Reproductive Biology and Development of the Water Rat, Hydromys chrysogaster, in Captivity

1982 ◽  
Vol 9 (1) ◽  
pp. 39 ◽  
Author(s):  
PD Olsen
Keyword(s):  
Breeding Season ◽  
Developmental Stages ◽  
Post Partum ◽  
Growth Curves ◽  
Gestation Length ◽  
Body Measurements ◽  
Sperm Production ◽  
Crown Rump Length ◽  
Rate Of Increase ◽  
Hydromys Chrysogaster

In a captive colony of H. chrysogaster most litters were born between September and March, although some were born in every month except June. Most females had regular oestrous cycles in the breeding season but there were isolated instances of oestrus in every month. In mature males, testes were scrota1 and there was full sperm production all year. There was some regression in weight of male accessory reproductive glands in the autumn and winter. Oestrus lasted 10 days (range 7-17), and its stages: pro-oestrus 1 day, oestrus 2 days, metoestrus 2 days, anoestrus 5 days. Some instances of delayed implantation were suspected. Gestation length was 34 days (33-41). Parturition was followed the next day by a postpartum oestrus, lasting 1 day. Lactation anoestrus was at least 3 weeks. Litter size was 3.29 � 1.26 (1-7) and the number of litters per breeding season was 2.6 � 0.97 (1-5). In the latter half of pregnancy there was a linear relationship between the crown-rump length of foetuses and gestation length. Young were born naked, blind and with the pinnae folded forward with edges attached to the head. The upper incisors emerged at 4 days, the lower incisors at 6 days, the auditory meatus opened at about 10 days, the eyes opened at about 14 days, some solids were eaten and young were more independent at about 3 weeks of age, and they were weaned at about 29 days. Phases in the rate of increase in weight were associated with each of these developmental stages. Females were first capable of breeding at 124 days (433 g); most matured about 240 days in the season following that of their birth. The testes descended in males between 90 and 120 days (475 g) but full sperm production did not occur until about 130-140 days. Females could breed for three seasons (until about 3.5 y old). Placental scars were visible for up to 6 months, but had sometimes disappeared at 4 months post partum. Growth curves of tail and weight were sigmoid, and those of other body measurements were exponential, as in the Rattus group of Australian rodents, and differing from the pseudomyine rodents. Body measurements showed a sigmoid relationship to the linear equivalence of body weight. Developmental events occurred earlier, in relation to growth, in Hydromys and Rattus lutreolus than in Pseudomys novaehollandiae.

scholarly journals [NO TITLE AVAILABLE]

2007 ◽  
Vol 67 (4) ◽  
pp. 707-713 ◽  
Author(s):  
V De Conto ◽  
R Cerqueira
Keyword(s):  
Sexual Dimorphism ◽  
Litter Size ◽  
Post Partum ◽  
Growth Curves ◽  
Gompertz Model ◽  
Significant Negative Correlation ◽  
Gestation Length ◽  
Significant Difference ◽  
In Captivity ◽  
Males And Females

The reproduction, development and growth of Akodon lindberghi were studied in captivity. The colony was derived from animals captured in Simão Pereira, Minas Gerais state, which represents a new area of geographical distribution known for this species. Twelve males and twelve females were crossed, producing 144 young in 53 litters. Post-partum oestrus was observed and gestation length was estimated in 23 days. Litter size ranged from 1 to 4 with a mean of 2.72 (SD = 0.97, n = 53) and modal size of 3. Sexual dimorphism was neither present in body mass at birth nor at weaning. There was a significant negative correlation between litter size and mass at birth or weaning. Permanent emergence of adult external appearance occurred at 15 days. Puberty for males and females was 43 and 42 days, respectively, and the first fecundation event for two females was recorded at 47 and 54 days of age. The weight growth was described by fitting a Gompertz model. No significant difference was found in any parameter of growth curves for males and females. Measurements (head-body, tail, hind foot and internal and external ear lengths) obtained for adult individuals also did not reveal the presence of sexual dimorphism.

