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PubMed1982

Forest malaria in Bangladesh. III. Breeding habits of anopheles dirus.

A thorough, repetitive, 21-month search for breeding sites of Anopheles dirus (=An. balabacensis s.l.) was conducted within a 3-km radius of an isolated, holoendemic malaria focus. During the annual 6-month monsoon, all breeding within 1.5 km of the focus took place at eight sites in 1975 and at nine sites in 1976. These sites were of two topographic types--puddles on footpaths and turbulence pits at the heads of drainage gullies--that shared the characteristic of being able to hold water for at least 5 days without supplemental rainfall. The only dry season breeding was in a stream 3 km from the focus. The effective flight range in forest of An. dirus was deduced to be about 1.5 km. Immatures were found to be peculiarly adapted to, and possibly dependent on, small, temporary pools. Eggs were deposited above the water line where they could remain viable for 2 weeks. Heavy rain produced a synchronous hatch that completed immature development in 5-6 days and could eventually produce waves of parous females biting man. Larvae were observed to leave a draining pool before it completedly emptied and to crawl overland as far as 53 cm, sometimes to another pool. Larvae stranded by receding water often escaped predation that eliminated cohabiting species. They could be recovered alive from drained pool bottoms up to 94 hours after being stranded. Fourth instar An. dirus are passively predatory of first and second instar mosquito larvae. The limited number and topographic distinctness of the habitat of immature An. dirus in Bangladesh may make larviciding an effective control measure.

Animals↗
PubMed1994

Geographic information system in malaria surveillance: mosquito breeding and imported cases in Israel, 1992.

Although a significant resurgence of malaria in Israel is unlikely at present, the risk for a localized outbreak of malaria cases due to infection of local anopheline mosquitoes by imported cases does exist. A national computerized surveillance system of breeding sites of Anopheles mosquitoes and imported malaria cases was established in 1992 using a geographic information system (GIS). Distances between population centers and breeding sites were calculated, and maps associating epidemiologic and entomologic data were generated. Risk of malaria transmission was assessed with consideration of vectorial capacity and flight range of each Anopheles species. The GIS-based surveillance system ensures that if a localized outbreak does occur, it will be associated rapidly with a likely breeding site, a specific Anopheles vector, and a probable human source, so that prompt control measures can be most efficiently targeted. This cost-effective GIS-based surveillance system can be expanded and adapted for countries with indigenous malaria transmission.

Animals↗
PubMed2001

Interspecific variability of prevalence in blood parasites of adult passerine birds during the breeding season in Alaska.

Blood parasite prevalence based on microscopic examination of stained blood smears was determined in adults of 11 passerine bird species sampled during their breeding season (May and June 1997-98) in interior Alaska (USA). These species included primarily Nearctic migratory species such as the dark-eyed junco (Junco hyemalis) and neotropical migratory species such as the blackpoll warbler (Dendroica striata), alder flycatcher (Empidonax alnorum), Swainson's thrush (Catharus ustulatus), northern waterthrush (Seiurus noveboracensis), and bank swallow (Riparia riparia) as well as one long-distance palearctic migrant, the arctic warbler (Phylloscopus borealis). The more prevalent parasites were Leucocytozoon dubreuili (73% of the sampled turdinids), L. fringillinarum (42% of the sampled fringillids and parulids), and Trypanosoma avium (39% of the sampled hosts). Other parasites (H. fallisi: 18% of the sampled turdinids; Haemoproteus paruli: 14% of the sampled parulids; H. fringillae: 5% of the sampled fringillids; microfilariae: 4% of the sampled hosts) were observed less frequently. Plasmodium vaughani was found only in two yellow warblers (Dendroica petechia). Overall parasite prevalence varied between 0% in the alder flycatcher to >80% in Swainson's thrush, arctic warbler, and Townsend's warbler (Dendroica townsendi). Prevalence of various hematozoa also was bird species-dependent. No relationship was observed between prevalence and either foraging (aerial versus trees/shrubs) or nesting habits (ground versus arboreal) or general location of the wintering area of the different species examined. Prevalence also was unrelated to average dates of arrival on breeding grounds and, therefore, to potential duration of exposure to local insect vectors before capture. Differences in blood parasite prevalence among species breeding in a same region and in the same type of habitat may result from differences in host specificity such as immunological resistance to infection or blood meal preference by potential vectors and/or in behavioral adjustments/physiological traits that alter exposure to vectors.

Alaska↗
PubMed1999

Response to wing-web challenge of Rous sarcoma virus subgroups in some chicken breeds.

