Although there is much duplication of content between these two archives, each has unique items.
Hathi Trust has a better search than Google Books.
Full text will usually be available for items published before 1923 (cutoff date in US copyright law); full text may or not be available for more recent publications, depending on the wishes of the copyright holders.
“Video Collection on Cattle, Sheep, and Pig Handling.” Accessed April 3, 2020. http://www.grandin.com/videos/videos.html