What's the difference between Lucerne Hay and Rhodes Grass?
The difference between Lucerne Hay and Rhodes Grass is their nutritional value and make up. As hay is the majority of a horses diet, knowing the nutritional value of the hay your feeding is very important.
Depending on when and how the hay is cut and baled greatly determines the nutritional value of both Lucerne and Rhodes Grass. Stalky, dry, yellow hay is an indication of poor quality hay and is not always best for your horse as it can cause health issues such as colic. There is a possibility that it was cut to late, left out to be rained on before baling or just to old to be fed to your horse. Fine, soft and green hay indicates good quality and higher nutritional value. It was cut on time and supplied to you, the customer, before the nutritional value decreased.
Lucerne Hay contains approximately 18% Protein, 28% Fiber and 16g/kg DM (Dry Matter) of Calcium (https://www.feedipedia.org/node/275). It's also high in Vitamin K and E. Due to the high amounts of Digestible Energy released it does tend to make horses go hot when fed on its own or in high quantities. Lucerne also tends to be more stalky than your Rhodes Grass.
Rhodes Grass contains approximately 10% Protein, 33% Fiber and 4g/kg DM of Calcium (https://www.feedipedia.org/node/12520). This means it's ideal for horses who simply need something to graze on during the day to fill their bellies. Rhodes Grass and other grasses like Wheaten and Oaten are usually chosen over Lucerne because of their lower levels of Digestible Energy. Most horse owners choose to mix the two, making sure to moderately add Lucerne in with the Rhodes Grass so their horse doesn't become lethargic.
At the end of the day, you really do need to know your horse and work out what your horse needs as an individual. Some horses can eat Lucerne with no issues and others can't. Some can only ever eat Rhodes Grass and that's ok too. Knowing the difference between what your feeding them will help you a lot in making the right decision.