Induction of lactation in dry dairy dattle.

Abstract

Abstract Lactation was successfully induced in 14 of 15 non-pregnant cows treated for 7 days with twice daily subcutaneous injections of 15 mg oestradiol-17β and 37.5 mg progesterone. The successfully induced cows were first machine-milked about 8 days after the end of treatment and, although they milked for as long as their naturally calving identical twins, produced significantly less milk, fat and lactose. Augmenting the basic regimen with Opticortenol or thyrotrophin-releasing hormone produced no advantage. Plasma and milk hormone analyses were conducted and used to study the onset of lactogenesis and possible meat and milk residues. Ten of the 15 treated cows showed frequent oestrous activity and 4 became lame. Pregnancy rates after an 8-week insemination period were 69% and 93% for treated and control cows, respectively. It is concluded that the technique is unlikely to gain wide acceptance in the form used here.