DRY GALLSICKNESS
The amount of protein is the first limiting factor in dry grass. Because there is only dry grass available for about six months a year, a disease condition called dry gallsickness can develop if the nutritional shortage is not supplemented by providing a protein lick.
Protein is the first nutrient natural grazing loses at the start of the dry season, when the crude protein percentage in the grass will start to fall below 10%.
At this stage grazing does not adequately provide the protein needs of the organisms in the gut of the animal. The number of organisms in the rumen decrease because they do not have enough protein to multiply fast enough. This directly reduces the food supply of the cow
because there are fewer gut microbes to digest it. Cattle that are pregnant but still producing milk for their calves will start to lose weight.
When the protein in the grass falls to 7% and below, the gut microbe populations decline further. The organisms need sufficient protein to multiply and at these levels they are not getting it. The grass will be digested even more slowly and the cattle will eat much less (as little as 1.5% of bodyweight) because undigested grass stays in the rumen for a longer time. Even if the calves are weaned, the cows will still lose condition because of the very slow rate of digestion.
Four to five months later, when it is completely dry, the protein content in the grass drops to 4% and below. At this stage the organisms in the rumen stop multiplying and die, and the grass cannot be digested. When this starts to happen cattle will lose weight rapidly and soon become too weak to walk. Once they lie down, they will die within a few days and in most cases can’t be rescued even if they are given good feed.
Dry gallsickness is caused by a long-term protein shortage and is a condition that will occur in most areas of South Africa if a protein supplement is not provided during the dry season. The digestibility of dry grass becomes too low to maintain good production and the goal of producing one calf every 12 months cannot be achieved without a protein supplement. There are many good licks on the market available at agricultural outlets.