Lactation Biology

About this course: 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.

Who is this class for: This course is designed for anyone interested in lactation, milk, the mammary gland or related topics. No prior experience is required.

Created by:  University of Illinois at Urbana-Champaign

• Taught by:  Dr. Walter Hurley, PhD, Professor Emeritus

  Department of Animal Sciences

Level Beginner Commitment 8 weeks of study; 4–5 hours/week Language English How To Pass Pass all graded assignments to complete the course. Coursework

Each course is like an interactive textbook, featuring pre-recorded videos, quizzes and projects.

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University of Illinois at Urbana-Champaign The University of Illinois at Urbana-Champaign is a world leader in research, teaching and public engagement, distinguished by the breadth of its programs, broad academic excellence, and internationally renowned faculty and alumni. Illinois serves the world by creating knowledge, preparing students for lives of impact, and finding solutions to critical societal needs.

Syllabus


WEEK 1


Course Orientation



The series of videos and readings provided here are aimed at introducing this course in Lactation Biology. Course organization is described. Requirements for participation in the course are summarized. And, opportunities for learners to engage in the course content, as well as with each other, are indicated.


2 videos, 5 readings, 2 practice quizzes expand

1. Video: Introduction to Lactation Biology
2. Reading: Course Syllabus
3. Video: Lactation Word Cloud
4. Reading: About the Discussion Forums
5. Practice Quiz: Orientation Quiz
6. Reading: Social Media
7. Reading: Updating Your Profile
8. Discussion Prompt: Getting to Know Your Classmates
9. Practice Quiz: Demographics Survey
10. Reading: Study Aid Activities Overview

Module 1: Introduction to Lactation Biology



In this module, we will introduce some basic definitions of terms related to the biology of lactation, provide an overview of milk, and briefly introduce the phylogenetic organization and evolution of mammals. Learning the definitions will be important for establishing a baseline vocabulary that will help reduce confusion about topics presented in subsequent videos. Milk, a primary product of the lactation process, will be introduced in an effort to provide a foundation for later modules in which milk and milk composition are explored in greater depth. The series of videos about mammals collectively offer a brief overview of the wide spectrum of these animal species, as well as some thoughts on how lactation came to be an integral part of the reproductive strategy of those species.


8 videos, 2 readings, 2 practice quizzes expand

1. Reading: Module 1 Overview
2. Reading: Optional: Study Aids
3. Video: Definitions Part 1
4. Video: Definitions Part 2
5. Practice Quiz: Lesson 1-1 Quiz
6. Video: An Overview of Milk
7. Video: How Much Milk?
8. Video: Milk Products
9. Video: Mammals
10. Video: Mammalian Evolution
11. Video: Why Lactate?
12. Practice Quiz: Lesson 1-3 Quiz

Module 2: Mammary Gland Structure



One of the most fundamental requirements for understanding any aspect of biology is to appreciate the relationships that exist between form and function, or anatomy and physiology. In the case of lactation and the mammary gland, it is important to be able to visualize the various levels of mammary gland structure in order to understand how the mammary gland grows and functions. This module presents an overview of mammary gland anatomy and macrostructure using the dairy cow as our primary example. In addition, the tissue, cellular, and subcellular levels of mammary structure are presented. The module provides a conceptual foundation that will allow you to individually explore mammary gland anatomy and microstructure in other mammalian species.


19 videos, 2 readings, 4 practice quizzes expand

1. Reading: Module 2 Overview
2. Reading: Optional: Study Aids
3. Discussion Prompt: Share Your Concept Map
4. Video: Mammary Gland as a Skin Gland
5. Video: Mammary Lobes
6. Video: Simple vs Complex Glands
7. Video: Mammary Anatomy at the Cow Side
8. Practice Quiz: Lesson 2-1 Quiz
9. Video: Mammary Suspensory System
10. Video: Median Suspensory Ligament
11. Video: Structure of Teats and Cisterns
12. Video: Supernumerary Teats
13. Video: Mammary Blood System
14. Video: Mammary Lymph System
15. Video: Mammary Nervous System
16. Practice Quiz: Lesson 2-2 Quiz
17. Video: Introduction to Mammary Microstructure
18. Video: Microstructure - 2D and 3D
19. Video: Lobules
20. Video: on Lobules
21. Practice Quiz: Lesson 2-3 Quiz
22. Video: Alveoli and Their Environment
23. Video: Myoepithelial Cells
24. Video: Mammary Cell Ultrastructure Part 1
25. Video: Mammary Cell Ultrastructure Part 2
26. Practice Quiz: Lesson 2-4 Quiz

Graded: Week 1 Quiz

WEEK 2


Module 3: Milk Composition



Milk is the product of the lactation process. Such a simple statement does not come close to doing justice to the complex nature of this biological fluid. In this module, we explore the major components of milk, as well as provide a basis for understanding milk as a product that we purchase in a store. Mechanisms of synthesis of milk components are introduced. And, several videos include discussions of the nature of differences in milk composition among mammalian species, including comparisons of cow milk with human milk.


