Breeding Capacity Research Articles

Reproductive abnormalities in human insulin-like growth factor-binding protein-1 transgenic male mice.

Adult transgenic mice overexpressing human insulin-like growth factor-binding protein-1 in the liver present reproductive abnormalities in both sexes. In the present work, we have investigated the mechanisms responsible for limiting breeding capacity in these transgenic male mice. Homozygous adult transgenic male mice (3-6 months old) exhibited irregular copulatory behavior and a reduction of the number of pregnancies per female as well as of litter size per pregnancy. Genital tract weight, more specifically epididymal and seminal vesicle weights, were reduced by 45% in homozygous transgenic vs. nontransgenic mice. Homozygous transgenic mice exhibited a 30% reduction of the length of seminiferous tubules (P = 0.007), a 30% decrease in daily sperm production per testis (P = 0.019), and a 50% decrease in the number of spermatozoa in testis (P = 0.037), associated with morphological abnormalities of the sperm heads leading to an approximately 50% reduction of fertilized two-cell eggs (P = 0.002) and of implanted embryos on d 5.5 after mating (P = 0.004). The round spermatids also appeared altered in their morphology. In addition, Leydig cells in homozygous transgenic mice exhibited an altered appearance, with a 1.8-fold increase in lipid droplets in their cytoplasm (P < 0.001). Moreover, the concentration of 3beta-hydroxysteroid dehydrogenase was 66% lower in testis from transgenics compared with those from normal mice (P = 0.01), leading to a tendency toward lower plasma testosterone levels (P = 0.1). Interestingly, LH concentrations were increased by 40% in transgenic pituitary extracts (P = 0.02), and basal LH secretion by pituitary explants in vitro was increased by 60% in homozygous transgenic vs. normal mice (P = 0.04), suggesting an alteration of LH pulsatile secretion in vivo. In conclusion, these data suggest that the breeding impairment of human insulin-like growth factor-binding protein-1 transgenic males is due at least in part to an alteration of the process of spermatogenesis, leading to a diminution of sperm production and of its quality. Minor impairment of steroidogenesis may also contribute to the reduced reproductive capacity of these animals. Our observations are consistent with the idea that normal spermatogenesis and perhaps also steroidogenesis are dependent on the actions of sufficient concentrations of unbound IGF-I.

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To demonstrate influence of water content of host tees on attacking behavior of Platypus quercivorus and on symbiotic fungi (yeasts and Raffaelea quercivora), the number of beetles landing on bait logs with their water content artificially changed and the number of entry holes bored by the beetles into the bait logs were counted, and the ratio of galleries with eggs or larvae and the ratio of wood pieces with the symbiotic fungi were investigated. A multiple regression analysis of the number of beetles captured and the number of entry holes bored by the beetles was performed with the length and water content of bait logs as explanatory variables. The result suggest that males land on bait logs by judging the length of bait logs or something related to their length, and that males bore into bait logs by judging both the length of the bait logs and water content of the bait logs at the time of breeding or by judging something related to both these factors. At a part with the low water content at the time of breeding, the number of entry holes per m2, the ratio of galleries with eggs or larvae, and the ratio of wood pieces containing symbiotic fungi were low, suggesting that P. quercivorus fails to reproduce in a part with low water content, because symbiotic fungi fail to propagate in this part. From the above, it is hypothesized that male P. quercivorus chooses host trees with large breeding capacity by a certain method, resulting in them tending to choose host trees where the symbiotic fungi grows easily because the water content is maintained for a long time.

Genetics of the guppy as a model for experiment in aquaculture.

