Research with rats shows the powerful negative effect of a bad first experience. If a rat was shocked the first time it entered a new corridor in a maze, it would never enter that corridor again. However, if it entered the corridor several times without getting a shock, it would still enter the same corridor after it had had a shock. Likewise, a horse's first experience with a trailer should be a good one and the first experience cattle have in a new corral should be something positive, such as being fed. If the first experience is negative, the animals may become permanently afraid of trailers or corrals.
First experiences make a big impression on prey species animals like cattle and horses.
The paradox about novelty is that it's scary if suddenly thrust on an animal. But, it is attractive if an animal is allowed to voluntarily approach it. A clip board or box placed in a field or pen will attract both cattle and horses. They'll approach, poke and sniff. But if the wind moves the paper, the animal quickly backs away.