Genetic evaluation of growth in Barki sheep using random regression models

The objective of the current study was to estimate covariance components of growth at different ages from birth to yearling in Barki lambs. A total of 16,496 records for body weights at birth (W0), 3 (W3), 6 (W6), 9 (W9), and 12 (12) months of age for Barki lambs were available. Two statistical approaches were used; multi-trait (MT) and random regression (RR) animal models assuming two random effects only, additive genetic effect (σ²_a) and permanent environmental effect (σ²_pe) of the animal. Regarding the RR model, Legendre polynomials (LP) of different orders for the random parts were compared in order to evaluate the most appropriate model. Bayesian information and Akaike information criteria suggested that the optimal RR model included the third order for fixed effect of lamb age and σ²_pe, and fourth order of LP for σ²_a (LP₃₄₃). Estimates of direct heritability (h²_a) from LP₃₄₃ showed an ascending pattern, as it was 0.06 ± 0.03 for birth weight and reached to the peak at 9 months (0.42 ± 0.02). Thereafter, it declined again at the end of trajectory (12 months of age; 0.27 ± 0.03). The MT model showed a fluctuated pattern and lower estimates of h²_a (0.19 ± 0.03, 0.11 ± 0.02, 0.12 ± 0.02, 0.11 ± 0.03, and 0.16 ± 0.04 for W0, W3, W6, W9, and W12, respectively). Considerably, similar ascending patterns of the ratio of σ²_pe to phenotypic variance were reported from both RR (from 3 to 50%) and MT models (from 5 to 20%). Of interest, the RR model showed higher predicting ability of the breeding values compared with the MT model, which is an indicator for the suitability of RR models for analyzing the consecutive growth traits in sheep. Results suggested that the Barki sheep has a potential for genetic selection based on weight at different ages with selection likely to be more efficient at 9 months of age.

     

Diagnosis and Surgical Management of Pythiosis in Draft Horses: Report of 33 Cases in Egypt

A total of 33 draft horses suffering from cutaneous pythiosis were referred to Mansoura Veterinary Teaching Hospital, Egypt, between October 2008 and January 2011. The animals presented ulcerative, granulomatous lesions located at the ventral aspect of the thorax (n = 10), abdomen (n = 14), forelimbs (n = 5), hind limbs (n = 2), and presternal region (n = 1) and at withers (n=1). The animals suffered from ulcerations composed of whitish yellow tissue having numerous draining tracts that discharge serosanguineous or bloody exudates. Initial diagnosis was based on location, gross lesion, and presence of kunkers. Histopathological evaluation revealed an eosinophilic granulomatous reaction associated with intralesional hyphae characteristic of Pythium insidiosum visualized by Gomori methenamine silver stain. The outcome of surgical excision revealed complete cure in 24 cases. Euthanasia was indicated in 9 cases.     

Comparison of the Bain system and Uniflow universal anaesthetic breathing systems in spontaneously breathing young pigs

OBJECTIVE: To compare minimum fresh gas flow (V(min)) requirements and respiratory resistance in the Uniflow and Bain anaesthetic breathing systems used in the Mapleson D mode. Animals Seven pigs, aged 8-12 weeks, anaesthetized for ophthalmic surgery. MATERIALS AND METHODS: Anaesthesia was maintained with halothane delivered in oxygen using a (Mapleson D) Bain breathing system. The V(min) that prevented re-breathing was found, and peak inspiratory (PIP) and peak expiratory (PEP) pressures measured. The fresh gas flow (V(f)) was then increased to V(min) + 50%, then V(min) + 100%, and respiratory pressures re-measured. A heat and moisture exchanger (HME) was inserted at the endotracheal tube and the procedure repeated. The breathing system was then exchanged for a Uniflow and the protocol repeated. After final disconnection from the breathing system, the animals' peak inspiratory and expiratory flows, tidal, and minute volumes (Vm) were measured over five respiratory cycles. RESULTS: The V(min) (L minute(-1); mL kg(-1) minute(-1)) required to prevent rebreathing in the Uniflow system [8.1(mean) +/-1.7 (SD); 332 +/- 94] was significantly greater than the Bain system (6.5 +/- 1.1; 256 +/- 64). At V(min), PEP with the Uniflow (3.5 +/- 0.1 cm H(2)O) was significantly higher than the Bain system (2 +/- 0.7 cm H(2)O), but PIP values did not differ (Uniflow -0.6 +/- 2.1 cm H(2)O; Bain system -0.2 +/- 0.6 cm H(2)O). With both systems, PEP increased significantly (p < 0.001) with each increase in V(f): Uniflow system 4.2 +/- 0.4 (V(min) + 50%) and 5.5 +/- 0.5 cm H(2)O (V(min) + 100%); Bain system 2.8 +/- 0.7 (V(min) + 50%) and 3.5 +/- 0.7 cm H(2)O (V(min) + 100%). Insertion of the HME did not alter pressures. The mean tidal volume was 6.4 +/- 1.6 mL kg(-1); mean Vm was 184.9 +/- 69.8 mL kg(-1) and mean respiratory rate was 28 +/- 5 breaths minute(-1). In one pig breathing with the Uniflow system PEP rose sharply; respiratory and heart rates increased, and ventricular dysrhythmias occurred. When the system was changed and V(f) reduced, physiological variables became normal. CONCLUSION: The study discredited the hypothesis that the two breathing systems behave similarly. Values for V(min) and PEP were higher with the Uniflow system. Increasing V(f) increased PEP with both systems. Insertion of an HME did not affect respiratory pressures. CLINICAL RELEVANCE: The Uniflow used in Mapleson D mode is not suitable for anaesthesia in young spontaneously breathing pigs.     

