Direct and correlated responses to selection for yearling weight on reproductive performance of Nelore cows     

Mercadante ME  Packer IU  Razook AG  Cyrillo JN  Figueiredo LA 《Journal of animal science》2003,81(2):376-384

Data from a selection experiment for growth carried out in Brazil were analyzed in order to evaluate the direct responses on yearling weight (YW) and the correlated responses on the size and reproduction traits of cows. The experiment was started in 1976, and in 1980 three lines of Nelore cattle were established: selection (NeS), traditional (NeT), both selected for higher YW, and control (NeC), selected for mean YW. The NeT was an open line that eventually received bulls from other herds. Yearling weight records for animals born from 1978 to 1998 and yearling hip height (H550) offemales born from 1985 to 1998 were analyzed by fitting an animal model in order to obtain the genetic trends. The means for weight, height, and body condition score at the start of the breeding season, days to calving, and calving success of cows born from 1993 to 1996 (pertaining to the third to fourth generations of selection) were compared between the selected (NeS and NeT) and control lines. The genetic trends obtained after 16 yr for YW were 1.7 +/- 0.2, 2.3 +/- 0.2, and -0.1 +/- 0.1 kg/yr for males and 1.9 +/- 0.2, 2.4 +/- 0.2, and -0.1 +/- 0.1 kg/yr for females, for the NeS, NeT, and NeC lines, respectively. Corresponding values for H550 were 0.25 +/- 0.03, 0.24 +/- 0.04 and -0.04 +/- 0.03 cm/yr for females. Heifers and cows from NeS and NeT were 19% and 15% heavier and 4% taller at the start of the breeding season than those from NeC. No significant differences between selected (NeS and NeT) and control females were detected for body condition scores and for reproductive performance. The results indicate that selection for body weight promoted high and consistent weight and height responses both at the yearling and later ages, without compromising the reproductive performance of the cows with respect to days to calving and calving success.  相似文献   

Second Oestrus Synchronization and Precocious Embryo Viability after Puberty Induction in Gilts by the Use of Gonadotrophin Treatment     

V do Lago  WL Vianna  RD Gama  A de  Campos Rosseto  ME Pinese  A de  Sant''Anna Moretti 《Reproduction in domestic animals》2005,40(2):141-144

The use of exogenous gonadotrophins in puberty inducement and ovulation synchronization is a technique that has a positive influence on the management of swine. The purpose of this study was to verify the effects of a second gonadotrophin treatment [equine chorionic gonadotrophin (eCG) and luteinizing hormone (LH), intramuscularly (i.m.)] upon the second oestrus synchronization and fertility in gilts. Seventy-one NAIMA (Pen Ar Lan) gilts had their first oestrus (puberty inducement) induced by a hormonal treatment (eCG and LH). Then, they were randomly distributed into two treatments, with (T1) and without (C) gonadotrophin treatment at the second oestrus. The animals were fed with a single ration (16% of crude protein and 3286.73 kcal ME/kg), and timed artificial insemination performed at the second oestrus. Gilts were slaughtered for embryo recovery and ovary examination about 5 days after insemination. There was no evidence of a difference in the percentage of the second oestrus expression (T1 - 90.90% and C - 86.84%), the duration of the oestrus cycle (T1 - 19.62 +/- 0.82 days and C - 19.67 +/- 4.14 days), the percentage of follicular cysts (T1 - 15.15% and C - 18.42%) and number of ovulations (T1 - 14.60 +/- 5.7 and C - 13.23 +/- 4.8) between treatments (p > 0.05). However, the hormonal treatment (T1) showed minor oestrus dispersion and embryo viability (T1 - 8.4 +/- 5.6 and C - 11.2 +/- 4.6) (p < 0.05). These results indicate that the better synchronization and expression of the second oestrus when using gonadotrophins (eCG and LH) is followed by a lower embryo viability, which is probably the consequence of the heterogeneous follicle recruitment during the injection of eCG.  相似文献   

Environmental and genetic variation of the effective radiative properties of the coat of Holstein cows under tropical conditions     

Alex Sandro Campos Maia  Roberto Gomes da Silva  Elaine Cristina Abaker Bertipaglia 《Livestock Production Science》2005,92(3):307-315

