Comparison of Nutrient Digestibility Between Adult and Aged Horses

The Effect of Diet Composition on the Digestibility and Fecal Excretion of Phosphorus in Horses: A Potential Risk of P Leaching?

“…This is well in line with the results of van Doorn et al [18] for adult horses (2.4-15.4%). However, higher values (4.2-28.7%) have also been reported [15,34,36] for adult horses (with a range between 4 and 25 years). In many studies the digestibilities show impaired values with increasing age.…”

“…The largest digestibilities (37-42%) have been reported for young horses (8-months-olds), but they decline quickly (to 2.0-7.7%) when the horses are between one and two years old [7,12]. Elzinga et al [36] reported digestibility of 4.2% for aged (19-28 years) horses. P digestibility is therefore influenced by the age of the horse.…”

Nutrition considerations for the aged horse

“…However, these changes may just have reflected parasitic damage and/or poor dentition rather than age per se (Ralston et al 2001;Ralston and Harris 2013). Elzinga et al (2014) compared the macronutrient digestibility of three different diets (hay only, hay with an oil rich complementary feed and hay with a starch and sugar rich complementary feed) when fed to both adult (5-12 years) and aged horses (19-28 years). No difference in the digestibility of energy, crude protein, fibre, fat, calcium or phosphorus was found between the two groups of healthy animals, which had received regular anthelmintic as well as dental treatment.…”

Nutritional Management of the Older Horse

“…Given the importance of the hindgut microbiome on the digestion of dietary fiber, it was noteworthy that age-related alterations in bacterial diversity were not accompanied by measurable differences in the apparent digestibility of any macronutrient or mineral evaluated. 37 Despite this evidence that digestive efficiency appears unaltered by age in healthy horses, many compounded senior horse diets contain extruded or finely ground cereals to improve fiber digestibility, increased concentrations of crude protein (12%-16%), phosphorous (0.45%-0.5%), and reduced calcium (<1%). Evidence for these products dates from a 1980s study that compared geriatric horses (>20 years) with younger animals.…”

“…19 However, studies performed over a decade later by the same and other research groups failed to demonstrate any clear requirement to alter nutritional provision for otherwise healthy Standardbred geriatric horses. 37,38 The investigators of the original study hypothesized that the nutritional impairment measured in the 1980s was most probably related to chronic scarring of the gut mucosa as a result of life-long endoparasitism and uncorrected, abnormal dentition. Similarly managed, elderly horses (20-33 years) had higher fecal strongyle egg counts than mature animals (5-15 years).…”