Ruminal degradation synchrony of crude protein and organic matter of forage species as a preference determinant in free-range goats in the Sonoran Desert of Baja California Sur

 The objective of the study was to evaluate the relationship between the preference index (IP) and synchrony (IS) of forage species from Baja California Sur. Samples of the 23 forage species of trees and shrubs were obtained to perform in situ digestibility analyzes using four Creole-Nubian goats. Collections were carried out in winter and spring of 2004 and summer and autumn of 2005. The extent of degradation per hour and total of 24 h was calculated from the amount of OM and PC degraded per hour; these data were used to calculate the IS. The seasonal PI data set was obtained from previously published information. A logistic regression model was used to explain the probability of occurrence of the IP with the IS. The regression model to explain the IP from the IS was significant and predictive for six species, being positive for Adelia virgata, Amaratus palmeri, Haematoxilon brasiletto, Lippia palmeri and Prosopis sp., and negative for Bursera microphyla. For other tree species and legumes in general, the model was significant, but not predictive, therefore, it is necessary to include other factors to fit the model.