The Breeding Cycle of the Female Humpback Whale, Megaptera nodosa (Bonnaterre)

1958 ◽  
Vol 9 (1) ◽  
pp. 1 ◽  
Author(s):  
RG Chittleborough
Keyword(s):  
Mammary Gland ◽  
Sex Ratio ◽  
Post Partum ◽  
Humpback Whale ◽  
The Other ◽  
Breeding Cycle ◽  
Sex Ratio At Birth ◽  
Modal Length ◽  
The Third ◽  
Normal Period

The gestation period in the humpback whale is of almost 12 months' duration, most conceptions occurring early in August with parturition at the beginning of the following August. The modal length of calves at birth is 14 ft. The sex ratio at birth is 51.4 per cent. males to 48.6 per cent. females. Twin foetuses are occasionally recorded. There is no preference towards either right or left ovary or uterine cornu with regard to ovulation or pregnancy. The breaking of the umbilical cord at birth is described. The histological appearances of the mammary gland during advanced pregnancy and during lactation are described and illustrated. Upon the evidence presented it is concluded that lactation in this species extends over 104 months, suckling generally commencing in mid August and terminating at the end of the following June. The composition of the milk has been determined during various stages of lactation. Oestrous cycles rarely occur during pregnancy, but examples of ovulation following shortly after parturition, while the females are suckling their calves, are cited. It is shown that when the calf is lost at or soon after birth, oestrous cycles usually recommence at once. Where the calf is suckled for the normal period (10½ months) there is no anoestrous period following the end of lactation as oestrous cycles recommence in July, immediately after (occasionally just before) weaning at the end of June. Three types of breeding cycle are shown for the humpback whale. In the most common cycle, absence of the post-partum ovulation, or its occurrence without conception, results in one calf in 2 years. On the other hand, a successful postpartum ovulation results in two calves in 2 years. In the third type of cycle, loss of the first calf at or just after parturition is balanced by a second pregnancy succeeding immediately afterwards. This results in two pregnancies in 2 years with only one calf reared.

Akodon molinae (Rodentia Cricetidae), a new laboratory animal: breeding, management and reproductive performance

1980 ◽  
Vol 14 (2) ◽  
pp. 129-131 ◽  
Author(s):  
Maria Susana Merani ◽  
Marta Susana Lizarralde
Keyword(s):  
Sex Ratio ◽  
Reproductive Performance ◽  
Sexual Maturity ◽  
Laboratory Animal ◽  
Post Partum ◽  
Animal Breeding ◽  
Haemorrhagic Fever ◽  
Sex Ratio At Birth ◽  
Breeding Management ◽  
Laboratory Colony

Akodon molinae, a vole mouse widely distributed in central Argentina, shows remarkable chromosome polymorphisms. It is one of the natural reservoirs of the actiologic agent of haemorrhagic fever, and a laboratory colony could be of great help in investigating this disease. Pregnancy lasted 23 (range 21-25) days. Litters of 4-5 young were born to monogamous breeding pairs about every 30 days, with weaning at 26 days post partum. The sex ratio at birth was 505 males to 500 females: at weaning it was 460 to 440. Sexual maturity was attained at about 16 weeks of age in males and 12-20 weeks in females. Akodon molinae is easy to handle, but fighting and killing or neglect of young are problems.

scholarly journals Терапевтична ефективність застосування FORTICEPT UDDER FORTE за маститу у корів

2017 ◽  
Vol 19 (82) ◽  
pp. 77-81 ◽  
Author(s):  
Yu.V. Zhuk ◽  
S.S. Derkach ◽  
O.А. Valchuk ◽  
A.M. Shevchenko
Keyword(s):  
Mammary Gland ◽  
Breast Milk ◽  
Therapeutic Efficacy ◽  
Subclinical Mastitis ◽  
The Other ◽  
Therapeutic Effectiveness ◽  
The Third ◽  
Experimental Group ◽  
Milk Treatment

The article presents the results of our own research on the therapeutic effectiveness of the use of FORTICEPT UDDER FORTE for post-milk treatment of cows with subclinical mastitis.As is known, one of the reasons for the emergence of mastitis of cows is the lack of proper sanitary-hygienic treatment of breast milk after milking. Taking into consideration the fact after milking, according to various authors, remains open for 30 minutes to 2 hours, it leads to the infection of the mammary gland with the microflora causing its inflammation.The study of the effectiveness of using FORTICEPT UDDER FORTE after milking treatment of cow's doses was performed in comparison with other existing agents: on the basis of chlorhexidine and iodine.The use of FORTICEPT UDDER FORTE for post-milking treatment of cow's dug reduces their incidence by subclinical mastitis by 30–40%.The therapeutic efficacy of using FORTICEPT UDDER FORTE in cows in the first experimental group was 20.1% higher than the other animals (chlorhexidine-based agent) and 13% in the third group (iodine-based). 

