Review: Current knowledge on mammary blood flow, mammary uptake of energetic precursors and their effects on sow milk yield

Abstract

Review: Current knowledge on mammary blood flow, mammary uptake of energetic precursors and their effects on sow milk yield. Can. J. Anim. Sci. 88: 195Á204. Dietary availability of nutrients to the mammary gland is a major limiting factor for sow milking potential. Nutrient availability to the udder is estimated by measuring mammary arteriovenous differences, which are affected by blood flow as well as circulating concentrations of nutrients. Mammary blood flow can be measured either directly or indirectly. Even though it is influenced by numerous factors, such as time since feeding, postural behavior, vasoactive substances, ambient temperature and litter size, authors report that the amount of plasma required to produce 1 kg of milk for a litter of 12 pigs ranges from 490 to 1050 L at peak lactation. Blood glucose is the major precursor for lactose synthesis and reported extraction rates of glucose by the mammary gland vary between 20 and 31%. Other metabolic precursors, such as triglycerides, phospholipids, acetate, propionate and lactate are also used for milk synthesis. There exists a discrepancy between estimates of energetic efficiency depending on the type of study conducted (metabolism vs. mammary balance). Endocrine status of the sow may affect mammary nutrient availability. There still exists a gap in our knowledge on relative mammary uptakes of energetic compounds other than glucose and on glucose transporter systems in porcine mammary tissue. The need for such information is of particular importance due to the increased milking demands currently made on lactating sows.Key words: Blood flow, lactation, mammary gland, nutrient uptake, sows Farmer, C., Trottier, N. et Dourmad, J. Y. 2008. Mise a`jour des connaissances sur le de´bit sanguin et la prise de pre´curseurs e´nerge´tiques par les glandes mammaires de truies en lactation. Can. J. Anim. Sci. 88: 195Á204. Le potentiel de lactation des truies de´pend largement de la disponibilite´des nutriments au niveau de la glande mammaire. Celle-ci est estime´e par le biais de diffe´rences arte´roveineuses qui sont elles-meˆmes influence´es par le de´bit sanguin ainsi que par les concentrations sanguines des divers nutriments. Le de´bit sanguin de la glande mammaire peut eˆtre mesure´directement ou indirectement. Quoi qu'il soit affecte´par divers facteurs tels l'intervalle depuis le dernier repas, la posture, les concentrations de substances vasoactives, la tempe´rature ambiante et la taille de la porte´e, la quantite´de plasma requise pour produire 1 kg de lait en pic de lactation pour une porte´e de 12 porcelets se situe entre 490 et 1050 L, selon les e´tudes. Le glucose est le pre´curseur pre´dominant pour la synthe`se de lactose et des taux d'extraction de glucose par la glande mammaire allant de 20 a`31% ont e´te´rapporte´s. D'autres pre´curseurs me´taboliques e´nerge´tiques, tels les triglyce´rides, phospholipides, l'ace´tate, le propionate et le lactate servent aussi a`la synthe`se du lait. Les estime´s de l'efficacite´e´nerge´tique pour la production ...

The metabolic status during the peri partum period affects the voluntary feed intake and the metabolism of the lactating multiparous sow

“…Metabolic adaptations such as a progressive decrease in insulin sensitivity during late gestation and lactation or an increased sow catabolism during lactation (Valros et al, 2003) allow the provision of glucose to the pregnant uterus (Père et al, 2000) or the mammary gland Farmer et al, 2008). Indeed, glucose is the main energetic fuel for metabolism and growth of the foetuses (Père, 2001(Père, , 2003, and for milk synthesis (Farmer et al, 2008). The transition between gestation and lactation involves rapid and important changes in numerous hormones and metabolites and may interfere on the metabolic status of the sow during further lactation.…”

Effects of dietary inclusion of Opuntia ficus-indica on the glycemia and productive performance in lactating sows

“…The physiological hypophagia that occurs in sows during lactation is established immediately after farrowing as a consequence of a high concentration of blood glucose from day 85 of gestation (Pére & Etienne, 2007;Mosnier et al, 2010). Before farrowing, the physiological objective is to provide energy to the foetuses for their growth during the last third of gestation (Farmer et al, 2008). After farrowing, high concentrations of blood glucose are maintained to supply energy requirements for synthesis and milk production during lactation (Bergsma et al, 2009).…”

“…This was a larger quantity of milk than was produced by the CG sows, but was similar to that observed in EG. However, these differences among studies in milk production are possibly attributable to differences in the genetic material and the environment (Farmer et al, 2008). In contrast, Thingnes et al (2012) suggested that additional feed intake by the sows during lactation is not reflected in milk production, but is used to reduce weight loss.…”

“…Physiologically, this causes an increased supply of blood glucose to the pregnant uterus and mammary gland (Thingnes et al, 2012;Bergsma et al, 2009, respectively). This increased energy supply supports the logarithmic growth of foetuses during the last third of gestation (Farmer et al, 2008) and milk production during lactation (Bergsma et al, 2009). However, the increase in blood glucose during the transition period affects the sow negatively by reducing feed intake and thus her consumption of energy (Mosnier et al, 2010).…”

14. Mammary blood flow and nutrient uptake

“…Because no other studies are available to compare the plasma flow estimated with calcium, it is unknown whether calcium is a valid marker. Unlike amino acids, calcium is not metabolized hence (Farmer et al, 2008b). Guan et al (2004a) Fick (lysine) 11 4.5 11.4 560 Guan et al (2004b) Fick (lysine) 11 3.6 10.7 490 Linzell et al (1969a) 2 Fick ( 3 HO) 6 1.9 3 6.2 441 3 Nielsen et al 2002bFick (lysine) 8 3.2 10 550 Nielsen et al 2002aFick (lysine) 12 5.5 7.4 1,050 Nielsen et al (2002a) Fick (methionine) 12 4.4 7.4 858 Nielsen et al (2002a) Fick (calcium) 12 2.8 7.4 548 Renaudeau et al (2002) Flow probe 12 3.6 3 11 471 3 Renaudeau et al 2002Fick (lysine) 12 3.9 4 11 511 Trottier et al (1997) Fick (lysine) 11 3.0 8.1 541…”