Reproduction and the Fetus

2021 ◽  
pp. 433-480
Author(s):  
Graham Mitchell
Keyword(s):  
Heat Exchange ◽  
Corpus Luteum ◽  
Milk Yield ◽  
Sex Chromosomes ◽  
Reproductive Organs ◽  
Calving Interval ◽  
Male And Female ◽  
Hypothalamic Pituitary Axis ◽  
Males And Females ◽  
Daily Milk Yield

The reproductive organs of male and female giraffes are similar to those of all other artiodactyls. Giraffes have 14 pairs of autosomes and a pair of sex chromosomes. A constant testis temperature depends on countercurrent heat exchange between a large pampiniform venous plexus and the testicular artery. The onset of puberty in males and females occurs at ~3 years of age and is marked by enlargement of testes and the onset of oestrous cycles. Oestrus cycles are ~15 days long. Courtship, conception, and pregnancy are delayed until ~5 years of age. The giraffe placenta is polycotyledonous and epitheliochorial. Pregnancy is sustained by progesterone secreted by a single corpus luteum, the placenta and fetal ovaries and testes. Gestation lasts ~450 days and is ended by hormones secreted by the hypothalamic-pituitary axis of a mature fetus. Birth takes ~30 minutes. Daily milk yield ranges between 2.5 L and 10 L. Protein, fat, and lactose are higher than in cow’s milk. Weaning occurs at ~6 months of age. The average calving interval is ~20 months but varies according to the degree of lactational stress itself partly determined by whether a calf survives. Female giraffes have ~8 calves of which ~3 will reach adulthood. Survival of giraffes as a species depends on fewer adults dying each year than the number of calves reaching adulthood.

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

An analysis of the Entebbe herd of Nganda cattle in Uganda

1961 ◽  
Vol 3 (1) ◽  
pp. 29-39 ◽  
Author(s):  
P. Mahadevan ◽  
H. J. S. Marples
Keyword(s):  
Milk Production ◽  
Milk Yield ◽  
Production Performance ◽  
Calving Interval ◽  
Indigenous Cattle ◽  
Factors Affecting ◽  
Lactation Length ◽  
The Government ◽  
To Come ◽  
Daily Milk Yield

In the herd of Nganda cattle at the Government Livestock Experiment Station, Entebbe, Uganda, it was found that of the known environmental factors affecting milk production, the more important ones were age (in lactations) and length of the calving interval preceding the second and third lactations. The correlations between performance in different lactations of the same animal were high for lactation milk yield (0·73) and average daily milk yield (0·62) and low for calving interval (0·21) and dry period (0·15). The repeatability of lactation length was intermediate (0·42). The heritability values were around 0·3 for the weight measurements, around 0·2 for yield characteristics and around 0·1 for length of lactation and age at first calving.The sires used in the breeding programme at Entebbe made little impact on production performance in the herd. The estimated genetic improvement in milk yield through selection of dams of cows was also low. It is argued from comparison with results from other parts of the tropics that superior genotypes for milk production are difficult to come by among indigenous cattle in these areas and that we should therefore look for other opportunities and methods to move ahead faster in the future.

Prostaglandins in the salivary glands and reproductive organs of Hyalomma anatolicum excavatum Koch (Acari: Ixodidae)

1979 ◽  
Vol 69 (3) ◽  
pp. 381-385 ◽  
Author(s):  
M Shemesh ◽  
A Hadani ◽  
Ania Shklar ◽  
L. S. Shore ◽  
F Meleguir
Keyword(s):  
Tissue Culture ◽  
Salivary Glands ◽  
Culture Medium ◽  
Reproductive Organs ◽  
Hyalomma Anatolicum ◽  
Male And Female ◽  
Specific Antibodies ◽  
Hepes Buffer ◽  
Prostaglandin F ◽  
Males And Females

AbstractProstaglandin F (PGF) and E2 (PGE2) were assayed in the reproductive organs, salivary glands and egg-batches of laboratory-bred males and females of Hyalomma anatolicum excavatum Koch. Salivary glands and reproductive organs were dissected from unfed male and female ticks as well as from ticks that had fed for six days on rabbits; these organs were cultured for 24 and 72 h in tissue culture medium-199 with Earle's salt and HEPES buffer at pH 7·6 and 37°C. The amounts of PGF and PGE2 accumulated in the culture were determined by a radioimmunoassay using specific antibodies. Both salivary glands and reproductive organs were shown to synthesise PGEa and PGF. This synthesis and also the prostaglandin content of the organs were significantly increased after engorgement. The synthesising capacity and content of PGE2 and PGF in both the salivary glands and reproductive organs were higher in the female than in the male.

