Feeding behavior of sheep fed diets with Elaeis guineensis palm kernel meal

Abstract

In order to evaluate the feeding behavior of sheep fed with diets containing different levels of palm kernel meal (PKM) substituted for corn silage, a metabolic assay was performed on 20 ewes (5 treatments × 4 replicates) over 25 d. The animals received corn silage diets with the addition of increasing levels of PKM (0, 15, 30, 45, and 60%). The following parameters were evaluated: dry matter (DM) intake, neutral detergent fiber (NDF) intake, feeding time, rumination time, idle time, number of merycism mastications per bolus, time spent ruminating each bolus, DM and NDF per bolus, number of ruminated boluses per day, feeding and rumination efficiency, total chewing time, and number of merycism mastications per day. The daily intake of both DM and NDF increased linearly (P < 0.05), and when sheep were fed diets of at least 43.18 and 39.15% PKM, respectively, the consumption values were significantly different than when sheep were fed diets with 0% PKM (P < 0.05). In contrast, feeding time declined linearly, and in response to diets with at least 28.05% PKM, the sheep exhibited significantly different feeding times from those of sheep fed 0% PKM, with a reduction of 0.0613 percentage points per 1% increase in PKM. Idle time, rumination time, and rumination time per bolus each exhibited quadratic responses (P < 0.05), and the minimum rumination time per bolus was 44.37 s with 35.19% PKM. A quadratic response was also observed for total chewing time and both measures of merycism mastications (P < 0.05). Therefore, we concluded that the inclusion of PKM in the diets of sheep improves some parameters of feeding behavior, and the use of PKM is recommended at DM percentages of up to 40%.