The Use of Oestrogen, Progesterone and Reserpine in the Artificial Induction of Lactation in Cattle

Abstract

Oestradiol-17 p, progesterone and reserpine were utilized in three experiments in an attempt to improve the success rate and the magnitude of hormonally induced lactations. Onset of lactogenesis induced by steroid administration was measured by a surge in the lactose content of the mammary secretion and lactations were regarded as being successfully induced if milk yields exceeded 3 kg/day.In all experiments, the dose rate of oestradiol-17 p was standardized at the reduced level of 20 mg/day (approximately 0·05 mg/kg body weight daily), and progesterone maintained at 100 mg/day (approximately 0·25 mg/kg body weight daily) for the initial 7 days (days 1-7). The halving of the dose rate of oestradiol-17 p from the commonly used 0·1 mg/kg body weight daily eliminated the occurrence of noticeable physical injuries in the 60 animals so treated.Induced milk yields were not improved by either repeating the standard ovarian steroid treatment on days 16-22, extending the standard treatment for days 8-21 or continuing the steroid treatment at one-quarter the standard rate for days 8-21.Addition of reserpine to an oestradiol-17 p-progesterone treatment does improve the success rate of the hormonal induction of lactation. In experiment 1, 86% (n = 14) of heifers receiving reserpine were successfully induced into lactation compared to 45 % (n = 15) which were not.In experiments 2 and 3, 95 % (n = 19) of cows receiving both ovarian steroids and reserpine were successfully induced into lactation. However, when we consider only the milk yields of those cows sucessfully induced into lactation, reserpine (3 mg/day) administration on days 1, 6, 11, 16, 21 and 22-28, on days 22-28 alone, or on days 8, 10, 12 and 14 did not enhance induced yields.In one experiment all eleven cows failed to be induced into lactation and this was attributed to an inadequate dry period (25-43 days).

Protocolo de indução de lactação: uma abordagem histórica

“…Artigos que versaram sobre protocolos empregando estradiol (E2), progesterona Considerando que os baixos níveis plasmáticos de prolactina em algumas vacas podem limitar a produção de leite em vacas induzidas por tratamento com esteroides (ERB et al 1976), alguns pesquisadores estudaram, sobretudo na década de 70, o uso de estimuladores de prolactina, como reserpina e hormônio liberador de tireotrofina, contudo os resultados foram conflitantes. Então, buscando confirmar as indicações de que a administração de reserpina melhora a confiabilidade dos tratamentos com esteroides na indução da lactação, Peel et al (1979) avaliaram 50 vacas e 29 novilhas induzidas com E2, P4 e reserpina e concluíram que a combinação foi favorável para a produção de leite de vacas que tivessem um período seco de 82 dias ou mais. Salama et al (2007) também avaliaram o uso de reserpina, um tranquilizante de ação prolongada, que atua como agente liberador de prolactina, mas em cabras nulíparas.…”

Detection of endoplasmic reticulum stress markers and production enhancement treatments in transgenic goats expressing recombinant human butyrylcholinesterase

“…In an attempt to address these findings therapeutically, a treatment was designed to stimulate transgenic goats with prolactin (via reserpine treatment) and corticoids (dexamethasone) at the end of gestation. Since these two hormones have been successfully used for their lactogenic effects in the induction of lactation in ruminant species (Collier et al 1977;Davis et al 1983;Kensinger et al 1979;Hart and Morant 1980;Peel et al 1979;Salama et al 2007), our rationale was to test if a therapeutical boost in these hormones could help transgenic goats have a better start of their lactation. The results showed a significant improvement in the productivity of the transgenic mammary gland which was particularly patent during the first stages of lactation.…”