Everything depends on how you want to identify these parasites. In the scientific database you can find many articles about molecular diagnostic methods. If you want to identify the parasites using only microscope I highly recommend you key created by Lichtenfels et al. [2008] about most common horse parasites ie. strongylid nematodes (Strongylidae). Additionally I attach an article about tapeworms [Lyons et al.].

Article Illustrated Identification Keys to Strongylid Parasites Stro...

Really depends what you need and how much money you have. Starting from concentration methods, Nilson method, through PCR, Real Time Pcr, ending with ELISA tests..

There are many methods of nematods identification, you shuold work according to your project and aim of study.

Generally the classical method including the direct and concentration (flotation and sedimentation) method to observe the eggs but these methods are not enough in certain parasite so you should be use the culturing of eggs to hatching to larvae that which used for difirentiation among nematods.

Other methods including serological and molecular.

As colleagues say, the method to be used depends on how far and how they want and can do things. You could do it

1 Hovoscopic Methods of Flotation. This would allow to reach up to suborder Strogylatha, Oxiuratha, Ascaridatha, eimeria and the cestodes

2 A more accurate identification of strongyles  would be by L3

3 Morphometric identification of adults. Lichtenfield et al. 2008 (It is laborious, but it is achieved with determination and few resources)

4  PCR or Elisa methods for the diagnosis of specific species  (It requires equipment and means that are expensive for many of us)

 If you want to perform a study based on coprological analysis of live horses, you may need to use the Mc Master technique to determine the level of excretion of strongyle type eggs and then use larval culture to diferenciate between the Strongyle spp. and the Cyathostomines.   You can look at: Nielsen, M.K., et al., Analysis of multiyear studies in horses in Kentucky to ascertain

whether counts of eggs and larvae per gram of feces are reliable indicators of numbers of strongyles and ascarids present. Vet. Parasitol. (2010).

I am referring you our veterinary parasitologist . Dr. Dennis Anderson; he should be able to give you a definitive answer

Email: [email protected]

the best method is direct smear than cultur the sample to identification the larval stage 

Distinguished colleage, here I attach you a work of Josmel Salas Romero, he is working in that field here in the University of Camaguey, Cuba, perhaps it could be useful to you

Generally the classical method including the direct and concentration (flotation and sedimentation) method to observe the eggs and you should be use the culturing of eggs to hatching to larvae that which used for difirentiation among nematods.