Forage intake and nutrition of range goats in a shrubland in northeastern Mexico

Voluntary intake and nutritive value of diets selected by goats grazing a shrubland at Marin county, N.L., Mexico were determined. Four esophageally cannulated Spanish female goats (average BW 35 kg), were used to collect extrusa samples monthly throughout 1 yr (June 1987 to May 1988). Organic matter intake (OMI) was estimated by total fecal collections from four castrated Spanish male goats (average BW 42 kg). Diets selected by goats were high in CP throughout the year (means = 18.9%). Available CP represented only about half the total CP. The ADF content of extrusa samples differed (P less than .05) among months, with high ADF values during winter months. Dietary lignin followed a similar pattern during the year. Goats consumed forage with sufficient amounts of Ca, Na, K, Mg, Cu, ZN, Mn, and Fe to meet requirements. The OMI of goats was different (P less than .05) among sampling periods. On the average, estimated OMI (means = 878.7 g/d) compared well with results of other studies in the area. Amounts of DE consumed by goats (1.1 Mcal DE/d) were not sufficient to meet requirements for maintenance plus low activity. High levels of browse in the diets presumably were responsible for low in vitro OM digestibility (means = 34.1%) throughout the year. Thus, productivity of range goats in these areas should be improved by supplementing with protein and energy.