Good herd fertility is the linchpin of dairy farming. However, infertility is with more than 20 % the most common cause of losses on German dairy farms. The reasons for poor fertility are manifold and cause high costs on the farm. The cost of an unused oestrus is around 40-100 €. The reasons for poor fertility are manifold and cause high costs on the farm.

The costs are even higher for uterine infections. If the loss of milk, reduced fertility, veterinary costs, and possible replacement are taken into account, the costs add up to about 290 € per cow.

Lack of herd fertility can have many causes, but a decisive factor for long-lived cows is management. Besides good hygiene, cow comfort and birth management, insemination management is of great importance. In order that the cow shows clear oestrus indications, attention should also be paid to heat stress and lameness.

Feeding plays a very important role in this context. Especially during the period of birth and in the first weeks after birth, energy and nutrient deficiencies lead to an increased occurrence of cysts. In addition, a lack of nutrients significantly reduces the quality of the follicle and the egg cell. A too high protein supply can also represent a fertility problem. The excess protein stresses the liver and leads to increased urea levels in the blood. If the liver function is disturbed, the immune system is weakened and infections, irritation of the uterus and also early embryonic death can occur.  In addition to an optimal protein supply, a sufficient supply of vitamins and minerals is of decisive importance.

Many nutrients have a direct or indirect influence on the fertility of the cow. For example, beta-carotene, the precursor of vitamin A, has a crucial influence on egg cell formation and corpus luteum development. In addition, beta-carotene is one of the most important antioxidants, along with vitamin E and selenium, and thus offers protection for the follicle and egg cell. However, beta-carotene has a low storage capacity in the body and must therefore be supplied in sufficient quantities every day. Fresh green fodder contains a lot of beta-carotene, but the content decreases dramatically due to storage and preservation, which is why many rations are deficient in beta-carotene.

Minerals such as calcium also have a decisive influence on egg cell maturation and its quality. Through the active ingredients PN-T, the calcium intake is continuously increased over the entire period and the calcium balance is thus stabilised.

Vitamin A has an important function in maintaining good fertility. It is mainly used to develop, protect, and regenerate the lining of the uterus. Among other things, it improves ovulation and the implantation of the egg cell. In addition, even a slight lack of vitamin A can significantly increase the risk for infections. The function of the immune system is also supported by vitamin E and selenium.

Vitamin D has an immunomodulatory effect and is one of the central elements of the immune system. In the first weeks of lactation, the immune system is particularly challenged because the negative energy balance leads to a deficiency of important nutrients for the immune response. Any support for the immune system during this period is essential to prevent inflammation and disease, thus balancing fertility and milk production.