Genetic evaluation of leg weakness and its estimation of genetic parameters in pigs
2009
Onodera, T.(Cimco Corp., Toyama (Japan). Yatsuo Breeding Center) | Touma, S. | Nishijo, Y. | Satoh, M.
Leg weakness is one of the most serious problems in pig farms, because leg weakness is one of the most common reasons for involuntary culling of breeding pigs. Various factors have been suggested to be important in influencing leg weakness. Genetics is a main cause of leg weakness. Leg weakness has to be recorded and scored objectively if we want to cull on leg weakness. Leg weakness can be scored by many different methods. Scoring systems are classified to a binary type of scoring system and a linear scoring system. The binary type of scoring system indicates whether the pig has a certain and the level of problem. The linear scoring system evaluates all pigs for certain leg locomotions. Although both types of scoring systems are used in practical breeding programs, the linear scoring systems is considered the superior method for leg evaluation in swine. Heritability estimates for leg score traits are low or moderate. Heritability estimates for osteochondral lesions are also low or moderate. High genetic correlations among leg score traits are high and favorable genetic correlations between leg score traits and osteochondral lesions are estimated in many reports. In general, unfavorable genetic correlations between leg soundness and growth and meat production traits are estimated. More research is needed to develop methods for improving leg soundness, for example, to standardize for scoring leg exterior traits and to study relationships between leg scores and lifetime prolificacy. After them, leg soundness can be genetically improved.
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