Sheep live-weight gain on cocksfoot-lupin compared with lucerne pastures in the first year (2014-2015) after establishment

Abstract

While 30 years of literature shows that lupins will thrive in the high country, there is little data on livestock performance of sheep fed lupin. Black et al. (2014) recently showed sheep performance on lupin was similar to that on control pastures but due to on farm conditions could not relate the differences to the feed type. This study aimed to identify any differences in livestock performance between animals on cocksfoot-lupin and lucerne pastures with respect to apparent intake, pasture composition and nutritional value. This dissertation reports the results from the first year of the grazing experiment (5 August 2014 – 28 May 2015) after the establishment period. Over the experimental period live-weight gain was 768 kg/ha for cocksfoot-lupin pastures and 1126 kg/ha for lucerne pastures. The difference in live-weight gain per hectare occurred in response to the higher mean live-weight gains per animal and the higher mean stocking rate over the year on lucerne. There was no significant difference in grazing days for cocksfoot-lupin and lucerne pastures due to cocksfoot-lupin grazing occurring earlier, indicating similar numbers of animals could be sustained over the year. Live-weight gains of 23.7 kg and 23.6 kg per animal was observed during the spring period for cocksfoot-lupin and lucerne fed animals respectively. However lucerne fed sheep grazed for 41 days less due to the lack of feed wedge. The higher intakes, rate of weight gain and stocking rate on lucerne pastures allowed lucerne to surpass the live-weight gain per hectare of cocksfoot-lupin a shorter period. Live-weight gain was 468 kg/ha and 614 kg/ha for cocksfoot-lupin and lucerne pastures respectively in spring. Cocksfoot-lupin pastures had a higher DMD and ME, but protein content was higher in lucerne. The higher protein would have aided live-weight gains. ME intake may have been higher due to increased pasture intake on lucerne. Over the spring summer period (28 November 2014 – 16 February 2015) live-weight gain was 171 kg/ha for cocksfoot-lupin pastures and 381 kg/ha for lucerne pastures. The difference in performance was linked to increased individual intake resulting in increased weight gains per animal on lucerne. Weight gain over the period was 14.5 kg/animal and 25.4 kg/animal for cocksfoot-lupin pastures and lucerne pastures respectively. In the autumn period (18 February 2015 – 28 May 2015) live-weight gain was 129 kg/ha for cocksfoot-lupin pastures and 131 kg/ha for lucerne pastures. Animal growth on lucerne stopped after 57 days but the increased stocking rate on lucerne prevented changes in the difference of cumulated growth between the pastures. A high proportion of dead material on offer and lack of leaf material in the autumn may be responsible for the reduced performance on lucerne at this time. There is evidence to suggest that sheep will graze lupin with particular preference to the leaves. The cocksfoot-lupin pastures produced forage of comparable quality to lucerne. Cocksfoot-lupin pastures show an advantage over lucerne as they may be able to be grazed earlier in spring possibly due to the high proportion of cocksfoot in the pasture. Overall production on cocksfoot lupin pastures was 70% of lucerne in the first year after establishment suggesting cocksfoot-lupin as an alternative forage in areas unsuitable for lucerne.