Agriculture Reference
In-Depth Information
14
Milk Production
Y.W. Park, PhD and G.F.W. Haenlein , PhD
KEY TERMS
Dry period—a rest period of about 8 weeks between lactations to allow for regeneration of the mammary secretory
epithelium.
Lactation curve—trend of milk production throughout the lactation, usually for 200-305 days.
Alveolus—hollow ball of milk secreting cell, forming a cluster of alveoli to join intralobular ducts.
Milk ejection—removal of milk from mammary gland by neurohormonal refl ex process.
Oxytocin—milk ejection hormone by stimulating the contractile units of myoepithelial cells around the alveoli.
ACTH—adrenocorticotrophic hormone, stimulating growth of adrenal cortex and secretion of corticosteroids.
Colostrum — The fi rst-drawn milk from the mammary gland for 0 to 5 days after parturition.
Lactose—carbohydrate in milk, which is a disaccharide composed of glucose and galactose.
Casein—major milk protein, constitutes 80% of total milk protein, precipitated by acid or coagulated by rennet enzyme.
Milk solids—solids in milk consisting of fat, protein, lactose, and ash, generally 12-13% in goat milk or cow milk.
OBJECTIVES
By completing this chapter, the reader will acquire knowledge on:
Physiology of lactation
Milk production in the tropics
Composition of goat milk
Factors affecting yield and composition of goat milk
Differences in composition of milk of goats and other species
Economics of goat versus cow milk production
Dairy goat records
Dairy herd improvement association
International aspects of the effi ciency of goat milk production
Differences in goat and cow milk products (i.e., cheese, yogurt)
INTRODUCTION
According to the FAO (2004), goats produce approxi-
mately 2% of the world's total milk supply. However,
more people drink milk from goats than milk of any other
animal species worldwide. Goat milk is vitally important
in underdeveloped countries because it provides basic
nutrition and subsistence to the majority of their popula-
tions in rural areas. Because cow milk is often unavailable,
goat milk and its products are important daily food sources
of protein, phosphate, and calcium for people of underde-
veloped countries (Park and Haenlein, 2007). The contri-
bution of goat milk and dairy goat products to the economy
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