27 videos, 2 readings, 6 practice quizzes expand

1. Reading: Module 3 Overview
2. Reading: Optional: Study Aid
3. Discussion Prompt: Share Your Concept Map
4. Video: Milk Components
5. Video: Milk Components Demo
6. Video: Perspectives on Milk Composition
7. Video: Milk Under the Microscope
8. Video: Major Milk Fractions
9. Video: From Cow to Store
10. Practice Quiz: Lesson 3-1 Quiz
11. Video: Total Solids
12. Video: Lactose
13. Video: Lactose Intolerance
14. Video: Lactose Synthesis
15. Practice Quiz: Lesson 3-2 Quiz
16. Video: Milk Protein
17. Video: Casein
18. Video: Casein Demo
19. Video: Why Proteins
20. Video: Milk Protein Synthesis
21. Practice Quiz: Lesson 3-3 Quiz
22. Video: Milk Fat
23. Video: Fatty Acids
24. Video: Milk Fat - Species Comparisons
25. Video: Milk Fat Synthesis
26. Practice Quiz: Lesson 3-4 Quiz
27. Video: Milk Minerals
28. Video: Milk Vitamins
29. Video: Cells in Milk
30. Video: on Milk Cells
31. Video: Milk Bioactive Factors
32. Practice Quiz: Lesson 3-5 Quiz
33. Video: Species Comparisons of Milk
34. Video: Cow vs. Human Milk Composition
35. Video: Wrapping Up Milk Composition
36. Practice Quiz: Lesson 3-6 Quiz

Graded: Week 2 Quiz

WEEK 3


Module 4: Mammary Gland Development



The tissue that we know of as the mammary gland (or udder or breast) may appear as relatively uncomplicated compared with some internal organs such as the heart or brain. The gland is outside the body wall, has a nipple or teat in most species, and has a series of ducts by which milk that is produced in microscopic blind tubes can be expressed from the gland. How can such a gland develop and what regulates that development? It turns out that the initial stage of development occurs extremely early in the fetal development of the animal. It then proceeds through a series of developmental phases, many of which are closely linked with the reproductive functioning of the animal, and eventually leading to the time when the gland is producing milk. Furthermore, the mammary gland is one of a few tissues that undergoes repeated cycles of development, functioning, regression, and redevelopment, again associated with the reproductive cycles of the animal. This module describes the various stages of mammary development and provides the framework for understanding how these stages relate to each other, as well as to the functionality of the gland.


11 videos, 2 readings, 3 practice quizzes expand

1. Reading: Module 4 Overview
2. Reading: Optional: Study Aid
3. Discussion Prompt: Share Your Concept Map
4. Discussion Prompt: Discussion 1: Compare biological milk vs plant-based milk
5. Discussion Prompt: Discussion 2: Discuss the value of milk
6. Video: Fetal Stage - 1
7. Video: Fetal Stage - 2
8. Video: Fetal Stage - 3
9. Practice Quiz: Lesson 4-1 Quiz
10. Video: Prepubertal Stage - 1
11. Video: Prepubertal Stage - 2
12. Video: Postpubertal Stage
13. Practice Quiz: Lesson 4-2 Quiz
14. Video: Development During Pregnancy - 1
15. Video: Development During Pregnancy - 2
16. Video: Development During Pregnancy - 3
17. Video: Lactation
18. Practice Quiz: Lesson 4-3 Quiz
19. Video: Bovine Mammary Development

Graded: Week 3 Quiz

WEEK 4


Module 5: Mother & Neonate



The peripartum period, the time shortly before, during, and after giving birth, is a time of rapid changes in the mammary gland, the mother, and the neonate. Extensive physiological coordination occurs between the processes leading up to and giving birth, the formation of colostrum, the initiation of lactation in the mammary gland, and the subsequent removal of milk by the neonate. In this module, we explore how the mammary gland changes around the time of giving birth when the gland transitions from a non-lactating to a lactating state. Part of this transition is the production of colostrum, the first mammary secretion produced by the gland after giving birth. Another part of the transition is the changing regulation of mammary gland function from one being driven primarily by hormones associated with pregnancy and parturition to one where milk removal, by the neonate or milking machine, is the driving force in gland function after birth. In this module, we examine some basic characteristics of the neonate, how lactation is initiated (lactogenesis), and the formation and special components of colostrum (immunoglobulins) and their impact on the neonate.