Response to wing-web challenge (WWC) of Rous sarcoma virus (RSV) subgroups was studied in 4-8 weeks old chicks of a light breed, a heavy breed and a cross between an indigenous black plumage Bantam fowl and Australorp breed. Wing-web tumor (WWT) began to develop within one week in response to virus subgroups A (BS-RSV) and C [RSV (RAV-49)] challenge. In chicks challenged with subgroup D [RSV (RAV-50)] virus it took a minimum of 4 weeks for development of WWT. Positive response to WWC by subgroups A, C and D virus was 84%, 100% and 52%, respectively. The duration of exhibition of positive response was maximum for subgroup A virus, followed by subgroup D and minimum for subgroup C virus.

Animals↗
PubMed1999

Breeding habitats & seasonal variation in the larval density of Aedes aegypti (L) & Ae. albopictus (Skuse) in an urban garden in Calcutta city.

A longitudinal study on the breeding habitats and variation in the relative larval density of Ae. aegypti and Ae. albopictus was conducted in an urban garden in Calcutta city. The observations of the study, during October 1995 to September 1996 revealed that both the species showed preference for breeding in earthen, and cement pots, plant pots, chowbachhas and molluscan shells. Ae. albopictus larvae were also found in accumulations of water in bamboo stumps and tree holes. The container positivity and relative larval density of both species was highest during monsoon (June 1996-September 1996) and lowest during summer (February 1996-May 1996). The seasonal variation in container index (CI) of each species was statistically significant (P < 0.05) and showed a positive correlation with rainfall, the seasonal variation in the larval density of both Ae. aegypti and Ae. albopictus in permanent breeding sites was however not statistically significant, indicating that the CI and relative larval density of the two species was unaffected by temperature and humidity. The variation between the larval density and their CI in the same season was not significant, suggesting a perfect adaptation of Ae. aegypti, an urban, and Ae. albopictus, a sylvatic species, to more or less similar aquatic biotypes in an urban garden.

Aedes↗
PubMed1999

Eye muscle nerves nuclear size in a breed of domestic rabbits with floppy ears.

In many wild species there is a correlation between the capacity for directional hearing and directional seeing, which is associated with the mobility of the eye balls. Among the breeds of domestic rabbits, there are some with pendulous, floppy external ears (e.g., Englische Widder, EW) that might limit directional hearing. The size of the brain stem nuclei in EWs has been determined and compared to rabbits with upright ears. In EW, the oculomotor nuclei are relatively larger than in the other breeds. Possibly, this indicates a compensation of a loss in directional hearing ability achieved through greater mobility of the eyes. At the same time, a variability of brain composition between the breeds, which is an intraspecific variability, is obvious.

Animals↗
PubMed2000

[RAPD-analysis of genetic polymorphism of ducks: differences in breeds].

Using randomly amplified polymorphic DNA (RAPD) obtained by polymerase chain reaction (PCR), the genetic differentiation of breeds of Peking and Musk ducks maintained at the Blagovarskii State Farm for Pedigree Poultry was studied. A comparison of genetic distances estimated by two different methods, as well as similarity dendrograms based on these estimates, was performed. The similarity dendrograms obtained using different primers and methods of construction were found to be similar. The pattern of breed clustering on these dendrograms adequately reflects their actual state known from the history and genealogy of breeds.

Animals↗
PubMed2000

Optimizing breeding decisions for Finnish dairy herds.

The purpose of this study was to determine the effect of reproductive performance on profitability and optimal breeding decisions for Finnish dairy herds. We used a dynamic programming model to optimize dairy cow insemination and replacement decisions. This optimization model maximizes the expected net revenues from a given cow and her replacements over a decision horizon. Input values and prices reflecting the situation in 1998 in Finland were used in the study. Reproductive performance was reflected in the model by overall pregnancy rate, which was a function of heat detection and conception rate. Seasonality was included in conception rate. The base run had a pregnancy rate of 0.49 (both heat detection and conception rate of 0.7). Different scenarios were modeled by changing levels of conception rate, heat detection, and seasonality in fertility. Reproductive performance had a considerable impact on profitability of a herd; good heat detection and conception rates provided an opportunity for management control. When heat detection rate decreased from 0.7 to 0.5, and everything else was held constant, net revenues decreased approximately 2.6%. If the conception rate also decreased to 0.5 (resulting in a pregnancy rate of 0.25), net revenues were approximately 5% lower than with a pregnancy rate of 0.49. With lower fertility, replacement percentage was higher and the financial losses were mainly from higher replacement costs. Under Finnish conditions, it is not optimal to start breeding cows calving in spring and early summer immediately after the voluntary waiting period. Instead, it is preferable to allow the calving interval to lengthen for these cows so that their next calving is in the fall. However, cows calving in the fall should be bred immediately after the voluntary waiting period. Across all scenarios, optimal solutions predicted most calvings should occur in fall and the most profitable time to bring a replacement heifer into a herd was in the fall. It was economically justifiable to keep breeding high producing cows longer than low producing cows.

