Growth of the Porcine Eye Lens as an Index to Chronological Age

Abstract

For five litters of pigs the relationship between eye lens growth and chronological age was high, therefore suggesting that lens growth (measured as total lens nitrogen) may serve as an objective index of age of market pigs. As a result of this evidence, 36 pigs from three litters were allotted by sex (females, males and castrate males) into three dietary intake groups (full-fed, full-fed-fasted and maintained). The test started when the pigs weighed 85 kg. and was terminated after the full-fed-fasted group had gained 21 kg. and then lost 21 kg. Carcass characteristics, including weight and some carcass measurements, were severely affected, but quantity of eye lens nitrogen in all treatments was similar. There was slightly less lens nitrogen in the maintenance group, and lenses of males contained slightly more nitrogen as compared to the other sexes. Also, there were small but explainable differences between litters. Because sex can be recorded and since differences due to dietary intake were relatively small, it was concluded that lens growth may prove useful as an index of age of pigs, even when they are subjected to dietary stresses after attaining market weight. Copyright © 1967. American Society of Animal Science. Copyright 1967 by American Society of Animal Science