[The composition of milk after artificial lactation induction in 12- to 19-month-old heifers].
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.
D000818:Animals; D002417:Cattle / Q000502:physiology*; D003126:Colostrum / Q000276:immunology; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D007136:Immunoglobulins / Q000032:analysis; D007774:Lactation / Q000187:drug effects* / Q000378:metabolism; D007785:Lactose / Q000032:analysis; D008892:Milk / Q000737:chemistry*; D008894:Milk Proteins / Q000032:analysis; D011374:Progesterone / Q000494:pharmacology*
D007136:Immunoglobulins; D008894:Milk Proteins; D011374:Progesterone; D004958:Estradiol; D007785:Lactose
Untersuchungen über die Zusammensetzung der Milch nach künstlicher Laktationsinduktion bei 12 bis 19 Monate alten Jungrindern.