Body composition of gilts at puberty

Area of Science:

• Animal Science
• Reproductive Biology
• Swine Nutrition

Background:

• Understanding factors influencing puberty onset is crucial for swine production efficiency.
• Body composition is hypothesized to play a role in reproductive maturation.
• Previous research has not definitively established thresholds for puberty attainment in gilts.

Purpose of the Study:

• To evaluate the relationship between body composition and the age of puberty in Yorkshire x Landrace gilts.
• To determine if specific body tissue amounts or accumulation rates are required for puberty onset.
• To analyze the variability in body composition at puberty in gilts under controlled feeding and exposure conditions.

Main Methods:

• Utilized 93 Yorkshire x Landrace gilts housed in confinement with ad libitum feed access.
• Initiated exposure to mature boars at approximately 120 days of age to stimulate puberty.
• Estimated empty body composition (water, fat, protein, ash) using deuterium dilution and prediction equations.

Main Results:

• Significant variation observed in age (138-240 days), weight (64.9-150.8 kg), and body composition at puberty.
• Backfat thickness ranged from 17.5 to 44.0 mm.
• No significant linear or quadratic relationship found between lifetime growth rate and age at puberty (P > .10).

Conclusions:

• Puberty occurrence in gilts with ad libitum feeding and early boar exposure is not dependent on minimum body tissue thresholds.
• The rate of body tissue accumulation does not appear to be a determining factor for puberty onset in this gilt population.
• Considerable natural variation exists in the body composition of gilts at the time of puberty.