This study evaluated the multivariate relationship among the crude protein (CP) intake and digestibility, the neutral detergent fiber (NDF) intake and digestibility, and the nitrogen excretion in hair sheep fed Mombasa grass silage mixed with açai palm seeds using canonical correlation analysis (CCA). For this purpose, a dataset was constructed using the information derived from a metabolic experiment with Santa Ines sheep (BW ± SE: 33.9 ± 1.37 kg) allocated into a 5 × 5 Latin square. The following two multivariate relationships were explored using CCA: (1) the N in both feces (Nfeces) and urine (Nurine) (canonical variate U) versus the intake of both CP (CPI) and NDF (NDFI) (canonical variate V). (2) the Nfeces and Nurine (canonical variate W) versus the digestibility of both CP (CPD) and NDF (NDFD) (canonical variate Z). Canonical loadings for relationship No. 1 revealed that Nfeces (0.971) and Nurine (- 0.249) had a positive and negative correlation, respectively, with U. Both CPI (0.960) and NDFI (0.997) had a positive and similar correlation with V. Regarding relationship No. 2, both Nfeces (0.860) and Nurine (0.500) had a positive correlation with W. Conversely, both CPD (- 0.910) and NDFD (- 0.889) had a negative and similar association with Z. In conclusion, our data showed that when a multivariate approach is used, an increase in both CPI and NDFI produces an increase in Nfeces, as well as a decrease in Nurine. Additionally, a decrease in both CPD and NDFD produces an increase in both Nfeces and Nurine.
Keywords: Metabolic assay; Multivariate analysis; Nitrogen excretion; Nutrition; Pollution; Ruminant.