You cannot do that with Nigerian Dwarfs. Nigerian dwarf doelings cycle at 9-12 weeks and bucklings can breed at 8. They are also year round breeders and not seasonal.
Dairy goats are primarily for milk meaning they kid and you milk for 10 months. Meat animals are different yet at the same time far too many tax their goats to death. Literally, death, because they get too run down and nutritionally deficient kidding over and over. Sadly this is why you don't see much longevity in breeding stock of meatgoats. Prolapses, inability to nurse or even to kid twins/triplets, low wean weights etc.
This is an 8 week old Nigerian dwarf kid... no way any responsible breeder would leave bucks run with the does. Notice her size in comparison to the chicken.
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Our Kikos have been run together and separate. They are meatgoats and quite different altogether. Even when run together they still only kidded 1x year. However triplets with high wean weights is not uncommon. Selling for meat market this is optimal. Nigerians, which is what the poster has does not fall into the meatgoat category.