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.
Calves are ideally weaned when they are 7 to 8 months old. The right time to wean a calf depends on the condition of the cow and not the age of the calf. Calves should be weaned before the condition score of the cow falls below 2,5 if adequate winter feed is available and the cows maintain their condition.