Comparing silvopastoral systems and prospects in eight regions of the world

Silvopasture systems combine trees, forage, and livestock in a variety of different species and management regimes, depending on the biophysical, economic, cultural, and market factors in a region. We describe and compare actual farm practices and current research trials of silvopastoral systems in eight regions within seven countries of the world: Misiones and Corrientes provinces, Argentina; La Pampa province, Argentina; northwestern Minas Gerais, Brazil; the Aysén region of Patagonia, Chile; the North Island of New Zealand; the Southeast United States; Paraguay; and Uruguay. Some countries use native trees and existing forests; some use plantations, particularly of exotic species. Natural forest silvopasture systems generally add livestock in extensive systems, to capture the benefits of shade, forage, and income diversification without much added inputs. Plantation forest systems are more purposive and intensive, with more focus on joint production and profits, for small owners, large ranches, and timber companies. Trends suggest that more active management of both natural and planted silvopastoral systems will be required to enhance joint production of timber and livestock, achieve income diversification and reduce financial risk, make more profit, improve environmental benefits, and realize more resilience to adapt to climate change.     

Comparative effects of the herbicide dinitro-o-cresol on mitochondrial bioenergetics

The herbicide dinitro-o-cresol (DNOC) was evaluated for its effects on bioenergetic activities of potato tuber mitochondria to elucidate its mechanism of action and to compare its toxicological properties with those of the chemically related uncoupler dinitrophenol (DNP). DNOC acts as a typical uncoupler, similarly to the classical uncouplers DNP and carbonylcyanide p-trifluoromethoxyphenyl-hydrazone (FCCP). Low concentrations of DNOC (<100 μM ) maximally stimulate succinate-supported respiration of plant mitochondria, with simultaneous collapse of trans-membrane electrical potential, more efficiently than DNP. The herbicide makes the plant mitochondrial membrane more permeable to protons, acting as a protonophore even in non-energized mitochondria. High concentrations of DNOC (>100 μM ) act also more efficiently than DNP simultaneously as a protonophore and inhibitor of respiration, especially when respiration is supported by substrates that are transported to the matrix. The efficiency of DNOC is decreased with increase of mitochondrial protein, BSA and exogenous orthophosphate. Although similar effects were observed for animal and plant mitochondria, rat-liver mitochondrial respiration was more sensitive to DNOC than plant mitochondria. Furthermore, in the presence of DNOC, liver mitochondria exhibited a higher state 3 respiratory coupling level than potato tuber mitochondria, as a result of a considerable stimulation (60%) of state 3 respiration. In conclusion, DNOC is a more potent mitochondrial uncoupler and respiratory chain inhibitor than DNP, although their chemical structures are very similar. Apparently, the additional methyl group of DNOC increases its efficiency as an uncoupler and as an inhibitor, as compared to DNP. Plant mitochondria were shown to be as useful as animal mitochondria in evaluating the toxicity of these xenobiotics. © 1998 Society of Chemical Industry.     

Distinctive histopathologic features of canine optic nerve hypoplasia and aplasia: a retrospective review of 13 cases

Canine optic nerve hypoplasia (ONH) and aplasia (ONA) are significant neuro-ophthalmologic disorders that have been reported in several species. The purpose of this study was to describe the distinctive histopathologic features of ONH and ONA in canine patients identified from a collection of 20 000 ocular submissions at the comparative ocular pathology laboratory of Wisconsin from 1989 to 2006. The following information about ONH and ONA cases was collected: signalment, and clinical and gross findings, including unilateral vs. bilateral involvement. Microscopic evaluation was performed, with attention to optic nerve malformation, retinal ganglion cell (RGC) and nerve fiber layer (NFL) loss, and retinal disorganization. The distribution of retinal vasculature was recorded and a search for unusual findings of ONH and ONA was performed. Information and histologic documentation was available for 13 cases. Eight cases of ONH and five cases of ONA were identified. The average group age was 20.2 months and 16.1 months, respectively. The most common breed was the Shih Tzu (3/13). ONH usually presented bilaterally (7/8); all ONA cases presented as a unilateral disease (5/5). The morphologic findings in the optic nerve (ON) in ONH included variable degrees of ON hypoplasia and gliosis, as well as ectopic vestigial ON remnants within orbital nerves and connective tissues. The NFL was detected in the majority of the ONH cases; however, RGCs were rare or absent. Mild retinal disorganization was seen occasionally. Most cases of ONH were associated with regional peripheral retinal blood vessel extension into the vitreous, leaving the peripheral retina avascular. In ONA cases the retinal blood vessels, NFL and RGCs were totally absent and retinal disorganization was severe. Distinctive microscopic features encountered in ONA included anterior segment dysgenesis in some cases. The retina in these cases was stretched across the posterior lens capsule, never making contact with the posterior pole of the globe. The current study reviews the human and veterinary literature pertaining to ONH and ONA, compares ONH and ONA in dogs, and presents related ophthalmic histopathologic findings that have not been reported previously.     

Disseminated panniculitis in a bottlenose dolphin (Tursiops truncatus) due to Mycobacterium chelonae infection

A 14-year-old female bottlenose dolphin was diagnosed with mycobacterial panniculitis based on punch biopsy specimens. The necropsy revealed numerous pyogranulomas in the blubber, as well as marked acute multifocal necrosuppurative pneumonia and lymphadenitis. In addition, the animal had marked scoliosis, which had first been noted clinically in the dolphin at about 1 mo of age. The animal had been treated with low-dose dexamethasone for approximately the last 19 mo to reduce perceived discomfort from spondyloarthritis and with the progestational agent altrogenest for approximately 8 yr to prevent pregnancy. Acid-fast positive bacilli were detected in the dermis but not in lung or lymph nodes. Mycobacterium chelonae was isolated from pooled skin, lung, and peripheral lymph-node tissue. Mycobacterial infection may be considered as a differential diagnosis in bottlenose dolphins with generalized cutaneous inflammation, particularly if chronic steroid and progesterone treatments were administered, both of which may have an immunomodulatory effect.     

