Observations on mammary development in calves and lambs

1953 ◽  
Vol 43 (4) ◽  
pp. 413-421 ◽  
Author(s):  
C. Wallace
Keyword(s):  
Experimental Treatment ◽  
Mammary Development ◽  
Prolonged Treatment ◽  
Mammary Tissue ◽  
Striking Difference ◽  
Oestrogen Treatment ◽  
Beef Breed ◽  
Beef Calves ◽  
Dairy Heifers ◽  
Gland Tissue

The normal course of mammary development has been briefly described, in sheep from 2 months of foetal age to 4 months after birth; and in dairy cattle from the 3-month foetus to calves 6 months old. Observations were also made on a series of udders from ewes during their first pregnancy. A small group of beef calves and a number of freemartins of various ages were also examined.Development was found to be closely similar in the two species, and in both, sex differences were marked.Experimentally it was found that in males of either species castration at birth had little effect on mammary growth, while prolonged treatment with oestrogen gave rise to enlarged teats, dilated cisterns and ducts, and to a certain amount of secretion. Little gland tissue was formed in oestrogen-treated males, and there was no increase in the spreading of mammary tissue from the neighbourhood of the teat.Females of the two species showed a striking difference in their response to experimental treatment. In sheep, removal of the ovaries at birth had no apparent effect on mammary development up to 4 months, while treatment with oestrogen stimulated gland formation in both spayed and intact lambs and also restricted the normal spread of mammary tissue into the udder. In cattle, on the other hand, heifers spayed at birth showed almost complete cessation of mammary development, while implants of oestrogen, in addition to inducing gland formation, promoted the spreading of tissue into the udder pad of the spayed animal.Udder development of freemartins appeared to be similar to that of normal heifers from 5 months foetal age to about a month after birth, but thereafter was more like that of a spayed animal. Removal of the abnormal gonads shortly after birth had no effect, while oestrogen treatment induced development of teats, ducts and glands exactly as in a normal heifer.Comparing small numbers of calves of the two types, it was found that heifers of the beef breed in general showed slightly poorer mammary development than dairy heifers that had been treated in the same way, with more connective tissue and numerous leucocytes in the mammary zone.

scholarly journals Windows in early mammary development: critical or not?

Reproduction ◽  
2001 ◽  
pp. 337-345 ◽  
Author(s):  
CH Knight ◽  
A Sorensen
Keyword(s):  
Breast Cancer ◽  
Milk Yield ◽  
Proliferative Activity ◽  
Mammary Development ◽  
Term Effect ◽  
Critical Window ◽  
Dairy Heifers ◽  
Long Term Effect ◽  
Long Term Consequences

Two critical windows in mammary development have been proposed. The first arises from observations in rodents that nutrition during fetal and neonatal periods can affect mammary ductular outgrowth, subsequent proliferative activity and, eventually, tumorigenesis, that is, potentially it could have a long-term effect on pathological outcome (breast cancer) in women. The second similarly involves early diet, but in this case the outcome is phenotypic, in that dairy heifers reared too quickly during the peripubertal period subsequently show impaired udder development and reduced milk yield persisting throughout life. Most mammary development occurs during pregnancy, but this period is usually thought of only in terms of the immediate outcome for the subsequent lactation; it is not believed to be a critical window, at least in terms of lifetime mammary productivity. This review examines the evidence underlying these various claims and attempts to define the mechanisms involved, and also considers whether derangements occurring earlier in life (prenatally) could also have long-term consequences for physiological or pathological mammary development.

In-vivo magnetic resonance imaging studies of mammogenesis in non-pregnant goats treated with exogenous steroids

1991 ◽  
Vol 58 (2) ◽  
pp. 151-157 ◽  
Author(s):  
Paul A. Fowler ◽  
Christopher H. Knight ◽  
Margaret A. Foster
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Maximum Size ◽  
Mammary Development ◽  
Mammary Tissue ◽  
Secretory Cells ◽  
Resonance Imaging ◽  
Secretion Efficiency ◽  
Cessation Of Treatment