The guppy, Poecilia reticulata, is one of the most famous tropical ornamental fish in the world. There are many varieties and breeds which have been bred by aqua lists for many years. The guppy has frequently been used as model organism for experiments in fish genetics because of its short life cycle, ease of breeding and reproductive capacity. The laboratory strains which were created from local (Japanese) strains and varieties were used as an experimental genetic model for aquaculture. These laboratory strains were maintained as closed colonies for five to 20 years in our laboratory. One of the roles of model experiments in fish genetics to perform experiments which take a long time in which are commercially important, such as genetic drift, as the effect of inbreeding during the growth and maintenance of population. In this review, we mainly considered the results obtained in our laboratory relating to genetic drift, and the effects of inbreeding, heterosis and inheritance of quantitative traits.

1118. クリーン開発メカニズムを活用した中国への原子力導入方策の検討

This paper examines an introduction scenario for nuclear power in China using the Clean Development Mechanism as a financial support for construction, based on quantitative evaluation of energy demand forecasts and the nuclear fuel cycle through 2100. The results of the case study concluded that in the short to mid term, large-scale light water reactors will primarily be sited in coastal areas where infrastructure development is advanced. In the future, as dispersed power sources in inland areas, small scale-metallic fuel FBRs will be preferred due to their promising safety, large breeding capacity, operation and maintenance characteristics, ease of transportation of plant equipment and plant construction and the possibility of on-site nuclear fuel cycle.

Polymorphism of the rabbit kappa kasein gene and its influence on performance traits

The rabbit kappa-casein encoding gene has previously been shown to possess two alleles. The two alleles do not differ in their coding region and in the accumulation levels of mRNA. However they differ greatly with respect to their intronic regions. The rearranged regions in the first and fourth introns were found to be inverse and complementary LINE sequences. The A allele was found to be more frequent in different European breeds. Correlation of the kappa-casein genotype with the breeding capacity in a New Zealand White rabbit stock has been examined.

POLYMORPHISM of the rabbit kappa kasein gene and its influence on performance traits.

The rabbit κ-casein encoding gene has previously been shown to possess two alleles. The two alleles do not differ in their coding region and in the accumulation levels of mRNA. However they differ greatly with respect to their intronic regions. The rearranged regions in the first and fourth introns were found to be inverse and complementary LINE sequences. The A allele was found to be more frequent in different European breeds. Correlation of the κ-casein genotype with the breeding capacity in a New Zealand White rabbit stock has been examined.

The potential for use of surplus dairy herd reproductive capacity for beef production

A quantitative analysis of the potential benefits of using in vitro‐produced embryos and embryo transfer (IVP and ET) technologies for beef production from spring‐calving dairy herds is presented. The study was conducted using computer simulation. Additional profit was assessed from the production of high quality 4‐day‐old calves for the beef industry, which are derived from surplus dairy industry breeding capacity. Twelve IVP and ET scenarios were investigated for comparison with artificial insemination (AI) methods. These IVP and ET scenarios were combinations of sex‐controlled or sex‐uncontrolled embryos with conception rates ranging from 35% to 60%. The study demonstrates that sex‐controlled embryo technology is able to capitalise on the significant beef production potential from dairy herds. Profit opportunities for the dairy farmer will be significant if beef IVP and ET costs are no more than AI costs and conception rates for the embryo transfer technology are at least 50%, otherwise oestrus synchronisation technology is required to maintain annual calving patterns.

The status and breeding biology of the Dotterel Charadrius morinellus in northern England during 1972–95

The status of the Dotterel in northern England as a migrant and breeding bird is considered. Data for spring and autumn passage were largely from information collated by local recorders and data on breeding were collected by a few enthusiastic individuals. The pattern of spring passage has changed since the 19th century. Few birds are now seen on the coastal plain of northwest England, 76% of birds being seen in the uplands above 300 m. In total, 41 breeding records were available for analysis and it is suggested that in good years up to five pairs may breed. Potentially the breeding capacity of northern England would appear to be much greater; even on recent evidence breeding has occurred on a minimum of 12 fells, but never on more than three fells in any one year. The mean date for completion of first clutches of 23 May and the mean clutch size of 2.85 are little changed from previous periods and comparable to the situation in the central Grampians, Scotland. Where full nest histories were known, hatching and fledging success were 1.45 chicks hatched and 1.07 chicks fledged per clutch. Reasons for the failure of Dotterel to colonize northern England to a greater extent are discussed; possible factors include habitat changes linked to increased acidification of soils and larger numbers of sheep on the hills in spring and increased recreational use of the hills. The status of the Dotterel in northern England still remains that of a regular spring migrant but a scarce breeder with a tenuous foothold in the region.

