The purpose of this review was to study the cow eye physiology, focusing on how it registers light, and to see how light affects the cow?s milk yield. It has been showed in studies that more hours of light per day (16 hours of light a day) as opposed to about 9-12 hours of light a day, increases milk yield for dairy cows. This review contains suggestions on how this is connected with the physiology of the eye. Vision is an important sense for many mammals, and is used to check out the animals surroundings. Sensor cells in the eyeball help in turning photons from the light into signals to the brain.

The aim of this study was to investigate the relationship between sleep, photoperiod, milk yield and hormones connected to milk formation. Variations of Prolactin (PRL) and Insulin-Like growth factor-1 (IGF-1) in plasma were measured during two different light programs. The light programs consisted of either 24 hours of light (L24:D0) or four hours of light and 20 hours of darkness (L4:D20). Five cows of the Swedish Red breed were used in a cross-over experiment and each light program consisted of five days. Milk yield was measured at every milking and milk samples were analyzed with regard to fat, lactose and protein.

Today, some kind of laboratory results is required for around 70% of the diagnostics and follow-ups for diseases. In many of the cases the time from sampling to a result is very critical. Therefore the discussion of how to improve this situation has begun. For many analyses serum has been the routine choice for a long time but now it is disputed. After blood collection in a serum tube it is essential to wait 30-60 minutes before centrifugation and analysis of the sample, a long time for someone in an acute state.

Pseudopregnancy is a condition that is estimated to affect 40 % of all female dogs. Common symptoms are decreased activity level, weight gain, mammary enlargement, milk production, nesting behavior, anorexia and maternal behavior. The symptoms are displayed during metoestrus. Prolactin is one of the causes behind pseudopregnancy, but the full process is not yet known. Due to the fact that the condition affects that many bitches and often is recurrent, it is relevant to examine how the condition affects the bitch?s behavior and performance.