Optimizing pasture management for cow-calf production: the roles of rotational frequency and stocking rate in the context of system efficiency

Abstract

An experiment was conducted on grass pasture in southwestern Quebec to evaluate the benefits of management intensive grazing (MiG). Sixty-one spring-calving cows, with calves, were assigned to nine treatments, arranged as a 3 x 3 factorial of rotational frequency (RF) (high, 2-d; medium, 6-d; continuous grazing) and stocking rate (SR) ( high, medium and low; 0.5, 0.7 and 0.9 ha per cow-calf pair, respectively). Hay harvested early in the season was used for pasture supplementation late in the season. Increasing RF had no effect (P > 0.05) on mean forage mass. Increasing SR from 0.9 to 0.5 ha per cow-calf pair resulted in a linear reduction (P < 0.01) in mean forage crude protein (CP) in September; forage CP was highest with 6-d rotation. At the start of the season, increasing RF caused a linear decrease (P < 0.01) in cow gain per head as well as gain per hectare, whereas increasing the SR caused a linear increase (P < 0.01) in cow gain per hectare without influencing cow gain per head (P > 0.05). Calf gain per hectare increased linearly (P < 0.01) in response to SR throughout the grazing season, but calf gain per head was unaffected (P > 0.05) by SR. Calf gains per head and per hectare were not influenced by RF until late season, when calves under a 6-d RF performed slightly better than both continuously grazed and 2-d RF calves. A 6-d-high SR system generated the greatest net revenue. The study showed little benefit of MiG on animal performance, but substantial benefit on efficiency of land use and economic performance. Key words: Grazing, cow-calf, net revenue, economics, animal performance