"By the time I became headmaster, however, Professor Kettleburn had mellowed considerably, although there were always those who took the cynical view that with only one and half of his original limbs remaining to him, he was forced to take life at a quieter pace."
-- Albus Dumbledore (TBB/FFF)
Silvanus Kettleburn was the Care of Magical Creatures Professor before Hagrid. (PA6) He was a reckless and eccentric wizard, who loved dangerous creatures (and often underestimated them). (Pm) This led him to lose most of his limbs, and by the time he retired in 1993, he only had one arm and half a leg remaining.
As a retirement present, Dumbledore gave him an enchanted set of wooden limbs, which often needed replacing because Kettleburn kept visiting dragon sanctuaries. He was at his home in Hogsmeade, however, when the Battle of Hogwarts took place. Kettleburn kept a number of Flobberworms, and, being physically unable to partake in the battle, he did his part by throwing them all at passing Death Eaters through his attic skylight. It was not very effective, but his effort was appreciated (Pm).
Kettleburn had a rather contentious relationship with Armando Dippet, who placed him on probation sixty-two times – a record that stands to this day. He mellowed out as he aged, and did not prove to be much of an issue during Albus Dumbledore’s tenure as Headmaster. (TBB/FFF) The most infamous incident involving Professor Kettleburn was Professor Beery’s attempt at a pantomime of “Fountain of Fair Fortune.” To represent the gigantic worm in the story, Kettleburn placed an Engorgement Charm on an Ashwinder, which laid eggs in the scenery that set the stage on fire. This contributed to Dippet’s blanket ban on all future pantomimes at Hogwarts.
Both of Kettleburn's parents were wizards; he had no wife or children.
Professor Kettleburn has an "encyclopedic knowledge" of magical creatures, and the fearlessness to wrangle them. (Pm)
Silvanus was a Roman god of woods and fields, which represents Kettleburn's connection to nature. The last name, a compound of "kettle" and "burn," probably refers to his knack for messing things up.
Kettlburn's sixty-two periods of probation (TBB/FFF) are actually an interesting clue regarding the timeline of Hogwarts staff's tenure. If we assume Dippet became Headmaster when Phineas Nigellus Black died in 1925 (BFT), that gives Dippet a tenure of 31 years as Headmaster. That averages out to exactly two periods of probation per year for Kettleburn, which seems too neat to be coincidence.
Not only does this support 1925 as the year Dippet's tenure as Headmaster began, it also indicates Kettleburn has been teaching at Hogwarts since then as well. That means Kettleburn taught at Hogwarts for at least 68 years (1925-1993), and probably a bit longer. That would make Kettleburn the longest-tenured Hogwarts professor we know of.
Professor Kettleburn and Newt Scamander are both Hufflepuffs with an immense knowledge of and appreciation for magical creatures.
The information from Professor Kettleburn's contribution in the Battle of Hogwarts is from the new Pottermore ebook.