The concentration of lactate in relation to other components of bovine mammary secretion during premature regression and after resumption of milking

Abstract

An experiment lasting 42 d was performed in 4 consecutive stages on 6 healthy Friesian cows during mid-lactation. Mean values for the different components of mammary secretion during normal lactation were established. Milking was then suspended on all quarters from d 1-14. The mean values for lactate increased 20-to 30-fold over the mean value for normal lactation. Over the same period the leucocyte count (polymorphonuclear leucocytes and lymphocytes) also increased, whereas the mean values for glucose and the estimated redox potential decreased. From d 15-28 milking was resumed on one half of the udder and from d 29-42 milking was also resumed on the other udder-half. When milking was resumed the above-mentioned changes were reversed, taking 5-7 d to reach values obtained during normal lactation in the udder-half which had not been milked for 14 d, but at least 14 d in the udderhalf which had not been milked for 28 d. The changes in the levels of lactate, glucose, leucocyte count and estimated redox potential are discussed in relation to changes in the secretory activity of the mammary gland (lactose, /Mactoglobulin and epithelial cell count), permeability changes of the mammary epithelium (Na + , K + and serum albumin) and the immune defence mechanism in the udder (immunoglobulins). The results indicate that lactate is formed during anaerobic glycolysis by the leucocytes in the mammary secretion, most probably due to reduced blood flow to the udder and the accumulation of secretion in the gland and teat cisterns on cessation of milking.Most studies on function and control of the bovine mammary gland have dealt with the gross composition of milk or with changes in the levels of tissue metabolites and enzymes during the onset of lactation, normal lactation and involution when changes in mammary secretory activity are greatest (Peaker, 1975;Fleet et al. 1975; Schanbacher & Smith, 1975). However, in terms of the physiology of the bovine mammary gland, the diagnosis of sub-clinical mastitis and the production of high quality milk, it is important to elucidate the phenomenon of premature regression. Premature regression is the premature degeneration of the lactating udder epithelium

Biochemical study of DNA markers for Bacterial infection in bovine mastitis

“…In the context of milk lactate being a potential diagnostic measurement for mastitis, Mayer et al (1988) reported that milk oxygen concentrations were reduced during mastitis suggesting that, given a favorable supply of substrates, the metabolism of somatic cells in milk and/or the mammary epithelium may become anaerobic leading to release of lactate into milk (Davis et al, 2004). Mackie et al (1977) found a relatively slow but substantial increase in lactate in milk during mammary involution with concentrations reaching approximately 5 mM, 5 days after the last milking. Kato et al (1989) reported highest LDH activity in milk samples infected with S. aureus.…”

Assessment of mammary gland metabolism in the sow: I. Development of methods for the measurement of cellular metabolites in milk and colostrum

“…Arthur et al (1991). 'Faulkner (1980), g Hoff & Wick (1963), h Kuhn & White (1975), 'Richardson et al (1980), 'George & DeFrancesca (1989, k Atwood, unpublished observations, , m Mackie et al (1977), "Faulkner & Pollock (1989), "Gil & Sanchez Medina (1982), "Neville et al (1984), "Skala et al (1981), 'Blatchford et al (1984, "Nicholas & Hartmann (1991), 'Grigor et al (1989, "Faulkner et al (1982), v Reineccius et al (1970), " Bowland (1966), "Noblet & Etienne (1986), y Klobasa et al (1987), z Holmes & Hartmann (1993), "Bencini et al (1992, b 'Kobata & Ziro (1965), c Giesecke et al (1984…”

Glucose levels in normal and mastitic milk

“…Since milk Na and Cl increase during mastitis, it is possible that glucose would move out of milk by this pathway to maintain osmolarity between the milk and extracellular fluid. Alternatively, the reduced glucose content of mastitic milk may be due to in vivo metabolism of glucose to lactate by polymorphonuclear leucocytes entering the gland (Mackie et al 1977). Even if this does occur, it appears from this present investigation that measurable metabolism of glucose does not continue after the milk is removed from the udder and stored at a low temperature for up to 2 d.…”

“…Recent studies by Giesecke & Van den Heever (1981) have shown that during the early stages of acute mastitis, glucose levels may decrease in the milk from affected quarters. Mackie et al (1977) found that milk glucose levels were reduced during premature mammary regression and that there was a significant negative correlation (r = -087) between glucose and leucocyte count. However, only a weak negative correlation (r = -0-18) between glucose and log somatic cell count was obtained by Luck & Botha (1982) on milks with relatively low cell counts.…”

“…Compared with lactose, the concentration of glucose normally present in milk is very low and has been reported in the range 018-1-03 mM (Reineccius el al. 1970;Mackie et al 1977;Giesecke & Van den Heever, 1981;Luck & Botha, 1982). Recent studies by Giesecke & Van den Heever (1981) have shown that during the early stages of acute mastitis, glucose levels may decrease in the milk from affected quarters.…”