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来自 University of Illinois at Urbana-Champaign 的课程

Lactation Biology

12 个评分

University of Illinois at Urbana-Champaign

Lactation Biology

12 个评分

Lactation and especially milk, which is the product of that unique mammalian process, are routinely encountered within our daily lives. Nevertheless, they often are poorly understood by many, even including many who are engaged in the business of producing milk. The overall course goal is to introduce fundamental concepts that form the basis for understanding the biology of lactation, the biology of the mammary gland, and the products of that important physiological process. As a learner in this course, you will be provided with a series of easily understood presentations that collectively will help you build a foundation for greater understanding of lactation. You will be able to engage with other learners so that you can extend your learning beyond the video presentations. Ultimately, you will be able to construct your own mental model for understanding the wide range of topics that relate to the biology of lactation. Upon completion of the course, you will be prepared to expand your knowledge and understanding of lactation from other sources and experiences as you pursue your individual interests. Before you start the course, I suggest that you identify a question or several questions about lactation that you already have on your mind. This could be from your own experiences, something you read about or saw, or something you have wondered about. Write down your question(s) and use that to help you decide how to engage with the content of this course. You might engage with the modules in the order they are presented, or start with a module that is of particular interest to you, or pick and choose modules in any order. I encourage you to engage in all of the types of learning activities that this course has to offer, including but not limited to, the discussion forums, quizzes, peer-review assignments, and concept maps and other learning aids.

从本节课中

Module 9: Mastitis

The mammary gland is an excretory gland, meaning that it produces a fluid that is secreted to the outside of the body. These secretions leave the gland through a series of ducts that eventually open to the outside of the skin. The presence of these openings not only means that the mammary secretion can leave the gland, it also means that microorganisms can enter the gland. When that happens, the gland may become infected and present as a disease known as mastitis. Mastitis is an inflammation of the mammary gland, the inflammation most commonly being caused by an infection by a pathogen. Mastitis is the most costly disease in dairy cattle, but is also prevalent in other species, including our own. We will examine many of the aspects of how this disease is manifested using the dairy cow as our primary example in this module. We will examine mastitis at the level of an individual cow, as well as at the whole herd level. And then to fully integrate and apply the knowledge gained about this disease, we will examine several real-life cases of herd-level mastitis problems faced by dairy producers.

Mastitis Syndromes11:12

Mastitis Types7:08

Contagious Pathogens7:32

Environmental Pathogens6:03

Other Pathogens5:39

与讲师见面

Dr. Walter Hurley, PhD
Professor Emeritus
Department of Animal Sciences

[SOUND].

We've examined now several types.

So we've talked about contagious mastitis,

mastitis species that are causing contagious mastitis.

Different kinds of pathogens, the staph aureus and the strep A.

The mycoplasma species, we've talked about environmental species, so

the coliforms, several of them.

We talked about the environmental streps.

There are other kinds of pathogens that will cause mastitis.

In fact, there's a whole range of different kinds of things that potentially

can cause mastitis in cattle, as well as other species as well.

A couple of those we'll just think of as minor pathogens.

Corynebacterium bovis affects the teat duct, usually.

And then the other types are kind of these coagulase-negative

staphylococci, again on the teat skin.

Usually only causes very mild inflammation,

a slight increase in somatic cells, maybe very low levels of acute mastitis.

Typically, the only thing you'd really see are maybe a few flakes or

clots in the milk, then that's about it.

So they're not a big problem, but they certainly can be there in herds.

And especially if the immune system's compromised in some way in a bunch

of the cows, they can get these guys in the teat duct or on the teat skin,

can cause mastitis.

So our list of potential pathogens causing mastitis is starting to get long, but

we're going to make it even longer here.

So let's take a look at some other species.

So over here I have different types of bacterial species,

Pseudomonas aeruginosa is one, and we'll spend an extra second or two on that one.

That particular one really likes water.

So if we have animals that are in a stream or something like that, or a pond,

and they're wading in it, in addition to the coliforms which would be in there,

there may be, the Pseudomonas in there could cause mastitis.

This one we hear stories about the situations where the hot water tank,

or the water line that you're using in the milking parlor,

can get this bacteria in there.

It's really hard to get rid of.

You basically have to replace everything, is what it amounts to.

And so when we see situations where there's water involved in one way or

the other, a lot of times we start thinking about that.

Again, it's not a guarantee that's what's causing the problem, but

it could be a whole range of other species of bacteria that have been identified.

Certainly not as common as some of the staph aureus or the coliforms and so on.

Yeast species, Candida species, a lot of times this is caused by

inappropriate use of teat cannulas and those kinds of things

that get yeast growing in them, and then you're just reusing those.

So that's why it's important to use the non-reusable, the sterile non-reusable

teat cannulas so you don't potentially get these guys in those canulas.

Prototheca, or algae, again could be the same kind of thing if it's inappropriate

use of the teat cannulas, but also then wading in ponds and so on.

Cows trying to cool themselves off, those kinds of things can occur too.

So again, the yeast here, and then the algae or the Prototheca types of species.

You see there's a wide range of microorganisms that can cause mastitis,

and be grouped in with these different kinds of pathogens,

as agents causing this particular disease.

In this video, we've looked at different pathogens,

again thinking of those as agents.

Again, most of them being bacterial, but we had a few exceptions there.

And so we started to kind of see, we started to kind of think about

the different agents, different pathogens in the context of the environment.

Contagious pathogens would be kind of cow-to-cow or host-to-host.

So we started to kind of put some meat onto this triangle in terms of,

we've looked at this a bit, we've looked at the host before.

And eventually we're going to start putting these together and

thinking about this in a more complex way.

But let's real quick review what we've talked about in this particular video.

Let's go to the next slide.

So again, we've talked about different mastitis-causing pathogens.

The contagious pathogens, the staph aureus, the strep ag,

the mycoplasma species.

They are passed from cow to cow, so one cow is infected,

we need to work really hard to make sure somehow she's not affecting other cows.

And again, that's usually happening,

that infection's usually transferred through during the milking process.

Environmental pathogens are always going to be in the environment.

And so we have too think about, how do we manage the environment?

How do we manage the cow in that environment?

Again, that can also be passed during the milking process as well, and

you start to see that milking process is right in the center of this whole thing.

So minor pathogens that are usually causing only very mild inflammation.

And then other pathogens, a wide range of them including

the Pseudomonas species, Pseudomonas aeruginosa.

And then other bacterial species, as well as yeast and

Prototheca-type species that are potentially causing mastitis.

Our major types though are the ones up here,

the contagious pathogens that we associated with contagious mastitis.

And then those that we associate with environmental mastitis.

So those are the major ones that we will continue and

examine in these video series on mastitis.

[SOUND]

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