I was recently asked the following questions regarding animal and tree species for silvopastures:
"... is silvopasture just suitable to beef breeds? Or would dairy and dual purpose breeds be equally suited to Silvopasture? I was also wondering about tree species composition. Obviously allelopathic species like Black Walnut are not conducive to growing good forage, but could you use a super dense Hemlock grove for a living barn (relying on hay for feed instead of depending naturally growing forage)?"
With respect to beef vs. dairy or dual-purpose breeds, the suitability of a silvopasture towards meeting a particular breed's needs will depend on three main factors: A) the nutritional quality of the accessible vegetation in the silvopasture; B) the way in which the livestock is managed; and, C) the animal's "biotype"
A) Research has shown that the nutritional quality and palatability of the "edible stuff" in well-managed silvopastures can be as good as, or even better than the same plant species in open pastures. The key here is that the silvopasture has to be managed so as to allow sufficient sunlight to reach the target vegetation. Plants growing in excessive shade may have unbalanced protein/energy ratios, and dangerous nitrate levels - not to mention poor growth. The quality and quantity of plants in any pasture will be influenced by numerous factors including weather, plant maturity, and grazing management. The later two can be controlled by the producer to meet the needs of his or her livestock. Another consideration is that the accessible vegetation in well-managed silvopastures is likely to be more diverse in terms of species and plant types - this may provide additional nutritional benefits to livestock by allowing them to pick and choose the plants in the sequence and amounts that best fit their needs, per the sensory feedback mechanisms between the animal's stomach (rumen) and brain. The more diverse mix of plants may also supply beneficial plant compounds not available in less-diverse plant communities.
B) Pasture (or silvopasture) management will also play a big role in maintaining adequate nutritional levels. More frequent rotation allows animals to have a fairly consistent and good-quality diet because they are given access to a fresh paddock on a regular basis. An analogy is putting a group of us at a buffet. First we will eat all of the good stuff, then the so-so stuff and finally the iceburg lettuce until all of the food is gone. If the buffet is replenished every day, we probably won't suffer much because we won't go long without eating the good stuff. If the buffet is only replenished every few days, we'll eat well the first day, so-so the second, and poorly on the third (or run out of food!). This roller coaster diet can be very detrimental for ruminant performance because the rumen is constantly trying to adjust to the different levels and quality of food.
C) Within species there are breeds. Within breeds there is genetic variation (genotypes) that allows some animals to perform better than others in particular environments. As managers, we can select for the most suitable genotypes (genetic makeup) by evaluating the phenotypes (appearance). A biotype would be a group of animals within a breed that appear to have very similar genotypes - this is usually judged from the phenotypes, that's to say, all of the animals appear and perform similar. Any biotype that has been proven to do well in an unsupplemented, pasture-based production system should also perform well in a silvopasture enviroment.