growth rate
It is usually expressed by the average daily gain during the measurement period (30 ~ 100 kg weight stage) or the age at which a certain target weight (100 kg) is reached. Weigh the measured boar and sow, and record their ages. When the measured weight is in the range of 80 ~ 105 kg, it can be converted into 100 kg age according to the following revised formula (borrowed from Canada):
Calibration day age = determination day age-[(measured weight-100)/CF] where
CF= (measured weight/measured age) × 1.826040 (boar)
CF= (measured weight/measured age) × 1.7 146 15 (sow back fat thickness)
When measuring the age of 100 kg body weight, the back fat thickness of living body was also measured. B-scan was used to measure the thickness of back fat in the penultimate to fourth intercostal space, and the unit was millimeter. For example, the average thickness of two points at the left side of thoracolumbar junction and lumbosacral junction along the back midline of 5 cm was measured by A-mode ultrasound. Finally, according to the following revised formula, the back fat thickness of the living body is converted into 100 kg (Table 3):
Table 3 Pig breeds with A and B values of different pig breeds and sexes ABABABABB Yorkshire Pig12.402 0.10653013.706 0.19624 Landrace Pig12.84