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Astrovirus species members of the Mamastrovirus genus (family Astroviridae) have been increasingly recognized as neuroinvasive pathogens in various mammals, including humans, mink, cattle, sheep, and pigs. While cases of astrovirus-associated encephalitis have been reported in North America, Europe, and Asia, their presence has never been documented in the Southern hemisphere. This paper describes a case of astrovirus-associated encephalitis in cattle in Uruguay that broadens the geographic distribution and genetic diversity of neuroinvasive astroviruses and provides phylogeographic evidence of viral introduction to the Americas from Europe. A 22-month-old Holstein steer from a farm in Colonia Department, Uruguay developed progressive neurological signs over a 3-days period before dying. Histopathological examination of the brain and proximal cervical spinal cord revealed disseminated, moderate to severe lymphocytic, histiocytic, and plasmacytic poliomeningoencephalomyelitis with neuronal necrosis. A Mamastrovirus strain in the CH13/NeuroS1 clade, that we called bovine astrovirus (BoAstV)-Neuro-Uy, was identified by reverse transcriptase PCR followed by nearly complete genome sequencing. Additionally, BoAstV was detected intralesionally in the brain by chromogenic RNA in situ hybridization within neuronal perikarya, axons and dendrites. Phylogenetic analysis of BoAstV-Neuro-Uy revealed a close relationship to neurotropic BoAstVs within the Virginia/Human-Mink-Ovine clade, which contains a growing cadre of neuroinvasive astroviruses. Analyzing the complete coding region of neuroinvasive BoAstVs sequences available in GenBank, we estimated an evolutionary rate of 4.27 × 10-4 (95% HPD 2.19–6.46 × 10-4) nucleotide substitutions/site/year. Phylogeographic analysis suggests that the common viral ancestor circulated in Europe between 1794–1940, and was introduced in Uruguay between 1849–1967, to later spread to North America and Japan. [ABSTRACT FROM AUTHOR]

Producer interest in using livestock guardian dogs (Canis lupus familiaris; LGDs) to protect domestic cattle (Bos taurus) is driven by expanding large carnivore predator populations and increased public concerns regarding lethal predator control in North America. However, few resources exist to guide livestock producers regarding the use of LGDs to protect cattle. This paper summarizes published information and personal ranch experiences regarding the use of LGDs to protect cattle, describes livestock-producer identified challenges to more widespread adoption of this method to deter predators, and provides guidelines for introducing pups to LGD-naïve cattle herds. I recommend more extensive research on the use of LGDs with cattle, increased development of programs to place LGDs with cattle herds, as well as educational efforts targeting resource managers, livestock producers, and the general public. [ABSTRACT FROM AUTHOR]

Pastureland maintenance is seen as a land-based measure to reduce dependency on feed concentrates and mitigate greenhouse gas (GHG) emissions from livestock production in the EU, while providing other ecosystems services. This paper assesses potential market-mediated impacts, including global Land Use Change (LUC) and GHG emissions, from increased subsidies to pasture-based livestock production in the EU. A tax recycling strategy (TRS) is simulated against a baseline up to 2030 under the shared socioeconomic pathway 2 (SSP2). This implies a budget-neutral increase in the level of pasture subsidies in individual Member States, as land subsidies for other cropping activities decrease. We employ the computable general equilibrium (CGE) model GTAP in its recursive-dynamic version, GTAP-RDEM, extended with the Multi-Regional Input-Output (MRIO) database FABIO to disaggregate agri-food sectors from 21 to 31. This approach allows considering price- and income-dependent feedbacks when assessing long-run changes in the global economy, improving the sectoral resolution relative to GTAP v10. The policy increases pastureland areas and cattle production in almost all EU Member States, whereas cropland and crop production decrease, causing significant changes across EU agri-food markets. Crop prices increase, leading to the reduced output of intensive animal production sectors, mainly pig and poultry. Cropland areas decrease and most EU countries increase imports of grain, oilseeds, and cakes, essentially soybean cake from Brazil and North America. While GHG emissions decrease in those EU countries where pasturelands expand mainly at the cost of croplands, GHG emissions increase in those countries where pastureland expansion comes with forest loss. As a result, net GHG emissions increase in the EU-27 in 2030 (+2.49 Mt CO 2 -eq). Emissions from LUC in major non-EU grain- and oilseed-exporting countries increase, e.g., by 102.52 Mt CO 2 -eq in Brazil and by 129.17 Mt CO 2 -eq in North America. The simulated policy shows that promoting extensive livestock per se does not meet the objectives of the Common Agricultural Policy and the EU Green Deal. The TRS should be complemented with policies to foster crop diversification and promote the use of domestic feed sources (e.g., legumes) to effectively ensure feed self-sufficiency and that extensive cattle production in the EU does not lead to deforestation in carbon-rich countries. [ABSTRACT FROM AUTHOR]

