**Edited** After re-reading for grammatical errors, I've decided that auto-spell correct really irritates the heck out of me! Makes me look like I don't know what I'm talking about at times.
I admire the writings of Sue Reith. I know some will not agree with her feeding technique(s) but I, for one, do.
I have known several people who feed incorrectly and have problems come kidding time with both kids (floppy kid syndrome) and does (ketosis & hypocalcemia, kidding problems such as retained placenta, poor labor, etc.), not to mention urinary calculi in bucks and wethers. Just last year a good friend of mine lost a good doe to hypocalcemia.
I urge you to read the following:
http://goats.wetpaint.com/page/Hypocalcemia+-+Feed+for+Prevention
Down toward the bottom there is a good analysis of protein and calcium. : http://www.barbibrownsbunnies.com/hay.htm
Page 1, bottom right will give you a better understanding of calcium and phosphorous ratio in some of the more common hays: http://www.uky.edu/Ag/AnimalSciences/pubs/id146.pdf
Now, these are general guidelines. When hay is cut, how and when it is baled and how it is stored, and location where it is grown along with any type of fertilizing will all affect the nutritional value of hay. But, as a general guidelines, these are good to use.
Remember, having too much calcium is also a problem. And for wethers, it's not about making sure they have little to no calcium, the balance has to be correct. Too much in either direction (i.e. too much calcium, to little, too much phosphorous or too little) also can cause major problems. Goats need a balanced diet, just like people.
I am sort of experimenting with a diet of alfalfa and brome. Last year, brome was only available free choice and they received alfalfa in the AM and PM. This year, with alfalfa prices being through he roof, we've gone to alfalfa in the morning (super good quality high protein alfalfa) and cut back on our protein in our grain (too much protein is hard on the organs and too much is really just unnecessary). Last year we did not get as nice a cut as we did this year. They also get (basically) free choice early (May) cut brome, which they love. Their feeders are filled with it in the morning, mid-day and then in the PM as well. I am watching them closely for signs of ketosis. So far, so good.
The early gestation does get NO grain. As soon as they are dry- which this year was before being bred or shortly there after, I did not milk to 2 months prior to kidding this year- I cut out the grain. About 6 weeks before they kid I have started giving them just about 1/4 cup of grain on the stand and slowly adding alfalfa pellets (they hated them at first), just to get them back in to the routine again and to get the first fresheners used to the routine. It also gives me a chance to feel fetal movement, checking udders that are starting to fill and going through (fake) milking motions which helps when it comes time to be milked. Waiting until kidding often makes for very jumpety first fresheners which is no fun. I take the time before hand so it's not a stress afterwards.
So, following good feeding techniques, along with plenty of proper minerals and possibly additives (Vit A & D, selenium an/or copper bolusing, etc. ) is a real good way to keep healthy producing goats!