This is an archived Horseadvice.com Discussion. The parent article and menus are available on the navigation menu below:
HorseAdvice.com » Horse Care » Equine Nutrition, Horse Feeds, Feeding » Grains and Concentrates for Horses, an Overview »
  Discussion on Research Summary: High Starch Diet Effect in Weanlings
Author Message
Moderator:
DrO

Posted on Tuesday, Jul 31, 2007 - 7:17 am:

This is a badly needed research project with conclusions that may buck some current assumptions of disease development in young horses. This experiment looks at the effect of starch concentration, in equal energy diets, on the health of growing foals.

Certainly the most interesting conclusion is that a high starch diet did not promote osteochonDrOsis (OC) lesions in growing horses in this experiment. However I still have some questions. It has been pretty well accepted that all foals have some OC lesions at birth or develop shortly after birth. Then these lesions tend to heal as the foal grows. Horses with lameness from OC lesions probably had these early OC lesions but for some reason these did not heal well or worsened. I would like to see an experiment that compared energy levels of the diet and the effect on OC development.
DrO

J Anim Sci. 2005 May;83(5):1033-43.
Influence of starch intake on growth and skeletal development of weanling horses.

Ott EA, Brown MP, Roberts GD, Kivipelto J.
Department of Animal Sciences, University of Florida, Gainesville, 32611-0910, USA\. ott@animal.ufl.edu

Forty-four weanling horses were used in two experiments to evaluate the effect of starch intake on growth and skeletal development\. In Exp\. 1, the weanlings were fed either a grain-based, high-starch (31.1%, DM basis) concentrate or a by-product-based, low-starch (0.0%) concentrate with coastal bermudagrass (Cynodon dactylon) hay\. Corn oil was used to equalize the energy concentration of the concentrates\. The concentrate:hay ratio was 64:36 (as-fed basis), and intake was the same for both diets\. Body weight gains were greater by the weanlings consuming the high-starch concentrate (0.81 vs\. 0.67 kg/d; P = 0.01)\. Total body length gain also was greater for the weanlings consuming the high-starch concentrate (15.5 vs\. 13.2 cm; P = 0.045)\. Other body measurements and bone mineral deposition were not influenced by diet or gender\. At the end of the experiment, postprandial blood glucose concentrations suggested that the horses on the low-starch diet were less efficient in metabolizing blood glucose than were those that had been consuming the high-starch diets\. In Exp\. 2, the weanlings were fed either a high-starch (34.7%) or medium-starch (17.0%) concentrate plus coastal bermudagrass hay\. Corn oil again was used to equalize the energy content of the medium-starch concentrate to that of the high-starch concentrate\. The concentrate:hay ratio was 64:36 (as-fed basis), and the intake was the same for both diets\. The diets did not influence rate of gain (0.75 kg/d; P = 0.98), body measurements (P = 0.11 to 0.93), or bone mineral deposition (P = 0.66)\. Animals on the medium-starch diet tended to have blood glucose concentrations that peaked earlier and were lower at later times than those consuming the high-starch concentrate\. Bone osteochonDrOtic lesions were not related to the diet and were found to decrease during the course of the experiment for both the high-starch and the medium-starch diets (P = 0.006 and 0.016, respectively).
Member:
stevens

Posted on Tuesday, Jul 31, 2007 - 8:37 am:

Hmmm, I'd always heard that while diet was important, that the primary issue for babies was turnout.

Did the study indicate the turnout situation for the weanlings in the study?
Moderator:
DrO

Posted on Wednesday, Aug 1, 2007 - 7:49 am:

Hello Chris,
In the above experiment turn out is controlled for across the different experimental groups so is not a factor that can be examined, it just compares different starch intake.

When you say "turn out" do you mean turn out causes an increase in clinical OC or that it is protective? While we know lots of stall time is bad for the healthy development of the cartilage of the joints and therefore logical to assume it may increase the incidence this is not clearly shown anywhere. Here is a wonderful synopsis of the current state of knowledge:

Etiology and pathogenesis of osteochonDrOsis.
Ytrehus B, Carlson CS, Ekman S.
Section for Wildlife Diseases, National Veterinary Institute, PO Box 8156, N-0033 Oslo (Norway). bjornar.ytrehus@vetinst.no.

OsteochonDrOsis is a common and clinically important joint disorder that occurs in human beings and in multiple animal species, most commonly pigs, horses, and dogs. This disorder is defined as a focal disturbance of enchondral ossification and is regarded as having a multifactorial etiology, with no single factor accounting for all aspects of the disease. The most commonly cited etiologic factors are heredity, rapid growth, anatomic conformation, trauma, and dietary imbalances; however, only heredity and anatomic conformation are well supported by the scientific literature. The way in which the disease is initiated has been debated. Although formation of a fragile cartilage, failure of chonDrOcyte differentiation, subchondral bone necrosis, and failure of blood supply to the growth cartilage all have been proposed as the initial step in the pathogenesis, the recent literature strongly supports failure of blood supply to growth cartilage as being the most likely. The term osteochonDrOsis has been used to describe a wide range of different lesions among different species. We suggest a refinement of this terminology to include the modifiers latens (lesion confined to epiphyseal cartilage), manifesta (lesion accompanied by delay in endochondral ossification), and dissecans (cleft formation through articular cartilage).
DrO
Member:
stevens

Posted on Wednesday, Aug 1, 2007 - 10:11 am:

Hi Dr. O,

I did mean to convey the idea that turn out was protective against OC. Thanks for clarifying and the great summary.

Sigh! Some day we'll have ALL the answers, right?

Regards,
Chris
Moderator:
DrO

Posted on Thursday, Aug 2, 2007 - 7:06 am:

I don't know Chris, the universe seems designed so that each answer leads to at least 2 more questions. We have a lot more questions today than did 17th century man and in the late 20th, just before Einstein, some physicist said that just about everything that can be known was or will shortly be known. In a way I hope not, life will be so boring on that day.
DrO
Member:
ilona

Posted on Tuesday, Aug 7, 2007 - 8:48 pm:

A most interesting thread. Thank you, especially as Nirvana is about to become a weanling. I can't believe 6 months has gone by so fast.
Home Page | Top of Page | Join Us!
Horseadvice.com is a BBB Accredited Business. Click for the BBB Business Review of this Horse Training in Stokesdale NC