Morphological characteristics, coat effective radiative properties, and the percentage of white colour were measured in the coats of 973 Holstein cows, and estimates of the genetic parameters were obtained for these traits, except morphological characteristics. The results showed that white coats are more dense with long, thin hairs, while the black coats are less dense with short, thick hairs. Effective transmissivity is greater in the less-dense coats with short, thin hairs, independently of coat colour. Effective reflectivity depends more on the variation in the radiative properties of the coat and skin surface rather than on the morphological characteristics of the coat. Effective absorptivity is greater in black and dense coats with long, thick hairs, than in the white and less-dense coat with short, thin hairs. All heritability estimates were of low magnitude, except for the percentage of white coat colour.  相似文献   

Eucalyptus occidentalis plantlets are naturally infected by pathogenic Agrobacterium tumefaciens     

Zoulikha Krimi  Aïda Raio  Annik Petit  Xavier Nesme  Yves Dessaux 《European journal of plant pathology / European Foundation for Plant Pathology》2006,116(3):237-246

In the Sidi M’djahed nursery (Algeria), over 60,000 eucalyptus (Eucalyptus occidentalis) plantlets exhibited tumour-like growths localized at the crown of the plants that resembled crown galls caused by Agrobacterium tumefaciens. Bacteria colonizing the galls were isolated and purified. Most (22 out of 24) of the isolates had cultural and biochemical characteristics similar to those of strains of the biovar 1 of A. tumefaciens. Twenty out of 22 Agrobacterium isolates induced tumour formation on various test plants. In PCR experiments, DNA extracted from these virulent strains yielded an amplification signal corresponding to a 247-bp fragment located within the virulence region of nopaline type Ti plasmid. Consistent with this, the opine nopaline was detected in the tumours induced on test plants – but not on eucalyptus plants. Nopaline was degraded by the 20 pathogenic isolates that were also sensitive to agrocin 84, indicating the presence of a nopaline-type pTi in these strains. The chromosomal region encoding the 16S rRNA was analyzed in a sub-population of the pathogenic agrobacterial isolates. The analyzed strains were found to belong to the ribogroup of the reference strain B6. Interestingly, Eucalyptus camaldulensis and Eucalyptus cladocalyx grown in the same nursery and in the same soil substrate developed no galls.  相似文献   

Two subpopulations of Colletotrichum acutatum are responsible for anthracnose in strawberry and leatherleaf fern in Costa Rica     

Michaela Schiller  Mette Lübeck  Thomas Sundelin  Luis Fernando Campos Meléndez  Solveig Danielsen  Dan Funck Jensen  Kenneth Madriz Ordeñana 《European journal of plant pathology / European Foundation for Plant Pathology》2006,116(2):107-118

Strawberry, Fragaria × ananassa, and leatherleaf fern, Rumohra adiantiformis, are two important crops in Costa Rica. One of the most severe diseases affecting these crops is anthracnose, caused by members of the fungal genus, Colletotrichum (teleomorph; Glomerella). Eighty single-spore isolates from strawberry and leatherleaf fern were identified as Colletotrichum acutatum by species-specific PCR, and were further characterised by Universally Primed PCR (UP-PCR) fingerprinting analysis, and sequence analysis of the ribosomal internal transcribed spacer (ITS) region. Morphological differences, genotypic variation revealed by UP-PCR fingerprinting analysis, and a single sequence polymorphism within the ITS2 region were found between the isolates from strawberry and leatherleaf fern, respectively. The UPGMA cluster analysis of the fingerprints clearly separated the isolates derived from strawberry and leatherleaf fern into two different clusters. Pathogenicity assays on detached strawberry fruits confirmed the apparent difference between the two groups of isolates. It is therefore suggested that the pathogens responsible for strawberry anthracnose fruit rot and leatherleaf fern anthracnose in Costa Rica, belong to two distinct subpopulations of C. acutatum.  相似文献   

Somatic embryogenesis and plant regeneration in Opuntia ficus-indica (L.) Mill. (Cactaceae)     

Francisco Linhares Arruda Ferreira Gomes  Fabíola Fernandes Heredia  Priscilla Barbeta e Silva  Olivardo Facó  Francisco de Assis de Paiva Campos 《Scientia Horticulturae》2006

We present here a method for the regeneration of the prickly-pear (Opuntia ficus-indica (L.) Mill.) through somatic embryogenesis (SE). Direct SE was induced by cultivating shoot apices devoid of leaf primordia on semisolid Murashige and Skoog (MS) basal medium supplemented with 4-amino 3,5,6-trichloropicolinic acid (picloram) at 4 mg l⁻¹. Somatic embryogenesis was influenced by the type, age, physiological and developmental stage of the explants, and also by light conditions, wounding, and the sucrose concentration in the induction medium. A histological analysis confirmed SE by revealing the presence of a closed vascular system in the developing embryos and the absence of a vascular connection between the somatic embryos and the explant.  相似文献   

