How many chromosomes does the cell have at the start of mitosis?

23 chromosomes

After mitosis two identical cells are created with the same original number of chromosomes, 46. Haploid cells that are generated through meiosis, such as egg and sperm, only have 23 chromosomes, because, remember, meiosis is a "reduction division."

sheep is a herbivore animal whereas grasshopper belongs to the class chordates but both of them feed on greens.  

if grasshopper and sheep feeding on a pasture land, i do not think both of them will have any impact on each other. however, the number of the species can make difference. since sheep feed on greens, there is a possibility there left no pasture land for the grasshoppers or they may get extinct.