Animal Husbandry↗
PubMed2000

Prediction of rates of inbreeding in populations selected on best linear unbiased prediction of breeding value

Predictions for the rate of inbreeding (DeltaF) in populations with discrete generations undergoing selection on best linear unbiased prediction (BLUP) of breeding value were developed. Predictions were based on the concept of long-term genetic contributions using a recently established relationship between expected contributions and rates of inbreeding and a known procedure for predicting expected contributions. Expected contributions of individuals were predicted using a linear model, u(i)(()(x)()) = alpha + betas(i), where s(i) denotes the selective advantage as a deviation from the contemporaries, which was the sum of the breeding values of the individual and the breeding values of its mates. The accuracy of predictions was evaluated for a wide range of population and genetic parameters. Accurate predictions were obtained for populations of 5-20 sires. For 20-80 sires, systematic underprediction of on average 11% was found, which was shown to be related to the goodness of fit of the linear model. Using simulation, it was shown that a quadratic model would give accurate predictions for those schemes. Furthermore, it was shown that, contrary to random selection, DeltaF less than halved when the number of parents was doubled and that in specific cases DeltaF may increase with the number of dams.

Journal Article↗
PubMed2000

Achondroplastic dog breeds have no mutations in the transmembrane domain of the FGFR-3 gene.

One of the most common skeletal affections in humans is achondroplasia, a short-limbed dwarfism that is, in most cases, caused by mutations in the transmembrane domain of the fibroblast growth factor receptor-3 (FGFR-3) gene. Due to the lack of sufficient radiological, genetic, and molecular studies, most types of skeletal anomalies in dogs are classified as achondroplasia. To initiate the molecular characterization of some osteochondrodysplastic dog breeds, we obtained the DNA sequence of the transmembrane domain of the FGFR-3 gene from the dachshund, basset hound, bulldog, and German shepherd dogs. All 4 breeds showed no mutation in the evaluated region. This indicates that the mutation responsible for the osteochondrodysplastic phenotype in the tested dog breeds lies either elsewhere in the FGFR-3 gene or in other ones involved in the formation and development of endochondral bone.

Achondroplasia↗
PubMed2000

Genetics of chemical carcinogenesis: analysis of bidirectional selective breeding inducing maximal resistance or maximal susceptibility to 2-stage skin tumorigenesis in the mouse.

We report on bidirectional selective breeding, initiated from a genetically defined foundation population and carried out to selection limit, for producing lines of mice endowed with maximal resistance (Car-R) or maximal susceptibility (Car-S) to 2-stage skin tumorigenesis. The initial population resulted from a balanced intercrossing of 8 inbred strains of mice. The tumors, induced by a single application of DMBA (initiation) and twice weekly applications of TPA (promotion), were benign papillomas; their number at the end of the promotion period was the phenotype chosen for assortative mating. Afterward, the majority of them regressed while others progressed to malignant carcinomas. The Car-R line was selected through a strong challenge, while the Car-S line selection was based on responses to decreasing concentrations of DMBA and TPA. The selection limit was reached after 14 or 15 generations showing progressive interline divergence, which strongly suggests the interaction of several quantitative trait loci (QTL). The phenotypic difference was extremely large: the tumor response was 73 times higher in Car-S than in Car-R mice, though the applied concentrations of DMBA and TPA were 100 and 40 times lower, respectively. The mean heritability realized during the selective breeding was 0.20 in Car-R and 0.49 in Car-S. Our results are compatible with a minimal QTL estimate of 8 in the Car-R line and of 9 or 10 in the Car-S line. The Car-S line is also much more susceptible to carcinoma induction. An association of coat color with tumorigenesis was observed in interline F2 segregants. The Car-R and Car-S lines, obtained through a long-lasting breeding program, are a unique model for identifying the QTL involved in chemical tumorigenesis and will be provided to interested investigators.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed2001

[Characteristics of some breeds of swine and populations of Georgian and Western Siberian wild boar by immunogenetic systems of blood serum proteins].

A bank of reagents for hog serum protein allotypes has been created. All of these allotypes passed international comparison tests in 1987-1988. The bank can be used for typing the animals for four generally accepted (Gp, LpB, Lpr, and IgGH) and several experimental systems. In this study, immunogenetic characteristics of some pig breeds (Large White, Lithuanian White, Swedish Landrace, Kakhetinskaya, and Svanetskaya) bred in Georgia are compared with those of western Siberian breeds (Large White, Kemerovskaya, and Northern Siberian), and some foreign breeds, as well as with European, Caucasian, and Siberian subspecies of the wild boar.

Animals↗
PubMed2001

[Structural organization of the gene pool of the Ukrainian steppe white pig breed from immunogenetic markers].

