The retina is a light-sensitive tissue at the back of the eye and is crucial for vision. As RP progresses, the field of vision narrows, a condition known as tunnel vision until only central vision (the ability to see straight ahead) remains. Many people with Usher syndrome also have severe balance problems.
Calves can be ready for weaning by 3 to 4 weeks of age; however, in Penn State studies calves weaned at 3 weeks required extra attention. The increased time and labor required to get these calves eating starter suggest that waiting until 4 weeks of age would be prudent.
At about 3 months the calf should be eating hay and be limited to 1 bottle of milk a day. A â¦ t 4 months the calf should be weaned. For beef calves, they should be weaned when they are 6 to 8 months of age by separating them from their mothers for a few weeks to several months. Beef calves can be naturally weaned at about 10 to 11 months of age when the cow decides when her calf needs to be weaned.