What I like to eat
Aside from trees providing our natural shade and shelter, we also need to be able to browse from diverse forage crops including some trees. When cows are browsing they forage for nutritious bits to eat, from such things as various grasses, clover, leaves, flowers etc. which are particularly found in mixed crop regenerative and organic farm systems. If cows are prevented from browsing dark green leaves, they don't have a full and balanced diet.
Sunflowers are my lollipop

How diverse trees and plant crops are beneficial to our wellbeing
We are natural herbalists as we instinctively know what to eat for some of our ailments. Like if we have an upset tummy, we will seek out nettles. Interestingly cows on organic farms require fewer visits from veterinarians. A good varied diet of plants and trees supply us with the nutrients and balanced diet we need, rather than chemical nitrogen drenched monocultural pasture grass. Naturally we would live up to at least 20 + years of age providing we are in an environment with the variety that provides us all the nutrients we need.
Cows have a well developed sense of taste and can distinguish the four primary tastes, (sweet, salty, sour, bitter).
Just like humans we like variety.
Imagine if you gave a child the same meal day after day. How happy or healthy would that child be? Just like you we like to have choices and only we know what our bodies need. If we have the choices we can choose things like Blackberries for our morning tea or Sunflowers. They are like our lollipop.
Why regenerative-organic agriculture is better for cows too
Material from research paper by Dr Christine Jones
It has been found that plants in communities assist each other by linking together in vast underground superhighways, through which they can exchange carbon, water and nutrients. What this does is increase plant resistance to pests and diseases as well as improving soil health. In contrast fields of one crop, (monoculture farming) have poor soil quality and suffer more from drought.
NZ dairy is largely based on low-diversity, shallow rooted crops such as ryegrass. It therefore requires a high usage of Nitrogen. If there is an excess of use of Nitrogen, this results in lameness, mastitis and infertility.