Long-Term Cover Cropping Suppresses Foliar and Fruit Disease in Processing Tomatoes.

While links between soil and plant health are implied, there are few opportunities to empirically evaluate this due to inherent differences among sites. An exception is a long-term experiment established in 2007 (repeated in 2008) in Ridgetown, ON, where improved soil health scores and changes in soil microbial communities were observed in the medium-term with annual cover crops (CC). This led us to hypothesize that CC-induced changes in soil health might affect bacterial spot (Xanthomonas hordorum pv. gardneri) and anthracnose (Colletotrichum coccodes) development in processing tomato. Five CC treatments (no CC control, winter cereal rye, oat, radish, and mix of radish + rye) planted after winter wheat harvest were evaluated in 2019 and 2020 (CC grown nine times over 12 years). Fruit yields and net revenue were similar or greater with CC than without. In 2019, there was greater defoliation (area under the disease progress stairs = 4,370 ± 204), percent red fruit (71.0% ± 5.38), and rots (1.91% ± 0.5) in no CC than with radish (3,410, 39.1%, and 0.62%, respectively, P ≤ 0.0366), indicating earlier fruit maturity in no CC plots. Similarly, no CC had a greater incidence of red fruits with anthracnose (25.8% ± 2.89) compared with all CCs but rye (7.4 to 12.1% ± 2.89; P = 0.0029). Environmental conditions in 2020 were less favourable for disease development. Defoliation was not affected by CC treatment (P = 0.1254), and anthracnose incidence was low (≥90.3 ± 1.22% healthy fruit), which may have limited the ability to detect treatment effects (P = 0.2922). Long-term cover crops have the potential to produce greater or equivalent tomato yield with decreased defoliation and anthracnose fruit rot.

Economic and environmental nitrate leaching consequences of 4R nitrogen management practices including use of inhibitors for corn production in Ontario.

Nitrate (NO3-) leaching has negative human and environmental health consequences that can be attributed to and mitigated by agricultural decision making. The purpose of this study is to examine the economic and environmental nitrogen (N) leaching reduction from 4R (Right Rate, Right Source, Right Time, Right Placement) agricultural management practices, including application methods, timing and rates, and the use of nitrification and urease inhibitors, for Ontario corn production. This study employed an integrated biophysical and economic GIS-based simulation model considering corn yields, prices, and production costs, and environmental losses, under historical weather scenarios, with NO3- leaching constraints. Reducing N application from historical to model optimized agronomic rates sharply lowered corn NO3- leaching from 75.3 to 24.9 kt N per year. Increasing model restrictions on corn NO3- leaching increased the use of broadcast and sidedress application methods compared to injection and lower overall production. They also increased the use of nitrification and urease inhibitors, which increased N use efficiency, because they allowed lower leaching from corn production, for a price. Leaching decreases from restrictions trade-off with ammonia (NH3) volatilization increases, but there was no trade-off with nitrous oxide (N2O) emissions. This highlighted the importance of considering net N losses and production trade-offs by policy decision-makers when developing N loss reduction strategies.

COVID-19 and the agri-food system in the United States and Canada.

Agri-food supply chains in North America have become remarkably efficient, supplying an unprecedented variety of items at the lowest possible cost. However, the initial stages of the COVID-19 pandemic and the near-total temporary loss of the foodservice distribution channel, exposed a vulnerability that many found surprising. Instead of continued shortages, however, the agri-food sector has since moved back to near normal conditions with prices and production levels similar to those typically observed in years prior to the pandemic. Ironically, the specialization in most food supply chains designed for "just-in-time" delivery to specific customers with no reserve capacity, which led to the initial disruptions, may have also been responsible for its rapid rebound. A common theme in assessing the impacts across the six commodities examined is the growing importance of understanding the whole supply chain. Over the longer term, a continuation of the pandemic could push the supply chain toward greater consolidation of firms and diversification of products given the increasing option value of maintaining flexibility. Other structural changes will be felt through input markets, most notably labour, as the trend toward greater automation will continue to accelerate as a response to meeting concerns about a consistent supply of healthy and productive workers. The economic fall out from the pandemic may lead to greater concentration in the sector as some firms are not able to survive the downturn and changes in consumer food buying behaviour, including movement toward online shopping and enhanced demand for attributes associated with resiliency, such as local. On the other hand, online shopping may provide opportunities for small producers and processors to shorten supply chains and reach customers directly. In the long term, COVID-19 impacts on global commerce and developing country production are more uncertain and could influence poverty reduction. While COVID-19's impacts on North American agriculture should have minimal effect on the Sustainable Development Goals (SDGs) through food prices, the ongoing global trends in trade and agribusiness accelerated by the pandemic are relevant for achievement of the SDGs.

