Abstract
A study was made of two savannah-like (dehesa) pastures on which cattle (Morucha cows × Charolais bulls) are raised for beef. The soil of dehesa system A was developed over slate, while that of B was developed over granite. The type of vegetation, dry matter yield (DM), raw protein (RP) content, digestible organic matter (DOM) content and the metabolizable energy (ME) of each system was determined to provide the nutritive value of the two types of pasture. Dietary supplements were assessed in the same way. The DM yields for 1989, 1990 and 1991 were 751, 1900 and 1438 for system A, and 577, 1937 and 1361 kg ha-1 for system B. The RP values for April and December were 17.6 +/- 1.4%, falling to a minimum of 6.7 +/- 0.4% in July-October. Intermediate values were seen for the rest of the year. The ME showed mean values of 9.4 +/- 0.3 and 7.9 +/- 0.2 MJ kg DM-1 for systems A and B respectively, while mean metabolicity was 0.50 +/- 0.2 and 0.44 +/- 0.1 (P < 0.05) and the DOM was 67.5 +/- 4.2% and 44.3 +/- 3.9% respectively. These values were affected by the year and harvest date (P < 0.05) and were always greater (P < 0.05) on soils developed over slates. The greatest pasture ME was achieved in spring and represented some 77-95% of total pasture production, depending on the year. Supplements represented approximately 20% of the total available ME.
Highlights
On the beef production ranches of the savannah-like grasslands of central-western Spain, the main food resource for livestock is pasture
Stock management and the stocking rate influence the length of this period
Humid pasture of Agrostis castellana was found in the low-lying areas of stream beds, while pasture of Agrostis castellana of different trophic nature was detected at mid slope, and pasture containing ephemeral species was seen in the highest areas
Summary
On the beef production ranches of the savannah-like grasslands (dehesas) of central-western Spain, the main food resource for livestock is pasture. There are periods when pasture species do not grow, and cattle diets need to be supplemented. This period normally lasts six months, but can go on for longer if temperatures and rainfall are below normal. Stock management and the stocking rate influence the length of this period. Jarrige (1980) indicates that extensive systems must carefully manage ecological, historical, economic and sociocultural factors. Martín Polo et al / Spanish Journal of Agricultural Research (2003) 1 (4), 41-49
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
