My mouth opens on a pretty regular basis and I shove my boot in. I have met few people in North America that get in trouble more often than I do while trying to be a nice guy by helping my fellow man.
Here's a case in point. A few years ago, I had two clients: One had lots of grass and was doing a really good job of grazing cattle. The other client had heifers that needed grazing. Both were nice guys and I put them together with one grazing the other's heifers.
There was lots of fresh grass with daily moves. Mineral supplement was readily available. Everything went well for several months. Pregnant heifers would come in and stay until they were six weeks from calving and then go back home. Several heifers calved and the calves were strong and the heifers had plenty of milk.
A few months later, the deal went south. The decision was made to leave the heifers for a longer grazing period. (I was not consulted.) The heifers started having weak calves and they had no colostrum. I do not remember how many were involved, but I was glad that the numbers were not significantly big.
What happened? The custom grazier was doing a good job grazing and a near perfect job of growing pretty fescue. The heifer owner left the heifers too long with the custom grazier. The major differences in management that led to the weak calf and agalactia syndrome was the winter program.
The custom grazier had plenty of pretty green fescue pastures after Christmas, but almost no other forages with which to dilute the fescue. Leaves were gone from the clover and other legumes. Tall warm-season grasses (C4) had been clipped in August in an attempt to control cocklebur. The supplement did not include energy. There was very little hay fed by the custom grazier and the hay used was 70-80% mature fescue hay.
The heifer owner normally feeds warm-season hay on short fescue pastures for 120 to 150 days from December through April.
Both programs are expensive. The custom grazier's program did not work because there were far too many days on "green" fescue. The result was weak calves and no milk.
Remember that fescue hay and/or standing fescue that are not green are much reduced in NPN and the toxic effects of green fescue.
Most winters south of Lexington, Kentucky, well-managed fescue stays green the entire winter. When planning for more than 60 days of green-fescue grazing, it becomes imperative we heavily dilute the green fescue with other grasses, hay that is hopefully C4, byproducts, and/or energy supplement. The best way to handle a wreck is well-planned prevention. The key to pollution is lots and lots of dilution.
Fescue grazed with long recovery is different from fescue that's conventionally stockpiled and grazed off in the fall and early winter. The effects of the endophyte and/or the NPN tend to hang on all through the winter with the green, tall fescue.