He looks good! The coughing afterwards is usually just from them guzzling their bottle, I wouldn't be alarmed unless he's doing it at other times too. Be sure not to let him suck on the empty bottle, he doesn't need to be sucking in air. A good way to tell whether he is a good weight is to look at his tail head. A skinny calf will have a bony tail head, a nice fat one will have a less noticeable join from body to tail.