Sorghum, which is closely related to corn, is very nutritious for most animals including rabbits. The following list includes the good points about sorghum and the not-so-good points.
Good Points: The syrup can be fed to rabbits instead of sugar or honey in carb loading situations where the rabbit needs a higher glucose level. The syrup can also be used as a training treat or mixed with veggies to make the rabbit eat them.
Sorghum is high in calcium, iron, and phosphorus which are all essential minerals needed for good bone formation and growth. It is an ideal grain for growing rabbits because it does not contain tannic acid as other grains do. Not only are rabbits able to eat sorghum all the time, they actually need it every day.
Bad Points: For adult rabbits, or those that are growing at a slower rate than normal, overfeeding on sorghum can lead to obesity. Sorghum is also very fattening for animals that are inactive such as pregnant or nursing does.

FAQS
Q: Can rabbits eat other types of grains?
A: Yes, all types of grains are good for rabbits as long as they are not moldy or contain any poisonous seeds. Rye, barley, oat, and wheat are all good options.
Q: What is the best way to feed sorghum to a rabbit?
A: Some rabbits are very picky when it comes to treats, but if your rabbit is willing to try it, simply place a few spoonfuls in the bowl at their next mealtime. If not, you can always use the syrup form of sorghum by mixing it with warm water and sprinkling some on your rabbit’s hay. Do not add any more than a tablespoon of syrup per day or you might risk obesity.
Q: Is sorghum good for all rabbits?
A: No, adult rabbits or those that are growing at a slower rate than normal should not be overfed on sorghum. It is also very fattening for rabbits that are pregnant or nursing.
Q: Will my rabbit get sick if they eat sorghum?
A: Like everything else, moderation is key! If you feed your bunny too much sorghum than normal, their diet will be unbalanced and lead to health issues down the road such as obesity. Other than that, sorghum is a very healthy grain for rabbits to eat.
Conclusion
In conclusion, yes, rabbits can eat sorghum and it is a very good grain for their diet. It is high in calcium, iron, and phosphorus which are all essential minerals needed for good bone formation and growth. It does not contain the harmful tannic acid as other grains do, making it the ideal grain for growing rabbits. However, adult rabbits or those that are growing at a slower rate than normal should not be overfed on sorghum as it can lead to obesity. So, be sure to feed your bunny in moderation!