A classic lift-the-flap book from Rod Campbell. The reader follows a sheepdog around the farm as he runs off in search of various animal noises. On each page there is a flap, usually with the offspring of the animal underneath. So you have plenty of opportunities to name farm animals, their young and make their noises. There's also scope for practicing counting up to 4 with the pictures of the offspring.
Let's face it there are scores of toddler books about farm animals. This one stands out for me though. The linking device of the sheepdog lends a feeling of narrative continuity when many other books simply present a sequence of unconnected pictures of animals. The friendly simplicity of these illustrations has made it a winner with both of my children from the age of about 10 months onwards. My 4 year old now likes showing it to his 18 month old sister. As far as these things go the flaps are reasonably substantial too.
I heartily recommend this to you.