SummaryMammogenesis and lactation were induced in five multiparous, non-pregnant goats by treatment with oestrogen and progesterone for 11 d, followed by dexamethasone for 3 d. Reserpine was administered during the last 5 d. All five goats lactated, although milk yield was less than had been achieved in previous natural lactations. Mammary development was assessed in vivo, using magnetic resonance imaging. Although parenchyma volume increased by more than 6-fold overall, only 25% of this increase occurred during steroid treatment. Most development took place after the cessation of treatment, when milking commenced. Maximum size was not achieved until week 8 of the induced lactation, and was only 70% of normal parenchyma volume. After 18 weeks lactation the activities of three key milk synthetic enzymes were very similar to values previously found in natural lactations, and secretion efficiency (milk production per unit volume of parenchyma) was also similar to that of natural lactations. We conclude that the lower than normal milk yields were associated with incomplete proliferation of mammary tissue, rather than inadequate differentiation of individual secretory cells.

285. Studies on experimental teat and mammary development and lactation in the goat

1941 ◽  
Vol 12 (3) ◽  
pp. 241-264 ◽  
Author(s):  
S. J. Folley ◽  
Helen M. Scott Watson ◽  
A. C. Bottomley
Keyword(s):  
Virgin Female ◽  
Young Female ◽  
Mammary Development ◽  
Early Age ◽  
Allometric Growth ◽  
Endocrine Activity ◽  
Oestrogen Treatment ◽  
Immature Male ◽  
Normal Males ◽  
Whole Mounts

1. Observations on five animals indicate that the teats of immature castrated male goats grow isometrically. Less extensive data on three animals allow of the tentative conclusion that the same is true of immature normal males. In the male goat therefore teat growth appears to be uninfluenced by the testes.2. Administration of diethylstilboestrol or its dipropionate to normal or castrated immature male goats causes the teats to grow allometrically for a time.3. No externally visible udder growth occurred even when oestrogen treatment was prolonged for periods of over a year and was supplemented by progesterone or ethinyltestosterone. Whole mounts of glands from treated animals indicated that some mammary growth had occurred. In two cases microscopic examination showed the presence of alveoli. No explanation can be offered of the failure to develop the udder in the male goat experimentally.4. Endocrine activity of the ovary as evidenced by a change from isometric to allometric teat growth often manifests itself in the young female goat at an early age. In one case allometric teat growth was in progress at 41 days of age. During the allometric phase the data agree with the simple allometric law.5. During the rutting season following its birth, teat growth ceases completely in the female goat; allometric growth is resumed when the rutting season ends. It therefore appears that the corpus luteum inhibits teat growth.6. Administration of diethylstilboestrol or its dipropionate (by inunction of the udder region) causes, in the virgin female, an increase in the rate of teat growth accompanied by udder growth.

The effect of dam’s parity on the first lactation performance of dairy heifers

1986 ◽  
Vol 1986 ◽  
pp. 102-102
Author(s):  
S. J. Furniss ◽  
A. Stroud ◽  
H. Barrington ◽  
S. P. J. Kirby ◽  
J. P. Wray ◽  
...  
Keyword(s):  
Market Value ◽  
Breeding Programme ◽  
Lactation Performance ◽  
Beef Breed ◽  
Genetic Merit ◽  
Dairy Heifers ◽  
Beef Bull ◽  
Dairy Bulls ◽  
First Time ◽  
Genetic Index

Whether they are planning to calve for the first time at two or three years old Many farmers choose to serve their maiden dairy heifers (animals not previously served, (M. A. F. F. 1985)) with a beef breed recognised for giving easier calvings .Often the heifer breeding programme is not well supervised and it is a matter of convienience to use a resident beef bull.There are however,considerable advantages to serving heifers with dairy bulls including an increased number of heifer calves for selection or the ability to serve older, nature cows (animals that have commenced at least their first lactation (M. A. F. F. 1985))with a continental beef breed giving large calves of higher market value. Because heifers tend to be calved as a group they provide a batch of calves which can be concentrated upon, easing management and improving control over performance.If heifers are served by bulls of as higher genetic merit as would normally be used on cows then increased genetic turnover will raise the genetic index in the younger dam which should be reflected in her daughter’s performance.

