The research, published in Animal Production Science, was carried out by scientists of the University of Melbourne and Rivalea Australia (formerly QAF Meat Industries).


The trial
In total, 240 pigs (120 entire boars and 120 gilts) were selected in three replicates of 40 boars and 40 gilts and housed in pens of 20 pigs of the same sex.


Pigs were allocated to a 2 by 2 factorial experiment, with the factors being sex (entire male or female) and age at weaning (13 or 21 days). Pigs within each replicate were weaned on the same day, with the pigs’ farrowing date differing by about eight days for the two weaning ages.


Pigs were offered ad lib access to feed for the entire experimental period. Eight randomly selected pigs from each pen were tagged as focus animals. These animals underwent scanning six times from weaning through to slaughter to measure changes in body composition.


Pig weight
The animals weaned at 13 days of age were lighter at weaning. During the first four days after weaning, pigs weaned at 21 days of age consumed more feed and gained faster than those weaned at 13 days.


The pigs weaned at 13 days did, however, 'catch up' to be the same weight as those weaned at 21 days by 53 days of age. Daily gain from birth to 146 days of age did not differ across treatments.


Scan analyses indicated that the animals weaned at 13 days had a greater percentage of lean tissue at 119 days of age, although this was not maintained through to slaughter. There were no treatment effects on the percentage of adipose tissue from 90 to 146 days of age, although the scan estimated adipose tissue mass was greater at 146 days of age in the animals weaned at 21 days.


Related websites:
• Animal Production Science
• University of Melbourne
• Rivalea Australia