harder to strengthen the industry.

Coincidentally, this is why student fees and current national budget are so hard to set. No one ever wants to pay more, but we certainly can’t take away any of our provided services either. Something has to give there.


You can read the full research proposal here.

You can read a statement from the FDA on “rBST free” labeling here.

You can read a short statement (followed by a list of stores that sell rBST free milk) from the Oregon Physicians for Social Responsibility here. This group has worked hard to discourage use of rBST in small dairy’s across Oregon.

Research: Effects of disposition and acclimation to human handling on feedlot performance and carcass characteristics of feeder steers

So as I’ve mentioned before, this summer/fall I’ll be interning at the Eastern Oregon Agricultural Research Station (EOARC) in Burns, Oregon under Dr. Reinaldo Cooke. So my next few blog posts leading up to that will concern the research that we will be conducting, as well as a brief look at previous similar experiments that have been conducted at the station or elsewhere.

The first one is one that I’ve actually discussed on this blog before, and it concerns the effects of disposition and acclimation to human handling on cattle in all life stages. Previous research has examined heifers and cows, looking mostly at reproduction, performance, and temperament (note, there has been more recent research on the subject, however it is not yet published online). The new proposal that I will get to help work on will be concerning steers and feedlot performance.

The overall purpose of the study isn’t to find anything drastically new, as calm disposition has already been shown to be beneficial for general and feedlot performance in other settings. Primarily the goal is to examine cow/calf operations as they are used in Oregon (large rangeland scenarios, not drylots), promote selection for calm disposition as a production trait, and show that acclimation to handling is a possible and beneficial way to attain higher yields (in terms of carcass quality).

In terms of the methods, I’m still reading and rereading all of these so that I’m very familiar with the experiments we will be running. As far as the acclimation process goes, we’re going to be spending time with the experimental group for two hours, three times a week before they go to the feedlot. During that time we will run them through basic handling procedures, and during feeding times we will walk around in close proximity to further acclimate them to our presence. At the end of the 60 days at the EOARC they’ll take a 24 hour truck ride (to simulate transport that would normally be long and stressful for most of Oregon cattle) then head to the feedlot in Boardman. The control group will remain free to graze during this time without excess human contact to keep them non-acclimated.

The quantitative data we will be collecting (at multiple points during the experiment) will include: cortisol, inflammatory proteins, IGF-1 (Insulin like Growth Factor), weight gain, feed intake, feed efficiency, health condition, morbidity and mortality, and several carcass characteristics. Our evaluation of cattle disposition will also be quantitative, as it will be evaluated based on chute exit velocity and chute score.

A quick note on exit velocity, when I visited the EOARC, Reinaldo showed me the infrared sensor that they use to measure chute exit velocity. I think that similar devices are used to measure fastballs. I just thought it was really cool. There are a lot of other experiments on temperament out there that examine exit velocity, it’s well proven as a method for determining excitability/temperament/disposition. I just think it’s really cool, and pretty brilliant.

I imagine that we’ll find the expected results, and that the acclimated steers will be less stressed and better producers than the control group. I’m also curious whether this is the last in the series examining this effect, or if there’s still another age group or factor to analyze. This effect on dairy cows has already been examined, so what could be left? There’s nothing except the feedlot. Given the compact and efficient nature of the feedlot, I don’t think it’s financially viable to take the time to further acclimate the animals to the human presence. Hopefully, the acclimation routine done in the cow/calf operation beforehand will be sufficient to promote better performance on the feedlot, and this study will examine just that. I’ll definitely be asking Reinaldo what his future proposals will be, and maybe even get to participate in that thinking process.

Click here to view the actual research proposal.

Article Review: Effects of acclimation to human interaction on performance, temperament, physiological responses, and pregnancy rates of Brahman-crossbred cows

Came across this article when searching for stress studies in cattle. I’ve been more and more interested in examining behavior and stress as I’ve read more Temple Grandin. I think it’s a field I can explore as I look for things I want to do with my DVM. Don’t get me wrong, I love working with clients and animals in a clinic setting, but I don’t see myself as a business owner, and I really want to look at what else is out there. Options I’ve been exploring are USDA jobs, lab work, and of course research through the college and elsewhere. Anyway, Giovanna Rosenlicht got me into the habit of reading journal articles in my spare time, which is great and actually really interesting….I am a nerd.

Anyway I don’t have too much to say about this article, the methods are sound and thorough, 395 animals used is a sample size I can get behind. Too many studies especially with companion animals have pitiful sample sizes of like 20 animals. Anyway, following reading the discussion, the dramatic difference I expected to see in the people acclimated group was not present. However there was a final statement that acclimation did have an inconsistent positive effect on reproduction success.

I have a vested interest in animal welfare, and I strongly support an approach that helps the industry see benefit, rather than dig trenches. Studies like this are the only way non-radical, educated, and effective welfare decisions can be made. What happens when people try to make knee-jerk responses to animal welfare? Look at the ban on horse slaughter and the subsequent problems associated with that piece of feel-good legislation.

Anyway, I get sidetracked, this post was supposed to be concerning the article. One of the main points that is crucial to the focus of the study was the correlation with excitable temperament (as often seen in Bos Indicus ancestry cattle) and elevated cortisol concentrations; which are detrimental to multiple physiological systems in the body, and result in “subclinical health disorders that negatively affect cattle reproduction, such as lethargy, lameness, and immunosuppression.” With cortisol levels (along with epinephrine and many other endocrine secretions that are a result of handling and housing stress) being a quantitative measure of animal health and contentment, this data will add onto the already large stack of evidence that the better we treat our meat/eggs/milk, the better product we receive.

It’s unfortunate that a larger and more consistent correlation was not found within the study, but the data is still sound, and definitely leaves room for further study in specific age groups, species and breeds, and other acclimation techniques.

It is also worth mentioning that this research was carried out in Florida, but one of the authors is now doing research at the Oregon State Burns research station. I’ll be looking for and have found many related articles from that location/author and will be discussing more of those in the future.