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In order to control rates of response and inbreeding, mate selection using fuzzy selective mating criteria (FMC) was investigated in adult multiple ovulation and embryo transfer nucleus schemes for dairy cattle. Stochastic simulation was used to model the closed nucleus scheme. This mate selection was examined in four alternative mating and male selection schemes: (i) a hierarchical scheme; (ii) a hierarchical sibship scheme (two males per sibship); (iii) a factorial scheme (two sires per dam); and (iv) a factorial sibship scheme (two males per sibship and two sires per dam). Genetic response and inbreeding rate tended to be reduced by increasing the trade-off parameter of FMC between the expected breeding value and inbreeding of progeny. Inbreeding rates in all schemes were reduced by reducing the variance of family size through selection and the average coancestry of mating pairs through mate allocation.  相似文献   
3.
ABSTRACT:   The reproductive traits and the monthly larval abundance of the mantis shrimp Oratosquilla oratoria were investigated in Tokyo Bay, Japan, in 2002. The goal of the study was to elucidate the cause of changes in the monthly pattern of larval abundance from the 1980s to the 1990s as these changes relate to variation in the stock size of the adult shrimp. Oogenesis was divided into 10 stages by histological observation. The developmental stage of oocytes in an individual's ovary was synchronous, suggesting that almost all the oocytes in an ovary are spawned at the same time. The size at first maturity was estimated to be 7 ≤ body length ( BL ) < 8 cm. Fecundity was expressed as a function of BL , ranging from 19 300 eggs for 8 cm BL to 92 100 eggs for 14 cm BL . Small female shrimps (<10 cm BL ) spawned around August. Most large female shrimps (≥10 cm BL ) spawned around May, and some large female shrimps also spawned until September. Although most large female shrimps spawned in spring, the larval abundance was low before July and high from August onwards. The results suggest that a substantial decrease in the stock size of large individuals causes the low larval abundance before July.  相似文献   
4.
L11A-Fukushima (L11A-F) derived from attenuated isolate LuA of Tomato mosaic virus (ToMV) has the highest ability to cross protect against virulent ToMV among LuA and its derivatives and is stably inherited. Growth, yield, fruit quality and symptom attenuation of inoculated tomato plants did not differ significantly between L11A-F and L11A. The infectivity of progeny viruses in tomato infected with LuA-F was less than 4% of that with virulent ToMV. From these results, L11A-F appears to possess the properties necessary for practical use. To manage L11A-F strictly, a PCR-based assay to detect trace contamination of virulent ToMV in L11A-F preparations was established. Received 10 June 2002/ Accepted in revised form 30 October 2002  相似文献   
5.
This study aimed to identify the potential allelopathic indigenous rice (Oryza sativa L. ssp. indica) varieties from Bangladesh using a performance study in a weed‐infested field and to assess the extent of allelopathic interference relative to resource competition in a glasshouse experiment. Six varieties – namely, “Boterswar,” “Goria,” “Biron” and “Kartiksail” as the most allelopathic, “Hashikolmi” as weakly allelopathic and “Holoi” as nonallelopathic – were raised following a nonweed control method. The infestation levels of weed species were calculated using Simpson's Diversity Index (SDI), which ranged from 0.2 to 0.56. However, a significant correlation coefficient (0.87, P < 0.001) was obtained from these field data compared with the root inhibition percentage from the laboratory bioassay, and the “Boterswar” variety was the most allelopathic. The interactions between the allelopathic variety “Boterswar,” weakly allelopathic variety “Hashikolmi” and Echinochloa oryzicola via a target (rice)‐adjacent (E. oryzicola) cogrowth culture were determined in a hydroponic arrangement. The relative competitive intensity (RCI) and the relative neighbor effect (RNE) values showed that the crop–weed interaction was facilitation for “Boterswar” and competition for “Hashikolmi” and E. oryzicola in rice/E. oryzicola cogrowth cultures. The allelopathic effects of “Boterswar” were much higher than the resource competition in rice/E. oryzicola cogrowth cultures. The converse was observed for “Hashikolmi.” Moreover, the mineral content of E. oryzicola was severely affected by “Boterswar”/E. oryzicola cogrowth cultures’ exudate solution. Therefore, the allelopathic potential of “Boterswar” variety might be useful for developing the weed‐suppressing capacity of rice, which will likely have a significant influence on paddy weed control.  相似文献   
6.