Fertility prediction in stallions

Abstract The prediction of a stallion's fertility is one of the main unresolved problems in horse breeding. Despite many studies of the relationship between seminal characteristics and fertility, we are not able to evaluate with certainty the breeding capacity of a stallion. Stallion selection and fertility prediction are routinely based on the analysis of seminal and behavioural parameters. Basal blood hormone concentrations and their modification after different stimulation are also used for diagnosis. Although the methods developed in some laboratories may explain established subfertility or infertility, mainly detected by abnormal seminal characteristics and/or pregnancy rate, they cannot yet be used for general infertility detection. Such tests are based on spermatozoal morphology, e.g. chromatin and membrane integrity analyses, and spermatozoal functionality, e.g. motility evaluation, zona pellucida-sperm binding assay, and on seminal plasma composition. At this stage we have no idea of the frequency of the abnormalities demonstrated by these methods nor any idea of their correlation with subfertility or infertility.

The relationship between ram breeding capacity and flock fertility

The effect of breeding capacity of rams on flock fertility was studied by exposing each of 15 rams to 1 of 15 flocks of 200 naturally-cycling ewes for 17 days. Five of the rams were arbitrarily designated as being of high breeding capacity (mean±SEM = 14.7±0.5 services in 2 3-hour pen breeding tests); five rams were designated as being of medium capacity (7.3 ± 0.2); and the remaining five were designated as being of low breeding capacity (1.7 ± 0.5). Breeding capacity was shown to be positively correlated with the number of services during flock mating, to the number of ewes mated and to insemination success. Breeding capacity as measured in a pen test of shorter duration (1 hour) was shown to be similarly related to flock fertility. Further, the number of services during flock mating was also positively correlated with the number of ewes mated and impregnated, as well as to the number of fetuses conceived and to insemination success. Breeding frequency of the ram is, therefore, closely related to flock fertility, but breeding capacity, as measured in the present study, is only a moderately accurate indicator of breeding frequency.

Growth potential and feed intake capacity of spanish sheep breeds from weaning to maturity

One of the principal restraints on the productivity of sheep in Less Favoured Areas of the EC is the small size of the native breeds which can only produce light finished carcases. The experiment reported here forms part of a collaborative study made between centres in Spain, Greece (Zygoyiannis, Stamataris and Katsaounis, 1993) and Great Britain (Friggens, Kyriazakis, Shanks and McClelland, 1993) aimed at assessing and comparing the potential and feed intake capacity of nine lesser known, small-sized European sheep breeds.

Effects of prenatal administration of testosterone and cortisone on the reproductive system of the female rat

Testosterone propionate, cortisone, or sesame oil vehicle were given to rats during the last week of pregnancy so that effects of the hormones on anogenital distance, breeding capacity and vaginal opening of the female progeny could be contrasted. Testosterone significantly increased anogenital distance and delayed vaginal opening of progeny. When females that had been exposed to testosterone in utero were tested for breeding capacity, a significantly smaller number mated than in the control group. Female rats that had been exposed to cortisone in utero exhibited premature vaginal opening but did not differ from controls in anogenital distance, and, unlike the testosterone-exposed rats, mated. Cortisone-exposed rats carried litters to term and the litters did not differ from those of controls in numbers of pups or numbers of living pups at birth. The pups born to cortisone-exposed rats had greater birth weights and a higher survival rate to 20 days of age than pups of controls. Results indicate that testosterone administration to rats during pregnancy is far more detrimental to the development and subsequent function of the reproductive system of female progeny than cortisone and suggest that similar changes which occur in response to maternal stress or to administration of ACTH during pregnancy are more likely to result from increases in testosterone than from increases in glucocorticoid secretion.

