Which of the following is not a factor of improvement in breeding cattle?

The factor of improvement in breeding cattle refers to the traits that breeders aim to enhance through selective breeding. These traits include high milk yield, fast growth, disease resistance, and good temperament, among others. Among the options provided, bloat, night blindness, milk fever, infertility, and anemia are all health conditions that can negatively impact the breeding potential of cattle. Bloat is a condition where the animal's stomach fills with gas and can be fatal if not treated quickly. Night blindness, caused by vitamin A deficiency, can reduce the animal's ability to see and lead to accidents or difficulty finding food. Milk fever is a metabolic disorder that can occur after calving and cause muscle weakness and decreased milk production. Infertility can affect both male and female cattle, and it can be caused by various factors such as disease, genetics, or poor nutrition. Anemia is a condition where the animal lacks sufficient red blood cells to transport oxygen to body tissues, which can cause weakness, fatigue, and decreased productivity. Therefore, the answer to the question is that "bloat" is not a factor of improvement in breeding cattle. Rather, it is a health condition that needs to be prevented or treated in order to maintain the health and productivity of the animal.