If anyone else was wondering about those cows:

Garret will appear in an upcoming episode of Elementary. No exact date yet (no #setlock either for that show – wah), but the episode airs some time next month.

Here are some details from TV Guide:

For those of you lamenting the loss of Raising Hope, I have some good news! Garret Dillahunt has been tapped to guest-star in an April episode as Bart Macintosh, the owner of a dairy farm in upstate New York whose brother is suspected of engineering a plot to release anthrax in New York City. Bart will become an integral part of Sherlock and Joan’s efforts to catch the supposed criminal.