Effects of resting perennial pastures during the sensitive pre-dormancy period in western Manitoba: Pasture productivity and beef cattle performance

Abstract

. 2015. Effects of resting perennial pastures during the sensitive pre-dormancy period in western Manitoba: Pasture productivity and beef cattle performance. Can. J. Anim. Sci. 95: 129Á141. The objective of this experiment was to determine whether avoiding grazing during the sensitive pre-dormancy period (ca. 6 wk prior to a dormancy-inducing frost) would improve forage production, stand quality, alfalfa persistence and animal productivity in perennial pastures. There were two pasture species (PS), alfalfaÁgrass (AG) or grass (G), and three grazing phases. Phase I was conventional rotational grazing of all AG and G sections. In Phase II, one half of AG and G was rotationally grazed (conventional treatment, CT) while the other half was not (rested treatment, RT). Resting AG and G in Phase II required transferring RT animals to swath-graze early-seeded cereals. In Phase III, RT animals that swath-grazed in Phase II were moved to graze the rested sections of the pastures while those that grazed the unrested sections (CT animals) were transferred to swath-graze late-seeded cereals. There was no PS (P 0.05) or rest period (P0.13) effect on total forage yield, carrying capacity, forage disappearance and forage residues. There was no effect (P0.13) of resting on botanical composition or yield in AG. The current study did not observe significant benefits of resting on pasture yield, botanical composition or animal performance.Key words: Resting, alfalfa, grass, persistence, pasture, pre-dormancy, meadow brome Durunna, O. N., Baron, V., Scott, S. L., Robins, C., Khakbazan, M. et Block, H. C. 2015. Les effets du repos des paˆturages permanents pendant la pe´riode sensible de pre´-dormance dans l'ouest du Manitoba : productivite´des paˆturages et performances des bovins de boucherie. Can. J. Anim. Sci. 95: 129Á141. L'objectif de cette expe´rience e´tait de de´terminer si restreindre le broutage pendant la pe´riode sensible de pre´-dormance (c.-a`-d. les 6 semaines avant le gel qui provoque la dormance) peut ame´liorer la production de fourrages, la qualite´du mate´riel sur pied, la persistance de la luzerne et la productivite´animale dans les paˆturages permanents. Il y avait deux espe`ces de paˆturage (PS Á « pasture species »), luzerne-foin (AG Á « alfalfaÁ grass ») ou foin (G Á « grass »), et trois phases de broutage. La phase I e´tait le paˆturage tournant traditionnel de toutes les sections AG et G. Dans la phase II, une moitie´d'AG et de G subissaient le paˆturage tournant traditionnel (traitement conventionnel, CT Á « conventional treatment ») tandis que l'autre moitie´ne l'e´tait pas (traitement repos, RT Á « rested treatment »). Le repos des paˆturages AG et G en phase II ne´cessitait le transfert des animaux RT pour qu'ils fasse paˆturage en andain dans les ce´re´ales seme´es de fac¸on pre´coce. Dans la phase III, les animaux RT qui ont fait paˆturage en andain dans la phase II ont e´te´relocalise´s pour brouter les sections des paˆturages mises au repos, tandis que ceux qui ont brouteĺ es sections sans repos (an...

An economic analysis of resting versus nonresting perennial pastures during the critical acclimation period

“…2b in Durunna et al 2015). The designations of rested and nonrested grazing remained the same for the duration of the trial.…”

“…2 in Durunna et al 2015). Details on the phases were presented in Durunna et al (2015). A brief description of phases is provided here.…”

“…The annual cycle of the experiment was divided into three grazing phases, whereby a group of 56 cow-calf pairs, hereafter known as groups, was assigned to each block of AG or G (Fig. 2 in Durunna et al 2015). Details on the phases were presented in Durunna et al (2015).…”

“…The treatments were composed of three phases: (I) perennial grazing (beginning early June; ending late July/early August), (II) perennial or early-seeded swathed cereal grazing (beginning late July/early August; ending late August/early-mid September), and (III) late-seeded swathed cereal or perennial grazing (beginning late September/mid-late October; ending early November/ mid December) ( Table 1 in Durunna et al 2015). By combining the two perennial pasture types with rested versus nonrested grazing alternatives, four treatments were tested, including (1) AG summer -AG late seasonswathed cereal, (2) AG summer -swathed cereal -AG stockpiled, (3) G summer -G late season -swathed cereal, and (4) G summer -swathed cereal -G stockpiled.…”

“…2a in Durunna et al 2015). The assignment of animals to each paddock was balanced by accounting for body weight (BW), calf sex, and cow age.…”