Longevity is an essential part of any breeding goal, reflecting the ability of an animal to cope successfully with the environmental conditions in a given production system. In Austrian Simmental cattle longevity is the economically most important functional trait in the total merit index (Miesenberger et al., 1998). However, by trying to increase the productive life span of livestock, the number of offspring born by older mothers also increases. One major effect of parental age, mainly maternal age, on postnatal development in mammals is due to chromosomal abnormalities, especially fetal aneuploidy. The finite ovaria stock of primary follicles and oocytes are produced only before birth in most mammals. Meiosis is resumed in the oocytes of mature follicles just before ovulation (Finch, 1990). Nucleus and mitochondrial DNA damage which is frequently observed (Richter et al., 1988) may be the result of the prolonged prophase of meiosis in germ cells. Beside the higher probabilities of chromosomal abnormalities in connection with higher parental age, there is also evidence of transmissible and cumulative effects of parental age on their offspring. In rotifers, clones from older mothers had shorter life spans (Lansing, 1947, 1948). A recent study in drosophila (Hercus and Hoffmann, 2000) showed that females from old mothers and grandmothers showed the lowest viability. The effect of maternal age was also analysed in humans according to the mitochondrial theory of aging. Mitochondrial DNA is assumed to be the major target of oxidative damage and may therefore be responsible for the age-related accumulation of genetic load (Wallace, 1994). Evidence for this theory was found by Gavrilov et al. (1996). Daughters of older mothers had a reduced lifespan, while sons did not seem to be affected. The latter might have been caused by a higher pre- or postnatal mortality, though. However, so far little attention was paid to the maternal age effect on the performance of offspring in livestock. Hence the objective of this study was to investigate the effect of maternal age on production and functional traits of dual-purpose Simmental cows.
Proceedings of the World Congress on Genetics Applied to Livestock Production, Volume 2002. Session 1, , 1.49, 2002
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