In Name of Allaah, The Most Merciful, The Bestower of Mercy.
The owners of camels and the owners of sheep praised [the animals they look after or own], so the Prophet [sallal laahu alayhi wasallam] said: “Moosaa was sent [i.e. as a messenger] and he was a shepherd; Dawud was sent and he was a shepherd, and I was sent and was a shepherd at Aj’yaad [i.e. a neighbourhood in Makkah]”.
Shaikh Zaid Bin Haadi [rahimahullaah] said: Those who look after livestock are different in what they look after: camels, cows and sheep. Ownership [of these animals] depends on what a human being is in need of. So, which type of livestock did the Prophet [sallal laahu alayhi wasallam] consider to be better? The hadeeth is proof to show that sheep is better, greater in blessing and more beneficial for their owners. [However], this does not negate the fact that one should be eager to own a camel and a cow, so that he can benefit from them in a number of other ways, such as to obtain milk, carry things and other than that. And Allaah knows best. [At-taleeqaatul Maleehah Alaa Silsilah Al-Ahaadeeth As-Saheehah vol 1.page 159. Slightly paraphrased]