In order to choose the best salt lick, you need to consider the type of animal it is for and the current dietary intake of that animal. Different species require varying amounts of sodium and other minerals in their diets, and a supplemental salt lick should reflect those needs. Some animals, such as sheep, should have their supplemental minerals given with their feed, so loose salt can sometimes be a better choice than a lick. Other animals need certain minerals under specific circumstances, such as cows that require selenium when they are calving. Providing mother cows with a salt lick that contains selenium and other trace minerals can help prevent various life-threatening diseases in the calves.
Salt licks, or mineral licks, are solid blocks that are composed primarily of sodium chloride. The term can also refer to natural deposits of salt and other minerals that animals seek out in the wild. Whether salt licks are natural or man made, they can provide certain macro and micro nutrients that animals need for survival. Many of these minerals can be found in high quality feed, though supplements are often necessary.
The first factor to consider when looking for the best salt lick is the type of animal it is for. You should always select a salt lick that contains the specific minerals that your animal requires. Salt licks that contain only sodium chloride are typically not enough, since animals that require that supplement often need other trace minerals as well. Sheep typically require calcium, phosphorous, and selenium, while cows typically also need magnesium and other trace elements.
It can also be important to supply particular elements under certain conditions. Cows in particular need a lot of salt when they are lactating, since their bodies use it up to make milk. Selenium is also important around the time that cows are giving birth, since a lack of that mineral can lead to fatal conditions such as white muscle disease.
The type of animal can also be important to consider due to the fact that some species do better with supplements that are mixed into their feed. Sheep are one example that tend to do better with mixed supplements instead of salt licks. Rather than providing a salt lick that contains all of the necessary trace minerals, it is typically a better idea to simply mix the supplements into their feed so that it all gets eaten in a timely manner. The type of feed is also important to consider since it may contain all of the necessary minerals, in which case you will not need a salt lick in the first place.