Assessment of the Predictive Accuracy of the Small Ruminant Nutrition System for Nutrient Digestibility and Energy Requirements in Goats in Early Lactation

The objective of this study was to evaluate the predictions of the small ruminant nutrition system (SRNS) for the digestibility of dietary nutrients and the energy requirements of goats in early lactation. Forty‐eight Alpine goats were assigned to a completely randomized design. During 8 weeks of lactation, six goats were slaughtered per week. All animals received only one experimental diet based on corn silage and a concentrate mix. A digestibility trial was conducted on six goats in early lactation. The SRNS accurately predicted the apparent digestibility of dry matter (−1.39 units; p > 0.1) and organic matter (4% of mean square error of prediction MSEP). However, it underestimated crude protein (96% MSEP) and fat digestibility (99% MSEP) and overestimated NDF digestibility (+4.28 units; RMSE P = 5.9). Metabolizable and net energy intake were accurately predicted, but metabolizable energy for maintenance (−1.56 Mcal/d; r 2 = 0.76) and energy balance (−1.84 Mcal/d; r 2 = 0.30) were underestimated. The AFRC (1998) equation overpredicted DMI by 0.45 kg/d ( p < 0.01). Despite these discrepancies, the SRNS showed acceptable accuracy for predicting energy use and body reserves in goats. The SRNS accurately predicted metabolizable energy for lactation and variation in body condition score and body weight. In conclusion, adjustments to the SRNS for goats are needed to improve its predictive reliability for nutrient and energy utilization.