scholarly journals Non Genetec Parameters and Repeatability for Milk Traits Goat in Northern Iraq

2019 ◽  
Vol 7 (3) ◽  
pp. 70-74
Author(s):  
Mevan I. Baper ◽  
Hani N. Hermiz
Keyword(s):  
Milk Yield ◽  
Random Effect ◽  
Likelihood Method ◽  
Lactation Period ◽  
Milk Traits ◽  
Male And Female ◽  
Northern Iraq ◽  
Natural Pasture ◽  
Daily Milk Yield ◽  
Selection Of

A total of 439, 436 and 437 records of average daily milk yield (ADMY), milk yield after weaning (MYAW) and total milk yield (TMY) respectively were analyzed. Data used in this study obtained from mountain does at private project in Raselain Village/ Akre Region/ Duhok governorate. The data related to two milking seasons (2016-2017) and (2017-2018). The animals were allowed to graze natural pasture and stubble, straw and ground oak acorns were providing whenever required. Does were flushed 2 weeks prior to mating and kidding season. The flock was placed on a regular health program. Does were milked by hand at biweekly intervals starting from the first week post kidding till the does are dried off. ADMY was calculated by multiplying test day milk yield * 2. While TMY calculated by multiplying ADMY by lactation period. Statistical analysis of data was carried out by using GLM procedure within SAS programme. This model includes effects of doe's age, year and season of kidding, birth's type and sex and weight of doe at kidding on milk traits. Effect of doe added to above model as a random effect to estimate their repeatability using Restricted Maximum Likelihood method. Overall means for ADMY, MYAW and TMY were 0.727, 54.49 and 129.32 kg respectively. Results showed that the age of does had significantly higher effect (P< 0.01) on all studied traits of milk. Does aged 4.5 years produce significantly higher ADMY (0.772 kg), and accordingly TMY (136.88kg), while higher MYAW recorded for does aged 3.5 years beside 4.5 years. The effectiveness of year was significant (P< 0.01) on all milk yield traits. Also season of kidding affect all studied milk traits significantly (P< 0.01), whereas the does kidding in winter had significantly higher ADMY, MYAW and TMY than those kidding in spring season. The effects of type of birth and sex of kids were significant on all milk traits. Does with female twins produced significantly more ADMY comparing with does having male or female singles only. Does with female twins and male and female twins produced significantly much MYAW. Does with female twins yield significantly higher TMY when compared to those in the other groups, on the same time there were no significant differences in TMY of does with male twin and does with male and female twin. There was no significant effect of doe weight at kidding on all studied traits and the regression coefficients were positive for ADMY (0.0003 kg/kg), and TMY (0.085 kg/kg) while the regression was negative for MYAW (- 0.0024 kg/kg). Repeatability estimates of ADMY, MYAW and TMY were 0.24, 0.31 and 0.27 respectively. It sum: due to the effectiveness of the fixed factors on the studied traits, hence adjusting records is necessary. The estimates of repeatability indicate that selection of does as well their kids depending on their milk production will improve the productivity in the next year.

Chromatin dynamics associated with sexual differentiation in a UV sex determination system

2020 ◽  
Author(s):  
Josselin Gueno ◽  
Simon Bourdareau ◽  
Guillaume Cossard ◽  
Olivier Godfroy ◽  
Agnieszka Lipinska ◽  
...  
Keyword(s):  
Gene Expression ◽  
Sex Determination ◽  
Histone Modifications ◽  
Sex Chromosomes ◽  
Sexual Differentiation ◽  
Chromatin State ◽  
State Transitions ◽  
Male And Female ◽  
Chromatin States ◽  
Males And Females

