Nutritional Profile and Intake of Forage Grazed by Spanish Goats in a Semi-arid Land

Abstract

Ramirez, R.G., Rios, E. and Garza, J. 1993. Nutritional profile and intake of forage grazed by Spanish goats in a semi-arid land. J. Appl. Anim. Res., 3: 113–122.

Nutritional adequacy and voluntary intake of forage selected by Spanish goats, grazing a shrubland dominated by blackbrush (Acacia rigidula) were evaluated during one year (June, 1988 through may, 1989) in Marín, county, N.L. Mexico. Four esophageally fistulated female goats and four male goats fitted with fecal collection bags, were used to collect monthly samples of fistula extrusas and total feces, respectively. Goats selected diets high in crude protein (CP) (Annual mean= 16.2%), of which almost40% was in the insoluble form. Fiber fractions of diets were high during the year due to the presence of grasses in extrusa samples. Mean estimates of minerals (Ca, Mg, Na, K, Fe, Zn, Cu, Mn) consumed by goats apparently covered the needs of grazing goats. Digestible energy intake was variable (P<05) among sampling periods and annual mean was 1.3 Meal DE/day. This value was not sufficient to cover maintenance plus minimal grazing activity of range goats. The diets of goats were highly diversified, composed of 21 shrubs, 36 forbs and 8gmsses. Furthermore, blackbrush accouted for 55% of the total annual diet of goats. This shrub is high in tannins (13%) and low in vitro organic matter digestibility (28%). High levels of blackbrush in extrusas might negatively influence the nutritional adequacy of diets throughout the year. In contrast, forbs selected by goats, during the rainy seasons, seemed to benefit the protein content of goat diets. Thus, it is recommended to consider range management programmes to improve the development of more nutritious herbaceous species, such as palatable forbs.

Key words:

• Spanish goats
• Nutrition
• Intake
• Ranges
• México