Selecting a buck as your herdsire is the single most important decision you will make with regards to your herd. A buck contributes 50% of the genetic makeup of every kid born - milking genetics, conformation, will affect generations that follow, and he will determine the overall pregnancy rate of your does. A buck's kids will carry his genes, good and bad, and will closely pattern him.
Keeping that in mind, regardless of the reason you have dairy goats, sooner or later you will need to sell some kids and having a buck with good milking genetics offer you a greater chance of his daughters passing that genetic trait to them. The same goes for a buck's conformation. If a buck is knock-kneed or cow hocked, more likely than not, his offspring will carry that genetic trait. If the buck has a high or steep rump, a doe with a high or steep rump could end up with kidding difficulties.
A herdsire should be chosen based upon structural soundness, milking genetics, breeding soundness.
Being familiar with the breed standard makes it a bit easier to help choose a buck for your herd.
The Nigerian Dwarf Goat Association Breed Standard for Bucks is:
Confirmation: Strong, Wide, and masculine with dairy character, standing no higher than 23 inches at the withers.
Head: Medium Length to long, lean, straight face or bridge of nose with symmetry and balance. Deep and wide muzzle.
Ears: Relativity long in comparison to head size, narrow, erect, dairy type.
Neck: Moderately long and masculine showing appropriate muscling in proportion to the size of the animal.
Body: Long, deep, wide, with level top line and nearly level or slightly sloping rump. Well sprung, flat ribs with increasing width and depth angling toward rear of barrel; sharpness at the withers above tightly assembled shoulders.
Coat and Skin: Short and straight, slick coat preferred with loose, thin, pliable skin; heavy beard.
Color: Any color or combination of colors.
Reproductive System: Well developed, balanced and strongly attached scrotum with even rudimentary teats.
The Nigerian Dwarf Goat is the only true miniature breed of dairy type and character. A nigerian Dwarf Goat conformation is similar to that of larger breeds of dairy goats. The parts of the body are balanced and proportionate to their size.
The ideal height of Nigerian Dwarf Bucks is 19" to 21" with up to 23" allowed in the breed standard. Ideal weight is to be about 75+- Pounds.
The next item to look at in helping to choose a herdsire is the goats pedigree.
Above is one of our herdsire Bucks, Spiced Tea's pedigree. Tea's pedigree shows that he is a registered *B buck which means "*B Stars on bucks are earned by virtue of parents with production records meeting ADGA minimums". We knew when we chose Tea that he had really good genetics based upon his pedigree. Spiced Tea's daddy was a Champion buck as was his grand daddy, great granddaddy and his great, great granddaddy.
On tea's mother's side, Sun Tea is a 4* M which means his mother is a 4th generation doe to earn a star based upon minimums set forth by ADGA. In April of 2003, Sun Tea lineal appraisal showed her as a +EEE (Appearance, Dairy Character, Body Capacity, and Mammary) E = Excellent, and a + on appearance. Looking at Sun Tea's mother, Tea's grandmother, on 5/2004 she had a lineal appraisal that showed her at EEEV (Appearance, Dairy Character, Body Capacity, and Mammary)
Hopefully you can see from this example some of the things you can look at to make the best choice by comparing a buck and determining if that buck is a good choice to become your new herdsire.