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1.
This study aimed to analyse genetic background of variation in reproductive performance between parities of a sow and to investigate selection strategies to change the “parity curve”. Total number born (TNB) recorded in Large White sows was provided by Topigs Norsvin. Analysis with basic (BM) and random regression (RRM) models was done in ASReml 4.1. The BM included only a fixed “parity curve”, while RRM included 3rd order polynomials for additive genetic and permanent sow effects. Parameters from RRM were used in simulations in SelAction 2.1. Based on Akaike information criterion, RRM was a better model for TNB data. Genetic variance and heritability estimates of TNB from BM and RRM were increasing with parity from parity 2. Genetically, parity 1 is the most different from parities 7 to 10, whereas most similar to parities 2 and 3. This indicates presence of genetic variation to change the “parity curve”. Based on simulations, the selection to increase litter size in parity 1 only increases TNB in all parities, but does not change the observed shape of “parity curve”, whereas selection for increased TNB in parity 1 and reduced TNB in parity 5 decreases differences between parities, but also reduces overall TNB in all parities. Changing the “parity curve” will be difficult as the genetic and phenotypic relationships between the parities are hard to overcome even when selecting for one parity.  相似文献   

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Progesterone plays important roles in the regulation of female reproduction. In this study, progesterone receptor (PR) mRNA levels in rat uterus during pregnancy, labor, lactation and the estrous cycle were examined by competitive RT-PCR. During pregnancy and lactation, PR mRNA levels had decreased on day 20 of pregnancy (P20) and P21 compared with P15 but increased during labor. After a decline on day 1 of lactation (L1), PR mRNA levels had increased again on L3 and L14 compared with P15, P18, P20, P21 and P21pm (at 2200-2300 h on P21). There was no significant change in the PR mRNA level during the estrous cycle. The PR mRNA level did not change during 1 week of progesterone treatment or afterwards. Injection of 17beta-estradiol did not affect PR mRNA levels in rats treated with progesterone or those without any injections. In rats on P18, 17beta-estradiol injection did not change PR mRNA levels after sham-operation but induced an increase in PR mRNA levels of rats ovariectomized 6 h before the treatment. These results suggest that uterine PR mRNA levels are differently regulated during late pregnancy, labor and lactation, and during labor estrogen is one of the essential factors for the increase in PR mRNA levels.  相似文献   

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The objective of this study was to investigate immunolocalization of steroidogenic enzymes 3βHSD, P450c17 and P450arom and their expression during the breeding season in wild male raccoon dogs. The testicular weight, size and seminiferous tubule diameters were measured, and histological and immunohistochemical observations of testes were performed. The messenger RNA expression (mRNA) of 3βHSD, P450c17 and P450arom was measured in the testes during the breeding season. 3βHSD was found in Leydig cells during the breeding and non‐breeding seasons with more intense staining in the breeding season. P450c17 was identified in Leydig cells and spermatids in the breeding season, whereas it was present only in Leydig cells in the non‐breeding season. The localization of P450arom changed seasonally: no immunostaining in the non‐breeding season; more extensive immunostaining in Leydig cells, Sertoli cells and elongating spermatids in the breeding season. In addition, 3βHSD, P450c17 and P450arom mRNA were also expressed in the testes during the breeding season. These results suggested that seasonal changes in testicular weight, size and seminiferous tubule diameter in the wild raccoon dog were correlated with spermatogenesis and immunoreactivity of steroidogenic enzymes and that steroidogenic enzymes may play an important role in the spermatogenesis and testicular recrudescence and regression process.  相似文献   

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Five mares and a stallion were studied from three to 30 months after experimental infection with Brucella abortus strain 544. The mares bred normally. No organisms were recovered from horses or from pregnant Friesian heifer contacts. Titres of serum antibody in the antiglobulin (Coombs) and complement fixation tests fell more slowly than those assessed by other tests. The serum of one foal yielded maternal antibody. An intradermal test was positive in infected adults only, and negative in all foals.  相似文献   

