Woohoo! Almost 2.5 years later the calf boluses are now back on the market - with limited availability. I ordered the cattle boluses yesterday from Valley Vet (already got them today) but the calf boluses were still unavailable. But I went to one of our local Co-Op's today and there was a brand spanking new 50 count container on the shelf. Snatched it up!
https://cattletoday.com/forum/viewtopic.php?f=7&t=113839&p=1482271&hilit=sustain+III+calf+bolus#p1482271
https://cattletoday.com/forum/viewtopic.php?f=7&t=113839&p=1482271&hilit=sustain+III+calf+bolus#p1482271