Abstract
ABSTRACTThe pre-weaning records (birth weight, weaning weight and gain from birth to weaning) of 291 male and female lambs and the post-weaning records (body weight, feedlot gain and food conversion) of 136 male lambs were used to study relationships between different traits. The lambs were derived from three fat-tailed Iranian sheep breeds (Karakul, Mehraban and Naeini) and their crosses with Corriedale and Targhee rams. All lambs were weaned at 75 + 5 days of age and the males were fed in a feedlot for 100 days after weaning. Feedlot measurements were taken at 20-day intervals.Weaning weight and pre-weaning average daily gain showed positive and significant associations with birth weight. Birth weight, weaning weight and gain from birth to weaning were positively associated with body weight at subsequent ages in feedlot as well as with final weight (P<0·01). Birth weight, weaning weight and pre-weaning average daily gain were positively and significantly associated with total feedlot gain.Of the different traits, total gain during the first 20 days in feedlot (adjust period) had the lowest and total gain during the second 20 days had the highest association with total feedlot daily gain. There was no evidence that the heavier lambs at weaning and those showing high growth rate before weaning, were more efficient in the feedlot. Gain during the second 20-day period in the feedlot had a significant negative association with the total food conversion (unit food/unit gain) and therefore was a good predictor for food conversion.When the feedlot period was divided into two 40-day periods, it was found that gain during both had a significant negative association with the corresponding food conversion. A similar association was observed between total feedlot gain and food conversion, indicating that the rate and efficiency of gain improved simultaneously.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.