Early mechanical stimulation of the nipple-areola receptors complex promotes the mammary milk ejection function in women delivered by cesarean section

2021 ◽  
Vol 50 (2) ◽  
pp. 38-41
Author(s):  
N. P. Alekseev ◽  
E. V. Omelyanjuk ◽  
N. E. Talalajeva
Keyword(s):  
Mammary Gland ◽  
Caesarean Section ◽  
Cesarean Section ◽  
Mechanical Stimulation ◽  
Post Partum ◽  
Milk Ejection ◽  
The Third ◽  
Milk Flow ◽  
Stimulation Of

Mechanical stimulation and milk ejection from mammary gland in women delivered by caesarean section since 1 day post partum by the breastpump with vacuum and compression stimuli promotes milk ejection function. On the third day postpartum the stimulated mothers had significantly more milk flow reflex peaks than those who were not subjected to stimulation during the 10 min milk ejection session.

EFFECT OF SUCKLING AND OF EXTEROCEPTIVE STIMULATION UPON PROLACTIN RELEASE IN THE RAT DURING LATE LACTATION

1972 ◽  
Vol 52 (1) ◽  
pp. 11-22 ◽  
Author(s):  
F. MENA ◽  
C. E. GROSVENOR
Keyword(s):  
Mammary Gland ◽  
Post Partum ◽  
Mammary Glands ◽  
The Other ◽  
Male Rats ◽  
Milk Secretion ◽  
Suckling Period ◽  
Prolactin Release ◽  
Other Hand ◽  
Rat Pituitary

SUMMARY The results of experiments in which the prolactin in the primiparous rat pituitary was bioassayed suggested that the failure of suckling to release prolactin after 8 h of non-suckling on day 21 post-partum was due to the fact that prolactin had been discharged from the pituitary during the 8-h non-suckling period, presumably by exteroceptive signals emanating from the general environment of the animal room. This was substantiated in other experiments in which prolactin release was assessed indirectly through its stimulatory effects upon milk secretion. In these experiments, the mammary glands of rats maintained continuously in the animal room filled faster on day 21 after complete emptying of the glands by exogenous oxytocin, than did either rats on day 14 post-partum maintained continuously in the animal room or rats isolated in a room without other rats on day 21 post-partum. The glands of the latter two groups of rats could be stimulated to fill faster provided prolactin was injected 4 h before the initial emptying of the glands. The exteroceptive stimuli in the animal room environment that stimulated the release of prolactin in the 21-day post-partum rat apparently emanated at least in part from other lactating rats and/or their litters, since faster mammary gland refilling occurred in isolated 21 day post-partum rats when they were exposed to the presence of lactating rats with their litters for 30 min halfway through the 8-h non-suckling period which preceded the initial emptying of the gland. Exposure to male rats, on the other hand, was totally ineffective. A release of prolactin occurred in response to animal room environmental stimuli in the day 14 primiparous rat provided 13–14 day old foster pups were inserted in place of the mother's own pups on day 7. Thus, the rapidly changing characteristics of the pups from 14 to 21 days of age in some manner is involved in the increasing responsiveness of the exteroceptive mechanism for prolactin release which occurs from day 14 to day 21 post-partum.

