Effect of concentrate supplementation and prolificacy on the productive and economic performance of autochthonous sheep breeds fed forage-based diets

Sheep farming systems in Spain are experiencing an intensification process, characterised by a general selection criteria of enhancing prolificacy in ewes, and by increasing indoor feeding with concentrates to the detriment of grazing. This study evaluated the effects of concentrate supplementation and prolificacy on productive and economic performance of a local sheep breed in different price scenarios. Ewes were fed forage hay ad libitum, without (in pre-partum period, PRE-HAY; and in post-partum period, POST-HAY) or with concentrates (300 g/d in pre-partum period, PRE-CON; and 750 g/d in post-partum period, POST-CON). The inclusion of concentrate during the pre-partum period (last 10 weeks of pregnancy) had no effect on the productive performance of the ewes. In contrast, the inclusion of concentrate in the post-partum period (6 weeks), resulted in greater milk yield (1009 vs. 1275 ± 89 g/d), lamb average daily gain (151±12 vs. 225±19 g/d) and lamb output (kg of lamb LW weaned). However, the greater productivity thanks to the use of concentrates did not always turn into greatest profitability, since the economic margin was highly influenced by the cost of the diet and extremely subjected to variability in price of concentrates. Hence, the inclusion of concentrates in sheep meat production was not always justified in economic terms. In conclusion, the use of concentrates should only be considered as long as prices of commodities remain low, and inadvisable when prices reach a certain threshold or are subject to certain volatility in markets.

This study was supported by the Ministry of Science and Innovation of Spain and the European Union Regional Development Funds (INIA PET2007-06-C03-01; RZP2009-005) and the Research Group Funds of the Aragon Government (A49 and A11).