 I'm Gerald Stocca, I'm an extension veterinarian and livestock stewardship person here at NDSU and this morning we're actually at the beef unit, the NDSU beef unit where typically we run a cow-calf operation here but due to circumstances associated with the pandemic we've got some cattle here on feed and our topic today is heat stress and pneumonia and it's probably a good place to start right here with these feedlot cattle in the background as you can see some are up here eating from the bunk a ration that consists of roughage and by that I mean hay and perhaps even a little bit of other components to that hay it's not all just grass hay it's not just alfalfa hay but there's other components in the hay and then some corn and some protein supplement and vitamin and mineral supplement as well and you can see some are up and if you look back in the pen there's some others in the pen that are just laying around and chewing their cud and relaxing so the purpose was to show you cattle that are loving life at this point and they certainly are so our topic today though is heat stress and these cattle are not in heat stress it's a beautiful day it's like 70 degrees humidity is I'm not sure but it's not real high so this is a very comfortable day it's comfortable for people and it's comfortable for cattle so when we get into this topic of heat stress though that presents a different situation it's when temperature increases humidity increases and we use a kind of an equation to come up with what we call heat index so when both temperature and humidity increase we get into a hint heat index category that puts stress on animals and what you'll notice about heat stress when the heat index is at certain numbers is that the cattle will increase respiration rate remember that you and I dissipate heat by sweating and trying to find cool air conditioning and shade and all those things well cattle will do the same things but cattle don't sweat and so they have to respire in other words they have to breathe off that extra heat and they'll try and seek shade and cool spots just like you and I do but in the feedlot it can be a little bit difficult if there's not shade so they'll increase their respiration rate these cattle are probably breathing at a rate somewhere around 30 to 40 breaths per minute when under heat stress they'll breathe a lot faster and when they get severe heat stress then you can have cattle that breathe maybe as many as a hundred times per minute and that's that's a sign that something some intervention needs to take place and maybe it's sprinkling the pen with water to decrease the heat that comes off the surface and there may be other things that you would need to do long-term if it if it continues for several days you may need to change the ration decrease the energy content of the ration you may need to start feeding during the evening late afternoon early evening hours so that that heat that's generated by the feed can kind of have a chance to dissipate when it's cooler outside make sure there's enough drinking water and so on and so forth so heat stress in confinement it's not so much related to respiratory disease that you and I typically think of but it's certainly related to stress on the respiratory system so I think the more important component of heat stress and respiratory disease may be related to the cow calf sector now cows and calves that are out on pasture have an advantage over confined cattle in that they most of the time can seek higher levels for the wind blows most of the time they can find shade sometimes they can even find water to stand in or a shallow place to stand in this water so they have ways to dissipate some of this heat out on pasture where confined cattle may not have that same advantage where this can translate into respiratory disease always is in usually manifested in our nursing calves are calves that are suckling their mothers and it's at a time in their life when we wouldn't expect pneumonia or respiratory disease to occur but it does it can occur in a very small number of animals and it's very sporadic from year to year but it does occur and really I would say it's it's a it's it's when the bacterial agents and viral agents take advantage of stressors in that calves life and so we're talking about heat stress today so if a calf becomes a little bit under heat stress and increases its respiration rate then that means that defense mechanism isn't working as well as it should and so it may allow those pathogens those bacteria and viral pathogens to gain access and actually cause disease and of course there's more to it than that and the other component that always has to be considered is do these calves have enough immunity in their system or was there something that happened to that calf in around the birthing process that he didn't get enough immunity from its mom and now is not protected against these pathogens so that's another component the other one is kind of social it's related to sorting cattle it's relating to cattle being crowded up and where they're in closer contact with one another and they can share bugs back and forth just a little bit easier and even that social crowding creates a little bit of psychological stress in the lives of these calves in addition to that synchronization programs AI programs anytime you're sorting even at branding and you're separating the cows from the cows per puts a little bit of stress in those calves so it's not usually just one thing it's not usually just heat stress it's not usually just immune function it's not usually just psychological but it's it's it's all of those components that come together that cause these calves that may develop pneumonia and the signs of it are calf that's off by himself droop deer you might find one that that is dead make sure your veterinarians involved in that and there may be some vaccination recommendation but most often that calf does need antibiotic antibacterial therapy in order to have him overcome what he's dealing with in the lungs so that's our topic for today I hope you enjoyed our conversation if you have any questions you can call me or one of our beef specialists to talk more about heat stress and summer pneumonia