The effect of stage of breeding season or pre-mating oestrogen and progestagen therapy on fertility in ewe lambs

1994 ◽  
Vol 59 (3) ◽  
pp. 429-434 ◽  
Author(s):  
N. F. G. Beck ◽  
M. C. G. Davies
Keyword(s):  
Breeding Season ◽  
Corpora Lutea ◽  
Oestrogen Therapy ◽  
Crown Rump Length ◽  
Ewe Lambs ◽  
Oestradiol Benzoate

AbstractAn investigation was conducted to determine the effect of mating at puberty or third oestrus or after pre-mating oestrogen and progestagen therapy, designed to mimic the changes that occur in plasma oestrogen and progesterone concentrations during the 1st, 2nd or 3rd oestrous cycles, on fertility in ewe lambs. Twenty-five ewe lambs were mated at puberty on mean date of 18 October and 21 were mated at third oestrus on 3 December. Of these, 28% and 81% of animals mated at puberty and third oestrus lambed, respectively (P < 0·05). A similar number of ewe lambs were mated within 24 h of ram introduction in the groups given one, two or three consecutive applications oestrogen and progestagen (25 μg oestradiol benzoate followed 48 h later by a progestagen pessary left in situ for days). Of the 43 corpora lutea, 21 were represented by viable embryos in the 37 animals holding to service after one application compared with 34 out of 46 corpora lutea in 40 animals given three applications (P < 0·05). Furthermore, embryo crown-rump length, embryo weight and amniotic sac width was greater (P < 0·05), on day of pregnancy, in animals given one compared with three applications of oestrogen and progestagen. These results demonstrate that fertility is improved in ewe lambs mated on third oestrus or after progestagen and oestrogen therapy designed to simulate three oestrous cycles.

Identical twins and developmental stability

1962 ◽  
Vol 4 (1) ◽  
pp. 144-164 ◽  
Author(s):  
C. S. Taylor
Keyword(s):  
Growth Curves ◽  
Identical Twins ◽  
Body Measurements ◽  
Frequency Distributions ◽  
Stability Of Development ◽  
Mean Size ◽  
Degree Of Maturity ◽  
The Stability ◽  
Average Size ◽  
Slow Growing

1. The stability with which dairy cattle develop in body size up to 2 years of age was studied in 60 pairs of uniformly treated identical twins, i.e. an assessment was made of the influence of season, genotype, mean size of twin pair, age and degree of maturity on the level of within-pair variability.2. The frequency distributions of size differences shown by one-egg twins were in many cases decidedly leptokurtic.3. The similarity in size of the identical twins studied was only slightly, if at all, influenced by season. Within-pair variability under free outdoor grazing was certainly not any greater than under semi-controlled conditions indoors.4. The stability with which cattle grew appeared to depend on their genotype. Identical twins of the Shorthorn breed were somewhat more alike in size than were the twins of other breed-types; crossbreds were, on average, 50 % less stable than purebreds in average size () ; although crossbreds grew with somewhat greater stability ().5. Whatever their mean size, all pairs of identical twins of the same breed appeared to grow postnatally with more or less equal stability (). Small, slow growing pairs showed a greater disparity in average size ().6. Stability of development continually changed with age but not violently. Each body measurement appeared to have its own characteristic age trend. It is false to believe that variation automatically increases with increasing age. As they grew older, identical twins tended to become less alike in their later maturing body measurements whereas their early maturing body measurements tended to decline in variability. There was an overall trend with degree of maturity; variability steadily increased to a maximum and subsequently declined.7. It is suggested that environmentally induced instability of development may remain at a minimum level so long as growth curves are not seriously distorted from their exponential path to maturity.

scholarly journals Reproductivity, Productivity and Management System of Indigenous Buffalo (Bubalus bubalis) Cows in Costal Areas of Pirojpur and Borguna District of Bangladesh

2014 ◽  
Vol 24 (1-2) ◽  
pp. 117-122 ◽  
Author(s):  
MR Karim ◽  
MZ Hossain ◽  
MR Islam ◽  
MS Parvin ◽  
MA Matin
Keyword(s):  
Birth Weight ◽  
Milk Yield ◽  
Management System ◽  
Post Partum ◽  
Bubalus Bubalis ◽  
Gestation Length ◽  
Calving Interval ◽  
Lactation Length ◽  
Daily Milk Yield ◽  
Daily Milk

