The science of breeding animals distinguishes between three types of constitution: typus respiratorius, typus digestivus and typus muscularis. The English Thoroughbred is an example for the first, the old pony types for the second, and the Quarter Horse for the third. Most often an individual or race does not belong to a single type but is a mixture of two of them. According to Saenger the Arabian horse should not belong to one of those extremes. But the Kuhaylan type is in his opinion strongly influenced by the typus muscularis and to a less degree by the digestivus type. The Saqlawi type is less influenced by the typus digestivus and also not so much by the typus muscularis, but to a certain degree more from the typus respiratorius. The Muniqui type, on the other hand, is even more tending to the respiratory type.

The modern show type of the Arabian horse belongs more or less to the Saqlawi type and this also seems to be the sort of horse that Nagel calls the Nejdi or Southern type. The Babson Egyptians in their majority resemble the Kuhaylan type, and those horses bred for racing or endurance riding the Muniqi type. But there are many, maybe most Arabians, that do not belong to one distinguished type but are a mixture of them. The use of the nomenclature of types is widespread among western breeders today and has its right. It is only misleading that Raswan used the same words for his three types that have already been in use for the strains or families of Bedouin horses. That had a reason, as Raswan believed that a horse of a certain strain should also belong to the type to which this strain was related. But here he stands rather alone, as we have already discussed in the chapter on strains.

The use of the three types of Raswan´s categories helps to classify the Arabian breed into subpopulations and make use of it for the practical questions of breeding, but in disagreement with Raswan this not necessarily means any accordance with the strains. Saenger shows the interested breeders how he can make intelligent use of those categories in his breeding decisions. For example breeding two Kuhaylan type horses together may result in a foal that will be more influenced by the typus digestivus, therefore tending to be too short and rounded, and inclined to become fat and therefore be of bad riding-horse qualities. (The Babson horses tell us a different story as they remained the versatile and athletic riding horses they were from the beginning.) On the other hand one can counteract those tendencies by choosing a breeding partner from a different constitution-type