Comparison of two dairy sheep breeding systems with animals with different reproduction rhythms : a multidisciplinary experimental approach

Abstract

A four-year interdisciplinary study was performed in an experimental farm to compare two organically managed sheep production systems(118 ewes each), differing in the ewes’ reproduction rhythm: one lambing per ewe per year (1/year), with the aim of maximizing foodself-sufficiency vs. three lambings over two years (3in2), with the aim of maximizing ewe productivity. The farming systems were evaluatedthrough economic results, animal health and performance, and forage and food self-sufficiency. Mean ewe productivity was 151% in1/year and 161,3% in 3in2, with a higher between-year variability in the latter. Concentrate feed consumption per ewe was higher in 3in2than in 1/year (+ 29%). Gross margin was € 59 in 3in2 and € 64 in 1/year. Lamb mortality and parasitism level were higher in 3in2 thanin 1/year. Lamb carcass conformation, fatness and subcutaneous fat colour were not different between systems, but carcass weight andsubcutaneous dorsal fat firmness were lower in 3in2 lambs than in 1/year. Intensification in an organically managed sheep system throughan increased reproduction rhythm thus did not lead to better economic results and proved more variable and more difficult to manage,and thus less sustainable. The less intensive system (1/an) was both highly efficient from the animal standpoint and highly food self-sufficient.The technical and economic results of this system were higher than those of organic private farms in the same area.