Systemic Proteoglycan Deposition Is Not a Characteristic of Equine Degenerative Suspensory Ligament Desmitis (DSLD)

Recently Degenerative Suspensory Ligament Desmitis (DSLD) has been proposed to be a disease characterized by systemic deposition of proteoglycan (PG) in connective tissues. To investigate this hypothesis, 6 clinically affected Peruvian Paso horses were compared to 2 unaffected quarterhorses and one unaffected standardbred. Histological sections of limb ligaments and tendons, nuchal ligaments, aortas, hearts, eyes, visceral organs and brains from both groups were stained with H&E as well as special stains for PG. Safranin-O stained sections were found to be optimal for elucidating the presence of PG. Although lesions characteristic of DSLD were present in suspensory ligaments of each clinically affected horse, including foci of chondroid metaplasia with abundant PG, a similar but less pronounced pattern of PG deposition was present in control horses. In contrast to findings of the previous study, PG deposition was not unique to DSLD horses, and PG deposition in aortas and nuchal ligaments of some control horses exceeded levels of PG present in similar tissue of DSLD horses. Furthermore, the “vascular lesion” described in the media of arteries as cellular separation and intercellular amorphous matrix deposition was within the spectrum of changes recognized in both affected and unaffected horses. We found no evidence that DSLD is a systemic PG deposition disease.     

ULTRASONOGRAPHIC DIAGNOSIS OF OVINE CYSTIC ECHINOCOCCOSIS

The sanitary and economic impact of cystic echinococcosis is serious in those countries where it becomes endemic. Ultrasonography is one technique that may be used to diagnose this disease in endemic areas. In parasitized sheep, hydatid cysts appear sonographically as a round hypoechoic structure. Twenty two sheep destined for slaughter were studied sonographically and imaging findings compared to post-mortem findings. Three sheep with hydatid cysts were identified. Eighty additional sheep not destined for slaughter were also studied. Echinococcus granulosus cysts were detected in three animals. Forty sheep from a non-endemic area had no hepatic cysts. The in vivo sonographic study of sheep provides a useful screening tool for echinococcosis.     

Eucalyptus benthamii Maiden et Cambage growth and wood density in integrated crop-livestock systems

Integrating trees in agricultural landscapes is a promising option to sustainably provide goods for society while increasing biodiversity, securing animal welfare, and generating profits for stakeholders. The choice of the species and knowing how timber quality is affected when trees are integrated to crop and/or livestock enterprises can provide additional insights into the usefulness of timber after harvest, and wood density is one of the most important properties in this regard. The present study aimed to evaluate how Eucalyptus benthamii growth and wood density are affected in integrated crop-livestock systems when compared to monoculture forestry 74 months after planting in subtropical environments. The integrated systems were in an alley cropping design where crop and/or grazed pasture were temporally rotated in between tree lines (14?×?2 m trees spacing), and those systems were compared to monoculture forestry (3?×?2 m spacing). Tree trunks (n?=?60) were sampled in five diameter classes of each treatment by cutting disks in six positions of the trunk (0.1 m, 1.30 m, 25%, 50%, 75% and 90% of the total height) (n?=?360). Trees growing in integrated systems increased trunk diameter at breast height by 24.7%, increased wood fiber production per tree by 17.9%, and produced wood 9.0% less dense than in the monoculture forestry system. Monoculture forestry increased tree height, and there was no difference of trunk volume among the production systems. The results suggest that integrated systems can produce timber with lower wood density, but faster individual tree growth than in forestry monocultures. Such a system can promote sustainable intensification of agricultural production, and enhance provision of complementary ecosystem services.

     

Emergence of fowl aviadenovirus C-4 in a backyard chicken flock in California

Fowl aviadenovirus (FAdV) species D and E are associated with inclusion body hepatitis (IBH); species C, serotype 4 (hereafter, FAdV4) is associated with hepatitis–hydropericardium syndrome (HHS) in young chickens. Outbreaks of HHS have led to significant losses in the poultry industry in several countries, predominantly in China. In April 2020, FAdV4 was detected in a remote backyard flock in California. In a mixed flock of chickens of various breeds and ages (6 mo to 2 y old), 7 of 30 were found dead within a week without premonitory signs. One additional bird died after the flock was relocated to fresh pasture, bringing the total mortality to 8 of 30 (27%). Postmortem examination of 3 birds revealed good body condition scores and active laying. One chicken had subtle hemorrhages throughout the liver, and the other 2 had diffusely dark mahogany livers. On histopathology, 2 chickens had hepatic necrosis with hepatocytes containing large, mostly basophilic, intranuclear inclusion bodies, identified by electron microscopy as 82.2-nm diameter adenoviral particles. Virus isolation and genomic sequencing performed on a liver sample revealed strains with 99.9% homology to FAdV4 isolates reported from China. To our knowledge, FAdV4 has not been reported in the United States to date. Furthermore, the chickens affected here were all adults and exhibited a variation of serotype 4 disease in which IBH was present but not hydropericardium.