Unfortunately, it doesn't look like animals are a part of this Double Mastery event, but you'll still be able to earn double the mastery points on each individual tree and crop you harvest during this time period. Furthermore, you can feel free to stuff your Orchards, earning double the mastery points on those trees as well (that is, you can rotate trees out of your Orchards for 40 mastery points per Orchard, instead of 20).
Remember, this boost applies across all of your farms, and with Wither being currently disabled due to some nasty in-game bugs, you can feel free to plant some short growth-time crops that you might otherwise forget about in order to earn a huge mastery boost on them as well. The only players that won't be affected by this boost are those with permanent Double Mastery statues on their farms, as this boost will not stack. We imagine this Double Mastery event will end sometime Monday evening, so make sure to play as much as you can this weekend to make the most progress possible!
Are you excited that Double Mastery has been turned on in FarmVille? What do you plan on mastering this weekend? Sound off in the comments.