Prospects for utilization of the relationship between zoometrical measurements and performance traits for poultry and livestock genetic improvement in developing countries

The preceding review looks at the prospects for utilization of the relationship between zoometrical measurements and performance traits for poultry and livestock genetic improvement in developing countries.  Improvement of poultry and livestock indigenous to developing countries is paramount in order to increase their contribution to the much needed animal protein due to human population increase in this part of the world. However, this is on the background that the estimates of genetic parameters for performance traits in poultry and livestock are scarce in  developing countries because of failure of  most attempted selection schemes, which has been  exacerbated  by the problems of measuring of performance traits due to lack of appropriate technologies.  Assessment of the performance of poultry and livestock species is done using various indices, most especially on growth and development traits as well as body conformational traits. The significant genotypic correlations between the body weight and the zoometrical measurements and the heritability of the body weight at various stages of livestock production indicate a systematic cause which can be important to consider for livestock breeding and selection purposes. In case, where the genetic correlations between zoometrical measurements and performance traits of concern are positive and high this implies that the traits are genetically linked. Morphological properties can provide to some extent a reasonable representation of the differences among the genotypes within the same species, though not exhaustive, it serves as the foundation upon which DNA analysis can be built. Selection for improved production within poultry and livestock breeds or ecotypes is problematic for one of the following reasons: for effective selection depends on accurate recording of pedigree and performance traits. The complexity of measuring some of the performance traits due to lack of necessary equipment or technology presents considerable obstacles to effective selection for improved performance in developing countries. Unlike the developing world, recently, DNA analysis through molecular markers has provided an invaluable new technology in poultry and livestock improvement for determining the relationships among individuals, breeds and ecotypes. To increase meat yield from poultry and livestock breeds in developing countries require genetic improvement of their live weight and other performance traits which have a history of relationship with linear body measurements. Proper measurement of live weight as a performance trait, which is often hard with resource poor rural farmers due to lack of weighing scale, is requisite for achieving this goal. The need for estimation of live weight from simple   and more easily measurable variable such as zoometrical measurements therefore arises. Therefore, the use of zoometrical measurements which are simple to measure and are highly correlated to desirable performance traits is feasible option for livestock genetic improvement in developing countries. The relationship between zoometrical measurements and performance traits, apart from being used for breed characterization should rather be used for pro poor poultry and livestock improvement ventures in developing countries, which are mainly constrained by lack of modern animal improvement technologies. Poultry and livestock improvement specialists need to establish the relationship that exists between easily measureable zoometrical measurements with performance traits and to organize the genetic improvement  programmes so as to achieve  optimum poultry and livestock performance  for maximum economic returns in developing countries.