Abstract

The endophytic alkaloid, ergovaline, is a secondary metabolite of a number of endophytes associated with perennial ryegrass. Ergovaline is known to protect ryegrass against attack by a range of insect pests, but can also negatively affect domestic ruminants. We have recently reviewed the physiological responses and metabolism of ergovaline and the effect of its consumption on animal production. The main focus of this paper is on the difficulties encountered in preparing these reviews. These include the lack of a cost-effective source of ergovaline to allow for robust dose-dependent trials resulting in ergovaline treatments based on seed sources presented in a range of processed forms, or as ryegrass pasture in which ergovaline is often associated with other alkaloids. Intake of ergovaline is often difficult to predict because ergovaline concentration of the diet on offer may not represent the concentration in the diet consumed. Furthermore, the mean live weight and level of production of the experimental animals is not always available to allow a prediction of ergovaline intake. Any change in gut-fill in response to ergovaline consumption needs to be accounted for when assessing any impact on body weight. Experimental objectives need to be clear, as the effects of short-term ergovaline exposure can be masked in a production system by subsequent compensatory growth/production. By identifying these difficulties, we hope that future work on ergovaline may be more consistent and of greater value to further reviews.

AM, Nicol, and JL Klotz

Proceedings of the New Zealand Society of Animal Production, Volume 75, Dunedin, 179-183, 2015