Publications by authors named "Susan H Hayes"

Titanium dioxide has been used as a marker for determining diet digestibility indirectly, but some authors have expressed difficulty in measuring TiO2 concentrations in fecal material. We developed an accurate and precise method to determine TiO2 concentrations in equine feces. The method includes dry-ashing samples, digestion with (NH4)2SO4 in concentrated sulfuric acid, followed by the addition of H2O2 to produce a yellow to orange color that can be read spectrophotometrically.

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The use of hair as a sample matrix to determine the mineral status of an animal has received a lot of interest. The objective of this study was to determine if the trace element content in horse mane hair changed with age when evaluated in a group of horses representing a large age range. As a second objective, whole blood trace element content was evaluated, and its relationship to mane hair trace element content, as well as age, were tested.

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Equine obesity is increasing in prevalence, and weight loss diets are frequently recommended for these horses. However, there are also management situations in which horses are deemed to be too thin. To monitor the efficacy of weight change programs, estimates of body fat are often made.

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Across the equine literature, estimates of true P digestibility range from -23% to 79%. This large range cannot be explained by differences in P intake or phytate-P intake alone. However, differences in endogenous P secretion into the GI tract may explain the variation.

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Dietary starch source has been shown to affect fecal bacterial communities of horses fed minimally processed cereal grains. However, processing may increase foregut starch digestibility, reducing effects of starch source on fecal bacterial communities. This study aimed to determine the effect of starch source in pelleted concentrates on fecal Lactobacillus spp.

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Adult horses depend on the microbial community in the hindgut to digest fiber and produce short-chain fatty acids that are use for energy. Colonization of the foal gastrointestinal tract is essential to develop this symbiosis. However, factors affecting colonization are not well understood.

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Starch from corn is less susceptible to equine small intestinal digestion than starch from oats, and starch that reaches the hindgut can be utilized by the microbiota. The objective of the current study was to examine the effects of starch source on equine fecal microbiota. Thirty horses were assigned to treatments: control (hay only), HC (high corn), HO (high oats), LC (low corn), LO (low oats), and LW (low pelleted wheat middlings).

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