Review: Inhibition of prolactin as a management tool in dairy husbandry

Abstract

Accumulating evidence supports that the hormone prolactin (PRL) is galactopoietic in dairy ruminants. Accordingly, the inhibition of PRL secretion by the dopamine agonists quinagolide and cabergoline causes a sharp decline in milk production and could be useful in several critical periods. First, PRL inhibition may reduce the incidence during the periparturient period of metabolic disorders caused by the abrupt increase in energy demand for milk production. Metabolic disturbances can be lessened by reducing milk output by milking once a day or incompletely in the first few days of lactation. The injection of cows with quinagolide for the first 4 days of lactation reduced milk production during the first week of lactation without any residual effects. Blood glucose and calcium concentrations were higher and β-hydroxybutyric acid concentration was lower in the quinagolide-treated cows. Second, PRL inhibition may help sick or injured lactating cows, considering that they can fall into severe negative energy balance when they are unable to consume enough feed to support their milk production. This leads to a weakened immune system and increased susceptibility to diseases. When cows were subjected to feed restriction and were treated with quinagolide, the decrease in milk production was accelerated without any residual effects. The quinagolide-treated cows had higher glucose and lower β-hydroxybutyric acid and non-esterified fatty acid concentrations than the control cows did. Third, PRL inhibition may facilitate drying-off in high-yielding cows, because they are often dried off while still producing significant quantities of milk, which delays mammary involution and increases risk of mastitis. Therefore, strategies that reduce milk production before drying-off and accelerate mammary gland involution could be an important management tool. In this context, inhibition of PRL was utilised to accelerate mammary gland dry-off. Quinagolide decreased milk production within the first day of treatment, and both quinagolide and cabergoline induced more rapid changes in several markers of mammary gland involution after drying-off. In addition, quinagolide improved the animals’ resistance to intramammary infection. These results suggest that the inhibition of PRL could be a strategy for facilitating drying-off, reducing metabolic stress during the postpartum period, and alleviating acute nutritional stress during illness without compromising the overall productivity of dairy ruminants.

Effects of melatonin treatment on milk traits, reproductive performance and immune response in Sarda dairy sheep

“…Conversely, Auldist et al (2007) found that melatonin treatment in cattle decreased milk yield and lactose concentration while increased milk fat, protein and casein content in late lactation. Melatonin administration causes a decrease in prolactin (PRL) secretion, and this reason could lead to the reduction in milk yield (Lacasse et al 2019). In fact, in cattle the administration of an antiprolactinic causes the decline in PRL and a reduction of milk production mainly in late lactation, so favouring the onset of the dry period (Lacasse et al 2019).…”

“…Melatonin administration causes a decrease in prolactin (PRL) secretion, and this reason could lead to the reduction in milk yield (Lacasse et al 2019). In fact, in cattle the administration of an antiprolactinic causes the decline in PRL and a reduction of milk production mainly in late lactation, so favouring the onset of the dry period (Lacasse et al 2019). Although the role of PRL in lacto-genesis is now recognised, it is still necessary to investigate its exact role in the milk synthesis (Lacasse et al 2011).…”

Interaction between stress hormones and phagocytic cells and its effect on the health status of dairy cows: A review

“…The inhibition of PRL has been reported as a promising strategy for reducing metabolic and acute nutritional stress during the postpartum period without compromising the overall productivity of dairy animals. Moreover, an improvement in some aspects of immune system has been associated with the inhibition of PRL during this period [ 70 , 79 ].…”

Sustentabilidad, Turismo y Educación TII

“…La concentración elevada de STH en sangre, aumenta la traducción ribosomal de la hormona prolactina (PRL) (Leyva-Corona et al, 2018), sin depender de la ingesta de alimento. Se presenta una estimulación directa sobre los miocitos estriados, miocitos cardíacos y adipocitos (Lacasse et al, 2019). Este hecho sugiere que la mayor concentración de PRL se realiza por lipólisis y proteólisis (Okamura et al, 2009).…”