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A total of 175 metapodials (MP) of Pleistocene and early Holocene bison (Bison priscus Boj.) from the vast area of northeast Russia were studied. MP were attributed to males and females both visually and statistically. Data on the withers height of bison from northeast Russia are provided. Stress markers were recorded, including so‐called “buttresses.” With rare exceptions, stress markers were not of a pathological nature. The origin and development of the buttresses are age‐related; their prevalence in bison females can be considered as the response to an increased load during pregnancy. Changes in the periosteum, found in males, are related to their greater activity. Buttresses are also well developed on metatarsals of the red deer and the elk; they are less developed in reindeer and not found in giant deer. A relationship among stress markers, locomotion and the environment is established. Possible peculiarities of the Rauchua River bison locomotion are discussed.  相似文献   

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Milk produced by the grazing system, referred to as “grazing milk” contains many components required for human health. The milk fatty acid (FA) profile is strongly associated with the diet on the farms. In the present study, based on the FA profile of farmer's bulk milk, we determined how to discriminate between milk produced on grazing and on a confinement system. A field survey was conducted four times (grazing and confinement season) in the Konsen (29 farms) and Okhotsk (25 farms) area in Hokkaido. Farmer's bulk milk samples and details of feeding management were collected and the FA profile of milk was measured. Milk produced during the grazing season contained less C16:0 and cis‐9 C16:0, and more C18:0, cis‐9 C18:1, trans‐11 C18:1, cis‐9,12 C18:2, cis‐9,trans‐11 C18:2 and cis‐9,12,15 C18:3 than milk produced during the confinement season. Discrimination analysis using 16 FA revealed that almost all milk samples were discriminated correctly (confinement season: 90% correct and 10% borderline, grazing season: 88% correct, 9% borderline and 3% incorrect). For farmers that were categorized incorrectly and were considered borderline in the grazing season, the dependency on pasture was low compared with that for farmers correctly discriminated. Therefore, to claim “grazing milk”, a high dependency on pasture is required for grazing dairy farmers.  相似文献   

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The aim of this study was to determine if the achievement of the “in vitro” capacitation (IVC) status and subsequent progesterone‐induced “in vitro” acrosome exocytosis (IVAE) was accompanied with overall changes in threonine phosphorylation (pThre) of boar spermatozoa. For this purpose, mono‐ and bi‐dimensional Western blot analyses as well as immunocytochemistry studies against pThre were performed in boar sperm subjected to IVC and subsequent IVAE. Mono‐dimensional Western blot in non‐capacitated samples showed that launching of IVC did induce an overall increase in signal intensity in all observed bands that was followed by a subsequent decrease afterwards. Bi‐dimensional Western blot analysis showed the presence of four main signal protein clusters. The attainment of IVC induced an overall decrease in the number and intensity of spots of Clusters A, B and C and a concomitant increase in the intensity of spots of Cluster D. The IVAE launching caused a rapid increase in the intensity of spots of Clusters B, C and D, which was followed by a subsequent decrease of the intensity together with a concomitant pI displacement of Cluster C. Finally, immunocytochemistry showed that the pThre signal of non‐capacitated cells was located at the whole sperm. The IVC did not induce prominent changes in this location. In contrast, the induction of IVAE caused the appearance of an additional an intense acrosome and tail pThre signal that subsequently decreased. In conclusion, our results indicate that IVC and further IVAE induced specific changes in the intensity and appearance of pThre protein phosphorylation which were linked to changes of specific protein characteristics as pI. These results support, thus, the existence of a specific role of pThre in IVC/IVAE of boar sperm.  相似文献   

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The skull-cap, the meninges, and the dorsal surface of the cerebral cortex were inspected in 20 Scottish Terriers subjected to euthanasia because of severe Scotty Cramp, and in 1 Cocker Spaniel and 2 Scottish Terrier puppies sacrificed because of Splay (inability to stand on the hind legs).Apparent abnormalities observed in the 12 younger (6 weeks to 18 months old) Scotty Cramp animals were firm medial adhesion of the dura to the skull-cap (all animals), meningeal hemorrhage (10 animals), and bony jags on the inner side of the skull-cap making impressions in the underlying dura and cerebral cortex (8 animals).Similar bony irregularities causing durai and cortical impressions were observed in 5 out of 8 Scotty Cramp dogs belonging to a senior age group (3 to 11 years old). Meningeal hemorrhage was observed only in 1 animal belonging to this group, but consistent observations were scarified appearance of the dura along the midline and induration around superior cerebral veins medially in the cruciate sulcus.Meningeal hemorrhage and firm medial adhesion of the dura to the skull-cap were consistent observations in the Splay puppies (6 weeks to 3 months old).The possibility is discussed that the ultimate cause of Scotty Cramp and Splay may be abnormalities in the development of the parietal and frontal bones, of their interconnection, and of their relation to the underlying meninges. This in turn may exert mechanical, circulatory or other influences causing dysfunction of the cerebral motor cortex.  相似文献   

