Its all about livestock type (e.g. ruminants or not), feedstock quality and source, tree specie (fast or slow growing), management dynamics and these can differ quite a lot. Can you narrow the question to which livestock type, if you are using external feedstock, tree specie you are aiming?
Crous-Duran 2019 might be an interesting read to start with, that tries to compare carbon balance between arable and an silvoarable. You can see in Fig 4 that AF systems, with slow growing species, only start to be positive after about 50 years, but pasture systems will be different (emissions from tractor operations may be less, but in other hand, if considering ruminants methane emissions need to be considered, or carbon storage in faeces, or shade effect reducing animal stress).
So, I would say from these figures that is very difficult to offset livestock emissions with slow growing trees, considering that to produce 1 Kg of Beef cattle, there are 100 kg of CO2eq emissions (image source). So, better to start planting trees straight away!
