Marco Antonio Alvarado-Vázquez

Leaf biomass determination on woody shrub species in semiarid zones

Leaf biomass over 20 native species from thornscrub canopies was evaluated by five non-destructive allometric methods and compared in order to determine the most accurate estimating procedure. Indirect relationships between leaf biomass and some ecological characteristics of the plants may be found by using regression models. Ecological and morphological characteristics of these species were determined using a structural analysis. No single standard method estimated leaf biomass for all species on site due to the diversity of geometric shapes in these species. However, Adelaide, double sampling and the dimensional methods were the most precise, practical and simplest methods for measuring the forage leaf biomass of many shrub species. The linear models gave a better estimate of tree biomass than the logarithmic functions. The regression equations showed a close relationship between foliar biomass and growth parameters.

In vivo and In situ Digestibility of Dry Matter and Crude rotein of Honeylocust Pods (Gleditsia triacanthos L.)

Abstract Foroughbakhch, R., Dupraz, C., Hernández-Piñero, J.L., Alvarado-Vázquez, M.A., Guzmán Lucio, M.A. and Rocha Estrada, A. 2006. In vivo and in situ digestibility of dry matter and crude protein of honeylocust pods (Gleditsia triacanthos L.). J. Appl. Anim. Res., 30: 41–46. The aim of this study was to estimate the nutritional content, the rate of digestibility (in situ and in vivo) of nutrients contained in entire pods from four varieties of Gleditsia triacanthos L. Pods of each variety were hand harvested from natural vegetation around Montpellier, France. The in vivo and in sacco techniques were used to estimate degradability of dry matter (DM) and crude protein (CP) using a lot of castrated male Aries Merino sheep and rumen fistulated sheep. The mean daily ingestion value per animal varied between 57–80 g of the dry matter of pods/kg live weight0.75; the digestibility values varied considerably between individuals (44.7–71.9% of the DM). More than 55% of the DM of the pods was digested after an incubation period of 8 h. The protein digestibility showed a rate of particle disappearance (kp=0.06) in rumen inferior to that obtained by the standard diet. The animals with a higher ingestion rate had a lesser digestion. The nitrogen digestibility rate (coefficient of digestive utilization = CDU) was superior for the fistulated animals (CDUN = 50–52%) compared to non-fistulated animals (CDUN=18–30%). The nutrient content and digestion parameters for varieties Milaud and Total were higher than Super-M and Voie-Ferré-Marchandise varieties.