Does the touching of a dog invalidate our woodoh?
In the name of Allah, The Ever Kind.
According to Ibn Taymiyyah if one's clothes get wet from touching a dog's fur, this doesn't render them najis (impure), while if a dog licks a pot or a container, what it touches must be thrown away and the container should be washed off. Also, if one touches the dog's fur after making wudu', it does not break the wudu', but if one gets touched with dog's saliva, then one has got tainted with najasa (impurity) which must be removed".
From this we can conclude that if a dog's saliva touches our clothes, our clothes become "najis" and we need to wash it before we can pray with those clothes again or just wash the area where the saliva touched and the person does not lose his wudu. But, if the saliva touches the skin, yes, the person loses the wudu.
Evidence: "Dogs are considered impure. Any container that a dog licks must be washed seven times, the first time with pure soil. Abu Hurayrah reported that the Messenger of Allah (peace and blessings be upon him) said: "Purifying a container that a dog licks is done by washing it seven times, the first time with pure soil (that is, water mixed with earth until it becomes muddy)." (Reported by Muslim, Ahmad, Abu Dawud, and Al-Bayhaqi).
If a dog licks a pot that has dry food in it, what it touches and what surrounds it must be thrown away. The remainder may be kept, as it is still pure. As for a dog's fur, it is considered pure."
Allah knows best.