Abstract

Ergovaline is one of the major toxins produced in tall fescue and perennial ryegrass pastures infected with wild type endophyte fungi. Animals grazing these pastures often have reduced productivity and in some cases lower reproductive performance. To date very little is known about the effects of ergovaline on sheep and in particular sheep fertility. A trial was conducted consisting of two groups (n = 20) of synchronised, Finnish landrace x Romney 2-tooth ewes. The groups were grazed on either of two lines of endophyte-infected tall fescue, one producing ergovaline (EV+) and the other ergovaline free (EV-) for two weeks and then mated on the treatments. Ovulation rate, conception rate, and numbers of lambs carried were recorded. Levels of serum prolactin and ergovaline in the pasture were determined. Ergovaline levels in the herbage were 3.30 ± 0.60 mg/g and 0mg/g in the EV+ and EV- pastures, respectively. Ewes grazing the EV+ treatment had significantly lower (P<0.05) ovulation rates and number of lambs carried to 90 days of pregnancy than the EV- group. Serum prolactin was significantly (P<0.001) reduced in the EV+ group. These results indicate that similar effects could be exhibited in ewes grazing endophyte-infected perennial ryegrass pastures containing ergovaline and further trials are being undertaken to examine this possibility.

R, Kramer, R Keogh, and MF McDonald

Proceedings of the New Zealand Society of Animal Production, Volume 59, , 263-265, 1999