Browsing by Author "Jokela, Eira"

Increasing proportion of horses is suffering from obesity and metabolic diseases. This has been associated with concentrate feeding. The aim of this thesis was to conduct a meta-analysis based on studies that examined the effect of dietary starch and NDF concentrations (g/kg DM), and starch intake (kg/day) on hindgut fermentation. Only studies that used fistulated horses or eu-thanized horses where included in the data. The inclusion criteria were that studies had to report results for diet composition, measured fermentation parameters and feed intake. Results from nine studies were used in this meta-analysis. Statistical analysis was conducted using SAS 9.3 program and Prox Mixed procedure. A linear mixed model and regression analysis was used to determine possible relationship between dietary starch concentration and NDF concentrations, starch intake and hindgut fermentation parameters. Dietary starch concentration (g/kg DM) and daily intake of starch (kg/day) increased pH (P=0,03) (P=0,04) and decreased acetate (P=0,01) (P<0,001). Increased dietary starch concentration also increased propionate (P=0,02) and low-ered the (C2+C4)/C3 ratio (P=0,02). Increase of one kilogram of starch intake lowered the hindgut pH by 0,12 units. Increase in dietary NDF concentration (g/kg DM) increased the hind-gut pH (P=0,01) and acetate (P=0,03) proportion and decreased butyrate (P=0,02) proportion. Increase in dietary NDF concentration (g/kg DM) increased pH and molar proportion of acetate in hindgut, and decreased the molar proportion of butyrate. Although data for the meta-analysis was limited and the backgrounds differ, for example diets and horse breeds, this analysis gave statistically significant results concerning hindgut fermentation parameters and diet composition. Changes in starch and NDF concentrations affect linearly to hindgut fermentation. The results of this meta-analysis emphasize that special attention should be paid to roughage-concentrate ratio when planning horses daily feeding.