The effect of grazing lucerne on ewe fertility

For efficient sheep production it is essential to get the largest possible number of viable lambs produced from the ewe flock. Any factor which causes a reduction in the lamb crop warrants close study in order to define that part of the reproductive process which is affected and the conditions under which the factor is operative. Following a number of isolated reports of disappointing lambing percentages where ewes were mated on lucerne, a trial was carried out at Lincoln College (Coop and Clark, 1960) which showed that mating ewes on lucerne may cause a delay in lambing and a reduction in the number of twin births. As in the trial of Coop and Clark (1960), the lucerne in the present trial was grown on a different soil type to that of the ryegrass-white clover pasture. The lucerne was grown at the Ashley Dene farm where the soil type is a shallow very silt stony loam and the ryegrass-white clover was grown at the Research Farm on a silt loam. This unavoidable situation could have an influence upon the results of the lucerne-grass comparison