Environmental Factors Affecting Rate and Efficiency of Gain and other Traits in Rambouillet Lambs

Publisher Website
Google Scholar
Abstract
The effects of age of dam, sex, type of birth and rearing, band and age of lamb on 84-day feedlot performance and other traits were studied over a 5-year period on 226 ram and ewe lambs individually fed a pelleted diet and on 218 ram and ewe lambs group-fed a non-pelleted diet. Individually fed lambs gained twice as fast, produced 50% more wool growth during the test and had significantly more condition at the end of the test than group-fed lambs. Offspring from mature dams were superior to lambs from 2-year-old dams in birth weight, gain from birth to weaning and weaning weight. The data indicate little is gained by adjusting post-weaning rate and efficiency of gain records of lambs for age-of-dam effects when the test period is some 4 mo. after weaning. Ram lambs in both experiments were superior to ewe lambs in birth weight, weaning weight, daily gain from birth to weaning, initial bodyweight, daily gain in the feedlot and final weight. Sex differences were greater for final weights than for initial weights, and greater under individual feeding than under group feeding conditions. Individually fed ram lambs consumed 0.74 kg. more feed per day and required 0.81 kg. less feed per kilogram of gain than ewe lambs. Type of birth and rearing contributed significantly to variation in birth weight, gain from weaning to feed test, initial bodyweight and final condition score in both experiments. Additional characteristics affected by type of birth and rearing in individually fed animals were weaning weight, initial condition, daily feed consumption and wool growth during the test. The band in which lambs were herded with their dams before weaning had significant effects for gain from birth to weaning, weaning weight, gain from weaning to test, initial bodyweight, gain during test, final type and final bodyweight under both individual feeding and group feeding conditions. Additional band effects were found for daily feed consumption and final condition in individually fed lambs and for initial type and wool growth in the group-fed lambs. The effect of age of lambs on the traits studied was generally found to be of minor importance. Copyright © 1967. American Society of Animal Science . Copyright 1967 by American Society of Animal Science