The study of structural organization of gene pool was conducted for eight blood-group genetic systems (transferrin, haptoglobin, and amilase) in three stock herds of pigs of the Ukrainskaya Stepnaya Belaya breed that were bred under the conditions of southern Ukraine. Typical gene combinations (complex genotypes) of this breed were detected, and the main breed-specific parameters of distribution of genetic markers were described.

Amylases↗
PubMed1975

Association between alphas1-, beta- and kappa-casein loci in two Italian cattle breeds.

The genetic polymorphism alphas1-, beta- and kappa-caseins was examined by gel electrophoresis in two Italian breeds, Valdostana and Piedmont. The results obtained from acid and basic migration show that the gene frequencies of the two breeds are very similar. Non independent assortment of genotypes among these milk protein loci was also studied. Results of analyses carried out on loci pairs showed that the genetic complex alphas1-CnB - beta-CnA2 was the most common in both breeds. In addition, the measure of linkage disequilibrium or gametic association (denoted delta) showed a close association between alphas1-Cn and beta-Cn, and between beta-Cn and kappa-Cn. No significant association was found between alphas1-Cn and kappa-Cn. This is in line with the model proposed by Grosclaude et al. (1973).

Alleles↗
PubMed2002

Commercial rodent feed as an occasional cause of morbidity and mortality in a rat breeding colony.

In the last fifteen years there were several feed-related outbreaks of morbidity and mortality in the Institute's breeding colony of Wistar rats. The last event took place in April 1999, one month after the use of a new supply of the usual standard rodent feed. Animals did not thrive and manifested generalised oedema, hypoalbuminaemia, elevated liver enzymes, and high mortality. The effect of feed was assessed first by feeding a group of sick females during 14 days with either suspected feed (A-March) or with the earlier supply of feed (A-January) of the same producer. Then a group of healthy male rats Y59 from another breeding colony was fed either suspected feed (A-March) or feed from another producer (feed B). Although neither chemical nor microbiological deviation in feed analysis had been detected, decreased consumption and slower body weight gain in all animals fed with feed A-March suggested an association between this batch of feed and the increased morbidity in those animals. Eventually, the entire rat colony was put down and replaced with a new breed which was given a new brand of feed.

Animal Feed↗
PubMed2002

The stability of internal equilibria in predator-prey models with breeding suppression.

We present two models that represent the suppression of breeding by prey in response to short-term increases in predation pressure. For both of these models, we have been able to produce analytic conditions for the local stability of the interior steady state, in terms of the values of combinations of these parameters. Although our models are as simple as possible to capture the effect of breeding suppression, the expressions for local stability, even in their simplest form, are complex. Thus, we come to the important conclusion that there is no simple and general rule for the effect of the behaviours described here (anti-predatory breeding suppression and prey switching by predators) on the stability of population dynamics. Rather, effects will be system specific. However, we hope that the results and methodological framework outlined here will provide a useful tool for others to investigate the consequences for particular real systems.

Animals↗
PubMedDate not supplied

[The laboratory breeding of lice].

The breeding of lice started in Poland as R. Weigl used to prepare a typhus vaccine from the guts of infected lice. Hélène Sparrow introduced this breeding technique in the Institut Pasteur of Tunis in 1927. Lice will feed only on human blood. They were put in small wooden boxes with a thin cloth bottom through which they could bite and feed. Once a day the boxes were placed against the skin of human feeders whose role was essential in the process. The breeding of lice at the Institut Pasteur of Tunis lasted until 1980 and allowed significant advances in the study of typhus and relapsing fever.

Animals↗
PubMedDate not supplied

[Gutteral pouch tympany in German warmblood foals: influence of sex, inbreeding and blood proportions of founding breeds as well as estimation of heritability].

The objective of the present study was to analyse the importance of the influences of sex, inbreeding coefficient, proportion of genes of the original breeds and the additive genetic contribution to the occurrence of guttural pouch tympany in foals belonging to German Warmblood breeds. Foals affected by guttural pouch tympany were ascertained in the Clinic of Horses, School of Veterinary Medicine Hannover. This data set comprised 22 German Warmblood foals with guttural pouch tympany, which were patients of the Clinic for Horses between 1994 and 2001. Information on the pedigrees and all available relatives of these patients allowed us to group the affected foals into five families with a total of 289 animals. Female foals were significantly more often affected by guttural pouch tympany. The difference was 16.6% in favour of female foals. The size of the inbreeding coefficient was not important for the occurrence of guttural pouch tympany. The proportion of the genes of the breeds Arabian, Thoroughbred and Trakehner were not significantly different from a randomly selected sample of 10% of foals born in the same birth years and the same region. The heritability estimates for the frequency of guttural pouch tympany using a threshold model was 0.81 +/- 0.16. This is the first report that could show a genetic component responsible for guttural pouch tympany in horses.

Animals↗

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