Observations on the sex ratio and the position of the lactating mammary gland in the brush-tailed possum, Trichosurus vulpecula (Kerr) (Marsupialia)

1972 ◽  
Vol 20 (2) ◽  
pp. 131 ◽  
Author(s):  
RM Hope
Keyword(s):  
Mammary Gland ◽  
Sex Ratio ◽  
Age Groups ◽  
Differential Mortality ◽  
Sex Ratio At Birth ◽  
Significant Excess ◽  
Lactating Mammary Gland ◽  
Left And Right ◽  
Significant Regression ◽  
The Right

Data on age, sex, and location of the lactating mammary gland in T. vulpecula have been obtained from animals captured in 14 different localities in southern Australia. There is no evidence of differences between localities in the sex ratio of pouch young and the overall totals of 113 males and 94 females do not differ significantly from equality. When these data are combined with data on the sex ratio of T. vulpecula pouch young obtained by other workers, there is a consistent and significant excess of males. On partitioning the data obtained in this study into four age groups of 50 days, the 0 to 50-day group contains a significant excess of males, whereas the older groups show a sex ratio close to 1. Also, there is a significant regression of sex ratio on age, the proportion of males decreasing with increasing age. These observations may be accounted for by proposing that the sex ratio at birth favours an excess of males, and that differential mortality between the sexes occurs during pouch life. A sample of adults and independently living juveniles from Rocky River, Kangaroo I., S.A., contains a highly significant excess of males (202 males, 92 females). In all other population samples the sex ratio is close to 1. In samples from two of the localities, namely Rocky River and Adelaide, there is a significant departure from equality with respect to the number of pouch young suckling from the left and right teat. At Rocky River the right teat appears to be favoured, while in Adelaide the situation is reversed.

Factors influencing the sex ratio at birth in Australia, 1902–65

1969 ◽  
Vol 1 (2) ◽  
pp. 125-144 ◽  
Author(s):  
G. N. Pollard
Keyword(s):  
Sex Ratio ◽  
Rural Areas ◽  
The Other ◽  
Multiple Births ◽  
Sex Ratio At Birth ◽  
Male And Female ◽  
Factors Influencing ◽  
Human Births ◽  
Mother’S Age ◽  
Urban And Rural Areas

SummaryUsing Australian records of human births for the first six decades of the twentieth century, the proportions of male and female births are studied in relation to the mother's age, the father's age, the parents' ages in combination, and certain other factors. The principal data used relate to the years 1931–55, during which over 3 million children were born, yet even so the significant features are not easy to discern.Masculinity tends to fall as the age of either parent increases. But it is only average or below if one parent is old while the other is young. For high masculinity, both parents must be young.The Australian data are available in a form which enables the sex ratio to be studied also in relation to (a) the season of the year; (b) urban and rural areas; (c) the different states of the Commonwealth; (d) births inside and outside marriage; and (e) single and multiple births. When the influence of the parents' ages is eliminated, however, it does not appear as though the sex ratio varies significantly with any of these factors.

DIFFERENTIALS IN SEX RATIO AT BIRTH AMONG NATIVES AND IMMIGRANTS IN GREECE: AN ANALYSIS EMPLOYING NATIONWIDE MICRO-DATA

2010 ◽  
Vol 42 (3) ◽  
pp. 425-430 ◽  
Author(s):  
GEORGIA VERROPOULOU ◽  
CLEON TSIMBOS
Keyword(s):  
Sex Ratio ◽  
Sex Ratios ◽  
The Other ◽  
Sex Ratio At Birth ◽  
Micro Data ◽  
Live Births ◽  
Level Information ◽  
Micro Level ◽  
The One ◽  
Migrant Groups

SummaryThis study uses micro-level information on the live births registered in Greece for 2006 to assess differentials in the propensity to have a male offspring between natives and immigrants. The sex ratio at birth for the whole population is 106.3 but it is considerably higher among immigrants (110.9) than among natives (105.4). Relatively high sex ratios at birth are observed for several migrant groups; differentials between natives, on the one hand, and Albanians (109.5) and Asians (129.0), on the other, are significant. The high sex ratio at birth for Albanians seems typical of that population. For Asians, the result is consistent with international findings though it may also be partly related to the small number of observations.