Using climate and vegetation studies in southern Greenland to estimate the natural resources during the Norse period

Agriculture in southern Greenland started when Eric the Red came from Iceland around 982 A.D., and the Norse era stopped approximately 500 years later. Modern sheep‐farming started in 1924, and recent climatic studies and stellite‐based monitoring have shown great variation in the biomass production from one year to another due to minor climate fluctuations. In areas populated to capacity with farms it can easily result in overgrazing which, in this föhn‐affected area, easily implies soil erosion. The results facilitate future agricultural management and planning of the potential breeding capacity in this vulnerable marginal environment, but the results also indicate some of the problems the Norse might have faced.

Monitoring Natural Vegetation in Southern Greenland Using NOAA AVHRR and Field Measurements

The application of the Normalized Difference Vegetation Index (NDVI) for monitoring natural vegetation and biomass production has been evaluated for a sheep farming area in southern Greenland. Field measurements of spectral reflectance data during the growing season have been used to make a calibration between NOAA AVHRR NDVIs and aboveground vegetation quantities. The potential biomass production is estimated as the product of mean NDVI and the length of the growing season. Lowest-order atmospheric as well as geometric corrections were carried out on the satellite data before the seasonal and regional variations were correlated with climate and water balance. Agriculture in southern Greenland started when Eric the Red came from Iceland around 982 A.D., and the Norse era ended approximately 500 years later because of climatic change, extensive overgrazing and soil erosion. Modern sheep farming started in 1924, but the threats to sheep breeding and the environment are the same today as during the Norse era. The satellite-based monitoring has proved to be a useful tool to avoid overgrazing, which in this foehn-affected area easily implies soil erosion. It is a quick and low-cost method, and in combination with meteorological and soil water data it is possible to forecast the dry biomass production at the beginning of each growing season. This facilitates agricultural management and planning of the potential breeding capacity in this vulnerable marginal environment. Key words: southern Greenland, NOAA-AVHRR, Normalized Difference Vegetation Index, atmospheric corrections, biomass production

Breeding capacity, behavior and fertility of bulls with Brahman genetic influence during synchronized breeding of beef females

The objective of this experiment was to evaluate the feasibility of using bulls of Brahman-derived breeds for synchronized breeding of females treated with Syncro-Mate-B (SMB). Suckled, postpartum cows (n = 261) and virgin heifers (n = 227) were given the standard SMB treatment. Calves were removed from cows for 48 h beginning at implant removal, and individual bulls were placed in pens with 15 to 20 females ( x = 1:15.7 ) for 48 h beginning at implant removal. Bulls (n = 31) were 18 to 36 mo of age and had scored satisfactorily on a breeding soundness evaluation (BSE). The mean ± SEM percentage of females in estrus, percentage of estrous females serviced and percentage of total females serviced were 77.2 ± 2.4, 72.9 ± 2.9 and 55.7 ± 3%, respectively. Total average services per bull was 23.6 ± 1.6; however, average number of individuals serviced was only 8.6 ± 0.42. Mean ± SEM percentage of females conceiving of those serviced, percentage conceiving of those in estrus and percentage conceiving of total females available were 57.3 ± 3.7, 40.6 ± 2.6 and 32.6 ± 2.5%, respectively. Mean BSE scores of eight Simbrah bulls tested immediately before and 5 d after synchronized breeding did not differ (P > 0.05). These data suggest that the conception rate of Brahman-influenced bulls servicing SMB-synchronized cows is within the normal range. However, the total number of individual females serviced and the total pregnancy rate under the protocol employed was low. This occurred because all estrous females were not inseminated, and some bulls exhibited unpredicted low fertility.

