Daily stimulation of gilts with boars can be started a few days after they enter the breeding barn, provided they are at least 130 days old, and the effect can be observed by swine ultrasound. A common method in pig production is to house sows in pens and continuously contact boars in adjacent pens to stimulate estrus, and the effect of estrus can be observed on swine ultrasound. Regardless of the type of housing system (stall or pen), gilts should not be kept in pens directly adjacent to boars for a long time, as they will become accustomed to the presence of boars. This may result in a decrease in estrus detection rate and a shortened duration of estrus observed. Another method for stimulating gilts goes to the other extreme, which is to allow gilts to have only a few minutes of contact with boars through the fence when boars walk by during daily estrus detection. Many pig farms are unable to estrus and breed gilts, and the two extremes of continuous contact with boars or daily contact with boars may cause this problem, and the effect of this process can be well observed by swine ultrasound.

Pig Ultrasound PRO

The ideal method for gilts to receive adequate boar stimulation may be to move small groups of sows to the boar pen for at least 10-15 minutes of physical contact each day. Although this method is less labor intensive and allows for easy boar movement around the gilt pen, the boar's effect on gilts' transition to puberty is more pronounced when the gilts are moved to the boar pen, and this can be well observed on pig ultrasound. This may be due to the fact that gilts will receive more boar "smell" when they are moved to the pen where boars are usually kept rather than when boars are brought into the gilt pen. This may also be related to the stress caused by the change in the environment in which the gilts are moved. The synchronized estrus that occurs in some gilts approaching puberty after being transferred from different pens or different farms is also a convincing example of this phenomenon, and the effectiveness can be well observed on pig ultrasound.

link: https://www.bxlimage.com/nw/305.html