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.
She won't have the experience to wean the calf, for one. The best time to pull the calf off is one of two indicators: 1) ideal age to wean the calf, which would be at around 6 months of age; or 2) if the calf is pulling the first-calf heifer down in terms of weight and condition.