To determine the relationships between age, weight and size in Holstein heifers between 100 and 300 kg liveweight

1999 ◽  
Vol 1999 ◽  
pp. 199-199
Author(s):  
H.J. Biggadike ◽  
C.A. Collins ◽  
S.B. Drew ◽  
P.N. Johnson
Keyword(s):  
Milk Production ◽  
Growth Rates ◽  
Deleterious Effect ◽  
High Growth ◽  
Mammary Development ◽  
Dairy Heifers

It is common practice to rear dairy heifers to calve at 24 months of age and expect first lactation milk yields of up to 10,000 litres. This requires growth rates of at least 0.7kg/d during rearing. Research has indicated that high growth rates in the prepubertal period can have a deleterious effect on mammogenisis (Capuco et al 1995), and a significant reduction in potential milk production (Sejrsen et al 1996) due to impaired mammary development. However, not all studies have found such effects (Sejrsen et al 1996). As a consequence, strategies of rearing are being studied to identify the optimum pattern of growth around puberty to achieve high milk yields. Skeletal measurements have also been demonstrated to be related to first lactation yields (Hoffman 1996). This study investigated the consequences of differing growth rates between 100 and 300kg liveweight on the size and relative dimensions of Holstein heifers.

scholarly journals Cyclic AMP-dependent protein kinase in rat mammary tissue: expression of catalytic and regulatory subunits throughout pregnancy and lactation

1994 ◽  
Vol 301 (3) ◽  
pp. 807-812 ◽  
Author(s):  
R A Gardner ◽  
M T Travers ◽  
M C Barber ◽  
W R Miller ◽  
R A Clegg
Keyword(s):  
Catalytic Activity ◽  
Protein Kinase ◽  
Mammary Development ◽  
Mammary Tissue ◽  
Early Lactation ◽  
Dependent Protein Kinase ◽  
Regulatory Subunits ◽  
C Subunit ◽  
Pregnancy And Lactation ◽  
Dependent Protein

‘Expressed’ and ‘total’ activities of cyclic AMP-dependent protein kinase (PK-A) were measured in extracts of rat mammary tissue sampled throughout pregnancy and lactation. Expression of the genes encoding the catalytic subunit (C-subunit) isoforms C alpha and C beta was examined by Northern blotting, as a function of mammary development, to determine relative levels of their respective mRNAs. The content of C-subunit protein (all isoforms) was estimated immunochemically and related to levels of C-subunit catalytic activity and of mRNAs. It was found that C-subunit isoform mRNAs are expressed co-ordinately during mammary development and that a marked decline in expression, per cell, at around parturition is paralleled by a fall in ‘total’ PK-A activity. The ‘expressed’ activity of PK-A activity underwent characteristic changes throughout pregnancy and lactation, reaching a peak late in pregnancy. The PK-A activity ratio reached a peak in early lactation. C-subunit protein mass closely parallel ‘total’ PK-A activity throughout pregnancy and lactation, thereby demonstrating the constancy of C-subunit specific catalytic activity during these developmental events. Regulatory subunits (R-subunits) were probed with the photoaffinity label 8-azido-[32P]cAMP. The abundance of R-II as a proportion of total R-subunit increased throughout pregnancy and lactation, and quantitative analysis of the photoaffinity labelling suggested inconstancy in the ratio of R:C subunits, with highest values occurring in late pregnancy/early lactation.

Review: Mammary development in swine: effects of hormonal status, nutrition and management

2013 ◽  
Vol 93 (1) ◽  
pp. 1-7 ◽  
Author(s):  
C. Farmer
Keyword(s):  
Detrimental Effect ◽  
Current Knowledge ◽  
Management Strategies ◽  
Mammary Development ◽  
Late Gestation ◽  
Mammary Tissue ◽  
Hormonal Status ◽  
Best Management ◽  
Lactating Sows ◽  
Endocrine Status

