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[RC] What the Abstracts Say...and Don't Say (was: Beet Pulp) Part 3 - katswig@xxxxxxxxxxxxxcontinued from part 2.... The second study: ----------------- Hydrolyzable carbohydrate intake in horse diets may become excessive when rapidly growing pastures are supplemented with grain-based concentrates. The substitution of fat and fiber for hydrolyzable carbohydrate in concentrates has been explored in exercising horses but not in young, growing horses. Our objective was to compare bone development in foals that were fed pasture and concentrates rich in sugar and starch (corn, molasses) or fat and fiber (corn oil, beet pulp, soybean hulls, oat straw). Forty foals were examined, 20 each in 1994 and 1995. In each year, 10 mares and their foals were fed a corn and molasses supplement (SS) and 10 others were fed a corn oil and fiber supplement (FF). The concentrates were formulated to be isocaloric and isonitrogenous, and mineral content was balanced to complement the pastures and meet or exceed NRC requirements. Dorsopalmar radiographs were taken of the left third metacarpal monthly from birth to weaning and then every other month until 1 yr of age. Bone density was estimated using imaging software and an aluminum stepwedge. Radiographic examination indicated differences in medial, lateral, and central bone mineral content of the metacarpal III. Bone mineral content increased with age, and a plateau was observed during winter. Bone mineral content was lower in weanlings and yearlings fed the FF supplement than in those fed SS. Subjective clinical leg evaluations indicated differences in physitis, joint effusion, and angular and flexural limb deformities in response to age, and possibly to season. Regression analysis indicated positive relationships between bone mineral content and body weight, age, and body measurements. Nutrient and chemical interactions, such as the binding of calcium by fat and fiber, may alter the availability of elements necessary for bone development. What it says they did: Over the course of two years they supplemented the pasture diets of 20 mares and foals with corn and molasses and 20 mares and foals with corn oil, beet pulp, soybean hulls, and oat straw. These two separate supplements were formulated so that they had the same amount of calories and the same amount of nitrogen, along with "balanced" minerals. What it doesn't say: It doesn't say what type of pasture the horses were on. It doesn't say (because it can't say, there is no way to know), what effect on pasture grass consumption the supplements had (so there is no way to know what was "taken out" of the horses diets by having been supplemented). In fact, because there is no way to monitor pasture grazing consumption of the horses in question, there is no way to know exactly what these horses were being fed; consequently, while the coloric content of the supplements was created to be the same, the caloric content of the entire diet is unknowable (this is not irrelevant). It doesn't say that the mineral content of both supplements was the same, only that they were balanced to the pastures to meet or exceed NRC requirements. What it says they observed: Through evaluation of x-ray it appears that mineralization in the left front coffin bone was less in the horses fed the fiber and fat supplement than for those on the corn and molasses supplement; however, that this was also correlated to age and size. It also says that they observed some differences in joint development and limb deformities, and that these appear to correlate to age and season. Bone mineralization was also affected by season. What it doesn't say: No mention is made of differences in joint development and limb deformities being correlated to diet. It doesn't say what the effect of beet pulp is because none of the horses were supplemented with just beet pulp. It is impossible to separate the effects of beet pulp from those of fat, soy hulls and oat straw included in the fat and fiber supplement. There were no mares and foals in the study on a "control" diet (i.e. not supplemented at all); consequently the effects of increased bone mineralization in the horses supplemented with corn and molasses v. those supplemented with fat and fiber may not be because the fat and fiber horses are getting beet pulp, but rather because they are not getting corn and molasses. No mention is made of observing or monitoring the exercise that these foals got. While the authors of the study speculate in the abstract that the lowered bone mineralization observed in the fat and fiber supplemented horses might be because fat and/or fiber might bind to calcium and make it unavailable, it is certainly not the only explanation. Since it is well documented that bone density is a function of activity/concussion, the observed differences in bone density could be a result of increased activity of horses on a sugar high rather than because beet pulp affects mineral absorption. It is also well documented (and is even confirmed by this study with the correlation of bone density to age, weight and size) that bone mineralization responds to the impact/concussion of having to carry around more weight, and that despite the fact that the supplments contained the same number of calories, that the overall diet of the corn/molasses supplemented horses had more calories because it was less bulky, could be consumed faster, and therefore did not reduce the pasture intake of the foals as much as the fat fiber supplement did. ----------------------------------- Most importantly, what none of these abstracts say is this (Tom Ivers 31 July, 2005): The gist of the papers is that beet pulp acts as a modest chelator. It does attach itself to forms of metals (minerals)and pull them out of feedstuffs to be eliminated. It does so enough to compromise bone density and bone mineral content in growing foals. It also limits digestion of other macro-nutrients, carbs and fats in the case of the paper included in that small batch submitted. In contrast, plain hay contributes some minerals and other micronutrients to the blood stream. 