SummaryIn many eukaryotes, such as dioicous mosses and many algae, sex is determined by UV sex chromosomes and is expressed during the haploid phase of the life cycle. In these species, the male and female developmental programs are initiated by the presence of the U- or V-specific regions of the sex chromosomes but, as in XY and ZW systems, phenotypic differentiation is largely driven by autosomal sex-biased gene expression. The mechanisms underlying sex-biased transcription in XY, ZW or UV sexual systems currently remain elusive. Here, we set out to understand the extent and nature of epigenomic changes associated with sexual differentiation in the brown alga Ectocarpus, which has a well described UV system. Five histone modifications, H3K4me3, H3K27Ac, H3K9Ac, H3K36me3, H4K20me3, were quantified in near-isogenic male and female lines, leading to the identification of 13 different chromatin states across the Ectocarpus genome that showed different patterns of enrichment at transcribed, silent, housekeeping or narrowly-expressed genes. Chromatin states were strongly correlated with levels of gene expression indicating a relationship between the assayed marks and gene transcription. The relative proportion of each chromatin state across the genome remained stable in males and females, but a subset of genes exhibited different chromatin states in the two sexes. In particular, males and females displayed distinct patterns of histone modifications at sex-biased genes, indicating that chromatin state transitions occur preferentially at genes involved in sex-specific pathways. Finally, our results reveal a unique chromatin landscape of the U and V sex chromosomes compared to autosomes. Taken together, our observations reveal a role for histone modifications in sex determination and sexual differentiation in a UV sexual system, and suggest that the mechanisms of epigenetic regulation of genes on the UV sex chromosomes may differ from those operating on autosomal genes.

scholarly journals The reproductive and milk performance merit of Butana cattle in Sudan

2005 ◽  
Vol 48 (5) ◽  
pp. 445-459 ◽  
Author(s):  
L. M.-A. Musa ◽  
M.-K. A. Ahmed ◽  
K. J. Peters ◽  
B. Zumbach ◽  
K. E. A. Gubartalla
Keyword(s):  
Milk Yield ◽  
Research Station ◽  
Calving Interval ◽  
Dry Period ◽  
Age At First Calving ◽  
Lactation Length ◽  
Parity Number ◽  
Heritability Estimates ◽  
Daily Milk Yield ◽  
Daily Milk

Abstract. Data from the Butana herd of Atbara Livestock Research Station were analyzed for the period 1949–1999. The least squares means for age at first calving, calving interval, milk yield per lactation, daily milk yield, lactation length and dry period were 45.05 ± 3.56 months, 382.38 ± 8.30 days, 1662.57 ± 108.96 kg, 6.10 ± 0.40 kg, 268.17 ± 5.56 days and 119.10 ± 8.30 days, respectively. The analysis of variance revealed that the sire and parity number influenced the studied traits, while year-season of calving influenced the milk yield per lactation, daily milk yield and lactation length. Linear and quadratic regressions on lactation length significantly influenced milk yield per lactation and daily milk yield. Heritability estimates for age at first calving, calving interval, milk yield per lactation, daily milk yield, lactation length and dry period were 0.19 ± 0.07, 0.09 ± 0.03, 0.26 ± 0.06, 0.27 ± 0.07, 0.04 ± 0.02, and 0.09 ± 0.03, respectively. This study highlighted the importance of conserving the indigenous dairy cattle breeds for future generations. The presence of significant variation and the corresponding heritability estimates give promise of reasonable genetic improvement under selective breeding with respect to milk yield characters.

Sex Ratios and Sex Allocation

2001 ◽  
Author(s):  
Steven Hecht Orzack
Keyword(s):  
Sex Ratio ◽  
Sex Allocation ◽  
Female Flower ◽  
Reproductive Organs ◽  
Evolutionary Analysis ◽  
Male And Female ◽  
Sex Ratio Theory ◽  
Males And Females ◽  
Descent Of Man ◽  
Evolutionary Aspects

Understanding the allocation of energy is the goal of the evolutionary analysis of sex allocation. Whether one is concerned with the relative sizes of male and female flower parts in plants like those discussed by Campbell (1998), the ratio of males and females in insects like those discussed by Orzack et al. (1991), or the relative sizes of male and female reproductive organs in hermaphroditic fish like those discussed by Leonard (1993), one is concerned with how energy allocated toward reproduction is apportioned into one sex as opposed to the other (or more in the case of some kinds of organisms). Here, the sexes are entities that at regular or irregular intervals produce gametes, some of which come together to produce zygotes. The abstract nature of this description underscores the degree to which there are common evolutionary aspects to all of these problems, despite the fact that the biological details involved are so diverse. One of the most influential and important agendas for evolutionary studies of sex allocation was laid out by Charnov (1982). He described the underlying evolutionary similarities between phenomena as diverse as sex change in shrimp and sex ratio in vertebrates like us. Even more important, he promoted sex allocation as a central evolutionary problem by describing how seemingly unrelated allocation problems could all be analyzed with a kind of mathematical approach elaborated by Shaw and Mohler (1953). I consider in turn four important examples of this approach. Shaw and Mohler’s goal was to understand the evolution of the proportions of males and females. This problem of the sex ratio was most famously addressed by Darwin in his 1871 book, The Descent of Man, and Selection in Relation to Sex, as well as by others in the subsequent decades. The most influential analysis is that of Fisher (1930); however, Carl Düsing, who worked in the 1880s, can rightly be regarded as the progenitor of modern sex ratio theory (see Edwards 1998).

