Comparative study of mammary gland development and differentiation between beef and dairy heifers

Keys, J.E.; Capuco, Anthony; Akers, R.M.; Djiane, Jean

doi:10.1016/0739-7240(89)90025-8

Cited by 29 publications

(29 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A comparison of mammary glands in cows from different breeds (Hereford/Holstein) clearly demonstrated that the difference in milk yield (3.5/20.3 kg·day -1 ) could be explained by changes in the mass and functioning of parenchymatous tissue [29]. Indeed, dairy cows have higher levels of total DNA per udder and a higher number of cells per alveolus than beef cows.…”

Section: Geneticmentioning

confidence: 99%

The number and activity of mammary epithelial cells, determining factors for milk production

2004

View full text Add to dashboard Cite

-The ability of ruminant mammary glands to produce milk is determined by the number of cells secreting milk and their level of activity. Changes in the number of cells in the udder occur during lactation. It has been shown that mammary cells proliferate during this process, while other cells die through apoptosis. The decline in milk production after peak lactation appears to be due to a gradual reduction in the number of milk-secreting cells, either through cell death or by the abrasion of epithelial cells during milk ejection. Other factors are also known to modify cell turnover in the udder, such as reproductive status, growth hormone treatment or milking frequency and nutrition. A description of the effects of husbandry practices makes it possible to envisage different processes for mammary tissue regeneration during lactation. Indeed, changes in milking frequency are capable of modifying the number of epithelial cells in an alveolus, while GH treatment acts on the total number of alveoli. Thus recent studies have demonstrated an heterogeneity of the processes of proliferation and cell death within the mammary gland. However, unanswered questions still remain concerning the presence of stem cells in ruminants, the lifespan of mammary epithelial cells or the relative rate of loss of mammary cells due to apoptosis and epithelial abrasion. ruminant / milk production / mammary gland / mammary cells / proliferation / apoptosis

show abstract

Section: Geneticmentioning

confidence: 99%

The number and activity of mammary epithelial cells, determining factors for milk production

2004

View full text Add to dashboard Cite

show abstract

“…It is well established that total mammary cell numbers and milk yield are positively correlated in both ruminants (Linzell, 1966;Keys et al, 1989) and rodents (Tucker, 1969;Nagai & Sarkar, 1978). The secretory activity of these cells is also an important factor involved in determining milk production potential.…”

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

View full text Add to dashboard Cite

“…These hormones, in addition to their metabolic effects, could improve the number of secretory cells and thus increase the volume of milk secreted [29,45,49]. In ruminants, the number of secretory cells slowly decreases throughout the course of an established lactation via apoptotic mechanisms [79], without modification of the secretory activities of the remaining cells [49].…”

Section: Systemic Effectsmentioning

confidence: 99%

Oxytocin and milk removal: two important sources of variation in milk production and milk quality during and between milkings

Lollivier¹,

Guinard-Flament²,

Ollivier-Bousquet³

et al. 2002

Reprod. Nutr. Dev.

View full text Add to dashboard Cite

-This review describes the effects of milking (routine and management) on milk yield and milk quality on dairy ruminants and examines the physiological effects of milking on the synthesis and secretion of milk. During milking, differences in the composition of milk as a result of milk ejection reflex are observed: the cisternal milk, immediately available, contains little fat, then milk ejection provokes active transport of high-fat content alveolar milk, into the cisternal compartment. Milking frequency has the capacity to affect milk production too. So, an increase in milking frequency augments milk yield whereas a decrease in milking frequency decreases milk production, with effects on milk composition. The milk ejection reflex is mediated by oxytocin, which induces myoepithelial cell contraction. Nevertheless, other actions of oxytocin may exist, such as a direct effect on proliferation and differentiation of myoepithelial cells and on secretory processes in the mammary epithelial cells. milking / milk ejection / oxytocin / physiological effects / milk quantity and quality Résumé -Ocytocine et vidange mammaire : deux facteurs de variation essentiels de la quantité et la qualité du lait pendant la traite et entre les traites. Cette revue bibliographique pré-sente les effets de la traite (technique et conduite) sur la production quantitative et qualitative de lait, puis précise les mécanismes d'action des effets physiologiques de la traite sur la synthèse et la sécrétion des composants du lait. Au cours d'une traite, la composition du lait évolue, grâce au réflexe d'éjection du lait qui provoque le transfert du lait alvéolaire, riche en matières grasses, vers la citerne. Ainsi, le lait de début de traite est pauvre en matière grasse, tandis que le lait de fin de traite est riche en matière grasse. Les rythmes de traite ont aussi un impact sur la production laitière. Ainsi, l'accroissement de la fréquence de traite augmente la production laitière alors que la réduction du nombre de traite la diminue, avec des répercussions en terme de qualité du lait. L'hormone responsable de l'éjection du lait, l'ocytocine, exerce son rôle de vidange mammaire par déclenchement de la Reprod. Nutr. Dev. 42 (2002) 173-186 173

show abstract

Comparative study of mammary gland development and differentiation between beef and dairy heifers

Cited by 29 publications

References 23 publications

The number and activity of mammary epithelial cells, determining factors for milk production

The number and activity of mammary epithelial cells, determining factors for milk production

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

Oxytocin and milk removal: two important sources of variation in milk production and milk quality during and between milkings

Contact Info

Product

Resources

About