Bovine Lactation Failure Study Guide

Overview and Clinical Importance

Lactation failure (agalactia) and reduced milk production (hypogalactia) in dairy cattle represent economically devastating conditions that significantly impact both calf survival and dairy profitability. Understanding the physiological mechanisms of lactation and the various etiologies of lactation failure is essential for the NAVLE examination and clinical practice.

Lactation failure in cattle can be classified as primary (developmental or endocrinologic abnormalities) or secondary (resulting from systemic disease, toxic exposure, nutritional deficiencies, or infectious causes). The clinical presentation, diagnostic approach, and treatment strategies vary significantly based on the underlying etiology.

Physiology of Bovine Lactation

Mammary Gland Anatomy

The bovine udder comprises four separate mammary complexes (quarters), each functioning as an independent unit with its own teat. The quarters are completely separated, meaning infection or dysfunction in one quarter does not directly affect others. The front quarters typically produce approximately 40% of total milk while rear quarters produce 60%.