Farmer experience of perennial ryegrass endophyte on a Manawatu dairy farm

Abstract

Case studies of two Manawatu properties currently experiencing ryegrass staggers (RGS) are presented; a dairy farm and a run-off grazing both dairy heifers and intensive bull beef. Before its conversion from a sheep and cattle enterprise to dairying an outbreak of RGS was experienced in 1987. Tall fescue-based pastures were established to minimise the potential threat of RGS. In the intervening 12 years high endophyte ryegrass cultivars have been established and hotter, drier summers are being experienced in this region. Severe cases of RGS have been observed in the last three years. On the dairy farm in 1998/99, 21 cows were dried off in January due to severe RGS. The loss in production is impossible to measure. Sixteen heifers and weaner bulls died during that summer due to RGS and those alive were 35 kg LWT below target. Management options to reduce the effects of endophyte-related disorders include establishing non-toxic pastures such as tall fescue or forage crops to utilise during periods of the year when RGS can be experienced. While limited in cultivar choice at present, the use of novel endophytes provides long-term options for farmers wishing to reduce RGS yet still maintaining ryegrass pastures. Including herbaceous species such as chicory or plantain in pasture mixes will provide high quality summer forage and can dilute the effects of endophyte in the total daily intake. Keywords: bull beef, dairy cows, endophyte, heifers, perennial ryegrass, ryegrass staggers