scholarly journals Productive and Reproductive Efficiency of Red Chittagong Cattle Under Farm Condition

2014 ◽  
Vol 18 (2) ◽  
pp. 109-114 ◽  
Author(s):  
MP Mostari ◽  
KS Huque ◽  
MS Hasanat ◽  
Z Gulshan
Keyword(s):  
Birth Weight ◽  
Milk Yield ◽  
Post Partum ◽  
Reproductive Efficiency ◽  
Male And Female ◽  
Lactation Length ◽  
Adult Body ◽  
Adult Body Weight ◽  
Daily Milk Yield ◽  
Daily Milk

The productive and reproductive efficiency of Red Chittagong cattle (RCC) reared at the Bangladesh Livestock Research Institute (BLRI) farm was evaluated. A total of 46 RCC of different categories were considered under this study. Parameters studied were birth weight, weight at 3, 6 months of age and adult body weight, growth rate, daily milk yield, lactation length, lactation yield, age at puberty, weight at puberty, age at first calving, post partum estrus period, service per conception, calving interval and gestation length of RCC were collected and recorded. The birth weight differed significantly (p<0.01) between male and female and the average birth weight of RCC calves at farm level was 14.87 kg. The growth rates and adult body weight also differed significantly (p<0.05 and p<0.01) between male and female except in growth rate from 3 to 6 months of age. The average daily milk yield, milk yield per lactation and lactation length of RCC were 2.24 kg, 526.81 kg and 238 days, respectively. The age at puberty, service per conception, post partum estrus period and calving interval of RCC heifers and cows were 15 months, 1.15, 40 days and 11 months, respectively. It can be concluded that the RCC is a genetically and economically superior variety of Bangladesh.DOI: http://dx.doi.org/10.3329/pa.v18i2.18166 Progress. Agric. 18(2): 109 - 114, 2007

scholarly journals Milk yield and reproductive performance of Friesian cows under Sudan tropical conditions

2007 ◽  
Vol 50 (2) ◽  
pp. 155-164 ◽  
Author(s):  
A. z. Abdel Gader ◽  
M.-K. A. Ahmed ◽  
L. M.-A. Musa ◽  
K. J. Peters
Keyword(s):  
Milk Yield ◽  
Calving Interval ◽  
Dry Period ◽  
Age At First Calving ◽  
Lactation Length ◽  
Tropical Conditions ◽  
Days Open ◽  
Daily Milk Yield ◽  
Daily Milk ◽  
Friesian Cows

Abstract. The data obtained from the dairy herd of the Arab Company for Agricultural Production and Processing (ACAPP) in a semi arid area 40 km south of Khartoum involved 337 cows with a total of 1049 records from 16 years between 1986 and 2002. The least squares means for age at first calving, calving interval, days open, lactation milk yield, daily milk yield, lactation length and dry period were 29.76±0.40 months, 433.12 ± 6.70 days, 167.79±7.08 days, 3475.53±78.89 kg, 12.29±0.28 kg, 294.10±3.62 days and 164.08 ± 6.70 days, respectively. The analysis of variance showed that the parity number had significant (p<0.05) influences on all studied traits, while year-season of calving influenced (p<0.05) age at first calving, milk yield per lactation and daily milk yield. The sire of cow influenced (p<0.05) lactation yield, daily yield, lactation length and days open. The effects of linear and quadratic regressions of both lactation yield and daily yield on length of lactation were also highly significant (p<0.01). Heritability estimates of age at first calving, calving interval, milk yield per lactation, daily milk yield, lactation length and dry period were generally low (0.098±0.104, 0.047±0.046, 0.130±0.042, 0.123±0.041, 0.172±0.062 and 0.044±0.031, respectively) except the heritability of days open which was 0.51±0.37. The productivity of the herd in this study which averaged 12.3 kg/cow/day was much lower than the expected productivity of Holstein Friesian cows, which reflects the negative impact of the prevalent environment in the Sudan. More records and economic data are required to examine the economic feasibility of raising pure Friesians under Sudan conditions.

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