Biochemical and ultrastructural aspects of milk synthesis and secretion

Nickerson, S.C.; Akers, R.M.

doi:10.1016/0020-711x(84)90144-7

Cited by 41 publications

(15 citation statements)

References 49 publications

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“…Around parturition, tight junctions start closing (McFadden et al, 1987) and lactose, which is the main osmole in milk (Linzell, 1972), remains in the mammary gland. Thus, water enters the secretory vesicles (Linzell, 1972) and influences the milk yield (Nickerson and Akers, 1984).…”

Section: Discussionmentioning

confidence: 99%

Milk production during the colostral period is not related to the later lactational performance in dairy cows

Kessler

Bruckmaier

Gross

2014

Journal of Dairy Science

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In dairy cows, milk yield increases rapidly after parturition until a peak at around wk 6 of lactation. However, the description of the shape of the lactation curve is commonly based on weekly average milk yields. For a more detailed analysis of the milk production curve from the very beginning of lactation including the colostral period and the effect of colostrum yield on further lactational performance, the first 10 milkings after parturition, daily milk yields from d 1 to 28 of lactation, and the cumulative milk production on d 100 to 305 of lactation were investigated in 17 primiparous and 39 multiparous cows milked twice daily. Milk yield at the first milking after parturition (colostrum) ranged from 1.3 to 20.7 kg (Δ = 19.4 kg) in multiparous and from 1.8 to 10.9 kg in primiparous animals (Δ = 9.1 kg). At the tenth milking, milk production ranged from 9.2 to 21.5 kg (Δ = 12.3 kg) in multiparous and from 7.0 to 15.2 kg (Δ = 8.2 kg) in primiparous animals. Immediately after parturition, daily milk production increased rapidly, but after approximately 1 wk in lactation, the slope of the daily milk production curve flattened and continued more linear. A nonlinear regression equation was used to determine this timely change, which occurred earlier in primiparous (d 6.9 ± 0.3) than in multiparous cows (d 8.2 ± 0.2). The correlation between the amount of first colostrum and milk production during further lactation decreased already from 0.47 on d 5 to 0.32 on d 14. In multiparous cows, the correlation between total milk production of the previous 305 d standard lactation and the amount of first colostrum was not significant (correlation = 0.29), whereas the correlation with the daily production increased from 0.45 on d 5 to 0.69 on d 14. However, in primiparous animals, correlations between first-colostrum yield and daily milk yields up to d 28 of lactation were not significant, possibly due to the smaller sample size compared with multiparous animals. First-colostrum yield and cumulative milk production of 100, 200, and 305 lactation days were not significantly correlated in multiparous and primiparous cows. In conclusion, the milk production during the first few milkings is widely independent from the overall production level of a cow. Potentially, genetic selection toward lower milk yield during the very first days after parturition at a simultaneously high lactational performance may be a tool to ensure sufficient colostrum quality and to reduce the metabolic load around parturition.

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Section: Discussionmentioning

confidence: 99%

Milk production during the colostral period is not related to the later lactational performance in dairy cows

Kessler

Bruckmaier

Gross

2014

Journal of Dairy Science

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“…During lactogenesis, the mammary epithelium becomes highly differentiated. This period is associated with an overall increase in the size and metabolic activity of each cell, closure of tight junctions between cells, an increase in mitochondrial size, and development of the endoplasmic reticulum (Nickerson & Akers, 1984). During established lactation, any new cells that are formed are thought to become differentiated almost immediately (Tucker, 1969).…”

Section: The Ultimate Determinants Of Milk Production Potential: Mammmentioning

confidence: 99%

Regulation of Mammary Development as It Relates to Changes in Milk Production Efficiency

Wall¹,

McFadden²

2012

Milk Production - An Up-to-Date Overview of Animal Nutrition, Management and Health

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“…Various types of vesicular traffic are abundantly present in epithelial cells of the lactating mammary gland (Nickerson & Akers 1984). Milk proteins are transported via bilayer membrane-bounded vesicles from the endoplasmic reticulum to the Golgi apparatus, to a secretory vesicle, to the plasma membrane and are then secreted into the alveolar lumen by exocytosis (Nickerson & Akers 1984).…”

Section: Discussionmentioning

confidence: 99%

“…Milk proteins are transported via bilayer membrane-bounded vesicles from the endoplasmic reticulum to the Golgi apparatus, to a secretory vesicle, to the plasma membrane and are then secreted into the alveolar lumen by exocytosis (Nickerson & Akers 1984). Because p115/TAP mediates the docking of traffic vesicles and acceptor membranes in intra-Golgi transport (Nakamura et al 1997) and exocytosis (Bajjalieh & Scheller 1995), the protein increase in the lactating epithelial cells is considered to be involved in the pathway for milk-protein secretion.…”

Section: Discussionmentioning

confidence: 99%

“…Lactating mammary epithelial cells contain abundant endoplasmic reticula, well-developed Golgi apparatuses and numerous secretory vesicles (Wooding 1977). Milk proteins are transported via bilayer membrane-bounded vesicles from the endoplasmic reticulum to the Golgi apparatus, to a secretory vesicle, to the apical membrane and are then secreted into the alveolar lumen by exocytosis (Nickerson & Akers 1984).…”

Section: Introductionmentioning

confidence: 99%

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Developmental changes in the protein and mRNA content of a p115/transcytosis-associated protein in the bovine mammary gland

Watanabe

Uchida²,

Kadota³

et al. 2000

Journal of Endocrinology

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We measured the amounts of a vesicular transport factor, p115/transcytosis-associated protein (p115/TAP) and its mRNA, in mammary glands from cows in which lactation was induced hormonally. The highest level of p115/TAP mRNA, determined by Northern blotting, was detected in the developing stage. In contrast to the mRNA level, the amount of protein, determined by immunoblot analysis using anti-p115/TAP antibodies raised against a p115/TAP-derived recombinant fusion protein, was higher during the lactating stages than at other times. Immunohistochemical study showed that p115/TAP was predominantly localized in mammary epithelial cells. The p115/TAP was also detected in tissues other than the mammary gland but, in contrast to the situation in the mammary gland, the protein and its mRNA levels in those tissues were independent of the stage of lactation. The increased level of p115/TAP mRNA during the developing stage and the maintenance of p115/TAP protein during lactation suggest that the synthesis of p115/TAP is regulated during mammary development and differentiation, and also that the protein is involved in a function related to lactation.

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Biochemical and ultrastructural aspects of milk synthesis and secretion

Cited by 41 publications

References 49 publications

Milk production during the colostral period is not related to the later lactational performance in dairy cows

Milk production during the colostral period is not related to the later lactational performance in dairy cows

Regulation of Mammary Development as It Relates to Changes in Milk Production Efficiency

Developmental changes in the protein and mRNA content of a p115/transcytosis-associated protein in the bovine mammary gland

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