Hore struck Bradley Davies from behind in New Zealand's 33-10 win at the Millennium Stadium.
Welsh lock Davies needed hospital treatment after being knocked unconscious by Hore in the opening minutes and disciplinary chiefs are expected to take stern action after the 34-year-old was cited by match commissioner Mike Rafter.
Davies could still feature against Australia at the weekend, despite suffering from severe concussion, but Howley gave a scathing assessment of Hore when asked about the incident.
"What Hore did has got no place on a rugby field, as far as I am concerned," he said. "It was an absolute disgrace. He has been cited, and I am sure it won't be taken too lightly.
"Situations and incidents like that have no place on the rugby field, and it had a huge impact on the game."
New Zealand coach Steve Hansen is preparing to lose Hore through suspension and has already called up Chiefs hooker Hika Elliot into the squad for Saturday's clash against England at Twickenham.
Gilbert has released a new line of rugby cleats. The Gilbert Virtuo 8S is part of the exciting new product. Check it out.
The entire All Blacks apparel line has been updated for 2013/14. Check out the New Zealand All Blacks polo.
The Nike Tiempo is a solid rugby cleat and one of few styles still made from full-grain natural leather.
The Gilbert Blitz 8S rugby cleat is a great cleat at a great price of $69.99. Get a new pair of cleats today.
A cool looking all black rugby cleat with the high performance adidas is known for. Get in the Gear!
Wear the crest of the British and Irish Lions on your t-shirt. A great look for the summer.
$29.99
The All Blacks Performance t-shirt is black with hints of blue from the training jersey. Very Cool.
The New Zealand All Blacks training jersey for 2013/14. Get in the Gear!
The USA Rugby Pro Alternate rugby jersey is perfect for any fan of the Eagles. Get yours to wear during the summer Test matches.
The NEW All Blacks 2013/14 jersey has arrived at World Rugby Shop. Dare to wear the colors of the All Blacks.
