Studies on Beef Production from Pasture

II. Comparison between the Gains of Spring and Autumn Born Young Steers from Pasture Alone

Abstract

1. Twenty heads of both autumn (A) and spring (S) born Japanese black steers (7.8±0.3 and 13.0±0.4 months old respectively at the start of grazing) were tested on the gains from both native and improved pastures alone.
2. During the whole grazing period of 19/May-20/Oct. the gains of A were 101.8±12.1kg (0.661kg daily) on improved pasture and 84.8±6.1kg (0.551kg daily) on native pasture, and the gains of S were 88.4±18.6kg (0.574kg daily) and 57.0±7.4kg (0.370kg daily) respectively. So the gains of A were higher and they varied less than the gains of S on both pastures.
And the gains from improved pasture were higher and they varied less than the gains from native pasture with A and S.
3. The difference between the gains of A and S was bigger on native than improved pasture, and the difference between the gains from both pastures was shown more remarkably by S than A.
As to seasonal changes of the difference between the gains of A and S, the remarkable difference was observed only during the middle grazing period on improved pasture, whereas during the whole grazing period on native pasture.
From analysing these results, it was presumable that unfavourable enviromental conditions, especialy pasture conditions affecting low nutritional level for animals, forced worse inflence upon S than A.