17 videos, 2 readings, 5 practice quizzes expand

1. Reading: Module 5 Overview
2. Reading: Optional: Study Aid
3. Discussion Prompt: Share Your Concept Map
4. Video: Peripartum Period
5. Video: A Cow Calving
6. Video: The Neonate
7. Practice Quiz: Lesson 5-1 Quiz
8. Video: Lactogenesis & Its Stages
9. Video: Secretory Differentiation
10. Video: Secretory Activation & Lactose Synthesis
11. Video: Hormonal Regulation
12. Video: Comparative Hormonal Regulation
13. Practice Quiz: Lesson 5-2 Quiz
14. Video: Prolactin - Sources
15. Video: Prolactin - Control of Secretion
16. Video: Prolactin - Other Regulation
17. Practice Quiz: Lesson 5-3 Quiz
18. Video: Colostrum Composition
19. Video: Immunoglobulins in Colostrum
20. Video: Colostrum & the Neonate
21. Practice Quiz: Lesson 5-4 Quiz
22. Video: Immunoglobulin Receptor
23. Video: Mammary Transport of Immunoglobulin
24. Video: Immunoglobulin Transport to the Neonate
25. Practice Quiz: Lesson 5-5 Quiz

Graded: Week 4 Quiz
Graded: Share a Milking Example

WEEK 5


Module 6: Lactation



In this module, we explore the many facets of lactation as a complex physiological process. We will find that removal of the milk in the gland is critical to continued production of that fluid. The interactions between milk removal, the systemic factors stimulating the gland to produce milk, such as several hormones, and the local factors that inhibit further milk secretion are examined. Some of the effects of milk removal, as well as the absence of milk removal, are discussed in this series of videos. The responses of the mammary gland to milk removal provide a means of understanding the impact of management practices on lactation.


27 videos, 2 readings, 4 practice quizzes expand

1. Reading: Module 6 Overview
2. Reading: Optional: Study Aid
3. Discussion Prompt: Share Your Concept Map
4. Discussion Prompt: Discussion: Cross-species nursing
5. Video: Introduction & Definitions
6. Video: Systemic vs Local Regulation
7. Video: Galactogogues
8. Video: Prolactin
9. Video: Measurement of Milk Production
10. Practice Quiz: Lesson 6-1 Quiz
11. Video: Prolactin - Nonruminants
12. Video: Prolactin - Ruminants 1
13. Video: Prolactin - Ruminants 2
14. Video: Growth Hormone - Cows
15. Video: Growth Hormone - Rats
16. Video: Other Hormones
17. Practice Quiz: Lesson 6-2 Quiz
18. Video: Feedback Inhibition of Milk Secretion
19. Video: Frequency of Milk Removal
20. Video: Cisternal vs Alveolar Milk Pools
21. Video: Frequency of Milk Removal - Cows
22. Video: Determinants of Milk Yield
23. Video: Intensity of Milk Removal
24. Practice Quiz: Lesson 6-3 Quiz
25. Video: Milk Stasis
26. Video: Mammary Secretions During Involution
27. Video: Mammary Tissue During Involution
28. Video: Dry Period
29. Video: Persistency & Relactation
30. Video: Mammary Involution - Sows
31. Practice Quiz: Lesson 6-4 Quiz
32. Video: Compensatory Milk Production
33. Video: Lactational History - Cows
34. Video: Lactational History - Sows
35. Video: Lactational History - Rats

Graded: Week 5 Quiz

WEEK 6


Module 7: Milk Ejection



This module introduces the physiological process known as the milk ejection reflex. The neural and endocrine pathways of this process are discussed, as is a broad overview of the hormone responsible for milk ejection, oxytocin. In addition, the consequences of ineffective milk ejection and ways that have been tried to manipulate the milk ejection process are presented.