Twenty five buffalo cows of Mothbaria Upazila of Pirojpur district and another twenty five indigenous buffalo cows of Pathorghata Upazila of Borguna district of Bangladesh were randomly selected and interviewed to collect data on reproductivity (gestation length, birth weight, age of first calving, post partum heat and calving interval), productivity (lactation length and daily milk yield) and management system (general management, housing, feeding, calf rearing and treatment facilities) of indigenous buffalo cows using pre-tested questionnaire during the period from January to June 2010. The reproductive parameters including gestation length, birth weight, age of first calving, post partum heat and calving interval of Mothbaria Upazila of Pirojpur district were 319.56 ± 5.93 days, 24.28 ± 4 kilograms, 50.88 ± 1.71 months, 153.6 ± 6.13 days, 547.92 ± 10.88 days respectively whereas in case of Pathorghata Upazila of Borguna district these parameters were 319.12 ± 4.69 days, 24.12 ± 3.6 kilograms, 51 ± 1.8 months, 153.44 ± 6.78 days, 547.24 ± 14.32 days respectively. The productive parameters including lactation length and daily milk yield of Mothbaria Upazila of Pirojpur district were 286.12 ± 11.27 days and 3.33 ± 0.68 liters/day respectively while in case of Pathorghata Upazila of Borguna district these parameters 290.44 ± 10.92 days and 3.43 ± 0.744 liters/day respectively. So, reproduction and production are almost regular comparing with other published reports with the exception of age of first calving which is almost 12 months later than the buffaloes of other countries. It could be concluded that the buffalo owners of these areas do not follow any scientific method of buffalo husbandry; they just follow traditional rearing system. The farmers mostly use buffaloes for draught purpose in these costal areas.DOI: http://dx.doi.org/10.3329/pa.v24i1-2.19113 Progress. Agric. 24(1&2): 117 - 122, 2013

Variation during growth of twin cattle

1967 ◽  
Vol 9 (1) ◽  
pp. 35-60 ◽  
Author(s):  
C. S. Taylor ◽  
Jean Craig
Keyword(s):  
Genetic Variation ◽  
Body Part ◽  
Body Measurements ◽  
Body Parts ◽  
Genetic Variances ◽  
Average Value ◽  
Coefficients Of Variation ◽  
Rate Of Increase ◽  
Early Maturing ◽  
Degree Of Maturity

Phenotypic variances within pairs of monozygotic and dizygotic twin heifers and also genetic variances and heritabilities were calculated for 12 linear body measurements at a sequence of eight ages up to two years old. The 60 pairs of fraternal and 60 pairs of identical twins used were reared as part of a larger uniformity trial in which feeding was effectively ad libitum throughout.Size differences between members of DZ twin pairs were found to be approximately normally distributed with about the same variance for all breeds and crosses. The variance within DZ pairs increased strongly with age, with a marked increase between 9 and 12 months of age and with most body measurements showing a broadly similar trend. On a logarithmic scale DZ variances increased roughly linearly with degree of maturity and at about the same rate in each body measurement. Coefficients of variation within DZ pairs corrected for measuring error had an average value of 2%. They did not change greatly with age, and were roughly the same for most body measurements although width measurements tended to be more variable than average.Coefficients of variation within MZ pairs had a corresponding overall average of 1·4%; they declined rapidly with age from 2·0% to 1·1%, were roughly the same for all body measurements, but at early ages tended to be greater in late than in early maturing body parts. However, they showed no association with the earliness of maturing of a body part provided variation was measured at the same degree of maturity for each body part.Genetic variation increased rapidly with age in all body measurements. The rate of increase with age was greater for late than for early maturing parts. The rate of increase with degree of maturity, however, was about the same for all body measurements. Coefficients of genetic variation increased slowly with age; they had an average value of 1·6%.Estimates of heritability are given at a sequence of eight ages for each of 12 body measurements. They increased strongly with age from 0·14 on average at three months of age to 0·67 on average at two years of age. At any fixed age, early maturing body parts tended to have higher heritabilities than later maturing body parts. However, if heritability was measured at the same degree of maturity in each body part, early and late maturing parts had about equal heritabilities.The present results are compared with those obtained from twin cattle studies in New Zealand, Sweden and Wisconsin, U.S.A.Inferences from twins about genetic variances and heritabilities for unrelated animals are discussed.

