CONVERSION OF A LAMB PRODUCTION SYSTEM TO ORGANIC FARMING: HOW TO MANAGE, FOR WHICH RESULTS?

Two sheep flocks were managed organically (for two years from conversion onwards) under different lambing strategies (1 lambing/year vs. 3 lambings every two years). The second system was tested as there was a producer’s interest in high productivity that is a guarantee of good economic results in conventional. Reproduction, feeding, lamb production, carcass quality, health (particularly internal parasitism), economic return of the flock, grass production, and pasture biodiversity were evaluated. The lambs were bred under low therapeutic input. The economical advantage of increasing lambing frequency was not demonstrated, whereas this strategy complexified management and resulted in higher internal parasitic infection of the lambs, and finally showed a lower stability. There were difficulties in establishing a very high feed self-sufficiency in both systems, especially the more intensive system (4 points lower), due to harsh climatic conditions; following this five-year experiment, we are changing our strategy to provide nitrogen in the systems

CONVERSION OF A LAMB PRODUCTION SYSTEM TO ORGANIC FARMING: HOW TO MANAGE, FOR WHAT RESULTS?

Two sheep flocks were managed organically for two years from conversion under different lambing strategies (1 lambing/year vs. 3 lambings every two years). The second system was tested because pf a producer’s interest in high productivity, which is a guarantee of good economic results in conventional production.. Reproduction, feeding, lamb production, carcass quality, health (particularly internal parasitism), economic return of the flock, grass production, and pasture biodiversity were evaluated. The lambs were bred with low therapeutic inputs. No economic advantage of increasing lambing frequency was demonstrated, whereas this strategy complicated management and resulted in higher internal parasitic infection of the lambs, and finally showed lower stability. There were difficulties in establishing a very high feed self-sufficiency in both systems, especially the more intensive system (4 points lower), due to harsh climatic conditions. Following this five-year experiment, we are changing our strategy to provide nitrogen in the systems

Incorporation du cial 40 dans un aliment concentré : effets sur les quantités ingérées et les croissances d'agneaux sevrés

*INRA, Centre de Clermont-Ferrand-Theix Diffusion du document : INRA, Centre de Clermont-Ferrand-TheixNational audienc

Plateforme de recherche en élevage ovin allaitant. Place des expérimentations « système »

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Supplémentation protéique de brebis fortement sous-alimentées

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Intérêts et limites de l'effet mâle pour la reproduction en contre-saison chez les ovins

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Effet de l'état corporel et du niveau alimentaire sur la réponse des brebis limousines à l'effet mâle

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Accessibilité des fourrages et préférences alimentaires des ovins et des bovins

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Maîtriser la reproduction en élevage ovin biologique : influence de facteurs d’élevage sur l’efficacité de l’effet bélier

 Colloque Dinabio mai 2008 à MontpellierNational audienceThe ram effect, which is a natural method for the control of reproduction in sheep, is an alternative to hormone treatments that are banned on organic farms. The ram effect induces a combination of ovulation and oestrus in ewes that is acyclic and conducive to artificial insemination. The proportion of acyclic females with induced ovulation and their subsequent fertility at the first oestrus is variable. The control of some breeding factors that have been studied here may help to reduce this variability. The proportion of ewes induced to ovulate by rams increased as the season advanced (54% in April vs. 84% at the end of May, p<0.05) and with a longer time period between drying-off and mating: from 29% to 84% (p<0.001) for 22 and 86 days elapsed, respectively. The fertility of these ewes at the first oestrus was also higher at the end of May than in April (86% vs. 39%, p<0.01) and increased with the amount of time elapsed since drying-off (55% and 81% for 22 and 86 days, respectively; p=0.09). The time that the first oestrus occurs is later for lean ewes because they have a higher proportion of short cycles (67%) than fat ewes (41%, p<0.05).Une des façons d’améliorer l’efficacité de l’effet bélier est de se placer dans de bonnes conditions d’élevage. Ainsi, la proportion de brebis dont l’ovulation est induite augmente lorsque la date d’introduction des mâles est plus tardive (55% en avril vs 81% fin mai, p<0,05) et avec l’allongement de l’intervalle entre le tarissement et la mise en lutte : de 29% à 84% (p<0,001) pour des intervalles respectifs de 22 et 86 jours. La fertilité de ces brebis est également meilleure fin mai qu’en avril (86% vs 39%, p<0,01) et lorsque l’intervalle écoulé depuis le tarissement est accru : respectivement 55% et 81% (p=0,09). Enfin, le moment d’apparition des premières ovulations fertiles est retardé chez les brebis en état corporel faible car elles présentent davantage de cycles courts (67%) que les brebis en bon état (41%, p<0,05)

Réponse de systèmes d'élevage innovants à la variabilité climatique : une expérimentation en production extensive ovin viande intégrant des préoccupations environnementales

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