The ‘teat order’ of suckling pigs: 3. Relation to competition within litters

1979 ◽  
Vol 92 (2) ◽  
pp. 257-261 ◽  
Author(s):  
D. Fraser ◽  
B. K. Thompson ◽  
D. K. Ferguson ◽  
R. L. Darroch
Keyword(s):  
Post Partum ◽  
Relative Size ◽  
Rank Correlation ◽  
The Other ◽  
Initial Weight ◽  
The Third ◽  
Weight Difference ◽  
The Difference ◽  
Selection Of

SummaryPiglets in litters, paired according to farrowing date, were redistributed during the first day after birth according to two schemes. In scheme AC–BD, one sow of the pair received the heaviest and the third heaviest quarters of the combined litters (based on weight post partum), while the other sow received the second heaviest and the lightest quarters. In scheme AB–CD, one sow received the heavier half, and the other the lighter half of the piglets. After 3 weeks under scheme AB–CD, the weight difference between the second and third quarters had become reversed, while under scheme AC–BD the difference was preserved. There was no evidence of a corresponding interaction in the selection of anterior or posterior teats. The rank correlation of the piglets' initial weight and suckling position was low for most sows. No marked differences were observed between fostered and unfostered piglets in the weight measures or suckling position. It is concluded that the growth of the piglets was influenced by the relative size of their litter-mates after redistribution, but that little of the effect could be explained by competition for the anterior teats.

Fostering in sheep: experiences with the use of neatsfoot oil

1987 ◽  
Vol 27 (6) ◽  
pp. 771 ◽  
Author(s):  
G Alexander ◽  
D Stevens ◽  
LR Bradley
Keyword(s):  
Post Partum ◽  
Acceptance Rate ◽  
The Other ◽  
The Third ◽  
Acceptance Rates

This paper reports the results of 3 studies on variables associated with the use of neatsfoot oil for substitutive or additive fostering of lambs. In the first study, neatsfoot oil was applied at the rate of 60 mL/kg of liveweight to 3-day-old lambs from Merino and Border Leicester x Merino ewes, and the lambs were exchanged between pairs of ewes of the same breed 3.5, 7 or 24 h later. The proportion of ewes accepting the alien lamb from the other ewe of the pair within 17 h generally increased with the period from application to exchange. Crossbred ewes accepted the foster lambs more readily than did the Merinos. Acceptance rates with batches of neatsfoot oil produced by different methods were similar. We found no advantage in smearing the ewe's nose with neatsfoot oil at the time the oil was applied to the lamb. Additive fostering in 20 ewes that accepted the alien lambs and were left with their own lambs was 95% successful and appeared permanent. In the second study using similar methods, with lambs of 28 crossbred ewes anointed 24 h prior to exchange, no advantage was found in presenting the foster lamb to the ewe at night over presentation during the day. Most foster lambs were accepted within 12 h, and all ewes reaccepted their own lambs after a 13 h absence. The acceptance rate of foster lambs by the crossbred ewes ranged from 70 to 83%. In the third study, 27 Merino ewes whose lambs were anointed with neatsfoot oil 7-40 h after birth, were presented with freshly anointed foster lambs 24 h later. The rate of acceptance of the foster lambs within the next 24 h was 74%,but many ewes required prolonged restraint before reaccepting their own lambs after 5-26 h separation. The results show that most ewes can be induced to accept foster lambs 1-2 days post partum, if their offspring have been liberally coated with neatsfoot oil for 24 h, and then substituted with neatsfoot-treated foster lambs. For additive fostering, the ewes' offspring should be returned within a few hours.

Omitting the dry period between lactations does not reduce subsequent milk production in goats

1991 ◽  
Vol 58 (1) ◽  
pp. 13-19 ◽  
Author(s):  
Paul A. Fowler ◽  
Christopher H. Knight ◽  
Margaret A. Foster
Keyword(s):  
Mammary Gland ◽  
Milk Production ◽  
Enzyme Activities ◽  
Secretory Cell ◽  
Cell Number ◽  
The Other ◽  
Dry Period ◽  
The Third ◽  
Significant Difference

SummaryFour goats were studied from the end of their second lactation. One mammary gland of each goat was dried off just prior to the start of the third gestation, whilst the other gland was milked throughout gestation, with no dry period. At the end of gestation the continuously milked gland was significantly smaller than the gland that had been allowed a dry period. However, this difference did not persist beyond parturition and there was no significant difference between the milk yields of the two glands in the next lactation, although the continuously milked gland tended to have the higher yield. At 18 weeks of lactation, mammary parenchyma weight and secretory cell number were significantly greater in the continuously milked gland, but mammary enzyme activities did not differ between the two glands.

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