
Herbicides - While herbicides can be effective measure, if you're near a sensitive waterway, or are concerned about the native species, soil health or your livestock, then goats offer a great chemical free alternative.
Machinery - Machinery are a great option if speed is the goal. However, they disturb the soil and shake all of the seeds, fruit and flowers around, reseeding for next season. They also can't access everywhere the goats can. Steep or uneven areas can be really dangerous in a machine, but the goats can handle it with ease.
Manual Removal - If the area is really small, manual removal can be effective. You need to carefully take out all of the seeds/fruit, then remove and bag up the problem weeds before disposing of them. However, if you value your time, back, and sanity, perhaps kicking back and watching the goats take the bulk out of it for you is better.
Each of these methods, and the goats, all need repeat treatments to tackle regrowth before it takes hold.
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Blackberry is extremely resilient and has three separate ways of beating you, which is why one pass at it never works.

The crown.That woody nodule at soil level is the plant’s energy store. Cut the canes and leave the crown and it pushes out a fresh set - often more vigorously than before.
Cane tips. Where a long cane arches over and touches the ground it roots at the tip and becomes a new plant.
Birds. They eat the fruit and spread the seed, so even a perfectly cleaned-up block gets reseeded from the neighbours.
They don't kill it in a single pass, and ultimately neither does anything else. But over repeated grazing, eventually the plant's energy is drained and it can no longer compete.
Three reasons. It reshoots from the root crown, which is the woody nodule at soil level where the plant stores its energy - leave that and you get vigorous regrowth. Canes that touch the ground root at the tip and become new plants. And birds spread seed, so reinfestation arrives from next door regardless of what you do.
Repeated treatment, and/or multiple tactics combined. For example, taking the bulk out and trampling the canes with goats, then removing or spot-treating the remainder, then grazing the regrowth again.
That's the part they're best at. Blackberry loves creek lines and gullies, which is exactly where a tractor can't safely go and where nobody wants to be swinging a brushcutter.
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