Cunningham, J. M. M.

2018-01-31T11:42:04Z

2018-01-31T11:42:04Z

1963

This experiment has shown that the principal advantage gained from the supplementary feeding of early weaned lambs, grazing good quality pasture, is that they reach a heavy market weight quicker than lambs given none.

The additional gain of 2.8 - 3.8 lb., obtained during the period from 13.7 to 14.9, requiring 52.9 lb. of feed, at a cost of 15.2/ -, is unlikely to be economic under most circumstances. Whether this additional expenditure is recouped or not will be dependent on price fluctuations for fat lambs and the practical advantages of earlier sale. This applies only to the production of fat lambs at 100 lb. liveweight.

The results show that if 90 lb. liveweight were the minimum acceptable figure then the advantages of feeding for earlier sale do not arise.

An experiment of this type has limitations in obtaining an objective assessment of many factors. For example, saving in time to slaughter cannot be accurately stated unless lambs are sent for slaughter in a condition which can be precisely defined or alternatively at a specified weight with only some restriction of condition.

Furthermore, objective information on carcass quality as affected by supplementary feed may be best obtained by having all animals slaughtered within a narrow liveweight range irrespective of condition. Such an investigation woula only be justifiea if critical carcass assessment techniques are used. This approach was not possible in the present experiment.

The differences recorded in carcass quality, while small and essentially subjective, would tend to suggest that supplementaïy feeding has cause a a slightly different growth pattern resulting in a leaner carcass. This aspect however would require a more critical appraisal before a conficent assertion could be made.

Nevertheless, the farmer -is likely to operate under the circumstances pertaining to this experiment and the results suggest that dense, leafy pasture is adequate to maintain adequate lamb growth, until mid-September, for fat lamb production.

It may be argued that the supplementary feed used in this trial would best be replaced by a high energy mixture and this aspect should be investigated.

There was no effect of either age or weight at weaning on subsequent liveweight gain during the experimental period or during a period of 29 days after weaning. This confirms the evidence, of the experiment reported previously, that weaning at 14 weeks is a satisfactory and practical possibility given good quality pasture after weaning.

http://hdl.handle.net/1842/27851

The University of Edinburgh

Annexe Thesis Digitisation Project 2017 Block 16

Some studies of lamb growth

Thesis or Dissertation

PhD Doctor of Philosophy