In this paper, we describe a novel approach to corporate involvement in on-farm assessment, driven by the desire to provide a service for dairy producers and to create a vehicle for engagement on issues of dairy cow welfare. This program provides producers with feedback on animal-based (including gait score, leg injuries, and lying time) and facility-based (including freestall design, bedding practices, feed bunk design and management, and stocking density) measures that can be used to better address their management goals. The aim of this paper is to describe variation in the prevalence of lameness and leg injuries, lying behavior, facility design, and management practices for high-producing cows on freestall dairy farms in 3 regions of North America: British Columbia (BC; n=42); California (CA; n=39); and the northeastern United States (NE-US; n=40). Prevalence of clinical lameness averaged (mean ± SD) 27.9±14.1% in BC, 30.8±15.5% in CA, and 54.8±16.7% in NE-US; prevalence of severe lameness averaged 7.1±5.4% in BC, 3.6±4.2% in CA, and 8.2±5.6% in NE-US. Overall prevalence of hock injuries was 42.3±26.2% in BC, 56.2±21.6% in CA, and 81.2±22.5% in NE-US; prevalence of severe injuries was 3.7±5.2% in BC, 1.8±3.1% in CA, 5.4±5.9% in NE-US. Prevalence of swollen knees was minimal in CA (0.3±0.6%) but high (23.1±16.3%) in NE-US (not scored in BC). Lying times were similar across regions (11.0±0.7h/d in BC, 10.4±0.8h/d in CA, 10.6±0.9h/d in NE-US), but individual lying times among cows assessed varied (4.2 to 19.5h/d, 3.7 to 17.5h/d, and 2.8 to 20.5h/d in BC, CA, and NE-US, respectively). These results showed considerable variation in lameness and leg injury prevalence as well as facility design and management among freestall farms in North America. Each of the 3 regions had farms with a very low prevalence of lameness and injuries, suggesting great opportunities for improvement on other farms within the region., (Copyright © 2012 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

Over a period of ~2 wk, 5 adult beef cows developed severe necrotizing skin lesions on the face and neck shortly after being moved to a field with a cover crop of Brassica spp. turnips. We describe here the clinical signs, hematology, and serum chemistry results, as well as gross and histopathologic findings, from this outbreak. We made a presumptive diagnosis of Brassica- associated liver disease (BALD) based on the similarities in the history and diagnostic findings observed with previously reported cases of BALD from elsewhere in the world. BALD has not been reported previously in cattle in North America, to our knowledge, despite the increasing usage of cover crops to improve soil conditions and provide forage for livestock. After the presumptive diagnosis of BALD was made, the cattle were removed from the turnip field and no additional cases were noted by the producer. BALD is well known in other parts of the world, and veterinarians and diagnosticians should be aware of this condition given that the usage of cover crops is likely to continue to increase. [ABSTRACT FROM AUTHOR]

Abstract: This paper reviews the effects of road transport on the welfare, carcass and meat quality of cattle, swine and poultry in North America (NA). The main effects of loading density, trailer microclimate, transport duration, animal size and condition, management factors including bedding, ventilation, handling, facilities, and vehicle design are summarized by species. The main effects listed above all have impacts on welfare (stress, health, injury, fatigue, dehydration, core body temperature, mortality and morbidity) and carcass and meat quality (shrink, bruising, pH, color defects and water losses) to varying degrees. It is clear that the effect of road transport is a multi-factorial problem where a combination of stressors rather than a single factor is responsible for the animal''s well-being and meat quality post transport. Animals least fit for transport suffer the greatest losses in terms of welfare and meat quality while market ready animals (in particular cattle and pigs) in good condition appear to have fewer issues. More research is needed to identify the factors or combination of factors with the greatest negative impacts on welfare and meat quality relative to the species, and their size, age and condition under extreme environmental conditions. Future research needs to focus on controlled scientific assessments, under NA conditions, of varying loading densities, trailer design, microclimate, and handling quality during the transport process. Achieving optimal animal well-being, carcass and meat quality will entirely depend on the quality of the animal transport process. [Copyright &y& Elsevier]

Bovine respiratory disease (BRD) has a complex pathogenesis and aetiology, being the costliest disease affecting the cattle industry in North America. In this study, we applied Nanopore‐based viral metagenomic sequencing to explore the nasal virome of cattle upon arrival at feedlot and related the findings to the development of BRD. Deep nasal swabs (DNS) from 310 cattle for which BRD outcomes were known (155 cattle developed BRD within 40 days and 155 remained healthy) were included. The most prevalent virus in on‐arrival samples was bovine coronavirus (BCV) (45.2%, 140/310), followed by bovine rhinitis virus B (BRBV) (21.9%, 68/310), enterovirus E (EVE) (19.6%, 60/310), bovine parainfluenza virus 3 (BPIV3) (10.3%, 32/310), ungulate tetraparvovirus 1 (UTPV1) (9.7%, 30/310) and influenza D virus (7.1%, 22/310). No relationship was found between BRD development and the number of viruses detected, the presence of any specific individual virus or combination of viruses. Bovine kobuvirus (BKV) was detected in 2.6% of animals (8/310), being the first report of this virus in Canada. Results of this study demonstrate the diversity of viruses in bovine DNS collected upon arrival at feedlot and highlights the need for further research into prediction of BRD development in the context of mixed infections. [ABSTRACT FROM AUTHOR]

