Management of Galega officinalis L. and preliminary results on its potential for milk production improvement in sheep

Abstract

Galega officinalis L. is a leguminous perennial herb that presents a demonstrated lac‐togenic effect. However, it is toxic to the ewe if it is eaten in substantial amounts, due to the presence of some alkaloids. The objective of this work was i) to optimise its management on Mediterranean‐type climate regions, and ii) to determine if controlled amounts of G. officinalis could increase milk yield in “Churra” ewes, without toxicity problems. The high level of specificity of the infective rhizobia makes it necessary to inoculate plants with selected strains, prior to the cultivation of G. officinalis. The optimum stand was 160 000 plants ha⁻¹ obtained after broadcast autumn sowing, which in Mediterranean‐type climatic conditions increased yield in the first cutting year. Optimum cutting height was between 6 and 10 cm above ground level. The maximum yield was 13 t dry matter ha⁻¹ in the first year, and 10 in the second year which allowed five cuttings per year before flowering. This avoids an increase in alkaloids at flowering. To increase the yield during the second year, delaying of the last cutting to avoid autumn regrowth is proposed. This cut would be left as green manure. Preliminary results on increasing milk yield indicated that a controlled daily dose of 2 g dry matter kg⁻¹ (body weight) from the first month after lambing until the third milk recording 60 days later, led to a 16.90% increase in total milk yield and a 10.86% increase when the milk yield is readjusted to a lactation length of 120 days.

Keywords:

• Galega officinalis
• goat's rue
• Churra
• Rhizobium meliloti
• cutting height
• density
• milk production
• toxicity