In arder to establish different production groups and to perform later selective erossings, dual purpose breeels, such as French ancl German: Merino and Corriedale, should be selected in accordance with their fleece weight. This can be done with the aid of tables through which animals can be separated according to their total production. Data obtaind on fleece and bojy weights in these experiments were divided into groups, starting with the average of each flock for the two variables. With these groups, curves were obtained in each flock which were then compared with the expansion of Newton's binomium, ancl constituted theoretical curves for normal clistribution. This comparison was based on graphics and took into consideratian the percentages of each group individualIy and cumulatively. From the different tables obtained, itwas considered that in the selection of French Merino, table (a + b)8 should be use for fleece weight, and table (a + b)20 for body weight. For Gennan Merino, expansion (a + b)18 is recommended [or neece weight and (a + b)14 for body weight. For Corriedale, table (a + b)34 is considered to be the most convenient for fleece weight, and table (a + b)14 for body weight. To perform planned crossings of the best with the best, there must be at least two groups, depending on the number o[ field available, in order to use the basis of the precognizeel System of Selection for Total Production. If there are only two groups, tables will not be necessary, as selection through visual evaluation mdde by a practical animal husbandman lllay be sufficient. However, the use of this table becomes important when there are more than two groups, since the efficiency in the use of the animals increases ancl the labor of a practical animal husbandman is subject to many errors. Notwithstanding the above, it is necessary that the tables under consideration should be made with theoretical curves al
|1 Ingeniero Agrónomo. Servicio Ovinos y Lanas, Departamento de Ganadería. Ministerio de Agricultura. Profesor de las Cátedras: Producción Ovina y Caprina, Facultad de Agronomía, Universidad de Chile; Ovinotccnia, Facultad de Agronomía, Universidad Católica de Chile; Ovinotccnia, Facultad de Agronomía, Universidad de Concepción. |
2 Ingeniero Agrónomo. Servicio Ovinos y Lanas, Departamento de Ganadería. Ministerio de Agricultura, Profesor de la Cátedra de mejoramiento y Genética Animal, Facultad de Agronomía, Universidad Católica de Chile.