The trees are growing but predators are attacking them!

Recently, I planted 2 avocado, 3 papaya and 2 guava trees by the roadside outside my house. Some of the trees are well protected with bamboo stick fences, tall and wide enough to prevent the cows. But they always seem to find the poor papaya tree leaves. These cows are reckless! They just finished 2 trees, so it looks like there will be no papayas this time. I’m regularly watering the fruit trees, it should take about 5 to 8 years before we can get any fruits from them.