The influence of various concentrate to roughage ratios on dietary intake and nutrient digestibilities of weanling

The objective of this study was to compare the feed intake and the apparent digestibilities of three different diets varying in concentrate to roughage ratios in weanling horses (n = 24) at 5 and 8 months. Horses were stratified by breed, gender, birth date, and bodyweight and were assigned to one of three dietary treatments containing the following concentrate to roughage ratios: 70:30 (High Con), 50:50 (Equal), and 30:70 (Low Con). All horses were fed their respective diets for a 10-d adaptation period and a 4-d collection period at 5 and 8 mo of age. There were no differences in body weights or daily feed intake between treatments with all treatments during both trials (5 and 8 mo) consuming between 28 and 29 +/- 1 g/kg BW/d. The horses consuming Low Con had a greater amount of fecal output than High Con at both 5 mo and 8 mo (P < .01). At 5 mo, High Con had the highest crude protein digestibility (P < .05). At 8 mo, High Con had a higher crude protein digestibility than Low Con (P < .01) and a trend to be higher than Equal (P = .07). Digestibility of ADF did not differ between treatments; however, horses fed the Low Con tended to digest a higher percentage of NDF than both the Equal and High Con treatments (P = 0.09). Horses in the High Con treatment tended to digest a higher percentage of energy than those in the Low Con treatment (P = 0.06). Weanlings seem to digest protein more thoroughly when fed high concentrate diets, and may digest fiber more efficiently when fed diets higher in fiber.