Combining sheep and beef cattle in a pasture-based system minorly influenced muscle and fat colour and dorsal fat firmness but increased fat skatole content in lambs.

A recent long-term system-level experiment, using grassland-based organic systems established as separate farmlets, showed that combining sheep and beef cattle within a mixed (MIX) system promoted self-sufficient production of grass-fed meat and improved economic and environmental performance in the sheep enterprise compared to a sheep-only (SH) system. In the present study, we used all male lambs produced over the first year in this experiment to evaluate the effect of this farming practice on some lamb carcass and meat sensory quality traits. Lambing took place at the end of February and lambs were pasture-fed from 1 month of age on average until slaughter, unless they were not ready for slaughter at 3-4 weeks before the start of the mating period in October, in which case they were finished indoors on a concentrate-based diet. All MIX lambs (n = 33) were finished at pasture. One SH lamb (out of a total of 85) had to be finished indoors with a concentrate-based diet. MIX lambs had a higher growth rate than SH lambs (P < 0.001), resulting in a lower lamb age at slaughter in MIX than in SH (150 vs 173 days, P < 0.001). Carcass weight and degree of fatness, kidney fat weight and dorsal fat thickness did not differ between systems. Kidney fat skatole concentration was higher in MIX than in SH (median value reaching 0.15 µg/g liquid fat and 0.11 µg/g liquid fat in MIX and SH, respectively, P < 0.05). This was most likely due to MIX lambs being slaughtered at a younger age and therefore eating younger grass. There were minor differences between MIX and SH lambs in dorsal fat firmness and in colour coordinates of longissimus thoracis et lumborum muscle. We conclude that while combining sheep and beef cattle within a mixed system offers advantages in terms of self-sufficient production of grass-fed meat and system economic and environmental performance, it could come at a cost to lamb flavour.

Combining beef cattle and sheep in an organic system. I. Co-benefits for promoting the production of grass-fed meat and strengthening self-sufficiency.

Numerous advantages of combining cattle and sheep have been demonstrated at the grazing-season level, but the effects of this practice on system self-sufficiency require system-level and longer-term studies. We established three grassland-based organic systems as separate farmlets: one mixed system combining beef cattle and sheep (MIX) and two specialised systems, beef cattle (CAT) and sheep (SH), to serve as reference points. These farmlets were managed for 4 years, to assess the benefits of combining beef cattle and sheep in promoting the production of grass-fed meat and strengthening system self-sufficiency. The ratio of cattle to sheep livestock units in MIX was 60:40. The surface area and stocking rate were similar across all systems. Calving and lambing were adjusted to grass growth to optimise grazing. Calves were pasture-fed from 3 months old on average until weaning in October, fattened indoors with haylage and slaughtered at 12-15 months. Lambs were pasture-fed from 1 month old on average until slaughter; if lambs were not ready for slaughter when the ewes mated, they were stall-finished with concentrates. The decision to supplement adult females with concentrate was based on the achievement of a target body condition score (BCS) at key periods. The decision to treat animals with anthelmintics was based on mean faecal egg excretion remaining below a certain threshold. A higher proportion of lambs were pasture-finished in MIX vs SH (P < 0.001) due to a higher growth rate (P < 0.001) which led to a lower age at slaughter (166 vs 188 days, P < 0.001). Ewe prolificacy and productivity were higher in MIX vs SH (P < 0.02 and P < 0.065, respectively). The levels of concentrate consumption and number of anthelmintic treatments in sheep were lower in MIX vs SH (P < 0.01 and P < 0.08). Cow productivity, calf performance, carcass characteristics and the level of external inputs used did not differ between systems. However, cow BW gain during the grazing season was higher in MIX vs CAT (P < 0.05). These outcomes validated our hypothesis that the association of beef cattle and sheep promoted the self-sufficient production of grass-fed meat in the sheep enterprise. It also promoted better ewe and cow BCS and BW at key stages of the reproduction cycle and better development of the females used for replacement, which may enhance animal and system resilience.

Combining beef cattle and sheep in an organic system. II. Benefits for economic and environmental performance.

Combining several animal species to optimise the performance of the whole farming system is one of the core tenets of agroecology. Here, we associated sheep with beef cattle (40-60% livestock units (LU)) in a mixed system (MIXsys) and compared its performances to those of a specialised beef cattle-only system (CATsys) and a specialised sheep-only system (SHsys). All three systems were designed to have identical annual stocking rates and similar farm areas, pastures and animals. The experiment was conducted for four campaigns (2017-2020) in an upland setting exclusively on permanent grassland under certified-organic farming standards. The young animals were fattened almost exclusively with forages: at pasture for lambs and indoors with haylage in winter for young cattle. Abnormally dry weather conditions led to hay purchases. We compared between-system and between-enterprise performances based on technical, economic (gross product, expenses, margins, income), environmental (greenhouse gas emissions (GHG), energy consumption) and feed-food competition balance indicators. The mixed-species association only benefited the sheep enterprise, with +17.1% meat production per LU (P < 0.03), -17.8% concentrate used per LU (P < 0.02), +10.0% gross margin (P < 0.07) and +47.5% income per LU (P < 0.03) in MIXsys vs SHsys, as well as environmental performance benefits via a reduction of 10.9% in GHG emissions (P < 0.09) and 15.7% in energy consumption (P < 0.03), and a 47.2% improvement in feed-food competition (P < 0.01) in MIXsys vs SHsys. These results are due to both better animal performance and lower concentrate consumption in MIXsys, as presented in a companion paper. These benefits outweighed the additional costs of the mixed system, especially for fencing, in terms of net income per sheep LU. There were no between-system differences in productive and economic performance (kilos live-weight produced, kilos concentrate used and income per LU) for the beef cattle enterprise. Despite good animal performances, the beef cattle enterprises in both CATsys and MIXsys had poor economic performance due to large purchases of conserved forages and difficulty selling the animals, which were ill-adapted to the traditional downstream sector. This multiyear study at the farming-system level, which has thus far been underresearched for mixed livestock farming systems, highlighted and quantified the benefits for sheep when combined with beef cattle on economic, environmental, and feed-food competition performance.