Dictyocaulus viviparus first-stage larva. Characteristic dark food granules are observed in the intestinal cells. Although D. filaria larvae have a small knob at the anterior end, D. viviparus larvae do not have it. 
First-stage larvae are passed in the feces of the host, and infective third-stage larvae develop on pasture and are ingested while grazing.

Click on the following link to watch a video of a live D. viviparus adult worm and first-stage larvae!: www.youtube.com/watch?v=ZfitLJPpgjc 

Reference: Zajac and Conboy, Veterinary Clinical Parasitology 8th edition.

Cystoisospora spp. oocysts - the bigger one was C. felis and the smaller one was C. rivolta. 
This protozoan parasite is commonly called as "coccidia" of dogs and cats although other parasites, such as Eimeria, Sarcocystis, Toxoplasma, and Neospora, also fall into this taxonomic group. When oocysts are freshly passed in feces, they typically contain a single, round cell (called "sporoblast"). Developing process (called "sporulation") occurs in the environment - oocyst with a single sporoblast (C. rivolta in photo #2) > sporoblast multiplies into 2 sporocysts (C. felis in photo #2) > each sporocyst contains 4 sporozoites with a single large, round residual body (photo #3). 
Cystoisospora infection is commonly found in young cats, and most of the time cats are asymptomatic. However, when kittens are stressed out due to weaning, change of owner, new environment, etc., clinical coccidiosis can occur and cause diarrhea, abdominal pain, and in a severe case, bloody diarrhea and anemia.  

Reference: 
Anne M. Zajac & Gary A. Conboy. 2012. Veterinary Clinical Parasitology 8th ed.  

They are Giardia spp. cysts. 

Since this fecal sample was taken from a dog it could either be Giardia duodenalis Assemblage C and/or D (G. canis).
 
There has been suspicions of Giardia being zoonotic, but current research is now questioning that theory -- Giardia may be more species specific, and may not be zoonotic.
 
It is important to note the difficulties of identifying Giardia cyst on centrifugal fecal flotation. When performing a fecal flotation, it is important to use a zinc sulfate solution (specific gravity of 1.18) allowing the cyst to float showing with more details of internal structures. The slide must be prepared and read immediately following the centrifugal flotation so not allow the cyst to collapse. The cyst will have a green hue to them when using a zinc sulfate solution, you must fine focus in and out to identify the distinguishing features that make up the Giardia cyst. 

Strongylus vulgaris -- This is a sheathed Strongylus vulgaris L5. There were 2 teeth in the bottom of the buccal cavity, which distinguish it from other Strongylus species. 

Migrating S. vulgaris larvae can cause thickening of the cranial mesenteric artery, which impairs intestinal blood flow and leads to colic. Clinical signs include fever, anorexia, weight loss and depression. This case was a rare find of a fourth stage larvae molting into an adult Strongylus vulgaris worm. An infected animal sheds eggs, and under the right humidity and temperature the eggs develop into L3. A naïve animal ingests the L3 while grazing, the L3 penetrate the submucosa of the cecum and ventral colon, molt into L4 and penetrate smaller arterioles and migrate through the intima of the vessels to the larges branches of the cranial mesenteric artery. As the larvae grow larger, and occlude smaller vessels, the larvae travel to the cranial mesenteric artery and become encapsulated in nodules where they molt to immature adults. Some larvae are found in the arteries, before the fifth molt occurs, with the sheath still present. The immature adults travel back to the cecum and colon, mature and reproduce producing eggs 6 months after the animal becomes infected.

Multiple nematode larvae are seen in the cerebral parenchyma and the morphology of the parasite is consistent with Baylisascaris spp. In the tissue sections, the parasites are 40-50 µm wide with variable lengths and are surrounded by eosinophilic and granulomatous inflammations. The parasites have several microscopic features that are characteristic for ascarids, including eosinophilic cuticle, thin hypodermis, polymyarian coelomyarian musculature, pseudocoelom, prominent lateral cords, and uni-cellular epithelium of the digestive tract. Multifocal randomly distributed foci of malacia are observed in the cerebrum, brainstem and cerebellum with gliosis and infiltrates of macrophages, eosinophils, and multinucleated giant cells. Multifocal and disseminated eosinophilic and granulomatous meningoencephalitis with intralesional nematode larvae is diagnosed.
 
Baylisascaris sp. infection and associated encephalitis has been reported in woodchucks, many other mammals, birds, and human. Baylisascaris procyonis and Baylisascaris columnaris are two of the most commonly reported species that can cause diseases in woodchucks. The usual definitive host of B. procyonis is a raccoon and the definitive host of B. columnaris is a skunk. Infection of Baylisascaris spp. occurs most likely due to ingestion of materials contaminated by raccoon or skunk feces.   

They are Cryptosporidium spp. oocysts. It is important to note that Cryptosporidium is very difficult to find via routine fecal examination. Use of Sheather's sugar solution is a key to find them because that will give the oocysts a pink hue. When using the acid-fast staining, the oocysts will appear pink against a blue background. 

Cryptosporidium is a one-cell protozoan parasite that causes diarrhea in calves and other mammals. Cryptosporidium parvum mainly affects calves younger than 30 days of age. Cryptosporidium ryanae more commonly affects older calves more than one year of age. Cryptosporidium bovis is often seen in adult cattle. There’s no approved treatment for cattle in the United States. The best treatment option is fluid therapy for dehydration, nutritional support and keep the animals in a clean and dry environment. However, halofuginon lactate (Halocur®) is the licensed product in the UK and Canada; it doesn’t cure the disease, but it reduces egg shedding and clinical signs. The best way to prevent cryptosporidiosis is to keep a clean environment where newborn calves are housed, don’t house older calves with newborn calves and keep feed and water off the ground to prevent fecal contamination.