HIV vaccine research: the way forward

The need to broaden research directed at answering fundamental questions in HIV vaccine discovery through laboratory, nonhuman primate (NHP), and clinical research has recently been emphasized. In addition, the importance of attracting and retaining young researchers, developing better NHP models, and more closely linking NHP and clinical research is being stressed. In an era of a level budget for biomedical research at the U.S. National Institutes of Health (NIH), HIV/AIDS vaccine research efforts will need to be carefully prioritized such that resources to energize HIV vaccine discovery can be identified. This article summarizes progress and challenges in HIV vaccine research, the priorities arising from a recent summit at NIAID, and the actions needed, some already under way, to address those priorities.     

Experimental challenge models for Johne's disease: a review and proposed international guidelines

An international committee of Johne's disease (JD) researchers was convened to develop guidelines for JD challenge studies in multiple animal species. The intent was to develop and propose international standard guidelines for models based on animal species that would gain acceptance worldwide. Parameters essential for the development of long-term and short-term infection models were outlined and harmonized to provide a "best fit" JD challenge model for cattle, goats, sheep, cervids, and mice. These models will be useful to study host-pathogen interactions, host immunity at the local and systemic level, and for evaluating vaccine candidates and therapeutics. The consensus guidelines herein list by animal species strains of Mycobacterium avium subsp. paratuberculosis used, challenge dose, dose frequency, age of challenge, route of challenge, preparation of inoculum, experimental animal selection, quality control, minimal experimental endpoints and other parameters.     

Forest structure and woody plant species composition after a wildfire in beech forests in the north of Iran

Beech (Fagus orientalis Lipsky) forest covers about 565,000 ha of land in Guilan province, north of Iran and forms a major carbon pool. It is an important economic, soil protection and recreation resource. We studied long-term effects of fire on the structure and composition 37 years after fire occurrence in these forests. To do this research, we selected 85 ha burned and 85 ha unburned beech forests). The results indicated that the fire had not changed the overall uneven-aged structure, but it changed forest composition from pure stands to mixed stands that now include species such as Carpinus betulus, Acer cappadocicum and Alnus subcordata. The density of trees and regeneration was significantly increased, while the density of shrubs significantly decreased. The main reasons for increased tree regeneration were attributed to (1) reduction of litter depth, and (2) increase in available light from opening of the canopy and reduction in shrub competition. It is apparent that the forest is on a path to return to its natural state before the fire after 37 years.     

Effect of temperature on the expression of cytoplasmic male sterility in cultivated barley (Hordeum vulgare L.)

Twenty‐three cytoplasmic male sterile BC₁F₁ barley lines were exposed to varying temperature treatments (TTs) to examine the effect of temperature on the stability of the expression of cytoplasmic male sterility (cms). The TTs used for this test were: (i) controlled low‐temperature treatment of 16°C (CL), (ii) controlled medium‐temperature treatment of 21–24/16–17°C day/night (CM) and (iii) ambient glasshouse‐temperature treatment of 24–41/16–17°C day/night (AG). The expression of cms was found to be variably influenced by temperature and by the genetic background of the cms recipient lines. Ten cms lines exhibited consistently complete male sterility over TTs, indicating that these lines are completely under cms genes control, while other lines showed partial revision to fertility across different TTs with profound influence of warm temperatures (CM and AG) in breaking down the cms in barley.     

Role of sponge gourd in apical leaf curl disease of potato in Northern India

Potato (Solanum tuberosum) is one of the important vegetable crops in the world and its production is seriously affected by apical leaf curl disease in northern India. This paper reveals the role of cucurbits in maintaining Tomato leaf curl New Delhi virus (ToLCNDV) and Potato apical leaf curl (PALCD) disease in that region. The affected plants showed severe leaf curling and stunted growth. The begomovirus causing leaf curling and mosaic disease in cucurbits could be easily transmitted by the whitefly to potato crops and develop apical leaf curl disease in northern India. The movement of the virus by whiteflies from cucurbits to potato and tomato is possible because of overlapping of planting and harvesting dates of these crops. The causal virus was identified as a begomovirus on the basis of whitefly transmission, PCR, dot blot hybridization, cloning and sequencing of the coat protein gene. The comparison of full length coat protein gene sequence homology revealed that 90% identity with the coat protein gene of ToLCNDV- [Luffa] isolate and the phylogenetic tree derived from these sequences with other selected begomoviruses formed a close cluster with ToLCNDV isolates. The findings proved that the virus causing disease in cucurbits could easily move to tomato and potato and cause leaf curl disease naturally. This is the first observation on the role of sponge gourd for maintenance of ToLCNDV and serving as a host for PALCD in northern India. The findings indicate that the causal organism is a strain of ToLCNDV.