Assessing the Value of Antibiotics on Farms: Modeling the Impact of Antibiotics and Vaccines for Managing Lawsonia intracellularis in Hog Production.

Increasing awareness of antibiotic resistance has correspondingly increased efforts to identify and reduce the causal behaviors that led to this severe public health threat. The consequences of these efforts are regulatory and market pressures limiting antibiotic use by livestock farmers which may lead to significant financial and welfare challenges on the farm, even if antibiotics can be substituted by vaccines. The purpose of this study is to measure the relative cost-effectiveness of antibiotics vs. vaccines for controlling L. intracellularis on a Canadian farrow-to-finish pig farm. This is done by modeling the production and economic impact of different antibiotics and vaccines available for managing this disease, listed in the Canadian Compendium of Veterinary Products. The economic impacts (in Canadian dollars) of the disease are estimated and the net benefits of alternative prevention and treatment options are compared to determine the relative cost-effectiveness of each strategy. Of the 12 options analyzed, four were preventative (antibiotic and vaccine) and eight were antibiotic treatments. Prophylactic chlortetracycline (an antibiotic) is the most cost-effective option for managing L. intracellularis, while Porcilis Ileitis (a vaccine) is the least cost-effective strategy. This result remains robust considering sensitivity analysis of the production parameters, which indicates that preventative antibiotics are more cost-effective than vaccines. This implies that banning preventative antibiotic treatments harms the bottom line of farmers under current market conditions.

An economic evaluation of intervention strategies for Porcine Epidemic Diarrhea (PED).

The economic losses of Porcine Epidemic Diarrhea (PED) and the net benefits of strategies to control the virus are calculated for individual farrow-to-finish herds. A production simulation model that estimates the number of pigs by population cohorts on a weekly basis for a farrow-to-finish farm depending on production parameters is simulated under normal operating conditions and then with an outbreak of PED. The estimated annual costs of a PED outbreak with the closure of the breeding herd as the only intervention is approximately $300,000 for a 700-sow farrow-to-finishing herd. The net returns per sow (hog) fall from $255 ($11.54) to a loss of $174 ($10.68). These losses can be significantly reduced with any of the 16 intervention strategies considered in this study. The most profitable strategy involving front loading of gilts with average feedback of infected material to improve herd immunity, intensive biosecurity protocols and no vaccination costs $27,000 to implement but reduces losses by 10 times this amount. Even the implementation of the least comprehensive strategy, which involves back-loading gilts after the herd reopens and an average feedback practice at a cost of $1000 reduces the losses caused by a PED outbreak by $130,000. Front-loading gilts in combination with herd closure is more cost-effective than back-loading. Despite the extra spending on intensive biosecurity protocols, the overall loss reductions achieved by the intensive biosecurity effort can be significant. Vaccination is the least cost-effective of the intervention practices considered. Even with significant increases in cost or effectiveness in the practices, intervention is justified across all strategies. The spreadsheet model of a farrow-finish hog farm developed in this study can be used to examine changes to the production parameters or to consider other swine disease outbreaks.

Evaluating critical factors to the economic feasibility of semi-intensive pig rearing in western Kenya.

The purpose of this research is to assess how season, ADG, opportunity costs of farm-grown feeds, pig weight, and butcher price variation impact the economic potential of semi-intensive pig rearing. We developed a unique algorithm that emulates least-cost pig feeding and used it to assess the impact of the aforementioned factors on farmers' maximum revenue and profit potential when pigs are sold to local butchers in western Kenya. When considered as independent factors influencing feed costs to grow a pig to a market weight of 30 kg, variation in ADG, opportunity cost of feed, and weaning season resulted in feed cost differences of up to 982, 947, and 379 Kenyan shillings (KES), respectively. The variation in revenues attributable to butcher or butcher negotiation and seasonal variance of butcher prices for a 30 kg pig was 744 and 225 KES, respectively. Feed items most commonly chosen for least-cost feed rations were small dried fish, cooked ground maize, whole maize, millet, cassava foliage, sweet potato vines, bone meal, avocado, and mango. Smallholder farmers who can feed pigs to reach higher ADG, have lower opportunity costs of feeds and/or who effectively bargain with butchers can benefit from semi-intensive pig rearing. Farmers without access to at least some zero-cost feeds and farmers with opportunity costs of feeds exceeding 50 % of the market price will not earn positive returns from semi-intensive pig rearing.

