Use of the gonadotrophin releasing hormone (GnRH) analogue, buserelin has been shown to be effective reducing embryo mortality, by a luteoprotective mechanism, in reproductively normal dairy cows. Drew and Peters, (1991) increased mean pregnancy rates to AI from 53.4 to 65.4% in dairy herds by a buserelin treatment, given 10-12 post service. The objective of this experiment was to determine whether buserelin can also have a beneficial effect on pregnancy rate, in normal and known problem suckler cows.

Seventy-eight Hereford x Friesian cows (from 0-4 parities) were used. Forty were considered reproductively normal ('normal' cows) having calved each year from their first season and currently with a 10 week old calf at-foot; while 38 had a history of reproductive disorders ('suspect' cows) and had not calved in the previous 15 months (May 1994 to July 1995).