15 videos, 2 readings, 3 practice quizzes expand

1. Reading: Module 7 Overview
2. Reading: Optional: Study Aid
3. Discussion Prompt: Share Your Concept Map
4. Video: Introduction
5. Video: Neuroendocrine Reflex
6. Video: Timing of Milk Ejection
7. Video: Rise in Intramammary Pressure
8. Video: Mammary Structure Changes During Ejection
9. Video: Microstucture of Milk Ejection
10. Practice Quiz: Lesson 7-1 Quiz
11. Video: Oxytocin
12. Video: Sources of Oxytocin
13. Video: Other Functions of Oxytocin
14. Practice Quiz: Lesson 7-2 Quiz
15. Video: Residual Milk
16. Video: Disturbed Milk Flow
17. Video: Manipulation of Milk Ejection
18. Video: Inhibition of Milk Ejection
19. Video: Species Comparisons
20. Practice Quiz: Lesson 7-3 Quiz
21. Video: Milk Ejection Demo - Optional

Module 8: Atypical Lactation



We typically assume that development of the mammary gland and production of milk are closely regulated by and are coordinated with the reproductive functioning of the animal. Most often that is true. From the knowledge gained from other modules in this course, it is clear that mammary gland development and lactogenesis are heavily regulated by hormones. As it turns out, the presence of mammary gland-regulating hormones is not always directly associated with the reproductive status of the animal. If the hormone activity is present, regardless of its source, it may impact mammary gland development and function. The series of videos in this module presents an overview of what we are calling atypical lactation. That is when the mammary gland undergoes development and lactation in the absence of the usual physiological cues that we associate with the process, such as an animal giving birth.


7 videos, 2 readings, 1 practice quiz expand

1. Reading: Module 8 Overview
2. Reading: Optional: Study Aid
3. Discussion Prompt: Share Your Concept Map
4. Video: Induced Lactation
5. Video: Estrogen
6. Video: Phytoestrogen
7. Video: Zearalenone
8. Video: Elevated Prolactin
9. Video: Relactation, Allosucking, Communal Nursing
10. Video: Lactation in Males
11. Practice Quiz: Lesson 8-1 Quiz

Graded: Week 6 Quiz
Graded: Phenomenon Related to Lactation

WEEK 7


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.


19 videos, 3 readings, 4 practice quizzes expand

1. Reading: Module 9 Overview
2. Reading: Optional: Study Aid
3. Discussion Prompt: Share Your Concept Map
4. Video: Mastitis Defined
5. Video: Milk Components
6. Video: Host-Agent-Environment
7. Video: First Line of Defense
8. Video: Inflammatory Response
9. Practice Quiz: Lesson 9-1 Quiz
10. Video: Detection
11. Video: Treatment & Control
12. Video: Prevention
13. Practice Quiz: Lesson 9-2 Quiz
14. Video: Mastitis Syndromes
15. Video: Mastitis Types
16. Video: Contagious Pathogens
17. Video: Environmental Pathogens
18. Video: Other Pathogens
19. Practice Quiz: Lesson 9-3 Quiz
20. Video: Mastitis at a Herd-Level
21. Video: Contagious vs Environmental
22. Video: Milking Procedure
23. Practice Quiz: Lesson 9-4 Quiz
24. Video: Mastitis Example Case 1
25. Video: Mastitis Example Case 2
26. Video: Mastitis Example Case 3
27. Reading: Mastitis Cases Answers

Graded: Week 7 Quiz
Graded: Mastitis Cases

WEEK 8


Module 10: Comparative Lactation



In this module, we provide a series of videos that expands what has already been learned in other modules about the basic principles of lactation biology to a range of mammalian species. These videos focus on these animals in their native state, as well as some that have been domesticated for use as dairy animals and domestic livestock. This module is optional.


21 videos, 2 readings, 1 practice quiz expand

1. Reading: Module 10 Overview
2. Video: Swine Lactation: Introduction
3. Video: Swine Lactation: Mammary Anatomy & Development
4. Video: Swine Lactation: Milk Composition
5. Video: Swine Lactation: Lactogenesis & Early Lactation
6. Video: Swine Lactation: Milk Production
7. Video: Swine Lactation: Milk Removal & Sucking Intensity
8. Video: Swine Lactation: Milk Ejection
9. Video: Swine Lactation: Mammary Involution
10. Video: Swine Lactation: Prolactin & Lactation
11. Video: Swine Lactation: Lactational History
12. Video: Swine Lactation: Mastitis 1
13. Video: Swine Lactation: Mastitis 2
14. Video: Swine Lactation: Mastitis 3
15. Video: Elephant Lactation 1
16. Video: Elephant Lactation 2
17. Video: Dairy Goats: Farm Introduction
18. Video: Dairy Goats: The Kids
19. Video: Dairy Goats: The Does
20. Video: Dairy Goats: Milking Parlor and Procedures
21. Video: Dairy Goats: Cheese Introduction
22. Video: Dairy Goats: Making Cheese
23. Reading: Solutions to Crossword Puzzles
24. Practice Quiz: End of Course Survey