Salvia reflexa (lance-leaf sage)-contaminated alfalfa hay was fed to ~500 mixed-breed beef cattle. Within hours of exposure, nearly half of the cattle developed lethargy, anorexia, depression, and recumbency, followed by bellowing, colic, and death. Even though the uneaten contaminated hay was removed the first day, nearly 100 animals died within the first 48 h. Three of these cattle were examined postmortem, and tissues and hay samples were collected for microscopic and chemical analysis. Several days later, a smaller number of the clinically poisoned cattle developed neurologic disease with aberrant behavior, aggression, icterus, blindness, exhaustion, and death. A total of 165 cattle were fatally poisoned. Poisoned cattle had swollen, dark, mottled livers that had a prominent nutmeg-like lobular pattern on cut section. Histologically, there was severe centrilobular-to-panlobular hepatic necrosis with marked hepatocellular swelling, degeneration, and necrosis. The surviving cattle developed liver disease characterized by altered serum biochemical analyses and microscopic hepatocellular degeneration and necrosis. In subsequent biopsies and analysis, these lesions resolved within 6–7 mo. After confirming toxicity of the hay in cattle, goats, and mice, followed by a mouse bioassay–guided chemical fractionation process, Salvia reflexa was identified as the contaminant in the hay responsible for the hepatotoxicity. S. reflexa has not been reported previously to cause fatal hepatotoxicity in livestock in North America, to our knowledge. [ABSTRACT FROM AUTHOR]

Prairie dogs (Cynomys spp.) have been eliminated from over 95% of their historic range in large part from direct eradication campaigns to reduce their purported competition with cattle for forage. Despite the longstanding importance of this issue to grassland management and conservation, the ecological interactions between cattle and prairie dogs have not been well examined. We address this issue through two complementary experiments to determine if cattle and prairie dogs form a mutualistic grazing association similar to that between prairie dogs and American bison. Our experimental results show that cattle preferentially graze along prairie dog colony edges and use their colony centers for resting, resembling the mutualistic relationship prairie dogs have with American bison. Our results also show that prairie dog colonies are not only an important component of the grassland mosaic for maintaining biodiversity, but also provide benefits to cattle, thereby challenging the long-standing view of prairie dogs as an undesirable pest species in grasslands. [ABSTRACT FROM AUTHOR]

In order to evaluate the expression of sire genetic evaluations obtained in North America for Chilean Black and White Cattle, genetic correlations were estimated for milk (MY), fat (FY) and protein (PY) yields, and for fat (F%) and protein (P%) contents between Chile, Canada and the US, from predicted transmitting abilities of common sires in two countries. Moreover, genetic correlations for the same traits were estimated between herd environmental categories formed according to MY levels, using bivariate analyses. Genetic correlation estimates for MY, FY, and PY between Chile-Canada (0.80, 0.61, and 0.70), and between Chile-US (0.79, 0.68, and 0.77), were lower than values obtained by simulation, assuming sire selection of the best 50%, and were also lower than the genetic correlations between Canada-USA, which were close to 1, suggesting a moderate genotype by country interaction. All genetic correlation estimates between countries for F% and P% were close to 1. No evidence of genotype-environment interaction was found for any trait between High and Low Chilean herd environmental categories based on MY, (genetic correlation estimates ≥0.96; not statistically different from 1). Results indicate that a single national dairy genetic improvement programme incorporating international evaluations could be implemented in southern Chile, rather than separate programmes for specific herd MY environments. Moderate genotype-environmental interaction between North American and Chilean environments was found for MY, FY, and PY. Results from across and within country analyses indicate that sire selection in North America for milk solids yield will produce relatively high correlated genetic responses for the southern Chile dairy production system characterized by grazing and a temperate climate. [ABSTRACT FROM AUTHOR]

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The origin of cattle on Chirikof Island, off the coast of Alaska, is not well documented. We assessed genetic differentiation of cattle isolated on Chirikof Island from several breeds commonly used for commercial production in North America including breeds popularly believed to have contributed to the Chirikof Island population. A set of 34 microsatellite loci was used to genotype Angus, Charolais, Hereford, Highland, Limousin, Red Angus, Salers, Shorthorn, Simmental, Tarentaise and Texas Longhorn cattle sampled from North America and the Chirikof Island population. Resulting FST statistics for these loci ranged from 0.06 to 0.22 and on average, 14% of total genetic variation was between breeds. Whether population structure was modelled as a bifurcating tree or genetic network, Chirikof Island cattle appeared to be unique and strongly differentiated relative to the other breeds that were sampled. Bayesian clustering for multiple-locus assignment to genetic groups indicated low levels of admixture in the Chirikof Island population. Thus, the Chirikof Island population may be a novel genetic resource of some importance for conservation and industry. [ABSTRACT FROM AUTHOR]