Biología de la Lactación Parte 4

Summary

This video discusses the complex process of milk production in cows, focusing on the physiology and biology of lactation. It covers key aspects like the role of hormones, the importance of milking for continued production, the different stages of lactation, and the physiological processes involved. The video explains how external factors, such as health and nutrition, influence milk synthesis. It also goes into detail about the precursors needed for milk components, including lactose, proteins, and fats, and how they are synthesized and secreted. The video concludes by highlighting the importance of proper milking and nutritional management in dairy production.

Takeaways

• 😀 The mammary gland's ability to maintain milk production is influenced by neuroendocrine controls, with hormones like oxytocin playing a key role in milk ejection.
• 😀 Milk production depends not only on hormonal control but also on external factors such as health, nutrition, and especially regular milking (order).
• 😀 If milking is interrupted, internal pressure builds in the mammary gland, which can lead to involution of the secretory cells and cessation of milk production, also known as drying off.
• 😀 The milk production curve shows a gradual increase in milk production after calving, peaking around the third to sixth week, followed by a decline as cell functionality decreases.
• 😀 The milk peak is a critical indicator of the cow's milk production over the entire lactation period, with the peak production in liters per day serving as a good predictor for the total milk produced over a typical 305-day lactation.
• 😀 Progesterone, produced during pregnancy, negatively impacts lactation by inhibiting the synthesis of lactose and reducing milk production as the cow approaches the next calving.
• 😀 Drying off before the next calving is crucial for mammary gland recovery, allowing for tissue regeneration to prepare for the next lactation.
• 😀 The precursors for milk solids, such as glucose, amino acids, and fatty acids, enter the mammary gland via blood and are transformed into the various components of milk.
• 😀 For the synthesis of lactose, glucose is needed, which can come from the fermentation of carbohydrates in the rumen, from enzymatic breakdown of starch, or from the conversion of propionic acid into glucose in the liver.
• 😀 The synthesis of milk fat involves the use of volatile fatty acids (like acetate and butyrate), which are produced by the rumen fermentation of fiber, along with dietary fats and mobilized body reserves.

Q & A

What is the main focus of this video?

The video focuses on the biology and physiology of lactation, specifically the factors that affect milk production, including hormonal regulation, external influences, and the role of oxytocin.

What role does oxytocin play in lactation?

Oxitocin is responsible for the expulsion of milk from storage sites within the mammary gland, helping to maintain ongoing milk production.

Why is milking important for sustaining milk production in dairy cows?

Milking is crucial to prevent internal pressure buildup in the mammary gland, which could lead to involution of the secretory cells and a cessation of milk production.

What happens if milking is not performed on time?

Failure to milk the cow on time leads to increased internal pressure in the mammary gland, which can cause the secretory cells to involute, leading to a decrease in milk production and the onset of the drying off process.

How does the milk production curve typically behave after calving?

Milk production begins a few days after calving, with an initial secretion of colostrum. It gradually increases until reaching a peak at around the third to sixth week, after which it begins to decrease due to a decline in secretory cell function.

What determines the peak milk production in dairy cows?

The peak milk production is determined by an increase in secretory cell numbers, their functionality, and nutrient delivery to the mammary gland. This peak is often an indicator of long-term milk production.

What role does progesterone play in the lactation process?

Progesterone inhibits lactation by decreasing the synthesis of lactose, which in turn reduces the volume of milk produced. As the pregnancy progresses, increasing progesterone levels contribute to the decline in milk production.

What is the purpose of the drying-off period in dairy cows?

The drying-off period allows the mammary gland to rest and recover by involuting the secretory tissue, enabling it to regenerate for the next lactation cycle.

What are the primary precursors required for milk synthesis?

The primary precursors for milk synthesis include glucose (for lactose), amino acids (for proteins like casein), and fatty acids (for milk fat), all of which are transported to the mammary gland via the bloodstream.

How do amino acids reach the mammary gland for protein synthesis?

Amino acids reach the mammary gland primarily through the bloodstream, either from microbial protein digestion in the rumen or from bypass proteins that pass directly to the intestines.