1. Not once is the word chelate mentioned although the bone mineralization study alludes to the possiblity that calcium might bind to fiber or fat. 2. Not all minerals are metals (calcium comes to mind). 3. The effect of feeding beet pulp on growing foals cannot be separated from the effect of feeding fat in the form of corn oil as well as soybean hulls and oat straw. 4. Nowhere in any of the abstracts does it say any of the subjects were fed plain hay, let alone what effect doing so may have. 5. The only analysis mentioned of what is in the blood stream were the plasma concentrations of amonia and creatinin, neither of which is a micronutrient, so none of the studies mentions anything about what effects any of the dietary variations (including hay or beet pulp) in these studies has on micronutrients in the blood stream. Nor does it say this (Tom Ivers 1 August, 2005): It means that beet pulp does interfere with mineral absorption in the horse--to the extent that its feeding in foals results in measureably weak bone. I refer you to note 3 above. However, (and here I confess to having cheated slightly, by reading beyond the abstract provided by Tom), in the bone mineralization study in foals the authors provide the following implications: "In growing horses, metacarpal bone mineral content increases may be modulated into seasonal waves with two plateaus, the first by a change in diet from mainly milk to mainly pasture and supplement, the second by a decrease in activity on ice and packed snow. Differences in energy source of concentrates fed in supplement to pasture may influence metacarpal bone mineral content in growing horses. Horses consuming diets containing fat, which may form calcium soaps, and fiber, which tends to capture cations, may have an increased requirement for calcium and other minerals. Nutrient and chemical interactions may alter the availability of elements necessary for bone development." So, it may be that the conclusions Tom leaps to that are not supported by reading the abstracts are because Tom did as he himself suggested and only read the first and last lines of the abstract, rather than reading the whole paper. Because, certainly, the authors of the paper, in their implications readily acknoledge that bone mineralization is most likely a function of energy and activity; although it might have something to do with feeding fat because fat can bind to calcium or by feeding fiber. "Nutrient and chemical intereactions [of diets containing fat and fiber] MAY (emphasis mine) alter the avilabiltiy of elements necessary for bone development" is a LOOOOOOONNNG way from saying "feeding beet pulp to foals results in measurably weak bone." So if I read these abstracts, they raise some questions that suggest further investigation, and, what this "science" tells me is that they don't KNOW very much. But what I do know is that I have little faith in Tom Ivers's ability to glean relevant information or report rational conclusions (if there are any to reasonably be drawn from the avialable data). Not just because the summation he provided in his post of 1 August is not supported by the abstracts he provided in his earlier post of 31 July but also because it is difficult for me to give any credence the rational abilities of any person who is so easily provoked into irrational invective, since he did so in response to Steph's virtually innocuous request of, in essence, "could you please explain?" while attempting to avoid provoking him by stroking his ego with, in essence, "you are so much smarter than all of us." This does not mean that he cannot provide useful information. Certainly he has investigated a great deal of the available literature with respect to what is currently being investigated, and, as a consequence, can provide a useful bibliography for anybody who wants to do any investigating on their own (and make no mistake this is an EXTREMELY valuable service). However, I would be leary of taking any of his advice without confirming the source for yourself, since he has demonstrated a proclivity for leaping to conclusioins not supported by the data. And I would take it as a given that if you ask for clarification that he will jump down your throat. This jumping down your throat MIGHT also include more bibliographical information, in which case you could get additional valuable information so long as you can ignore the accompanying invective; which isn't really all that hard to do. Because I find the bibliographical information extremely valuable (it is, in fact, in essence, what the Internet was invented for, scientists who wanted to be able to hyperlink to relevant papers), I am thrilled that he has joined us to provide this information. Just be careful about accepting his conclusions or asking him to interpret things for you. In this, I have found him to be less than 100% reliable. kat Orange County, Calif. -------------------------------------------------------------------- mail2web - Check your email from the web at http://mail2web.com/ . =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Ridecamp is a service of Endurance Net, http://www.endurance.net. Information, Policy, Disclaimer: http://www.endurance.net/Ridecamp Subscribe/Unsubscribe http://www.endurance.net/ridecamp/logon.asp Ride Long and Ride Safe!! =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
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