[Nutritional biochemical aspects of the significance, of the utilization, of metabolism and of the administration of vitamin E and of selenium in sheep (review)]. / Ernährungsbiochemische Aspekte der Bedeutung, der Verwertung, des Stoffwechsels und der Anwendung von Vitamin E und von Selen beim Schaf (Ubersichtsreferat).

A review is given on the significance, availability, metabolism and application of vitamin E and selenium in sheep. Vitamin E deficiency commonly occurs in spring. Selenium deficiency occurs in certain areas where the selenium content of plants is low. A further factor is the low availability of selenium as a consequence of reduction reactions in the forestomachs. When the supply of vitamin E and selenium is suboptimal, activity of the immune system and growth are impaired.

[Artificial lactation induction in 12- to 19-month-old heifers with regard to the behavior of the concentration of sex hormones and lactogenic proteohormones in the blood plasma]. / Untersuchungen zur künstlichen Laktationsinduktion an 12 bis 19 Monate alten Jungrindern unter Berücksichtigung des Verhaltens der Konzentrationen an Sexualhormonen und laktogenen Proteohormonen im Blutplasma.

In 24 prepubertal heifers the lactation was artificially induced by two different methods of hormone application. The changes in milk yield and the concentrations of estradiol-17 beta (E), progesterone (P), prolactin, somatotropin and insulin-like growth factor I in blood plasma during the first 55 days of lactation were analyzed. Depending on the age, the animals were divided in three experimental groups (EG) of eight animals each: 12 months old (EG I), 15 months old (EG II) and 19 months (EG III). Four animals of each EG were treated similarly: group E and P, which was injected by estradiol benzoate and P for 7 days, or group E, which received only estradiol benzoate for 10 days. The oldest heifers (EG III) showed an induction rate of 100% with E and P treatment and of 75% with E alone. On the other hand, in heifers of EG I and EG II the induction rate was only 50% irrespectively of the treatment. The animals of EG III had the highest milk yield. The daily milk yield on the 50th day of lactation was 7.0 kg and 4.0 kg in group E and P or group E, respectively. Comparable levels in 15 months old heifers (EG II) were 4.8 kg and 1.4 kg, and in 12 months old heifers (EG I) 2.5 kg and 2.5 kg. The changes of the concentrations of the hormones in blood plasma are demonstrated in diagrams, their effect on the milk production is discussed.

[The composition of milk after artificial lactation induction in 12- to 19-month-old heifers]. / Untersuchungen über die Zusammensetzung der Milch nach künstlicher Laktationsinduktion bei 12 bis 19 Monate alten Jungrindern.

In 24 prepubertal heifers the composition of milk after an artificial induction of lactation was investigated. Depending on the age, the animals were divided in 3 experimental groups (EG) of 8 animals each: 12 months old (EG I), 15 months old (EG II), and 19 months old (EG III). Four animals of each EG were treated similarly: either with estradiol benzoate and progesterone for 7 days (group E and P) or only with estradiol benzoate for 10 days (group E). During the first 18 days of lactation the protein and lactose content of the milk showed similar changes compared to the period of milk maturation during natural lactation of same duration. However, a typical colostral period with high concentrations of immunoglobulins in the milk was not observed. After the artificial induction of lactation, in the period until to the 53rd day of lactation no age dependent differences in the composition of milk were found, except whey proteins. Formation of milk substances, which are synthesized in the mammary gland, is much more induced by treatment with E and P than by treatment of E alone, with the exception of caseins.