Effects of Mechanical Lead System for Boar Control During Heat Detection on Libido and Salivary Androstenone and Androstenol

N. Sugai, S. Probst Miller, DVM, and R.V. Knox, PhD, University of Illinois College of Veterinary Medicine, AgCreate Solutions, Inc, University of Illinois Department of Animal Science
Daily boar exposure for weaned sows shortens weaning-toestrus interval.6,13 Boar libido impacts a technician’s ability to correctly identify heat6. Mechanical leads are used for human safety and to reduce labor for boar movement and heat detection. To date, we are unaware of other studies that have measured impact of mechanical lead on libido and salivary androstenone and androstenol levels.
This study compared two options for mechanical leads, the Boar Bot (BB) and Contact-O-Max (CM) on measures of boar libido during heat detection and effects on salivary androstenone and androstenol as a potential indicators for libido.
Overall, the study shows boar handling for heat checking has a significant difference on boar libido and performance. Investigating further on the effects of age and training for boars can help formulate better boar protocols for improving heat checking efficiency on sow farms.

The Results:

Statistics were performed using SAS for the main effects of mechanical lead, and boar and sow order of exposure (1-200, and 201-400 sows/day). BB boars showed doubled contact time (p<0.0001), increased chomping/saliva production (p<0.0001), and increased urination (p<0.02), with females over CM boars (Figure 1). There was no significant difference for vocalization. It was common to observe boar libido waning over time for both lead systems. CM libido waned more than BB (P<0.05).
There was a difference between pre- and post- androsterone and androstenol for all boars, but no significant difference between BB and CM boars (Figure 2).


Of note to veterinary practitioners providing reproductive consulting, boars in CM tended to lay down more frequently, especially as heat detection shifts progressed. By choice, BB farms rotated boars more frequently than CM farms, resulting in better libido scores. In fact, all CM farms used the same boar for the entire morning. We observed that some farms had a favorite boar (usually elderly) they chose to use every day. Farms using the same boar daily had lower libido scores. In addition, psychological attachment may make staff reluctant to cull boars viewed as “pets.” Training on why a boar replacement program is important to impact boar libido and human safety could be valuable to the industry. Of note is that the farm with highest post heat checking salivary androstenone and androstenol did the best job of rotating, culling old, and training new boars. This suggests that testing at height of boar excitement or just after, could be a better timing to measure boar libido. Further studies are needed with saliva collection during heat checking to determine if libido difference between method of boar control.

What the professionals are saying:

  • I believe Boar Bots increase boar activity and sow response time.
    Dr. David Bishop, PhD
    Reproductive Designs
  • The Boar Bot 2.0 helps bring boar and sow in closer contact (i.e. nose to nose) which can help with reproductive issues, and have some very positive effects.
    Dr. Ross Kiehne
    Swine Vet Center