Estimate of the direct production losses in Canadian dairy herds with subclinical Mycobacterium avium subspecies paratuberculosis infection.

The objective of this study was to estimate the annual losses from Mycobacterium avium subspecies paratuberculosis (MAP) for an average, MAP-seropositive, Canadian dairy herd. A partial-budget simulation model was developed with 4 components of direct production losses (decreased milk production, premature voluntary culling, mortality, and reproductive losses). Input values were obtained primarily from a national seroprevalence survey of 373 Canadian dairy farms in 8 of 10 provinces. The model took into account the variability and uncertainty of the required input values; consequently, it produced probability distributions of the estimated losses. For an average Canadian dairy herd with 12.7% of 61 cows seropositive for MAP, the mean loss was $2992 (95% C.I., $143 to $9741) annually, or $49 per cow per year. Additional culling, decreased milk production, mortality, and reproductive losses accounted for 46%, 9%, 16%, and 29% of the losses, respectively. Canadian dairy producers should use best management practices to reduce these substantial annual losses.

Carbon banks: an efficient means to exchange sequestered carbon.

Carbon sequestration is one of the options that can be used to reduce atmospheric carbon, but its use in an offset market is complicated by the temporary nature of sequestered carbon and the risks associated with carbon release and price. In this paper a carbon bank is proposed to handle these problems. The bank is both an aggregator and a risk bearer. Sink generators deposit their credits with the bank and are paid for maintaining their "savings" with the bank. The carbon bank is also the source where large-scale emitters can come and buy either a temporary or permanent credit and pay the bank in return for the credit and services provided. The advantages of the bank over alternative institutional designs include lower transaction costs, flexible carbon credits and price, and lower risk to risk-averse parties. The carbon bank could be an effective means to deal with many of the unresolved issues within the forthcoming Canadian offset system.

Management factors related to seroprevalences to bovine viral-diarrhoea virus, bovine-leukosis virus, Mycobacterium avium subspecies paratuberculosis, and Neospora caninum in dairy herds in the Canadian Maritimes.

Bovine viral-diarrhoea (BVD), enzootic bovine leukosis (EBL), Johne's disease (JD), and neosporosis lower on-farm productivity, reduce export competitiveness, and increase consumer concerns regarding safety. Our purpose was to examine the relationship between 27 control practices and the estimated true seroprevalences for these four diseases for 2604 cattle in 90 dairy herds in the Maritimes provinces of Canada. Overall, 37.8, 20.4, 3.4, and 19.2% of all sampled cattle were truly exposed to the agents of BVD, EBL, JD, and neosporosis, respectively. The median within-herd true prevalences were 0, 9.3, 0, and 12.3%, respectively. Factor analysis reduced the 27 control practices to two highly correlated factors. Tobit-regression analyses determined that vaccination practices were associated with reduced prevalence of exposure for Bovine viral-diarrhoea and EBL. Also, farms that tended to purchase their dairy animals were associated with higher seroprevalence for Johnes' disease. Neither of these two factors was associated with the seroprevalence of Neospora caninum infection. The few routine biosecurity measures that were investigated in this study were generally not related to the seroprevalences of these farms.

Direct production losses and treatment costs from bovine viral diarrhoea virus, bovine leukosis virus, Mycobacterium avium subspecies paratuberculosis, and Neospora caninum.

Our purpose was to determine direct production losses (milk loss, premature voluntary culling and reduced slaughter value, mortaliy loss, and abortion and reproductive loss) and treatmetn costs (veterinary services, medication cost, and extra farm labour cost) due to four infectious diseases in the maritime provinces of Canada: bovine viral diarrhoea (BVD), enzootic bovine leukosis (EBL), Johne's Disease (JD), and neosporosis. We used a partial-budget model, and incorporated risk and sensitivity analyses to identify the effects of uncertainty on costs. Total annual costs for an average, infected, 50 cow herd were: JD$ 2472; BVD$ 2421; neosporosis $ 2304; EBL$ 806. The stochastic nature of the proportion of infected herds and prevalence of infection within a herd were used to estimate probability distributions for these ex post costs. For all diseases, these distributions were right skewed. A sensitivity analysis showed the largest effect on costs was due to milk yield effects. For example, changing milk production loss from 0 to 5% for BVD increased the costs for the disease by 266%.