Are either the Bahima or Bairu people lactose intolerant? From the descriptions it seemed the Bahima were Tutsi and the Bairu Bantu, but I'm not sure. 
 
If so, it is possible the Bahima may be overly attached to their status as lactose-tolerant Tutsis amongst lactose-intolerant Bantu populations and the ankole cattle that have conferred this nutritional advantage. The rise of dairy cattle as an export industry allows the potentially lactose-intolerant Bairu to profit off Holstein dairy cattle in a way that threatens the previous genetic-driven division of labor between the two populations.  
 
I thought this article as especially interesting if viewed through a human genetics lens of lactose tolerance. How genetic variability between Bahima and Bairu produced the Ugandan social structure, and perhaps how the differing traits have slowly evinced themselves in marriage patterns and their creation myths: 
 
http://www.ugandatravelguide.com/ankole-culture.html 
 
The NYT article fails to talk about the cheapest method of saving the ankole. Allow a small feral population to breed like the Texas longhorns or the feral Dromedaries of Australia. Both populations have become valuable gene banks for the American cattle industry and Middle Eastern camel trade at practically no cost.