Question
I have two PRE geldings that live out 24/7 on pasture in southern Spain. They have “greenstuff” to nibble all day, though I would hesitate to call it all grass, as there are thistles and other wild plants. The forage doesn’t last long, as the land is parched most of the year. Grass hay is impossible to get in this area, and the locals feed “paja” or straw. I can occasionally get alfalfa and cereal hay, but this year the weather has made it difficult to obtain. My horses are good-doers and are fed 400 g (just shy of 1 lb) of a balancer pellet fortified with Kentucky Equine Research (KER) micronutrients (Kentucky Optimo) with a handful of whole oats twice a day. In winter, I add a handful of soaked beet pulp. As summer approaches, the green will soon disappear, and I will have to give them more dry forage. I am concerned that paja lacks nutrition but would like to ask if, fed along with balancer, they are getting the nourishment they require? They certainly look fine, but I read so much about all the wonderful types of grass hays available, and it makes me wonder if I should be doing something differently.
Answer
If straw is the only thing you can get, it is definitely better than nothing, as long as it is clean and free of mold. Straw will give the horses the fiber they need to keep the digestive tract functioning properly, and it will provide horses with the chewing satisfaction they crave. The fact that they have access to some green forage part of the year helps as well. Some breeds of horses handle lower quality forage better than others, and PRE is one of those breeds. If you had Thoroughbreds, the recommendations would be a little different.
The major concerns with feeding straw are the low energy, protein, mineral, and vitamin values. If your horses are maintaining their weight well and able to perform as needed, then the energy they are getting from the sparse pasture, oats, and straw is meeting their energy requirement. If you find they lack energy, then you can increase the amount of oats.
For the other nutrients, the locally-available Kentucky Optimo has been formulated specifically for providing mature horses what is missing from a local forage like paja (protein, vitamins, and minerals). The amount of Optimo needed for this balance may vary depending on the size of your horses, and I realize that is quite variable with PRE. If your horses weigh between 400-450 kg (880-1,000 lb), then 800 g (1.75 lb) daily of Optimo will be sufficient. However, if your horses are between 450-500 kg (1,000-1,100 lb), then they should get 1 kg (2.2 lb) per day to compensate for the poor-quality forage.
Whatever other types of roughage you can offer them with the straw will be appreciated by the horses, such as a little alfalfa (lucerne) or the beet pulp, but as long as you keep them on the Optimo they should be getting adequate nutrition.