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White blood cells, especially lymphocytes, are susceptible to radiation exposure. In the present study, red blood cell, total white blood cell, and lymphocyte counts were repeatedly measured in cattle living on three farms located in the “difficult‐to‐return zone” of the Fukushima nuclear accident, and compared with two control groups from unaffected areas. Blood cell counts differed significantly between the two control groups, although almost all the values fell within the normal range. The blood cell counts of the cattle in the “difficult‐to‐return zone” varied across sampling times even on the same farms, being sometimes higher or lower than either of the two control groups. However, neither a statistically significant decrease in blood cell counts nor an increase in the rate of cattle with extremely low blood cell counts was observed overall. The estimated cumulative exposure dose for the cattle on the most contaminated farm was within a range of 500–1000 mSv, exceeding the threshold for the lymphopenia. Because of the low dose rate on these farms, potential radiation damages would have been repaired and have not accumulated enough to cause deterministic effects.  相似文献   

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Fifty five suckling kids from three genotypes and two sexes protected by the PGI “Cabrito de Barroso” European quality label were used in this experiment. Carcass quality was assessed using indices from carcass measurements, dressing percentages, refrigerated losses, higher priced joints proportion and tissue composition of the carcass. Meat pH, colour, total pigment, fat, dry matter, collagen determinations (total and soluble), cooking losses and shear force estimated in longissimus thoracis et lumborum (LTL) and gluteobiceps (GB) muscles were used to characterize meat quality. Principal component (PC) analysis was performed in order to examine carcass quality traits (n = 16) and meat quality (n = 16) traits. The five first principal components (PCs) explained about 86% of the total variability for carcass quality and 75% of the total variability for meat quality. Compactness indices of carcass and leg, carcass weight and subcutaneous fat were the most effective variables for the PC1, whereas the higher priced joints proportion, muscle proportions of the higher priced joints and of the carcass and the muscle and bone ratio were useful to define the PC2. The first PC of the meat quality parameters was characterized by colour traits (L, b, a, C, H and total pigment) whereas collagen determinations (total collagen and collagen solubility) defined the second PC. When the carcass quality data were projected on the plane defined by the first two PCs, two separate groups of points appeared, corresponding to the animals with slaughter live weight higher or lower than 10 kg. The distribution of the meat quality data on the plane defined by the first two PCs allowed the identification of two separate groups, corresponding to the muscles GB and LTL. The differences between genotypes tend to be small and related to slaughter live weight, which implies certain constancy in carcass and meat quality of the PGI “Cabrito de Barroso”.  相似文献   

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Curious eroded depressions, most resembling an eye shedding an elongate tear, are found in gently sloping, intertidal, carbonate‐rich arenite outcropping on the sea coast near Lakes Entrance, Victoria, southeast Australia. The depressions, known locally as “Tears of the Virgin,” are evidently formed by multiple generations of a barnacle, Chthamalus antennatus Darwin, 1854 in association with cyanobacteria. While the round part of a depression offers the barnacle a modicum of protection from impacts during high tides, it is also partially inhabited by cyanobacteria, which extend into and tend to fill the elongate tear. As such, this appears to be the first case of mutualism between a higher invertebrate and cyanobacteria, with the cyanobacteria reducing the barnacle's risk of desiccation while receiving metabolic wastes from it during low tides. It is also the first record of a balanomorph barnacle eroding calcareous arenite beneath its shell, the net effect of which would be expected to reduce its adhesion to the substrate. However, the siliceous residue, resulting from the barnacle's dissolution of the more than 80% of the calcite‐rich sedimentary rock, is sequestered in delicate folds on the inside of the shell wall as it grows. A brief review of cirripedes capable of excavation includes the first photographic documentation of excavation of a mollusc shell by a verrucomorph.  相似文献   

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