Technology and Dairy

Dairy Carrie reports spending $20,000 on necklaces for their dairy cows.  These are high-tech jobs, which provide indicators when the cow is in heat (high activity) and is sick (not chewing cud). In a dairy above a certain size, and I'm not sure how large this dairy is but not humongous, the dairyman needs help to keep track of these two critical factors.  (Miss a heat, and the cow is going to lose production, effectively 1/12 of annual production.  That's money, that's the difference between profit and loss.)