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

An experiment was conducted on grass pasture in southwestern Quebec to eval uate the benefits of management intensive grazing (MiG). Sixty-one spring-c alving cows, with calves, were assigned to nine treatments, arranged as a 3 x 3 factorial of rotational frequency (RF) thigh, 2-d; medium, 6-d; contin uous 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 w as used for pasture supplementation late in the season. Increasing RF had n o effect (P > 0.05) on mean forage mass. Increasing SR from 0.9 to 0.5 ha p er cow-calf pair resulted in a linear reduction (P < 0.01) in mean forage c rude 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 S R caused a linear increase (P < 0.01) in cow gain per hectare without influ encing cow gain per head (P > 0.05). Calf gain per hectare increased linear ly (P < 0.01) in response to SR throughout the grazing season, but calf gai n per head was unaffected (P <greater than> 0.05) by SR. Calf gains per hea d 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.