The ultrastructure of oogonia and oocytes in the foetal and neonatal rat

1962 ◽  
Vol 157 (966) ◽  
pp. 99-114 ◽  
Keyword(s):  
Meiotic Prophase ◽  
Developmental Stages ◽  
Post Partum ◽  
Chromatin Condensation ◽  
Complex Form ◽  
Neonatal Rat ◽  
Mitotic Chromosomes ◽  
Thin Sections ◽  
Cytoplasmic Organelles ◽  
Spindle Fibres

Ovaries from eighty foetal and neonatal rats (aged 16·0 days post coitum to 4 days post partum ) were examined under the electron microscope. All the normal developmental stages (oogonia and oocytes in the leptotene, zygotene, pachytene, diplotene and dictyate phases of meiotic prophase) were identified. Patterns of degeneration (‘atretic divisions’, ‘ Z ’ cells and atresia at the diplotene phase), whose histological appearance and incidence have been recorded by Beaumont & Mandl (1962), were also recognized. The nuclei of oocytes at the leptotene phase contain single electron dense threads which become aligned in parallel pairs at the following phase (zygotene). A third finer fibril half-way between them appears at pachytene (tripartite ribbon). The longitudinal segments of threads, visible in ultra-thin sections, become shorter, presumably due to coiling. Nuclei at the diplotene phase contain single threads essentially similar to those seen at leptotene. As the oocyte enters the dictyate or resting phase, electron dense threads disappear from the nucleus. These observations suggest that the threads represent chromosomal ‘cores’. Nucleolus-like components persist throughout meiotic prophase, and at the diplotene phase regain the more complex form typical of oogonia. The cytoplasmic organelles become more numerous and complex as the oocyte approaches the dictyate phase. ‘Atretic divisions’ in oogonia are characterized by the persistence of long segments of nuclear membrane and the appearance of vesicles enveloped by a double membrane resembling the nuclear envelope. The dense masses of ‘chromatin’ (mitotic chromosomes) are more rounded than in normal cells at metaphase, and tend to coalesce. Spindle fibres have not been observed. Cytoplasmic organelles tend to increase in number and complexity. ‘ Z ’ cells (cells degenerating largely at the pachytene phase) show heavy ‘chromatin’ condensation around the tripartite ribbons. The major cytoplasmic changes consist in swelling of the endoplasmic reticulum, vacuolation of mitochondria and increase in incidence of multilamellar bodies. Atretic oocytes at the diplotene phase differ markedly from ‘ Z ’ cells in that ‘chromatin’ condensation around electron dense threads (single) is markedly less prominent. Cytoplasmic changes are similar to those of ‘ Z ’ cells, but also include a rise in the incidence of multivesicular and other complex bodies. All three types of degenerating cells are removed from the ovary by the phagocytic activity of neighbouring somatic cells.

scholarly journals Genotype, gestation length, season, parity and sex effects on growth traits of two rabbit breeds and their crosses

2014 ◽  
Vol 30 (4) ◽  
pp. 717-729 ◽  
Author(s):  
S.S.A. Egena ◽  
G.N. Akpa ◽  
I.C. Alemede ◽  
A. Aremu
Keyword(s):  
Growth Traits ◽  
Tail Length ◽  
The Body ◽  
Gestation Length ◽  
Body Measurements ◽  
Season Of Birth ◽  
Trunk Length ◽  
Body Dimensions ◽  
Sex Effects ◽  
Foundation Stock

