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.
The length of this labour intensive milk feeding period is totally controlled by the rearing system used. If the following points are adhered to, it is quite easy to wean off milk by 5 weeks and have a calf weighing over 90 kg and gaining in excess of 1.5 kg per day by 10 weeks of age. 1  Confine the calf off pasture, in sheds and group penned with no less than 1.5 sq. meters per calf.