Preliminary study of short-term preservation of ovine ovarian tissue containing preantral follicles in saline solution of TCM199     

Andrade ER  Amorim CA  Costa SH  Ferreira MA  Rodrigues AP  Dode MA  Figueiredo JR 《The Veterinary record》2002,151(15):452-453

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Investigation of putative CDT gene in Escherichia coli isolates from pigs with diarrhea     

da Silva AS  da Silva Leite D 《Veterinary microbiology》2002,89(2-3):195-199

In this study, 98 Escherichia coli isolates from 42 diarrheic neonatal piglets were screened for the presence of cytolethal distending toxin coding gene by polymerase chain reaction (PCR). PCR yielded a single product which was specifically generated for E. coli cdt(+) control strain and not for other control strains. Twenty two (22.4%) of the isolates tested were cdtB positive, and 50% of the cdtB(+) isolates were also estII positive. The most prevalent pathotype was O32 cdtB(+) estII(+), which accounted for 59% of the cdtB positive strains. These results indicate an association between the presence of the cdtB gene and diarrhea, and support the need for further studies to determine the role of this toxin in diarrhea.  相似文献   

Morphological aspects of the capybara stomach (Hydrochaeris hydrochaeris): gross and microscopic structure     

Moraes PT  Pacheco MR  de Souza WM  da Silva RA  Neto PB  Barreto CS  Ribeiro AA 《Anatomia, histologia, embryologia》2002,31(6):362-366

The digestive system of the capybara has been investigated because of its coprofagia habits, important for their absorptive activity. These species present differences in terms of gastrointestinal morphological characters when compared with other rodents. Macroscopiclly, the stomach of the capybara is constituted of the following parts: cardiac, pyloric, body, fundic and gastric diverticulum. It presents two curvatures, one big and another small. Externally, the presence of gastric bands (tenias) is observed. With regards to the volumetric view, the gastric capacity varies from 850 to 2010 ml, with an average of 1498.57 ml. So, the stomach of this animal can be classified as a simple stomach, in the format of a curved sack and similar to an inverted letter 'J'. The gastric mucous membrane presents a surface filled by numerous tortuous gastric folds and longitudinally distributed along all its extension. The mucous tunic also possesses recesses located among the successive gastric folds, which were denoted as gastric parts with numerous openings described as gastric pits. In the cardiac part, a glandular epithelium with cardiac glands is noticed containing a lot of parietal and mucous neck cells. The fundic part, body and gastric diverticulum contain proper gastric glands with main, parietal and mucous neck cells. Finally, the pyloric part has pyloric glands with two cellular types, mucous neck and parietal cells.  相似文献   

Seroepidemiology of rinderpest in bovids in Sri Lanka using the enzyme linked immunosorbent assay (ELISA) technique     

Indira Silva  Ashoka Dangolla  John Allen 《Preventive veterinary medicine》1998,37(1-4):69-75

Approximately 0.2% (n=4397) of the bovids (cattle and buffalo) in Sri Lanka were sampled, from June 1992 using a multi-stage sampling procedure. Serum antibodies for the rinderpest virus were detected using the competitive enzyme-linked immunosorbent assay. The age, the agroclimatic zone, the management system practiced in the farms, and the vaccination history of the sampled bovids were studied as potential risk factors for being seropositive.

The prevalence of rinderpest antibodies in non-vaccinated bovids was 3.5% (n=4101). The prevalence was higher in the dry zone (9%; where the outbreak emerged in 1987), compared to bovids in the other zones (1%). Seropositive bovids over three years of age were approximately at fourfold higher chances of being seropositive compared to those that were ≤3 years old. The higher prevalence in older animals is probably due to exposure to the virus during the 1987 epidemic. Bovids from the dry zone (annual rainfall 20 to 35 inches) were at higher odds of being seropositive even after controlling for the possible effects of age, agroclimatic zone, management system and vaccination. The fact that 62% of bovids from the dry zone in this study were reared under extensive management system (free grazing) which allow unrestricted contact between animals, may be the reason for the above finding. A relatively poor response to vaccination observed in vaccinated bovids (seroprevalence=12%; n=296) could be attributed to difficulties in maintaining the vaccine at recommended temperatures in the field. This is the first island-wide study on seroprevalence of rinderpest in Sri Lanka.  相似文献