One hundred and thirty rabbits were used to evaluate the effect of genotype, gestation length, season, parity and sex on growth traits of two breeds of rabbit and their crosses. The rabbit used for the experiment were breeds of the New Zealand White (NZW) and Chinchilla (CH) breed. Six breeding bucks (three/breed) and eighteen breeding does (nine/breed) served as the foundation stock. Traits measured include: body weight (BW), nose to shoulder length (NTS), shoulder to tail length (STL), heart girth (HG), trunk length (TL) and length of ear (LE). Results revealed that, BW of the rabbits were influenced (p<0.05) by genotype, gestation length and season. CH x (CH x NZW) progenies had better BW at 35-d and 49-d of age while NZW x CH progenies had better BW at 21-d of age. Kittens born late (32-34 days) had better BW at 21-d, 35-d and 49-d while kittens kindled during early dry season had better BW at 21-d, 35-d and 49-d. Genotype affected (p<0.05) all the body measurements at 21-d, 35-d and 49-d. Gestation length affected (p<0.05) all the body measurements except for NTS at 21-d and HG at 49-d respectively. Season of birth also influenced (p<0.05) all the body measurements except for LE 21-d. Parity and sex had no effect (p>0.05) on BW, NTS, STL, HG, TL and LE. It was concluded that genotype, gestation length and season influenced BW and body dimensions of the two breeds of rabbit and their crosses while parity and sex had no effect.

scholarly journals Research on the Coupling Coordinative Degree of Tourism Development and Poverty Alleviation Effects in China Based on the Model of DPSIR--an Example of Guizhou

2020 ◽  
Vol 14 ◽  
Keyword(s):  
Poverty Alleviation ◽  
Developmental Stages ◽  
Comprehensive Evaluation ◽  
Coupled Model ◽  
Coordination Mechanism ◽  
Guizhou Province ◽  
Coordinated Development ◽  
State Response ◽  
Rate Of Increase ◽  
Degree Of Coupling

Based on the framework of driving forcepressure-state-response, a DPSIR framework for thecoupling and coordination mechanism between tourismdevelopment and poverty alleviation effects wasconstructed by comprehensively considering the povertyalleviation process and poverty vulnerabilitycharacteristics of Guizhou Province. On this basis, byusing the data from 2006-2017, the paper made anempirical analysis on the development relation of tourismdevelopment and ecological environment coupling inGuizhou Province by using the coupled model. The resultsshowed that the degree of coupling between tourismdevelopment level and poverty alleviation effects showedmultiple different stages as human production activitiesprogress. The comprehensive evaluation index of tourismdevelopment and poverty alleviation effects in GuizhouProvince showed an upward trend from 2012 to 2019, andthe rate of increase was fast. The degree of coupling wascontinuously rising rapidly, experienced two stages:Firstly, the period from the severe imbalance period to theimminent imbalance period from 2012 to 2013. Secondly,the imbalance period to the primary coordination periodfrom 2014 to 2016. Lastly, the primary coordinationperiod to the good coordination period from 2017 to 2019.A transition from a serious imbalance to a wellcoordinated phase was achieved. According to thedifferent developmental stages of the couplingcoordination mechanism, we put forward some measuresfor the coordinated development between tourismdevelopment and poverty alleviation effects in GuizhouProvince.

Oestrous cycle and gestation length in the musky rat-kangaroo, Hypsiprymnodon moschatus (Potoroidae : Marsupialia)

2001 ◽  
Vol 49 (1) ◽  
pp. 37 ◽  
Author(s):  
Shan Lloyd
Keyword(s):  
Epithelial Cells ◽  
Captive Breeding ◽  
Common Ancestor ◽  
Post Partum ◽  
Reproductive Physiology ◽  
Oestrous Cycle ◽  
Gestation Length ◽  
Vaginal Smears ◽  
Breeding Colony ◽  
Male And Female

Wild-caught male and female H. moschatus were maintained in a captive breeding colony. Vaginal smears were taken three times a week until oestrous cycles were detected and gestation lengths approximated. Thereafter, smears were usually taken daily when oestrus was expected. The gestation period (considered to be the number of days from the detection of sperm in the smear until the day young were found in the pouch) was found to last 19 days. Sperm were usually detected in the smear two days before the influx of semi-cornified and cornified epithelial cells, which occurred 17 days before parturition. A pre- or post-partum oestrus was not detected and females did not return to oestrus until at least 6 days after the removal of the last pouch young. H. moschatus has the shortest recorded gestation for any macropod, and gestation occupies approximately 75% of the oestrous cycle. The reproductive physiology of H. moschatus is similar to that of most phalangerids, which may be indicative of a common ancestor.

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