Farmer, C. 2013. Review: Mammary development in swine: effects of hormonal status, nutrition and management. Can. J. Anim. Sci. 93: 1–7. There are three phases of rapid mammary accretion in swine, namely, from 90 d of age until puberty, during the last third of gestation and throughout lactation. Nutrition, endocrine status and management of gilts or sows during those periods can affect mammary development. More specifically, in growing gilts, feed restriction as of 90 d of age hinders mammary development and either supplying the phytoestrogen genistein or increasing circulating concentrations of prolactin stimulates mammogenesis. In late gestation, inhibition of relaxin or prolactin drastically diminishes mammary development and overly increasing dietary energy has a detrimental effect on mammogenesis. It also appears that feeding of the gestating sow can affect the mammary development of her offspring once it reaches puberty. Various management factors such as litter size, nursing intensity and use or non-use of a teat in the previous lactation will affect the amount of mammary tissue present at the end of lactation. Mammary development is followed by the essential process of involution whereby a rapid and drastic regression in parenchymal tissue takes place. It can occur either after weaning or in early lactation when teats are not being regularly suckled. Despite our current knowledge, much remains to be learned in order to develop the best management strategies for replacement gilts, and gestating and lactating sows that will maximize their milk production.

Uteroplacental insufficiency alters the mammary gland response to lactogenic hormones in vitro

2008 ◽  
Vol 20 (4) ◽  
pp. 460 ◽  
Author(s):  
Rachael O'Dowd ◽  
Mary E. Wlodek ◽  
Kevin R. Nicholas
Keyword(s):  
Gene Expression ◽  
Mammary Gland ◽  
Postnatal Growth ◽  
Mammary Development ◽  
Mammary Tissue ◽  
Sham Surgery ◽  
Uterine Vessel ◽  
Lactogenic Hormones ◽  
Vessel Ligation

Adequate mammary development and coordinated actions of lactogenic hormones are essential for the initiation of lactation. Pregnancies compromised by uteroplacental insufficiency impair mammary development and lactation, further slowing postnatal growth. It is not known whether the initiation of lactation or galactopoesis is compromised. Uteroplacental insufficiency induced in rats by bilateral uterine vessel ligation (Restricted) or sham surgery (Control) on Day 18 of gestation preceded collection of mammary tissue on Day 20 of pregnancy. Mammary explants were cultured with combinations of insulin, cortisol and prolactin and analysed for α-lactalbumin and β-casein gene expression. Mammary tissue from late pregnant Restricted rats had elevated α-lactalbumin, but not β-casein, mRNA, which is consistent with premature lactogenesis resulting from an early decline in peripheral maternal progesterone. Explants from Restricted rats were more responsive to hormone stimulation after 3 days in culture, indicating that compromised galactopoesis, not lactogenesis, most likely leads to the reduced growth of suckled pups.

FAMILIAL IDIOPATHIC HYPOGONADOTROPHIC HYPOGONADISM

1977 ◽  
Vol 84 (2) ◽  
pp. 246-253 ◽  
Author(s):  
B. Bétend ◽  
E. Lebacq ◽  
L. David ◽  
B. Claustrat ◽  
R. François
Keyword(s):  
Prolonged Treatment ◽  
Striking Difference ◽  
Hormonal Stimulation ◽  
Peripheral Tissues ◽  
Hypogonadotrophic Hypogonadism ◽  
Infancy And Childhood ◽  
Males And Females ◽  
Male Sex ◽  
Lh Rh ◽  
Artificial Cycle

ABSTRACT A new case of familial idiopathic hypogonadotrophic hypogonadism is presented: 3 males and 2 females among 9 siblings are affected. Very low to non-detectable levels of plasma LH and FSH levels were found in each patient. LH-RH stimulation test gave in one male a slight increase in plasma LH levels while no change was observed in the others. Prolonged treatment with gonadotrophins or testosterone gave poor results in the males while evidence of ovulation was obtained in the two females during a unique induced artificial cycle with combined HMG and HCG treatment; rapid feminization was also obtained in the females with oestrogen therapy. The striking difference in the results of the substitution treatments between males and females suggest that some degree of acquired insensitivity of the testes to gonadotrophins and of peripheral tissues to male sex hormones are present in male hypogonadotrophic hypogonadism. This may be the consequence of a lack of hormonal stimulation or impregnation during infancy and childhood.

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