Satellite Monitoring of the Biomass Production in Southern Greenland

Birger Ulf Hansen: Satellite Monitoring of the Biomass Production in Southern Greenland. Geografisk Tidsskrift 88:94–99. Copenhagen, 1988. Based on satellite data from Southern Greenland the application of Normalized Difference Vegetation Index (NDVI) for monitoring biomass production has been evaluated. Field measurements of spectral reflectance data are quantitatively correlated with clipped samples of total above-ground biomass production. The relation between NDVI measured on the ground and biomass production is discussed. The seasonal and geographical variation in NDVI is correlated with the climate and water balance. The potential production is estimated as the product of mean NDVI and the length of the growing season. The results suggest that operational satellite monitoring of NDVI provides valuable assistance in agricultural management and forward planning of the potential breeding capacity in an arctic/subarctic environment.

Ureaplasmas and mycoplasmas in chimpanzees of various breeding capacities.

Adult chimpanzees (24 male, 76 female) with low and high rates of conception were examined for ureaplasmas, arginine-metabolizing mycoplasmas and chlamydiae. Ureaplasmas were isolated from the throat of only 1 male and 1 female animal, but from the urethra of 29% of the males and from the vagina of 95% of the females. Mycoplasmas were isolated from the throat more often than were ureaplasmas, but from the genital tract with about the same frequency as ureaplasmas. The numbers of organisms, of either type, isolated from the vagina were larger than the numbers isolated from the male urethra. Chlamydiae were not isolated from any animal. The occurrence of ureaplasmas and mycoplasmas and the numbers of these organisms isolated were similar in animals with low or high rates of conception. Furthermore, no association was noted between the organisms in the lower genital tract and the occurrence of abortion and/or stillbirth.

Exposure of females and pups of the levant vole to diethylstilbestrol (DES)-treated nesting material: Effect on the breeding capacity of the female offspring

Adult Levant vole (Microtus guentheri) females, which at the age of 1 or 4 days had been in direct contact for 2 h with filter paper impregnated with a suspension of diethylstilbestrol dipropionate (DES) in soybean oil (0.125 mg DES/cm2), or whose nursing mothers had been in similar contact with DES during that period, were found to be sterile in the overwhelming majority of cases. Females slightly older (5–6 days old) at the time of such contact with DES (direct, or through their nursing mothers) retained their fertility.

Reaction balance and efficiency analysis of a D-D fusion/fission hybrid with satellite D-3He reactors

Selected reactor physics and isotope balance characteristics of a fusion hybrid supported D-3He satellite nuclear energy system are formulated and investigated. The system consists of two types of reactors: a parent D-fueled fusion device and a number of smaller reactors optimized for D-3He fusion. The parent hybrid station breeds the helium-3 for the satellites and also breeds fissile fuel for an existing fission reactor economy. Various hybrid operational regimes are examined in order to determine favorable reactorQ values and effective fusion and fission efficiencies. A number of analytical correlations between power output, plasma energetics, blanket neutronics, breeding capacity, and energy conversion cycles are established and evaluated. Numerical examples of performance parameters such as fission-to-fusion power, overall conversion efficiency, and the ratio of satellite to parent fusion power are presented. The range of reactor efficiencies is elucidated as affected by the internal plasma power balances. As an upper bound based on optimistic injection and direct conversion efficiencies, we find the D-3He satellite system power output attaining at best 1/3 of the parent fusion power.

Effect of [formula omitted][formula omitted] infection on spermatogenesis in three Zebu bulls ( [formula omitted][formula omitted]). A case report

This case report addresses the occurrence of Brucellosis and its effect on the cattle in developing countries. Three Zebu bulls ( Bos indicus ) are presented and the clinical and pathologic signs are described. Conception rates declined following an abortion storm in one herd and without prior abortions in another herd. Semen collected by electro-ejaculation was found to be azoospermic or with very few spermatozoa. B. abortus was isolated from seminal vesicles, testes and epididymides. Organs affected and showing microscopic lesions were testes, epididymides and seminal vesicles. The latter were not consistently affected. None of the bulls showed impairment of libido or breeding capacity.