Study design/Study CThe results for the previous three trials were then considered together and five 'best-bet' accessions chosen based on yield and adaptation. These were: 14984 Best accession in Study B2 Forty eight young male lambs, weighing up to 20 kg were purchased in local markets. They were quarantined for six weeks, treated for internal parasites, vaccinated against common diseases and adapted to consuming green Napier grass before starting the experimental phase. The experiment is described by Hanson and Fernandez-Rivera (2005) but one or two aspects of the design of the experiment are unclear. These are investigated further in some of the Study questions. We think the following closely represents the steps taken and describes more explicitly the way such animal experiments should be designed. Lambs were weighed, sorted according to their body weight and put into eight groups of six so that the six heaviest lambs were in group 1, the next six in group 2 and so on. Five lambs within each group were then randomly allocated to each of the five accessions and a sixth to be slaughtered at the beginning of the experiment to determine initial carcass characteristics. The lambs on experiment were then assigned in group order to pens (thus group 1 to pens 1-5, group 2 to pens 6-10 etc,) so that any variations due to the position of a pen within the building can be confounded with the lamb's initial weight grouping. The lambs were fed for 12 weeks and weighed at the beginning and at two-week intervals during the experiment. |
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