This year has been one of uncertainty for U.S. pork producers with the supply chain disruptions following the COVID-19 pandemic. Many producers have found themselves implementing new production practices and feeding new rations to optimize growth to the dynamic market conditions.
Some producers are not only slowing pigs down for a period of time, but they may also be "speeding other pigs up" to hit a market window. Pigs are no longer finishing in the standard timeframe and space has been a constraint for many producers. Some growers are overstocking for the first time or to new levels and some growers are using new facilities.
One of the outcomes of these alternate practices and dietary strategies has been a higher incidence of vices in finishing pigs. Vices include conditions like tail biting, ear biting or necrosis, flank lesions/nudging and/or vulva biting. Unfortunately, exactly when vices will occur in a population of animals is not always predictable and it can be a combination of factors that "push pigs over the edge" and increase their stress level enough to cause it to start.
As you are making the difficult decisions to implement new practices on your farm work with your veterinarian, nutritionist and industry production experts to understand the risk that vices may occur and have a plan in place to respond quickly if they do.
The most obvious change that is being utilized is feeding either a very low-energy or high-fiber ration to slow growth in pigs. Both of these factors in and of themselves can cause vices, however the nutritionist will keep the amino acid profile and salt concentration in check to minimize the likelihood of vices occurring. As you consider utilizing higher levels of some ingredients, alternate ingredients in your rations or pulling mycotoxin binders to save cost, consider the number of mycotoxins that may be present in your final diet as these are a risk factor to vice behavior.
Simply changing the diet may not be enough to initiate vice behavior and resource availability in pens is another critical component to consider. Pigs form a social hierarchy or structure in their pen that makes the ability to get to feed, water and a dry (draft-free) laying space more difficult for some pigs versus others. Inadequate feeder space, feed availability (pan coverage,) water space, water pressure, stocking density and poor ventilation (primarily temperature variation, high humidity, drafts and/or high levels of ammonia, hydrogen sulfide or carbon dioxide) are all risk factors for vice behavior.
As adjustments are made to increase barn temperature to slow growth or increase stocking rate to utilize space or buy time until the next finishing barn is available, consider each of these factors and which ones you can control. Changing only one factor may not be enough to initiate the vice behavior and if you can control the others you may minimize the incidence you see. If you have choices in which barns to apply certain production practices to and variation in facility design, consider the resource availability and any easy solutions to provide more resources like adding another water source if possible.
Do not underestimate the role that overall pig health and disease may play in both initiating vice behavior and/or secondary infections that ensue in affected pigs. Sick pigs may be prone to show vice behavior because their immune response is increased or the infection is causing an uneasiness or stress that results in aggression. Viruses that affect the immune system of the pig and bacterial infections that cause general sepsis or skin disorders are at the top of my differential list when evaluating vice behaviors. These may include and are not limited to circovirus, porcine reproductive and respiratory syndrome, Actinobacillus, Streptococcus, Erysipelothrix and Staphylococcus hyicus.
Once the pigs have started biting, they have created an open wound that leads to either a local or systemic infection in that individual pig. Tail-biting in particular is worrisome due to the location of the wound as it is connected to the spinal cord and can lead to spinal abscesses and subsequent carcass damage.
While there are many things in 2020 that we have not been able to control, focus on those things that you can control. For example, if you have pigs that are overly stressed due to stocking density and you are not limited on pig growth, then pay extra attention to your minimum ventilation settings to be sure they are set properly for that size of pigs, do everything possible to avoid feed outages, reevaluate your feed order procedure/timing, watch pan coverage more closely, keep your temperature variation in the barn within acceptable ranges, keep up on barn maintenance that may impact resource availability and double check your water pressure.
If you are forced to implement practices that may put your pigs at a higher risk, consider giving the pigs something else to do. Some producers find benefit from enrichment tools like hanging chains in the pens or putting items in the pens they can play with (bowling balls, old boots, wood posts, etc.)
Finally, respond quickly if vice behavior starts. Sometimes simply removing the offending animal can be enough to minimize biting in the pen. Depending on what production practice you implemented and the constraints you are facing, you may be able to undo some of what has been done.
Remember these are often multifactorial and adjusting one factor may not be enough to prevent losses. Consult a veterinarian to see if there are underlying bacteria that can be treated. Consult your nutritionist to see if there can be tweaks made to the diet or if the ration should be evaluated. Focus on what you can control and optimize the pigs' environment to the best of your ability.