Farm managers' decision to cull dairy cows is based on the cows' milk production, history of disorder(s), and reproductive performance, each of which affects dairy cows' lifetime (herd life and productive lifespan). We investigated the relationships among the incidence of clinical mastitis (CM), the reproductive performance, and the culling rate. We also assessed the effects of these relationships on the lifetimes of dairy cows, using the records made before and after the introduction of an automatic milking system (AMS) at Hiroshima University Farm. Milk yield, CM incidence density, and culling rate of dairy cows increased after the AMS introduction. The CM incidence was associated with an elongation of the calving interval in cows with the same parity. CM in the 1st parity might have caused the reductions of the cows' lifetime and their parity at culling. A higher age at first calving (AFC) was associated with an increase in culling rate but did not lead to a significant decrease in lifetime. Investigations of the factors mediating CM in the 1st parity or AFC with CM incidence or culling rate in the later stages might contribute to the control of lifetime of dairy cows.  相似文献   
7.
Alpha‐melanocyte stimulating hormone (α‐MSH) is one of the main regulators for melanocytes, and the adenohypophysis is one of the major tissues for the synthesis of this hormone. The Silky fowl is a characteristic breed of chicken with hyperpigmentation throughout the body. The involvement of the adenohypophysis in the hyperpigmentation of this breed is not known. In the present study, the proportion of melanocyte stimulating hormone‐immunopositive cells (MSH cells) in the adenohypophysis was immunocytochemically compared between Silky, Red Cornish × New Hampshire (RN) crossbred and Japanese bantam cockerels at 15 weeks of age. After the body and gland were weighed, the adenohypophyseal cells were enzymatically dispersed and immunostained for α‐MSH, and the immunopositive MSH cells were counted. The weights of the body and adenohypophysis were heaviest in the RN crossbred, followed by the Silky and lightest in the bantam cockerels. In contrast, the ratio between adenohypophysis and bodyweight was much larger in the Silky and the bantam than in the RN crossbreed (P < 0.05). The population of MSH cells in the adenohypophysis was larger in the Silky (14.3%) than in the RN crossbreed (8.0%) and the bantam (8.1%) cockerels (P < 0.05). From these results, it was concluded that prepubertal Silky cockerel have numerous MSH cells in the adenohypophysis suggesting a relationship to hyperpigmentation.  相似文献   
8.
The erythrocyte-exchanged chimera mouse model has become to be a significant tool for studying animal and human (hu) protozoan haemoparasites, though the usefulness of this model varies depending primarily on the acceptability of xenogeneic red blood cells (RBC). To find a superior recipient in comparison with C.B-17/Jcl mouse with severe combined immuno-deficiency (scid) mutation, we examined in this report the non-obese diabetes (NOD)/shi-scid mouse, a recently available strain of SCID. When 2.5 x 10(8) of fluorescent dye-labeled hu-RBCs were transfused, C.B-17scid mouse eliminated them logarithmically by a simple linear regression, while NOD-scid mouse eradicated hu-RBCs by a unique two-step fashion, i.e., a potent but only briefly functioning RBC eradication followed by a weak steadily functioning step. The means of regression line constance +/- their standard deviations (SD) of 205 C.B-17scid and of 213 NOD-scid mice for their short- and long-lasting steps were -0.73 +/- 0.63, -0.53 +/- 0.25 and -0.16 +/- 0.10, respectively. Hu-RBC half-lives determined from these means of C.B-17scid mice and of NOD-scid mice for the short- and long-living steps were 3.6, 4.9 and 16.3 hr, respectively. Higher hu-RBC acceptability of NOD-scid mouse, especially at their long-lasting step, was also demonstrated under at an activated state of mouse innate immunity. Treatment with 1.0 mg heat-killed Candida cells caused an acceleration of hu-RBC elimination in both mouse strains but the magnitudes for the short- and long-living steps of NOD-scid mice evaluated by "stimulation index" were only 1/2.6 and 1/7.6 of C.B-17scid mice, respectively.  相似文献   
9.
The gene constitution of polymorphisms of the four calpain genes (µ‐calpain, m‐calpain, p94, and µ/m‐calpain) were analyzed in South‐East Asian native chickens, White Leghorn and Broiler commercial chickens, and Red and Green jungle fowl. Polymorphisms were detected at all loci in chickens and Red jungle fowl, but only for CAPN1 (µ‐calpain gene) in Green jungle fowl. CAPN2 and CAPN1.5 are linked on chicken chromosome 3, and the genotype for these loci were treated as haplotype. Some combinations of calpain loci were tested using principal component analysis, and the best combination (CAPN1, CAPN3, and CAPN1.5) was determined. The proportion of polymorphic loci (Ppoly) and heterozygosity (H?) were 1.00 and 0.316–0.465 in domestic chickens and red jungle fowl, and 0.33 and 0.137 in Green jungle fowl, respectively. GST values suggested that the degree of subdivision among native chickens was relatively low except for Thailand, which was highest. Pair‐wise FST testing, dendrogram and principal component analysis from the results of calpain loci showed that the four South‐East Asian native and commercial chicken populations were close genetically.  相似文献   
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