2. Lactation Physiology (part 1)
Isfahan University of Technology, Isfahan, Iran
Lactation Physiology (part 1)
By: A. Riasi
(PhD in Animal Nutrition & Physiology)

3. Introduction and general information
Cow milk is a nutritious liquid and known to be consumed by humankind for centuries. Its consumption had probably started with the domestication of the cow. The word milk is derived from Old English word meoluc, Dutch word melk, or the German milch. Milk contains protein, calcium, iodine, vitamins B2 and B12, phosphorus, and potassium. Nowadays, milk is processed before packaging to ensure that harmful bacteria in the milk are killed. Apart from being popular as a beverage, cows' milk is used to make a large number of products, including cheese, cream, butter, yogurt, liquid milk, ice cream, whey protein, and many more. Approximately 85% of the milk produced worldwide is sourced from cows and the other 15% from goats, sheep, buffalos, camels, horses, and donkeys. The recommended daily milk intake is three glasses a day. Until 2016, Russia and China were the world's biggest importers of milk. A closer look at the milk consumption of countries globally reveals that Finland tops the list. ( available at 2018).
Milk is popular beverage worldwide, and is also used extensively in cooking and baking (adapted from

4. Introduction and general information
Cow milk is a nutritious liquid and consumed by humankind for centuries.
The word “milk” is derived from Old English word “meoluc”, Dutch word “melk”, or the German “milch”.
The recommended daily milk intake is three glasses a day.

5. Introduction and general information

6. Countries Who Drink the Most Milk
Introduction and general information
Countries Who Drink the Most Milk
Rank
Country
Per Capita Milk Consumption (Kg) 1
Finland
361.19 2
Sweden
355.86 3
Netherlands
320.15 4
Switzerland
315.78 5
Greece
314.69 6
Montenegro
305.87 7
Lithuania
303 8
Denmark
295.62 9
Albania
281.17 10
Romania
266.19 11
Luxembourg
265.9 12
Kazakhstan
262.61 13
Norway
261.52 14
France
260.48 15
Italy
256.1
adapted from

7. Countries Producing the Most Milk
Introduction and general information
Countries Producing the Most Milk
Rank
Country
Production (Metric Tonnes) 1
United States
91.3 2
India
60.6 3
China
35.7 4
Brazil
34.3 5
Germany
31.1 6
Russia
30.3 7
France
23.7 8
New Zealand
18.9 9
Turkey
16.7 10
United Kingdom
13.9
adapted from

8. Introduction and general information
Data from Dairy Co at

9. Introduction and general information

10. Introduction and general information
Adapted from: Wageningen Economic Research Report 2017

11. Introduction and general information

12. Introduction and general information
Mammals are the vertebrates within the class Mammalia possession of a neocortex (a region of the brain), hair, three middle ear bone, and mammary glands.
Females of all mammal species nurse their young with milk, secreted from the mammary glands.

13. Introduction and general information
Mammals range in size from the 30–40 mm (bumblebee bat) to the 30-meter (blue whale).

14. Introduction and general information
Mammary gland is a modified sweat gland.
Mammary gland serves a reproductive function; nourishment of the neonate.
Mammary glands are modified sweat glands, which secretes milk (exocrine gland) and serve as accessory glands to the reproductive system. Mammary gland development commences embryonically from ectoderm and mesoderm, The growth of mammary gland continue post natal even during lactation. The mammary gland can repeatedly undergo growth, functional differentiation, and regression. It relies on same endocrine (hormonal) support for development and function (gonadal steroids, prolactin, etc).
In order to understand mammary gland physiology, anatomical features of the gland should be studied.

15. Introduction and general information
Mammary gland can repeatedly undergo growth, functional differentiation, and regression.
Relies on same endocrine support for development and function.
Example: gonadal steroids, prolactin, etc.

16. Intermediate (abdominal)
Introduction and general information
Species
Anterior (thoracic)
Intermediate (abdominal)
Posterior (inguinal)
Total
Goat, sheep, horse guinea pig 2
Cattle 4
Cat 8
Dog
2 or 4
8 or 10
Mouse 6 10
Rat 12
Pig 18
Proboscideans, primates
Adapted from

17. Introduction and general information
The weight of empty cows udder is about kg.
The udder weight is affected by:
Age
Stage of lactation
Amount of milk in the udder
Inherited differences among cows
Average capacity of cows udder is about 35 kg. The weight and capacity of the udder increases with age of the cow up to six years, with the greatest increases occurring between the first and the second lactation. It is very important for the dairy producer to have cows with udders that are large enough to produce large volume of milk and in the same time not to have them excessively large or with poor udder attachment.