When we dairied our nutritionist was a key player, he was also a very good friend. All of our feed was bought except for the barley silage, pellets beet pulp and calf starter were purchased from the same feed company. The nutritionist was part of the program ,he would visit us once a month go through our herd and our DHI records. My husband is a whiz when it comes to finding just the right tmr but even he went to the nutritionist for advice when milk production dropped suddenly or other problems. Our nutritionist would even take a feed analysis of our standing crop so we would know the best time to chop to get the most out of it. It is very common here for a top producing herd to use a nutritionist regularly.
A beef herd is and can be different, you do not have to be as strict with your feed plan you have a little more leeway. If you have flush cows and recips you need to be on top of your game so I used him alot when I was first getting set up. I rarely use our nutritionist anymore, except in times where I am trying something new, like this year, we also get our feed analyzed each year so we know what feed program to use. It is a free visit over a cup of coffee/tea or a free phone call when I am in a bind. Just like my vet is a free phone call any time I need an answer..
If you are in a new situation or if your program is not working to where it should be and you need help a nutritionist can be yours and your cattle's best friend.